EP2621934A1

EP2621934A1 - Electrolyte formulations containing cyano-alkoxy-borate anions

Info

Publication number: EP2621934A1
Application number: EP11751830.8A
Authority: EP
Inventors: Nikolai Ignatyev (Mykola); Michael Schulte; Kentaro Kawata; Jan Sprenger; Maik Finze; Walter Frank
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2010-09-28
Filing date: 2011-08-31
Publication date: 2013-08-07
Also published as: JP5950916B2; JP2013546118A; WO2012041434A1; TW201223960A

Abstract

The present invention relates to electrolyte formulations containing cyano-alkoxy-borate anions, their preparation and their use, in particular as part of electrolyte formulations for electrochemical or optoelectronic devices and special compounds containing cyano-alkoxy-borate anions.

Description

Electrolyte formulations containing cyano-alkoxy-borate anions

The present invention relates to electrolyte formulations containing cyano- alkoxy-borate anions, their preparation and their use, in particular as part of electrolyte formulations for electrochemical or optoelectronic devices and special compounds containing cyano-alkoxy-borate anions.

The salts of formula I or formula as described below can on the one hand be used as part of electrolyte formulations for electrochemical or

optoelectronic devices, on the other hand the salts can be used for the synthesis of ionic liquids of said formula I or I^*.

Ionic liquids or liquid salts are ionic species which consist of an organic cation and a generally inorganic anion. They do not contain any neutral molecules and usually have melting points below 373 K.

The area of ionic liquids is currently the subject of intensive research since the potential applications are multifarious. Review articles on ionic liquids are, for example, R. Sheldon "Catalytic reactions in ionic liquids", Chem. Commun., 2001 , 2399-2407; M.J. Earle, K.R. Seddon "Ionic liquids. Green solvent for the future", Pure Appl. Chem., 72 (2000), 1391-1398; P.

Wasserscheid, W. Keim "lonische Fliissigkeiten - neue Losungen fur die Clbergangsmetallkatalyse" [Ionic Liquids - Novel Solutions for Transition- Metal Catalysis], Angew. Chem., 112 (2000), 3926-3945; T. Welton "Room temperature ionic liquids. Solvents for synthesis and catalysis", Chem. Rev., 92 (1999), 2071-2083 or R. Hagiwara, Ya. lto "Room temperature ionic liquids of alkylimidazolium cations and fluoroanions", J. Fluorine Chem., 105 (2000), 221-227.

The properties of ionic liquids, for example melting point, thermal and electrochemical stability, viscosity, are strongly influenced by the nature of the anion. E. Bernhardt et al, Z. Anorg. Allg. Chem. 2000, 626, 560, E. Bernhardt et al, Chem. Eur. J. 2001 , 7, 4696 and E. Bernhardt et al, Z. Anorg. Allg. Chem. 2003, 629,1229 disclose the novel chemically and electrochemically stable borate anions [B(CN)₄]^~, [F_XB(CN)_4-X , where x = 1 to 3, and [B(CF₃)₄]^~

EP 1205480 A1 describes tetrakisfluoroalkylborate salts and the use thereof as conductive salts or ionic liquids.

WO 2006/010455 describes alkoxytris(perfluoroalkyl)borate salts and their use as precursor for the synthesis of ionic liquids or their use as ionic liquids.

WO 2006/045405 describes salts of the formula [B(R_f)4_-x-y(CN)x(F)y]^" in which x is 1 , 2 or 3, y = 0 or 1, x+y < 4 and R_f denotes a perfluorinated or partially fluorinated alkyl group having 1 to 12 C atoms, particularly potassium tris(trifluoromethyl)cyanoborate, guanidinium

tris(trifluoromethyl)cyanoborate and tritylium

tris(trifluoromethyl)cyanoborate.

WO 20 0/086131 describes alkoxy-tricyano-borate salts as ionic liquids, especially potassium tricyanomethoxyborate, 1-ethyl-3-methylimidazolium tncyanomethoxyborate, N-(n-butyl)-2-methylpyridinium

tricyanomethoxyborate, tetraethylammonium tricyanomethoxyborate and tetra-(n-butyl)-phosphonium tricyanomethoxyborate. General applications of ionic liquids are described. The special application of said ionic liquids is not described.

Electrolyte formulations form a crucial part of electrochemical and/or optoelectronic devices and the performance of the device largely depends on the physical and chemical properties of the various components of these electrolytes. The term electrolytes is used herein in the sense of electrolyte formulation as defined below and will be used equally to electrolyte formulation within the disclosure.

Factors which are still impeding the technical application of many

electrochemical and/or optoelectronic devices and in particular of dye or quantum dot sensitized solar cells, are reliability problems caused by the volatility of organic solvents based electrolytes. It is very difficult to maintain a tight sealing of the electrolyte in e.g. a DSC panel, which has to withstand the temperature differences of daily day-night cycles and the concomitant thermal expansion of the electrolyte. The abbreviation DSC means dye sensitized solar cell. This problem can be solved in principle by the use of ionic liquid-based electrolytes. For review "Ionic liquid electrolytes for dye- sensitized solar cells" see: William R Pitner et a/., "Application of Ionic Liquids in Electrolyte System" Green Chemistry, vol.6, (2010).

Ionic liquids or liquid salts are typically ionic species which consist of an organic cation and a generally inorganic anion usually having melting points below 373 K. Various binary ionic liquid electrolytes have recently been applied to dye-sensitized solar cells. WO 2007/093961 and WO

2009/083901 describe so far the best power conversion efficiencies in ionic liquid-based electrolytes for DSC containing a significant quantity of organic salts with tetracyanoborate (TCB) anions.

However, there continues to be a demand for new and improved

electrolytes based on ionic liquids with improved properties providing better DSC efficiency

The object of the invention is therefore to provide electrolyte formulations for electrochemical and/or optoelectronic devices with improved power conversion efficiency in a broad temperature range (between -20 °C to 85 °C) such as a photovoltaic cell, a light emitting device, an electrochromic or photo-electrochromic device, an electrochemical sensor and/or biosensor, especially for dye or quantum dot sensitized solar cells, especially preferably for dye sensitized solar cells.

Surprisingly it was found that electrolyte formulations comprising borate anions of formula la fulfil such demands.

The invention therefore relates to an electrolyte formulation comprising at least one compound containing borate anions of formula la

in which x is 1 or 2 and R^* denotes in each case, independently of one another, straight-chain or branched alkyl groups having 1 to 12 C atoms which can be partially subsituted by Hal and

Hal denotes F, CI, Br or I.

The invention relates in addition to electrolyte formulations comprising at least one compound of formula I

[Kt]^z+ z[B(CN)_4-x(OR^*)_x]- I in which [Kt]^z+ denotes an inorganic or organic cation or H⁺ _,

z is 1 , 2, 3 or 4,

x is 1 or 2 and R^* denotes in each case, independently of one another, straight-chain or branched alkyl groups having 1 to 12 C atoms which can be partially subsituted by Hal and

Hal denotes F, CI, Br or I. Preferably Hal denotes F or CI. Particularly preferably Hal denotes F.

In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible.

An electrolyte formulation according to the invention is therefore an electrically conductive medium, basically due to the presence of at least one substance that is present in a dissolved and or in molten state i.e. supporting an electric conductivity via motion of ionic species.

The invention realtes in addition to compounds of formula

[Kt]^z+ z[B(CN)₂(OR^*)₂r I*,

in which R* denotes in each case, independently of one another, straight- chain or branched alkyl groups having 1 to 12 C atoms which can be partially subsituted by Hal and

Hal denotes F, CI, Br or I, z is 1 , 2, 3 or 4,

[Kt]^z+ denotes H⁺; an inorganic or organic cation selected from the group of NO⁺, H⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, or Mg²\ Cu⁺, Cu²⁺, Zn²⁺, Ag\ Ca²⁺, Y⁺³, Yb⁺³, La⁺³, Sc⁺³, Ce⁺³, Nd⁺³, Tb⁺³, Sm⁺³ or complex (ligands containing) metal cations which include rare-earths, transitions or noble metals like rhodium, ruthenium, iridium, palladium, platinum, osmium, cobalt, nickel, iron, chromium, molybdenum, tungsten, vanadium, titanium, zirconium, hafnium, thorium, uranium, gold; or an oxonium cation of formula [(R°)3O]⁺ (1) or a sulfonium cation of formula [(R°)3S]⁺ (2), where R° independently of each other denotes straight-chain or branched alkyl groups having 1-8 C atoms, or

nonsubstituted phenyl or phenyl which is substituted by R°, OR⁰, N(R°)₂, CN or halogen and in case of sulfonium cations of formula (2) additionally denotes each independently (R"')2N and R'" is independently of each other straight-chain or branched Ci to C6 alkyl; or an ammonium cation, which conforms to the formula (3) [NR₄]⁺ (3),

where

R in each case, independently of one another, denotes

H, OR', NR'₂, with the proviso that a maximum of one substituent R in formula (3) is OR'or NR'₂,

straight-chain or branched alkyl having 1-20 C atoms,

straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds,

straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms,

where one or two R may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -CN, -NR'₂, -C(O)OH,

-C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -NO₂, -SR', -S(O)R', -SO₂R' and where one or two non-adjacent carbon atoms in R which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N+R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each

independently is halogen; or

a phosphonium cation, which conforms to the formula (4)

where

R² in each case, independently of one another, denotes

H, OR' or NR'₂,

straight-chain or branched alkyl having 1-20 C atoms,

straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds, straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds,

where one or two R² may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -CN, -NR'₂₎ -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -NO₂, -SR\ -S(O)R', -SO₂R' and where one or two non-adjacent carbon atoms in R² which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluohnated or perfluorinated straight-chain or branched Ci- to C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each

independently is halogen; or a uronium cation, which conforms to the formula (5)

[C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺ (5),

where

R³ to R⁷ each, independently of one another, denote

H, where H is excluded for R⁵,

straight-chain or branched alkyl having 1 to 20 C atoms,

where one or two of the substituents R³ to R⁷ may be partially or fully sub- stituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', - NR'_2> -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -SR', - S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R³ to R⁷ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -0-, -S-, -S(O)-, -S0₂-, -S0₂0-, -C(O)- , -C(O)0-, -N⁺R'₂-, -P(0)RO-, -C(0)NR'-, -S0₂NR'-, -OP(O)R'0-,

-P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched C to Ci₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or a thiouronium cation, which conforms to the formula (6)

[C(NR³R⁴)(SR⁵)(NR⁶R⁷)]⁺ (6),

where

R³ to R⁷ each, independently of one another, denote

H, where H is excluded for R⁵,

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R³ to R⁷ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'_2l -CN, - C(O)OH, -C(O)NR'₂, -SO₂NR'₂₎ -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R\ - SO₂R\ -NO₂ and where one or two non-adjacent carbon atoms in R³ to R⁷ which are not in the α-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)RO-, -C(O)NR'-, -SO₂NR'-, -OP(O)RO-,

-P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Cr to Ci₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or a guanidinium cation, which conforms to the formula (7)

[C(NR⁸R⁹)(NR¹⁰R )(NR¹²R ³)]⁺ (7),

where

R⁸ to R¹³ each, independently of one another, denote

H, -CN, NR'₂, -OR',

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R⁸ to R¹³ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'_2l -CN, - C(O)OH, -C(O)NR'₂, -SO₂NR'_2l -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', - SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R⁸ to R¹³ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, - C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)RO-,

-P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'-, where R' each independently is H, non-fluorinated, partially fluohnated or perfluohnated straight-chain or branched Ci- to Cie-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or [Kt]^z+ conforms to the formula (8)

[HetN]^z+ (8)

where

HetN^z+ denotes a heterocyclic cation selected from the group imidazolium 1 H-pyrazolium 3H-pyrazolium 4H-pyrazolium 1-pyrazol linium

2-pyrazolinium 3-pyrazolinium 2,3-dihydroimidazolinium 4,5-dihydroimidazol liinniium

2,5-dihydroimidazolinium pyrrolidinium ^.Mriazolium 1 ,2,4-triazolium 1 ,2,3-triazolium

pyridazinium pyrimidinium

piperazinium pyrazinium thiazolium

isoquinolinium quinoxalinium indolinium

where the substituents

R¹' to R⁴' each, independently of one another, denote

H;

F, CI , Br, I, -CN, -OR', -NR'₂, -P(0)R'₂, -P(0)(OR')_2> -P(0)(NR'₂)₂, -C(O)R', -C(O)OR', -C(0)X, -C(0)NR'₂, -S0₂NR'₂, -S0₂OH, -SO₂X, -SR', -S(O)R', - S0₂R' and/or NO₂, with the proviso that R¹', R³', R⁴' are H and/or a straight- chain or branched alkyl having 1-20 C atoms;

straight-chain or branched alkyl having 1-20 C atoms, which optionally may be fluorinated or perfluorinated;

straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds, which optionally may be partially fluorinated;

straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds, which optionally may be partially fluorinated;

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms;

saturated, partially or fully unsaturated heteroaryl, heteroaryl-Ci-C₆-alkyl or aryl-CrCe-alkyl;

where the substituents R¹ , R² , R³ and/or R together may also form a ring system,

where one, two or three substituents R^r to R⁴ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, - OR', NR'₂₎ -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, - SR', -S(O)R\ -SO₂R', -NO₂, but where R^r and R^4' cannot simultaneously be fully substituted by halogens and where, in the substituents R¹ to R⁴ , one or two non-adjacent carbon atoms which are not bonded to the heteroatom may be replaced by atoms and/or atom groups selected from the -O-, -S-, - S(O)-, -SO2-. -S0₂0-, -C(0)-, -C(0)0-, -N⁺R'₂-, -P(0)RO-, -C(0)NR'-, - S0₂NR'-, -OP(0)R'O-, -P(0)(NR'₂)NR'-, -PR'₂=N- or -P(0)R'-, where where R' each independently is H, non-fluorinated, partially

fluorinated or perfluorinated straight-chain or branched Ci- to C ₈-alkyl, saturated C3- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen.

The compounds of formula I (and therefore also the compounds of formula I*) having organic cations are posessing low viscosity. Some of the viscosities are even lower compared with the corresponding

tetracyanoborates having the same organic cation. For example, 1-ethyl-3- methyl-imidazolium tetracyanoborate (emim TCB) has the dynamic viscosity of 22 mPas (at 20°C) and the corresponding 1-ethyl-3-methyl- imidazolium tricyano-methoxy-borate has a viscosity of 20 mPas (at 20°C). The positive influence of an alkoxy group (R^*O), e.g. the methoxy, ethoxy or 1 ,1 ,1-trifluoroethoxy group, on the viscosity of compounds of formula I is totally unexpected. In comparison to electron-withdrawing groups like fluoro, perfluoroalkyl or cyano groups which are able to delocalise the negative charge of the borate anion effectively, alkoxy groups (R^*0) are electron donating groups. The introduction of at least one alkoxy group to boron should increase the coordination ability of the tricyanoalkoxyborate anion, causing an increase in the viscosity of the organic salts having tricyanoalkoxyborate or dicyanodialkoxyborate anions. But the experimental results are opposite to this theoretical point of view.

Another advantage of compounds of formula I (and therefore also of the compounds of formula ) is that they can be prepared from inexpensive starting materials available from industry via a simple reaction protocol.

A straight-chain or branched alkyl group having 1 to 12 C atoms is, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert.-butyl, 1- (2,2-dimethyl)-propyl, pentyl, hexyl, heptyl, octyl, x-methylbutyl with x being 1 ; 2 or 3, x-methylpentyl with x being 1 ; 2; 3 or 4, x-methylhexyl with x being 1 ; 2; 3; 4 or 5, x-ethylpentyl with x being 1 , 2 or 3, x-ethylhexyl with x being 1 ; 2; 3 or 4, n-nonyl, n-decyl, n-undecyl or n-dodecyl, which can be partially substituted by Hal as defined above. Examples for preferred partially fluorinated alkyl groups are 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 4,4,4- trifluorobutyl or 1 ,1 ,1 ,3,3,3-hexafluoro-2-trifluoromethyl-propan-2-yl.

R* in formula la or in formula I or in formula I^* is in particular independently of each other straight-chain or branched alkyl with 1 to 8 C atoms which can be partially subsituted by Hal. R^* in formula la or in formula I or in formula I* is particularly preferably independently methyl, ethyl, n-propyl, n- butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2,2,2-trifluoroethyl or 3,3,3- trifluoropropyl.

There are no restrictions per se regarding the choice of cation of the compound of formula I in accordance with the present invention. Thus, [Kt]^z+ can be an inorganic or organic cation. Compounds of formula I or of formula with alkali metal cations are preferred starting materials for the synthesis of compounds of formula I or compounds of formula I^* having organic cations or metal cations other than the used alkali metal cation of the starting material for synthesis. The cations are preferably organic cations when the use of salts of formula is in the field of applications for ionic liquids or the organic salts per se. The cations are preferably metal cations when the use of the salts of formula I or formula I^* is as precursors for the synthesis of ionic liquids, conducting salts with organic cations or Bronsted acids or in the field of catalysis, conductive salts for electrochemical devices or sensors and corresponding electrolyte formulations comprising said salts.

The cations are preferably organic cations when the use of salts of formula I or formula is as part of the electrolyte formulations for optoelectronic devices, preferably for dye or quantum dot sensitized solar cells, especially preferably for dye sensitized solar cells.

Preferably the organic cations are selected from the group comprising sulfonium, oxonium, ammonium, phosphonium, uronium, thiouronium, guanidinium cations or heterocyclic cations. Examples of organic cations are also polyammonium ions having a degree of charging z = 4 or tritylium cation in which the phenyl groups may be substituted by straight-chain or branched alkyi groups having 1 to 20 C atoms, straight-chain or branched alkenyl having 2 to 20 C atoms and one or more double bonds or straight- chain or branched alkynyl having 2 to 20 C atoms and one or more triple bonds.

Sulfonium cations can be described, for example by the formula (1) and oxonium cations can be described, for example, by the formula (2)

[(R°)₃S]⁺ (1)

[(R°)₃O]⁺ (2)

where R° independently of each other denotes straight-chain or branched alkyi groups having 1-8 C atoms, or nonsubstituted phenyl or phenyl which is substituted by R°, OR⁰, N(R°)₂, CN or halogen and in case of sulfonium cations of formula (2) additionally denotes each independently (R"')2N and R'" is independently of each other straight-chain or branched Ci to C₆ alkyi.

R° of the [(R°)3O]⁺ cation or [(R°)₃S]⁺ cation is preferably independently of each other straight-chain alkyi having 1-8 C atoms, preferably having 1-4 C atoms, in particular methyl or ethyl, very particularly preferably ethyl. A particularly preferred sulfonium cation is diethyl-methylsulfonium.

Ammonium cations can be described, for example, by the formula (3)

[NR₄]⁺ (3),

where

R in each case, independently of one another, denotes H,

OR', NR'₂, with the proviso that a maximum of one substituent R in formula (3) is OR', NR'₂₎

straight-chain or branched alkyl having 1-20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two R may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', and where one or two non-adjacent carbon atoms in R which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched d- to Cis-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each

independently is halogen.

Phosphonium cations can be described, for example, by the formula (4)

[ΡΡ Γ (4),

where

R² in each case, independently of one another, denotes

H, OR' or NR'_2>

straight-chain or branched alkyl having 1-20 C atoms,

straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds, saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two R² may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'_2l -SO2NR 2, -C(O)X, -SO2OH, -SO₂X, -SR', -S(O)R\ -SO2R', -NO2 and where one or two non-adjacent carbon atoms in R² which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO2-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)RO-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched C-i- to C₁₈-alkyl, saturated C3- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each

independently is halogen.

However, cations of the formulae (3) and (4) in which all four or three sub- stituents R and R² are fully substituted by halogens are excluded, for example the tris(trifluoromethyl)methylammonium cation, the tetrakis(tri- fluoromethyl)ammonium cation or the tetrakis(nonafluorobutyl)ammonium cation.

Uronium cations can be described, for example, by the formula (5)

[C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺ (5), and thiouronium cations by the formula (6)

[C(NR³R )(SR⁵)(NR⁶R⁷)]⁺ (6), where

R³ to R⁷ each, independently of one another, denote

H, where H is excluded for R⁵,

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R³ to R⁷ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'₂, -SO2NR 2, -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R³ to R⁷ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-,

-P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched C to Cis-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen.

Guanidinium cations can be described by the formula (7)

[C(NR⁸R⁹)(NR¹⁰R¹¹)(NR¹²R¹³)]⁺ (7), where

R⁸ to R¹³ each, independently of one another, denote

H, -CN, -NR'₂, -OR',

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R⁸ to R¹³ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R⁸ to R ³ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -0-, -S-, -S(O)-, -S0₂-, -S0₂0-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(0)RO-, -C(0)NR'-, -S0₂NR'-, -OP(0)R'0-,

-P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched C to ds-alkyl, saturated C3- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen.

Heterocyclic cations can be described, for example by the formula (8)

[HetN]^z+ (8)

where

HetN^z+ denotes a heterocyclic cation selected from the group

imidazolium 1H-pyrazolium 3H-pyrazolium 4H-pyrazolium 1-pyrazolinium

2-pyrazolinium 3-pyrazolinium 2,3-dihydroimidazolinium 4,5-dihydroimidazolinium

2,5-dihydroimidazolinium pyrrolidinium _{1 2},4-triazolium 1,2,4-triazolium

pyridinium pyridazinium

where the substituents

R¹' to R⁴' each, independently of one another, denote

H;

F, CI, Br, I, -CN, -OR', -NR'_2l -P(O)R'_2> -P(O)(OR')₂, -P(O)(NR'₂)₂, -C(O)R', -C(O)OR', -C(O)X, -C(O)NR'₂, -SO₂NR'₂, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R' and/or NO₂, with the proviso that R ', R³', R⁴' are H and/or a straight-chain or branched alkyl having 1-20 C atoms;

straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds, which optionally may be partially fluorinated; straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds, which optionally may be partially fluorinated;

saturated, partially or fully unsaturated heteroaryl, heteroaryl-Ci-C6-alkyl or aryl-Ci-Ce-alkyl;

where the substltuents R¹ , R² , R^3' and/or R⁴ together may also form a ring system,

where one, two or three substltuents R¹' to R⁴' may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, - OR', -NR'₂₎ -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R\ -SO₂R', -NO₂, but where R^1' and R^4' cannot simultaneously be fully substituted by halogens and where, in the substltuents R¹' to R⁴', one or two non-adjacent carbon atoms which are not bonded to the heteroatom may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-,

-P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to Ci₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen.

For the purposes of the present invention, fully unsaturated substltuents are also taken to mean aromatic substltuents.

In accordance with the invention, suitable substltuents R and R² to R¹³ of the compounds of the formulae (3) to (7), besides H, are preferably: d- to C₂₀-, in particular C-i- to C₁₄-alkyl groups, and saturated or unsaturated, i.e. also aromatic, C₃- to C₇-cycloalkyl groups, which may be substituted by C-i- to C₆-alkyl groups, in particular phenyl. The substituents R and R² in the compounds of the formula (3) or (4) may be identical or different. The substituents R and R² are preferably different.

The substituents R and R² are particularly preferably methyl, ethyl, iso- propyl, propyl, butyl, sec-butyl, pentyl, hexyl, octyl, decyl or tetradecyl.

Up to four substituents of the guanidinium cation

[C(NR⁸R⁹)(NR¹⁰R¹¹)(NR¹²R¹³)]⁺ may also be bonded in pairs in such a way that mono-, bi- or polycyclic cations are formed.

Without restricting generality, examples of such guanidinium cations are:

where the substituents R⁸ to R¹⁰ and R ³ can have a meaning or particularly preferred meaning indicated above.

If desired, the carbocycles or heterocycles of the guanidinium cations indicated above may also be substituted by C to C6-alkyl, C-i - to C₆-alkenyl, -CN, -N0₂, F, CI, Br, I, -OH, -d-Ce-alkoxy, -NR'₂, -SR\ -S(O)R', -S0₂R\ -C(O)OH, -SO₂NR 2, -SO2X' or -SO3H, where X and R' have a meaning indicated above, substituted or nonsubstituted phenyl or an nonsubstituted or substituted heterocycle.

Up to four substituents of the uronium cation [C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺ or thiouronium cation [C(NR³R⁴)(SR⁵)(NR⁶R⁷)]⁺ may also be bonded in pairs in such a way that mono-, bi- or polycyclic cations are formed.

Without restricting generality, examples of such cations are indicated below, where Y = O or S:

where the substituents R³, R⁵ and R⁶ can have a meaning or particularly preferred meaning indicated above.

If desired, the carbocycles or heterocycles of the cations indicated above may also be substituted by d- to C₆-alkyl, d- to C₆-alkenyl, -CN, -NO₂, F, CI, Br, I, -OH, -CrCe-alkoxy, -NR'_2l -SR', -S(O)R', -SO₂R', -COOH, SO₂NR'₂₎ SO₂X or SO₃H or substituted or nonsubstituted phenyl or an nonsubstituted or substituted heterocycle, where X and R' have a meaning indicated above.

The substituents R³ to R¹³ are each, independently of one another, preferably a straight-chain or branched alkyl group having 1 to 16 C atoms. The substituents R³ and R⁴, R⁶ and R⁷, R⁸ and R⁹, R ⁰ and R¹¹ and R¹² and R¹³ in compounds of the formulae (5) to (7) may be identical or different. R³ to R¹³ are particularly preferably each, independently of one another, methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, sec-butyl, phenyl, hexyl or cyclohexyl, very particularly preferably methyl, ethyl, n-propyl, isopropyl, n-butyl or hexyl.

In accordance with the invention, suitable substituents R^r to R⁴ of compounds of the formula (8) are each, independently of one another, preferably,

H

straight-chain or branched alkyl having 1 to 20 C atoms, which optionally may be fluorinated or perfluorinated,

straight-chain or branched alkenyl having 2 to 20 C atoms and one or more double bonds, which optionally may be partially fluorinated ,

straight-chain or branched alkynyl having 2 to 20 C atoms and one or more triple bonds which optionally may be partially fluorinated or

straight-chain or branched alkoxyalkyl having 2 to 8 C atoms.

In accordance with the invention, suitable substituents R² and R³ of compounds of formula (8) are particularly preferably: H, C to C₂₀-, in particular C to Ci₂-alkyl groups, and saturated or unsaturated, i.e. also aromatic, C3- to C₇-cycloalkyl groups, which may be substituted by d- to C₆-alkyl groups, in particular phenyl.

In accordance with the invention, suitable substituents R and R⁴ of compounds of formula (8) are particularly preferably, each independently of each other straight-chain or branched C to C₂o-, in particular d- to C12- alkyl groups, and saturated or unsaturated, i.e. also aromatic, C₃- to C₇- cycloalkyl groups, which may be substituted by C to C6-alkyl groups, in particular phenyl.

The substituents R¹ and R⁴ are each, independently of one another, particularly preferably methyl, ethyl, allyl, iso-propyl, propyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, phenyl or benzyl. They are very particularly preferably methyl, ethyl, n-butyl or hexyl. In pyrrolidinium, piperidinium or indolinium compounds, the two substituents R and R⁴ are preferably different.

The substituent R² or R³ is in each case, independently of one another, in particular H, methyl, ethyl, iso-propyl, propyl, butyl, sec-butyl, tert-butyl, cyclohexyl, phenyl or benzyl. R² is particularly preferably H, methyl, ethyl, iso-propyl, propyl, butyl or sec-butyl. R² and R³ are very particularly preferably H.

The C Ci2-alkyl group is, for example, methyl, ethyl, iso-propyl, propyl, butyl, sec-butyl or tert-butyl, furthermore also pentyl, 1-, 2- or 3-methylbutyl, 1 ,1-, 1 ,2- or 2,2-dimethylpropyl, 1-ethylpropyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl or dodecyl, which optionally may be fluorinated or

perfluorinated. The term "perfluorinated" means that all H atoms are substituted by F atoms in the given alkyl group. The term "fluorinated" means that at least one H atom of the given alkyl group is substituted by an F atom. Examples of "fluorinated" or "perfluorinated" groups are

difluoromethyl, trifluoromethyl, pentafluoroethyl, heptafluoropropyl or nonafluorobutyl.

A straight-chain or branched alkenyl having 2 to 20 C atoms, in which a plurality of double bonds may also be present, is, for example, allyl, 2- or 3- butenyl, isobutenyl, sec-butenyl, furthermore 4-pentenyl, iso-pentenyl, hex- enyl, heptenyl, octenyl, -C₉H₁₇, -C ₀H₁₉ to -C20H39, preferably allyl, 2- or 3- butenyl, iso-butenyl, sec-butenyl, furthermore preferably 4-pentenyl, iso- pentenyl or hexenyl, which optionally may be partially fluorinated. The term "fluorinated" means that at least one H atom of the given alkyl group is substituted by an F atom.

A straight-chain or branched alkynyl having 2 to 20 C atoms, in which a plurality of triple bonds may also be present, is, for example, ethynyl, 1- or 2- propynyl, 2- or 3-butynyl, furthermore 4-pentynyl, 3-pentynyl, hexynyl, hept- ynyl, octynyl, -C₉H-15, -Ci₀H₁₇ to -C20H37, preferably ethynyl, 1- or 2-propyn- yl, 2- or 3-butynyl, 4-pentynyl, 3-pentynyl or hexynyl, which optionally may be partially fluorinated. The term "fluorinated" means that at least one H atom of the given alkyl group is substituted by an F atom.

A straight-chain or branched alkoxyalkyl having 2 to 12 C atoms is, for example, methoxy methyl, 1-methoxyethyl, 1-methoxypropyl, 1-methoxy-2- methyl-ethyl, 2-methoxy-propyl, 2-methoxy-2-methyl-propyl, 1- methoxybutyl, 1-methoxy-2,2-dimethyl-ethyl, 1-methoxy-pentyl, 1- methoxyhexyl, 1-methoxy-heptyl, ethoxymethyl, 1-ethoxyethyl, 1- ethoxypropyl, 1-ethoxy-2-methyl-ethyl, 1-ethoxybutyl, 1-ethoxy-2,2- dimethyl-ethyl, 1-ethoxypentyl, 1-ethoxyhexyl, 1-ethoxyheptyl,

propoxymethyl, 1-propoxyethyl, 1-propoxypropyl, l-propoxy-2-methyl-ethyl, 1-propoxybutyl, 1-propoxy-2,2-dimethyl-ethyl, 1-propoxypentyl,

butoxymethyl, 1-butoxyethyl, 1-butoxypropyl or 1-butoxybutyl. Particularly preferred is methoxymethyl, 1-methoxyethyl, 2-methoxy-propyl, 1- methoxypropyl, 2-methoxy-2-methyl-propyl or 1-methoxybutyl.

Aryl-Ci-C₆-alkyl denotes, for example, benzyl, phenylethyl, phenylpropyl, phenylbutyl, phenylpentyl or phenylhexyl, where both the phenyl ring and also the alkylene chain may be partially or fully substituted, as described above, by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'2, -CN, -C(O)OH, -C(0)NR'₂₎ -S0₂NR'₂, -C(O)X, -S0₂OH, -S0₂X, -SR', -S(O)R', -SO₂R', -N0₂.

Non-substituted saturated or partially or fully unsaturated cycloalkyi groups having 3-7 C atoms are therefore cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopentenyl, cyclopenta-1,3-dienyl, cyclohexenyl, cyclohexa-1 ,3-dienyl, cyclohexa-1 ,4-dienyl, phenyl, cycloheptenyl, cyclo- hepta-1 ,3-dienyl, cyclohepta-1 ,4-dienyl or cyclohepta-1 ,5-dienyl, each of which may be substituted by d- to C₆-alkyl groups, where the cycloalkyi group or the cycloalkyi group substituted by d- to C6-alkyl groups may in turn also be substituted by halogen atoms, such as F, CI, Br or I, in particular F or CI, or by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂.

In the substituents R, R² to R¹³ or R¹ to R⁴ , one or two non-adjacent carbon atoms which are not bonded in the oc-position to the heteroatom may also be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)RO-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'-, where R' = non-, partially or perfluorinated Ci- to Cie-alkyl, C₃- to C₇-cycloalkyl, nonsubstituted or substituted phenyl.

Without restricting generality, examples of substituents R, R² to R¹³ and R to R modified in this way are:

-OCH₃, -OCH(CH₃)₂, -CH₂OCH₃, -CH₂-CH₂-O-CH₃, -C₂H₄OCH(CH₃)₂, -C₂H₄SC₂H_5l -C₂H₄SCH(CH₃)₂, -S(O)CH₃, -SO₂CH₃, -SO₂C₆H₅, -SO₂C₃H₇₎ -SO₂CH(CH₃)₂, -SO₂CH₂CF₃, -CH₂SO₂CH₃, -O-C₄H₈-O-C₄H₉, -CF₃, -C₂F₅, -C₃F₇₎ -C4F9, -C(CF₃)₃, -CF₂SO₂CF₃, -C₂F₄N(C₂F₅)C₂F₅, -CHF₂, -CH₂CF₃, -C₂F₂H₃, -C₃FH₆, -CH₂C₃F₇, -C(CFH₂)₃, -CH₂C(O)OH, -CH₂C₆H₅, -C(O)C₆H₅ or P(O)(C₂H₅)₂. In R', C₃- to C₇-cycloalkyl is, for example, cyclopropyl, cyclobutyl, cyclo- pentyl, cyclohexyl or cycloheptyl.

In R', substituted phenyl denotes phenyl which is substituted by C to C_&- alkyl, C to C₆-alkenyl, -CN, -N0₂, F, CI, Br, I, -OH, -C C₆-alkoxy, NR"₂, - COOH, -SO2X', -SR", -S(O)R", -SO2R", SO₂NR"₂ or SO₃H, where X' denotes F, CI or Br and R" denotes a non-, partially or perfluorinated Ci- to C6-alkyl or C3- to C₇-cycloalkyl as defined for R', for example 0-, m- or p- methylphenyl, 0-, m- or p-ethylphenyl, 0-, m- or p-propylphenyl, 0-, m- or p-isopropylphenyl, 0-, m- or p-tert-butylphenyl, 0-, m- or p-nitrophenyl, 0-, m- or p-hydroxyphenyl, 0-, m- or p-methoxyphenyl, 0-, m- or p-ethoxy- phenyl, 0-, m-, p-(trifluoromethyl)phenyl, 0-, m-, p-(trifluoromethoxy)phenyl, 0-, m-, p-(trifluoromethylsulfonyl)phenyl, 0-, m- or p-fluorophenyl, 0-, m- or p-chlorophenyl, 0-, m- or p-bromophenyl, 0-, m- or p-iodophenyl, further preferably 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dimethylphenyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dihydroxyphenyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-difluoro- phenyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dichlorophenyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dibromophenyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dimethoxy- phenyl, 5-fluoro-2-methylphenyl, 3,4,5-trimethoxyphenyl or 2,4,5-trimethyl- phenyl.

In R to R , heteroaryl is taken to mean a saturated or unsaturated mono- or bicyclic heterocyclic group having 5 to 13 ring members, in which 1 , 2 or 3 N and/or 1 or 2 S or O atoms may be present and the heterocyclic radical may be mono- or polysubstituted by C to C₆-alkyl, C to C₆-alkenyl, -CN, -NO2, F, CI, Br, I, -OH, -NR"₂, -d-Ce-alkoxy, -COOH, -SO₂X', -SO₂NR"₂, -SR", -S(O)R", -SO₂R" or SO₃H, where X' and R" have a meaning indicated above.

The heterocyclic group is preferably substituted or nonsubstituted 2- or 3- furyl, 2- or 3-thienyl, 1-, 2- or 3-pyrrolyl, 1-, 2-, 4- or 5-imidazolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 2-, 4- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 2-, 3- or 4-pyridyl, 2-, 4-, 5- or 6-pyrimidinyl, further- more preferably 1 ,2,3-triazol-l-, -4- or -5-yl, 1 ,2,4-triazol-1-, -4- or -5-yl, 1- or 5-tetrazolyl, 1 ,2,3-oxadiazol-4- or -5-yl, 1 ,2,4-oxadiazol-3- or -5-yl, 1 ,3,4- thiadiazol-2- or -5-yl, 1 ,2,4-thiadiazol-3- or -5-yl, 1 ,2,3-thiadiazol-4- or -5-yl,

2- , 3-, 4-, 5- or 6-2H-thiopyranyl, 2-, 3- or 4-4H-thiopyranyl, 3- or 4-pyridaz- inyl, pyrazinyl, 2-, 3-, 4-, 5-, 6- or 7-benzofuryl, 2-, 3-, 4-, 5-, 6- or 7-benzo- thienyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-1 H-indotyl, 1-, 2-, 4- or 5-benzimidazolyl, 1-,

3- , 4-, 5-, 6- or 7-benzopyrazolyl, 2-, 4-, 5-, 6- or 7-benzoxazolyl, 3-, 4-, 5-,

6- or 7-benzisoxazolyl, 2-, 4-, 5-, 6- or 7-benzothiazolyl, 2-, 4-, 5-, 6- or 7- benzisothiazolyl, 4-, 5-, 6- or 7-benz-2,1 ,3-oxadiazolyl, 1-, 2-, 3-, 4-, 5-, 6-,

7- or 8-quinolinyl, 1-, 3-, 4-, 5-, 6-, 7- or 8-isoquinolinyl, 1-, 2-, 3-, 4- or 9- carbazolyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-acridinyl, 3-, 4-, 5-, 6-, 7- or 8- cinnolinyl, 2-, 4-, 5-, 6-, 7- or 8-quinazolinyl or 1-, 2- or 3-pyrrolidinyl.

Heteroaryl-CrC₆-alkyl is, analogously to aryl-CrC₆-alkyl, taken to mean, for example, pyridinylmethyl, pyridinylethyl, pyridinylpropyl, pyridinylbutyl, pyri- dinylpentyl, pyridinylhexyl, where the heterocycles described above may furthermore be linked to the alkylene chain in this way.

HetN is preferably

pyridinium pyrimidinium

where the substituents R¹ to R⁴ each, independently of one another, have a meaning described above. ^z+ is particularly preferably

where the substituents R¹ to R⁴ each, independently of one another, have a meaning described above.

HetN²⁺ is very particularly preferably

imidazolium pyrrolidinium

where the substituents R¹ to R each, independently of one another, have a meaning described above. Preferred 1 ,1-dialkylpyrrolidinium cations are, for example, 1 ,1-dimethyl- pyrrolidinium, 1 -methyl- 1-ethylpyrrolidinium, 1-methyl-1-propylpyrrolidinium, 1-methyl-1-butylpyrrolidinium, 1-methyl-1-pentylpyrrolidinium, 1-methyl-1- hexylpyrrolidinium, 1 -methyl-1 -heptylpyrrolidinium, 1 -methyl-1 -octylpyrroli- dinium, 1 -methyl-1 -nonylpyrrolidinium, 1 -methyl-1 -decylpyrrolidinium, 1 ,1- diethylpyrrolidinium, 1-ethyl-1-propylpyrrolidinium, 1 -ethyl-1 -butylpyrrolidin- ium, 1 -ethyl-1 -pentylpyrrolidinium, 1 -ethyl-1 -hexylpyrrolidinium, 1 -ethyl-1 - heptylpyrrolidinium, 1 -ethyl-1 -octylpyrrolidinium, 1 -ethyl-1 -nonylpyrrolidinium, 1 -ethyl-1 -decylpyrrolidinium, 1 ,1-dipropylpyrrolidinium, 1-propyl-1- methylpyrrolidinium, 1 -propyl-1 -butylpyrrolidinium, 1 -propyl-1 -pentylpyrroli- dinium, 1 -propyl-1 -hexylpyrrolidinium, 1 -propyl-1 -heptylpyrrolidinium, 1- propyl-1 -octylpyrrolidinium, 1 -propyl-1 -nonylpyrrolidinium, 1 -propyl-1 -decyl- pyrrolidinium, 1 ,1-dibutylpyrrolidinium, 1-butyl-1-methylpyrrolidinium, 1- butyl-1-pentylpyrrolidinium, 1-butyl-1-hexylpyrrolidinium, 1 -butyl-1 -heptyl- pyrrolidinium, 1 -butyl-1 -octylpyrrolidinium, 1 -butyl-1 -nonylpyrrolidinium, 1-butyl-l-decylpyrrolidinium, 1 ,1-dipentylpyrrolidinium, 1 -pentyl-1 -hexyl- pyrrolidinium, 1-pentyl-1-heptylpyrrolidinium, 1-pentyl-1 -octylpyrrolidinium, 1 -pentyl-1 -nonylpyrrolidinium, 1 -pentyl-1 -decylpyrrolidinium, 1 , 1 -dihexyl- pyrrolidinium, 1 -hexyl-1 -heptylpyrrolidinium, 1 -hexyl-1 -octylpyrrolidinium, 1-hexyl-1 -nonylpyrrolidinium, 1 -hexyl-1 -decylpyrrolidinium, 1 ,1-dihexyl- pyrrolidinium, 1 -hexyl-1 -heptylpyrrolidinium, 1 -hexyl-1 -octylpyrrolidinium, 1 -hexyl-1 -nonylpyrrolidinium, 1 -hexyl-1 -decylpyrrolidinium, 1 ,1-diheptyl- pyrrolidinium, 1-heptyl-1 -octylpyrrolidinium, 1-heptyl-1 -nonylpyrrolidinium, 1-heptyl-1 -decylpyrrolidinium, 1 ,1-dioctylpyrrolidinium, 1-octyl-1 -nonylpyrrolidinium, 1-octyl-1 -decylpyrrolidinium, 1 ,1-dinonylpyrrolidinium, 1- nonyl-1 -decylpyrrolidinium or 1 ,1-didecylpyrrolidinium. Very particular preference is given to 1 -butyl-1 -methylpyrrolidinium or 1-propyl-1-methyl- pyrrolidinium.

Preferred 1-alkyl-1-alkoxyalkylpyrrolidinium cations are, for example, 1-(2- methoxyethyl)-1 -methylpyrrolidinium, 1 -(2-methoxyethyl)-1 -ethyl- pyrrolidinium, 1-(2-methoxyethyl)-1-propylpyrrolidinium, 1-(2-methoxyethyl)- 1 -butylpyrrolidinium, 1 -(2-ethoxyethyl)-1 -methylpyrrolidinium,

1-ethoxymethyl-1 -methylpyrrolidinium. Very particular preference is given to 1-(2-methoxyethyl)-1 -methylpyrrolidinium.

Preferred 1 ,3-dialkylimidazolium cations are, for example, 1-ethyl-3-methyl- imidazolium, 1-methyl-3-propylimidazolium, 1-methyl-2,3- dimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1-propyl-2,3- dimethylimidazolium, 1-butyl-2,3-dimethylimidazolium, 1 -butyl-3-methyl- imidazolium, 1-methyl-3-pentylimidazolium, 1-ethyl-3-propylimidazolium, 1 -butyl-3-ethylimidazolium, 1 -ethyl-3-pentylimidazolium, 1 -butyl-3-propyl- imidazolium, 1 ,3-dimethylimidazolium, 1 ,3-diethylimidazolium, 1 ,3- dipropylimidazolium, 1 ,3-dibutylimidazolium, 1 ,3-dipentylimidazolium, 1 ,3- dihexylimidazolium, 1 ,3-diheptylimidazolium, 1 ,3-dioctylimidazolium, 1 ,3- dinonylimidazolium, 1 ,3-didecylimidazolium, 1 -hexyl-3-methylimidazolium, 1-heptyl-3-methylimidazolium, 1-methyl-3-octylimidazolium, 1-methyl-3- nonylimidazolium, 1-decyl-3-methylimidazolium, 1-ethyl-3-hexyl- imidazolium, 1-ethyl-3-heptylimidazolium, l-ethyl-3-octylimidazolium, 1-ethyl-3-nonylimidazolium or 1-decyl-3-ethylimidazolium. Particularly preferred cations are 1-ethyl-3-methylimidazolium, 1-butyl-3-methyl- imidazolium or 1-methyl-3-propylimidazolium.

Preferred 1-alkoxyalkyl-3-alkylimidazolium cations are, for example 1-(2- methoxyethyl)-3-methylimidazolium, 1-(2-methoxyethyl)-3-ethylimidazolium, 1 -(2-methoxyethyl)-3-propylimidazolium, 1 -(2-methoxyethyl)-3-butyl- imidazolium, 1-(2-ethoxyethyl)-3-methylimidazolium, 1-ethoxymethyl-3- methylimidazolium.

Preferred 1-alkenyl-3-alkylimidazolium cations are, for example 1-allyl-3- methyl-imidazolium or 1-allyl-2,3-dimethylimidazolium.

Preferred 1-alkyl-pyridinium cations, are for example, 1-methylpyridinium, 1-ethylpyridinium, 1-n-propylpyridinium, 1-isopropylpyridinium, 1-n- butylpyridinium, 1 -n-butyl-3-methylpyridinium, 1 -n-butyl-4-methylpyridinium, 1-n-butyl-3-ethylpyridinium, 1-n-pentylpyridinium, 1-n-hexylpyridinium, 1-n- heptylpyridinium, 1-n-octylpyridinium, 1-n-nonylpyridinium, 1-n- decylpyridinium, 1-n-undecyl-pyridinium or 1-n-dodecylpyridinium.

The cation [Kt]^z+ of the compound of formula I or formula I^* may in addition also be inorganic, in particular a metal cation or NO⁺. The metal cation may comprise metals from groups 1 to 12 of the Periodic Table.

Preferred metal cations are alkali metal cations, such as Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Ag⁺, Mg²⁺, Cu\ Cu²⁺, Zn²⁺,Ca²⁺, Y⁺³, Yb⁺³, La⁺³, Sc⁺³, Ce⁺³, Ce⁺⁴, Nd⁺³, Tb⁺³, Sm⁺³ or complex (ligands containing) metal cations which include rare-earths, transitions or noble metals like Rhodium, Ruthenium, Iridium, Palladium, Platinum, Osmium, Cobalt, Nickel, Iron, Chromium, Molybdenium, Tungsten, Vanadium, Titanium, Zirconium, Hafnium,

Thorium, Uranium, Gold. The alkali metal is preferably lithium, sodium or potassium.

Compounds of formula I or formula I* in which [Kt]^z+ is Li⁺ can be preferably used as conductive salts in primary batteries, secondary batteries, capacitors, supercapacitors or electrochemical cells, optionally also in combination with further conductive salts and/or additives, as constituent of a polymer electrolyte or phase-transfer medium. Electrolyte formulations comprising at least one compound of formula I in which [Kt]^z+ is Li⁺ can be preferably used in primary batteries, secondary batteries, capacitors, supercapacitors or electrochemical cells, optionally also in combination with further conductive salts and/or additives.

Compounds of formula I or compounds of formula I^* in which [Kt]^z+ is Na⁺ or K⁺ can be preferably used as starting materials for compounds of formula I or compounds of formula I^* in which [Kt]^z+ is an organic cation or another metal cation than sodium or potassium.

The organic cations of the compounds of formula I as part of the electrolyte formulation according to the invention are preferably sulfonium, ammonium, phosphonium cations of formula (1), (3) and (4) or heterocyclic cations of formula (8).

The organic cations of the compounds of formula according to the invention are preferably sulfonium, ammonium, phosphonium cations of formula (1), (3) and (4) or heterocyclic cations of formula (8).

The organic cations of the compounds of formula I as part of the electrolyte formulation according to the invention or of the compounds of formula are particularly preferably heterocyclic cations of formula (8) in which HetN^z+ is imidazolium, pyrrolidinium or pyridinium, as defined above, where the substituents R¹ to R⁴ each, independently of one another, have a meaning described above. The organic cation of the compound of formula I or formula is very particularly preferably imidazolium, where the substituents R¹ to R⁴ each, independently of one another, have a meaning described above or has one of the particularly preferred meanings of 1 ,1- dialkylpyrrolidinium, 1-alkyl-l-alkoxyalkylalkylpyrrolidinium, 1 ,3- dialkylimidazolium, 1-alkenyl-3-alkylimidazolium or 1-alkoxyalkyl-3- alkylimidazolium as described above.

Particularly suitable organic cations of compounds of the formula I or formula I* are 1-butyl-1-methylpyrrolidinium, 1-ethyl-3-methylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1-(2-methoxyethyl)-3-methylimidazolium, l-butyl-3-methylimidazolium, tributyl-methylammonium, tetra-n- butylammonium, tributyl-methylphosphonium, tetra-phenylphosphonium, diethyl-methylsulfonium, S-ethyl-N,N,N',N'-tetramethylisothiouronium, 1- allyl-3-methylimidazolium, 1-allyl-2,3-dimethylimidazolium, 1-cyanomethyl- 3-methylimidazolium, 1-methyl-3-propinylimidazolium, 1 ,1- dimethylpyrrolidinium or trimethylsulfonium.

It goes without saying to the person skilled in the art that substituents, such as, for example, C, H, N, O, CI, F, in the compounds according to the invention may be replaced by the corresponding isotopes.

The compounds of the formula I in which [Kt]^z+ is an alkali metal cation (z = 1) and x is 1 which denotes a compound of formula 1-1

[Me]⁺ [B(CN)₃(OR*)r 1-1

in which Me⁺ is an alkali metal cation, such as Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, preferably Na⁺ and K⁺, and R^* has a meaning as described above can be prepared, for example, by reaction of a compound of formula II

[Me]⁺ [B(OR^*)₄]- II

in which [Me]⁺ has a meaning as defined above and R^* has a meaning as described above with trialkylsilylcyanide in which the alkyl groups

independently denotes straight-chain or branched alkyl groups having 1 to 4 C atoms.

Such a reaction of tetraalkoxyborates with trialkylsilylcyanide is not described in the literature. The reaction of tetrafluoroborates M⁺[BF₄]^" (M⁺ = Li⁺, K⁺) with trimethylsilyl cyanide, (CH₃)₃SiCN, has been studied by E. Bernhardt at al. [Z. WrAnorg. und Allg. Chem., 629, (2003), p. 677-685]. It was reported that this reaction proceeds very slowly with reaction times of some hours to several weeks and results in the mixtures of dicyanodifluoro- [BF₂(CN)₂ and tricyanofluoroborates [BF(CN)₃]\ All attempts to synthesise and isolate monocyanotrifluoroborates [BF₃(CN)]^~ in this way failed.

Surprisingly, opposite to the reaction with tetrafluoroborates M⁺[BF₄]^", the reaction of [B(OR^*)₄]^~ with (CH₃)₃SiCN proceeds much faster and results in the formation of monocyano-aikoxyborates (detected by mass-spectrometry and NMR spectroscopy) as intermediate and dicyano- and tricyano- alkoxyborates as major products. Unexpectedly, trimethylsilylcyanide selectively replaces the alkoxy-groups bonded to boron and does not attack the fluorine atoms in the carbon chain of R^*.

The invention therefore also relates to a process for the preparation of compounds of the formula I in which [Kt]^z+ is an alkali metal cation and x denotes 1 which denotes a compound of formula 1-1

[Me]⁺ [B(CN)₃(OR^*)J- 1-1

in which Me⁺ is an alkali metal cation and R^* has a meaning as described above comprising the reaction of a compound of formula II

[Me]⁺ [B(OR^*)₄]^" II

in which [Me]⁺ has a meaning as defined above and R^* has a meaning as described above with at least three equivalents of trialkylsilylcyanide in which the alkyl groups independently denotes straight-chain or branched alkyl groups having 1 to 4 C atoms. This process can be carried out in air, preferably in a dry atmosphere, for example under dry air, nitrogen or argon.

Compounds of formula II are in some cases commercially available or can be synthesized by known processes e.g. via the reaction of alkali metal borohydride (Me[BH₄]) with the alcohol R^*-OH, in which alkali metal and R^* has a meaning as described herein according to J.H. Golden et al, Inorg. Chem. 1992, 31 , 1533. Lithium tetramethoxy borate may be prepared via the reaction of lithium methanolate with boric acid thmethylester in methanol according to R. Koster in Houben-Weyl, Vol. VI 2, 1963. As a conclusion, compounds of formula II can be synthesized by the reaction of an alkali metal alkoxylate (Me(OR^*)) with a boric acid trialkylester B(OR^*)₃, in which Me is the alkali metal and R^* has a meaning as described herein.

In the process as described above for the synthesis of compounds of formula 1-1 , it is possible and sometimes preferable to generate the compound of formula II in situ as described above.

Trialkylsilylcyanide in which the alkyl groups independently denotes straight-chain or branched alkyl groups having 1 to 4 C atoms are in some cases commercially available or can be synthesised by known processes. For example, it is possible to generate trialkylsilylcyanide by the reaction of alkalimetalcyanide with trialkylsilylchloride in the presence of

alkalimetaliodide and optionally elemental iodine (M.T. Reetz, I.

Chatziiosifidis, Synthesis, 1982, p. 330; J.K. Rasmussen, S. M. Heilmann and L.R. Krepski, The Chemistry of Cyanotrimethylsilane in G.L. Larson (Ed.)„Advances in Silicon Chemistry", Vol. 1 , p. 65-187, JAI Press Inc., 1991 ; WO 2008/102661 A1).

The use of sodium cyanide and sodium iodide or potassium cyanide or potassium iodide is particular preferred. Preferably, the alkalimetaliodide will be used in 0,1 mol/l related to 1 mol/l alkalicyanide and

trialkylsilylchlorlde. The reaction has to be carried out in a dry atmosphere, for example under dry air, nitrogen or argon.

The alkyl groups of trialkylsilylcyanide may be the same or different.

Preferably, they are the same. Examples of trialkylsilylcyanides are such as trimethylsilylcyanide, triethylsilylcyanide, dimethylethylsilylcyanide, triisopropylsilylcyanide, tripropylsilylcyanide or tributylsilylcyanide.

Particularly preferred is the use of trimethylsilylcyanide.

The process for the preparation of compounds of the formula I in which [Kt]^z+ is an alkali metal cation and x denotes 1 which denotes a compound of formula 1-1 as described above may be carried out in an organic solvent or in the absence of an organic solvent if one starting material is liquid at the reaction temperature, at a temperature between 10°C and 150°C.

Useful organic solvents are for example, acetonitrile, dimethoxyethane, diglyme, tetrahydrofurane, or methyl-tert-butyl ether.

In one embodiment of the invention it is preferable to carry out the reaction in a solvent as described above at temperatures between 10°C and 100°C to obtain compounds of formula 1-1 in which x is 1 as major product if stoichiometric amounts of the compound of formula II and

trialkylsilylcyanide (three equivalents) or trialkylsilylcyanide in an excess are used. The preferred temperature range is room-temperature (25°C) to 80°C. The preferred solvent is acetonirile.

In another embodiment of the invention it is preferable to carry out the reaction at room temperature in the presence of an organic solvent to obtain compounds of formula I in which x is 2 as major product which denote a compound of formula I-2 if two equivalents of trialkylsilylcyanide per equivalent of tetra-alkoxy-borates are used in a dry atmosphere. For details, it is referred to the examples.

The following general scheme addresses this issue for compounds of formula 1-1 in which Me is sodium:

Na[B(OCH₃)₄] ⁺ 2 (CH₃)₃SiCN _{. 2 (CHj3Si0CH}» Na[B(CN)₂(OCH₃)₂] Na[B(OCH₃)₄] + 3 (CH₃)₃SiCN _{. 3 (CH3)3SiOCH} ^> Na[B(CN)₃OCH₃)

The invention, in addition, also relates to a process for the preparation of a compound of formula I as described before in which [Kt]^z+ is an alkali metal cation and x denotes 2 or a compound of formula I^* in which [Kt]^z+ is an alkali metal cation which denotes a compound of formula I-2

[Me]⁺ [B(CN)₂(OR^*)₂r I-2

and R* has a meaning as described before

comprising the reaction of a compound of formula II

[Mef [B(OR^*) ]^" M

in which [Me]⁺ denotes an alkali metal cation and R^* denotes in each case, independently of one another, straight-chain or branched alkyl groups having 1 to 12 C atoms with trialkylsilylcyanide at room temperature in the presence of an organic solvent and two equivalents of trialkylsilylcyanide per equivalent of the compound of formula II.

The invention, in addition, also relates to a process for the preparation of compounds of the formula I in which [Kt]^z+ is an alkali metal cation and x denotes 1 which denotes a compound of formula 1-1

[Me]⁺ [B(CN)₃(OR^*)r 1-1

in which Me⁺ is an alkali metal cation and R^* has a meaning as described above comprising the reaction of a compound of formula III

[Me]⁺ [BF₄]^" III

in which [Me]⁺ has a meaning as defined above with trialkylsilylcyanide and with alkoxytrialkylsilane in which alkoxy means OR^* and R^* has a meaning as described above and in which the alkyl groups of the silyl compounds independently denotes straight-chain or branched alkyl groups having 1 to 4 C atoms.

Also this process preferably should be carried out in a dry atmosphere, for example under dry air, nitrogen or argon .

Compounds of formula III are commercially available.

The process for the preparation of compounds of the formula I in which [Kt]^z+ is an alkali metal cation and x denotes 1 which denotes a compound of formula 1-1 as described above may be carried out in an organic solvent or in the absence of an organic solvent if one starting material is liquid at the reaction temperature, at a temperature between 10°C and 150°C, preferably between room temperature and 80°C.

In both processes as described above for the synthesis of compounds of formula 1-1 , it is possible and sometimes preferable to generate trialkylsilylcyanide in situ before addition of the compound of formula II or III. This in-situ generation may be carried out under the reaction conditions as described before.

In one special embodiment of the invention, the process for the synthesis of compounds of formula I in which [Kt]^z+ is an alkali metal cation and x denotes 1 as described herein is carried out through reaction of an alkali metal tetrafluoroborate of formula Me[BF₄] with R^*OH, MeCN and trialkylsilylchloride, in which Me is the alkali metal cation [Kt]^z+, R^* has a meaning as described above and the alkyl group of the silicium compound is independently of each other straight-chain or branched alkyl with 1 to 4 C atoms.

In a further embodiment of the invention Me[BF₂(CN)₂], in which Me is an alkali metal cation, can be used as starting material for the synthesis of compounds of formula I in which [Kt]^z+ is an alkali metal cation and x denotes 1 as described herein by means of the reaction with trialkylsilyl cyanide and alkoxytrialkylsilanes.

The process for the preparation of compounds of formula I in which the cation is an organic cation or an inorganic cation other than an alkalimetal cation is a metathesis reaction (salt-exchange reaction) in which the cation will be replaced as commonly known.

The invention therefore also relates to a process for the preparation of a compound of formula I or a compound of formula in which [Kt]^z+ is another cation than the used alkali metal cation in the starting material in a salt-exchange reaction as described above, characterized in that an alkali metal salt of formula 1-1

[Mef [B(CN)₃(OR^*)]- 1-1

or of formula I-2

[Me]⁺ [B(CN)₂(OR^*)₂r I-2

in which Me is an alkali metal cation or H[B(CN)₃(OR^*)] or H[B(CN)₂(OR^*)₂] and R* has a meaning as described above is reacted with a compound of formula V

KtA V,

in which

Kt has a meaning of an organic cation or a metal cation other than the alkali metal cation of the compound of formula 1-1 or formula I-2 and

A denotes F ^~, CI ^~ Br^", I ^", OH^" (OH^" merely for the synthesis of compounds of formula l-1),[HF₂]^", [CN]^" [SCN]^", [^0(0)0] ^" [^00(0)0]^" [RiSO₃] - [R₂C(O)O]- [R2SO3] - [R1OSO3] - [SiF₆] ²- [BF₄] [HOCO2] - [HSO₄] ¹- [NO3] - [(Ri)₂P(0)O]^", [R₁(R₁O)P(O)O]^", [(R₂)₂P(O)O]^", [R₂P(O)O₂]^2", tosylate, malonate, the malonate optionally substituted with straight-chain or branched alkyl groups having 1 to 4 C atoms, [SO ]^2"or [CO₃] ^2~ ( [SO₄]^2" or [CO₃] ^2_ merely for the synthesis of compounds of formula I with a metal cation), in which Ri is each independently of another H or a straight-chain or branched alkyl group having 1 to 12 C atoms and

R₂ is each independently of one another a straight-chain or branched perfluorinated alkyl group having 1 to 12 C atoms and where electroneutrality should be taken into consideration in the formula of the salt KtA.

The invention therefore also relates to a process for the preparation of a compound of formula I in which [Kt]^z+ is another cation than the used alkali metal cation in the starting material in a salt-exchange reaction as described above, characterized in that an alkali metal salt of formula I-2 [Me]⁺ [B(CN)₂(OR^*)₂)r I-2

in which Me is an alkali metal cation or H⁺ and R^* has a meaning as described above is reacted with a compound of formula V

KtA V,

in which

A denotes F^", CI ^" Br^", I ^" [HF₂] ^~ [CN] ^", [SCN] ^", [^0(0)0]^"

^00(0)0]^" [R1SO3]- [R₂COO]-, [R2SO3] - [R1OSO3]- [SiFe] ²- [BF₄]^~ [SO,] ^2", [HSO4] ¹-, [NO3] - [(Ri)₂P(0)0]-, [^(^0)Ρ(Ο)0]^", [(R₂)₂P(O)0]-, [R₂P(0)0₂]^2", tosylate, benzoate, oxalate, succinate, suberate, ascorbate, sorbate, tartrate, citrate, malate or malonate, the malonate optionally substituted with straight-chain or branched alkyl groups having 1 to 4 C atoms,

in which Ri is each independently of another H or a straight-chain or branched alkyl group having 1 to 12 C atoms and

R₂ is each independently of one another a straight-chain or branched fluorinated or perfluorinated alkyl group having 1 to 12 C atoms or pentafluorophenyl and where electroneutrality should be taken into consideration in the formula of the salt KtA. R₂ is particularly preferred trifluoromethyl, pentafluoroethyl or nonafluorobutyl, very particularly preferred trifluoromethyl or pentafluoroethyl. is particularly preferred methyl, ethyl, n-butyl, n-hexyl or n-octyl, very particularly preferred methyl or ethyl.

Substituted malonates are for example methyl malonate or ethyl malonate.

The compounds of formula V are in most cases commercially available or can be synthesised by known processes. Known processes for the preparation of of compounds of formula V are described, for example, in P. Wasserscheid, T. Welton (Eds.), Ionic Liquids in Synthesis, Second Edition, WILEY-VCH, Weinheim, 2008.

The anion in the formula V is preferably OH^" (OH^" merely for the synthesis of compounds of formula 1-1), CI^", Br^", Γ, [HF₂]^~, [CN] ^", [SCN]^~,

[CH₃COO]-, [CH3SO3] -, [CF3COO] -, [CF₃SO₃]-, [CH3OSO3] - [SiF₆] ²- [BF₄] ^", [HSO4] ¹- [NO3] - [C₂H₅OS0₃r. [(C₂F₅)2P(O)O]- [C₂F₅P(O)O₂]²- tosylates, malonates or [SO₄] ^2~ and [CO₃] ^2" ([SO₄] ^2" and [CO₃] ^2~ merely for the synthesis of compounds of formula 1-1), particularly preferably OH^" (OH^" merely for the synthesis of compounds of formula 1-1), Cl^~, Br^~, Γ, [CH₃SO₃]-, [CH₃OSO₃r, [CF3COO]- [CF₃SO₃]-, [(C₂F₅)₂P(O)O]- or [CO₃]²- very particularly preferably OH^" (OH^" merely for the synthesis of compounds of formula 1-1), CI^", Br^", [CH₃OSO₃]^", [CF₃SO₃]^", [CH₃SO₃]^" or

Suitable organic salts for the preparation of the compounds of the formula I or formula in which [Kt]²⁺ is an organic cation are salts with cations of formula (1) to (8) or their preferred embodiments together with anions as defined as A described above or its preferred embodiments which means preferably salts of cations of formulae (1) to (8) or their preferred embodiments and OH^" (OH^" merely for the synthesis of compounds of formula 1-1), CI ^" Br^", [CH₃OS0₃r. [CF₃SO₃]^", [CH₃SO₃]^~ or [(C₂F₅)₂P(0)or

Suitable inorganic salts for the preparation of the compounds of the formula 1-1 in which [Kt]^z+ is a metal cation e.g. from the group silver, magnesium, copper, zinc and calcium are, for example,

Ag₂O, Ag₂CO₃, MgCO₃, CuO, ZnO, Zn[HCO₃]₂, CaCO₃ or Ca(CO₂CH₃)₂. Useful salts for metathesis reaction to another alkali metal salt of formula I than potassium are e.g. LiBF₄, or for the reaction with compounds of the formula 1-1 in which [Kt]^z+ = H⁺ - Na₂CO₃, NaOH, Li₂CO₃, LiOH,

CH₃C(O)OLi, Rb₂CO₃, RbOH, Cs₂CO₃ or CsOH.

The reaction is advantageously carried out in water in the case of the compounds of formula 1-1 or in dry organic solvent in the case of the compounds of formula I-2, where temperatures of 10°-100°C, preferably 15°-60°C, particularly preferably room temperature, are suitable.

However, the reaction can alternatively also be carried out for the compounds of formula 1-1 in organic solvents at temperatures between 10° and 100°C. Suitable solvents here are acetonitrile, dioxane,

dichloromethane, dimethoxyethane or an alcohol, for example methanol or ethanol.

In a special embodiment of this salt-exchange reaction it is possible to use the compounds of formulae 1-1 or I-2 directly after their synthesis as crude materials without purified isolation. It is preferred to separate volatile side products such as the reaction products trialkylsilylfluoride and

alkoxytrialkylsilanes or the excess of trialkylsilylcyanide and to use the crude material for the salt-exchange reaction. The present invention furthermore relates to the use of the compounds of formula I* with organic cations as described in detail above as solvent or solvent additive, as acidic catalyst (in the case [Kt]^z+is H⁺) as phase-transfer catalyst, as extractant, as heat-transfer medium, as surface-active substance, as plasticiser, as conductive salt, organic salt or additive in electrochemical cells. In addition, compounds of formula I can be used as acidic catalysts if ]Kt]^z+ is H⁺.

In the case of the use of the said organic salts of formula I* as solvents, these are suitable in any type of reaction known to the person skilled in the art, for example for transition-metal- or enzyme-catalysed reactions, such as, for example, hydroformylation reactions, oligomerisation reactions, esterifications or isomerisations, where the said list is not exhaustive.

On use as extractant, the organic salts of formula I^* can be employed to separate off reaction products, but also to separate off impurities, depending on the solubility of the respective component in the ionic liquid. In addition, the ionic liquids may also serve as separation media in the separation of a plurality of components, for example in the distillative separation of a plurality of components of a mixture.

Further possible applications for compounds of formula I^* are the use as plasticiser in polymer materials and as conductive salt or additive in various electrochemical cells and applications, for example in galvanic cells, in capacitors or in fuel cells.

Further fields of applications of the organic salts of formula , according to this invention are solvents for carbohydrate containing solids in particular biopolymers and derivatives or degredation products thereof. In addition, these new compounds can be applied as lubricants, working fluids for maschines, such as compressors, pumps or hydraulic devices. A further field of application is the field of particle or nanomaterial synthesis where these ionic liquids can act as medium or additive.

The compounds of formula I^* with organic cations, e.g. ionic liquids according to this invention may be preferably used in electrochemical and/or optoelectronic devices, especially in electrolyte formulations.

Electrolyte formulations comprising compounds of formula I or at least one compound of formula I^* in which [Kt]²⁺ is Li⁺ or an organic cation can be preferably used in primary batteries, secondary batteries, capacitors, supercapacitors or electrochemical cells, optionally also in combination with further conductive salts and/or additives, as constituent of a polymer electrolyte or phase-transfer medium. Preferred batteries are lithium batteries or lithiumion batteries. A preferred capacitor is a lithiumion capacitor.

Electrolyte formulations comprising at least one compound of formula I as described or preferably described above can be preferably used in electrochemical and/or optoelectronic devices such as a photovoltaic cell, a light emitting device, an electrochromic or photo-electrochromic device, an electrochemical sensor and/or biosensor, particularly preferred in a dye sensitised solar cell.

Electrolyte formulations according to the invention are alternatives to already known electrolyte formulations. They show especially in the field of electrolyte formulations of dye sensitised solar cells an increased power conversion efficiency particularly under low temperature. The advantage of the use of compounds of formula I as described above is their low viscosity, and subsequently the smaller Nernst diffusion resistance of the oxidant spiecies especially, at lower temperature. Typical molar concentrations of the compound containing the inventive borate anion of formula la as described above in the electrolyte

formulations range from 0.1 to 5.5 M, preferably from 0.8 to 3.5 M. This molar concentration in the electrolyte may be achieved with one or more compounds of formula I or one or more compounds of formula in which [Kt]^z+ is an inorganic or an organic cation.

Preferably, the molar concentration is achieved with at least one compound of formula I or of formula I^* in which [Kt]^z+ is an organic cation as described or preferably described above.

For the purpose of the present invention, the molar concentration refer to the concentration at 25°C.

The present invention relates furthermore to an electrolyte formulation comprising at least one compound of formula I or of formula I^* as described above or preferably described together with redox active species such as iodide/tri-iodide, Ferrocene derivatives or Co(ll)/Co(lll) complex couples such as Co(ll)/Co(lll)(dbbip)₂ in which dbbip means 2,6-bis(1'- butylbenzimidazol-2'-yl)pyridine, Co(ll)/Co(lll)(bpy)3 where bpy denotes bipyridine or alkylated bipyridine derivates thereof, the counter anion being either perchlorate, fluoroperfluoroalkylphosphate such as

perfluoroethylpentafluorophosphate, or (fluoro)cyanoborate, particularly tetracyanoborate, preferably a redox couple of iodine and at least one iodide salt.

The electrolyte formulation of the invention preferably comprises iodine (l₂). Preferably, it comprises from 0.0005 to 7 mol/dm³, more preferably 0.01 to 5 mol/dm³ and most preferably from 0.05 to 1 mol/dm³ of l₂.

The iodide salt consists of an inorganic or organic cation and as anion. There exists no limitation to the kind of cation. However, to limit the amount of different cations in the electrolyte formulations, especially for DSC, organic cations preferably be used as already described for the compounds of formula I or formula . Particularly preferably, the electrolyte formulation comprises at least one iodide salt in which the organic cation is

independently selected from the group of

imidazolium pyrrolidinium

in which the substituents

R² and R³ each, independently of one another, denote H or straight-chain or branched alkyl having 1 to 20 C atoms,

R¹ and R⁴ each, independently of one another, denote

straight-chain or branched alkyl having 1-20 C atoms, which optionally may be partially fluorinated or perfluorinated,

straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds, which optionally may be partially fluorinated,

straight-chain or branched alkynyl having 2-20 C atoms and one or more triple bonds, which optionally may be partially fluorinated.

Particularly preferred examples of the at least one iodide salt are 1-ethyl-3- methylimidazolium iodide (emim I), 1-propyl-3-methylimidazolium iodide (pmim I), 1-butyl-3-methyl-imidazolium iodide (bmim I), 1-hexyl-3- methylimidazolium iodide (hmim I), 1 ,3-dimethyl-imidazolium iodide (mmim I), 1-allyl-3-methylimidazolium iodide (amim I), N-butyl-N-methyl- pyrrolidinium iodide (bmpl I) or Ν,Ν-dimethyl-pyrrolidinium iodide (mmpl I).

Other components of the electrolyte formulation are one or several further salts, solvents, and others, as indicated further below.

If the electrolyte formulation is a binary system, it comprises two salts, one further salt or iodide salt and a compound of formula I or formula I^* as described above. If the electrolyte formulation is a ternary system, it comprises two further salts and/or iodide salts and a compound of formula I or formula as described above. The binary system comprises 90-10 weight %, preferably 70-30 weight %, more preferably 55-40 weight % of the further salt or iodide salt and 10-90 weight %, preferably 30-70 weight % or more preferably 45-60 weight % of the compound of formula I as described above. The percentages in this paragraph are expressed with respect to the total of salts (= 100 weight %) present in the electrolyte formulation according to the invention. Amounts of further, generally optional components (additives) indicated below, such as N-containing compounds having unshared electron pairs, iodine, solvents, polymers, and nanoparticles, for example, are not considered therein. The same

percentages apply to ternary or quaternary systems which means the total of the further salts has to be used in the given ranges, e.g. two further ionic liquids are comprised in e.g. 90-10 weight.% in the electrolyte formulation according to the invention.

According to another embodiment of the present invention, the electrolyte formulation comprises at least one further salt with organic cations comprising a quaternary nitrogen and an anion selected from a halide ion, such as F^", CI^", a polyhalide ion, a fluoroalkanesulfonate, a

fluoroalkanecarboxylate, a tris(fluoroalkylsulfonyl)methide, a

bis(fluoroalkylsulfonyl)imide, bis(fluorsulfonyl)imide, a nitrate, a

hexafluorophosphate, a tris- , bis- and mono-(fluoroalkyl)fIuorophosphate, a tetrafluoroborate, a dicyanamide, a tricyanomethide, a tetracyanoborate, a thiocyanate, an alkylsulfonate or an alkylsulfate, with fluoroalkane-chain having 1 to 20 C atoms, preferably perfluorinated, fluoroalkyi having 1 to 20 C atoms and alkyl having 1 to 20 C atoms. Fluoroalkane-chain or fluoroalkyi is preferably perfluorinated.

Preferably, the further salts are selected from salts comprising anions such as thiocyanate or tetracyanoborate, particularly preferred further salts are tetracyanoborates. The cation of the at least one further salt or of a preferred further salt may be selected amongst organic cations as defined above for the compounds of formula I or formula I^* including also the preferred meanings.

In another embodiment of the invention, guanidinium thiocyanate may be added to the electrolyte formulation according to the invention.

In a preferred embodiment, the electrolyte formulation of the present invention further comprises at least one compound containing a nitrogen atom having non-shared electron pairs. Examples of such compounds are found in EP 0 986 079 A2, starting on page 2, lines 40-55, and again from page 3, lines 14 extending to page 7, line 54, which are expressly incorporated herein by reference. Preferred examples of compounds having non-shared electron pairs include imidazole and its derivatives, particularly benzimidazole and its derivatives.

The electrolyte formulation of the present invention comprises less than 50 % of an organic solvent. Preferably, the electrolyte formulation comprises less than 40%, more preferably less than 30%, still more preferably less than 20% and even less than 10 %. Most preferably, the electrolyte formulation comprises less than 5% of an organic solvent. For example, it is substantially free of an organic solvent. Percentages are indicated on the basis of weight %.

Organic solvents, if present in such amounts as indicated above, may be selected from those disclosed in the literature. Preferably, the solvent, if present, has a boiling point higher than 160 degrees centigrade, more preferably higher than 190 degrees such as propylene carbonate, ethylene carbonate, butylene carbonate, gamma-butyrolactone, gamma- valerolactone, glutaronitrile, adiponitrile, N-methyloxazolidinone, N- methylpyrrolidinone, Ν,Ν'-dimethylimidazolidinone, N,N-dimethylacetamide, cyclic ureas preferably 1 ,3-dimethyl-2-imidazolidinone or 1 ,3-dimethyl- 3,4,5,6-tetrahydro-2(1H)-pyrimidinone, glymes preferably tetraglyme, sulfolane, sulfones which are preferably asymmetrically substituted such as 2-ethanesulfonyl-propane, 1-ethanesulfonyl-2-methyl-propane or 2- (propane-2-sulfonyl)-butane, 3-methylsulfolane, dimethylsulfoxide, trimethylphosphate and methoxy-substituted nitriles. Other useful solvents are acetonitrile, benzonitrile and or valeronitrile.

If a solvent is present in the electrolyte formulation, there may further be comprised a polymer as gelling agent, wherein the polymer is

polyvinylidenefluoride, polyvinylidene-hexafluropropylene, polyvinylidene- hexafluoropropylene-chlorotrifluoroethylene copolymers, nafion,

polyethylene oxide, polymethylmethacrylate, polyacrylonitrile,

polypropylene, polystyrene, polybutadiene, polyethyleneglycol,

polyvinylpyrrolidone, polyaniline, polypyrrole, polythiophene. The purpose of adding these polymers to electrolyte formulations is to make liquid electrolytes into quasi-solid or solid electrolytes, thus improving solvent retention, especially during aging.

The electrolyte formulation of the invention may further comprise metal oxide nanoparticles like SiO_2> TiO₂₎ AI₂O₃, MgO or ZnO, for example, which are also capable of increasing solidity and thus solvent retention.

The electrolyte formulation of the invention has many applications. For example, it may be used in an optoelectronic and/or electrochemical device such as a photovoltaic cell, a light emitting device, an electrochromic or photo-electrochromic device, an electrochemical sensor and/or biosensor. Also the use in electrochemical batteries is possible, for example in a lithium ion battery or a double layer capacitor.

The present invention therefore relates further to the use of the electrolyte formulation as described in detail above in an electrochemical and/or optoelectronic device which is a photovoltaic cell, a light emitting device, an electrochromic or photo-electrochromic device, an electrochemical sensor and/or biosensor. Preferably, the electrolyte formulation may be used in dye sensitized solar cells.

The present invention therefore relates furthermore to an electrochemical and/or optoelectronic device, for example a photovoltaic cell, a light emitting device, an electrochromic or photo-electrochromic device, an

electrochemical sensor, biosensor, primary battery, secondary battery, capacitor or supercapacitor comprising an electrolyte formulation

comprising at least one compound of formula I

[Kt]^z+ z[B(CN)_4-x(OR*)x]- I

in which [Kt]^z+ denotes an inorganic or organic cation,

z is 1, 2, 3 or 4,

x is 1 or 2 and R^* in each case, independently of one another, straight- chain or branched alkyl groups having 1 to 12 C atoms which can be partially subsituted by Hal and

Hal denotes F, CI, Br or I or a preferred embodiment of such a compound of formula I as described above.

According to a preferred embodiment, the device of the resent invention is a dye or quantum dot sensitized solar cell, particularly preferably a dye sensitized solar cell.

Quantum dot sensitized solar cells are disclosed in US 6,861 ,722, for example. In dye -sensitized solar cells, a dye is used to absorb the sunlight to convert into the electrical energy. Examples of dyes are disclosed in EP 0 986 079 A2, EP 1 180 774 A2 or EP 1 507 307 A1.

Preferred dyes are organic dyes such as MK-1 , MK-2 or MK-3 (its structures are described in figure 1 of N. Koumura et al, J.Am.Chem.Soc. Vol 128, no.44, 2006, 14256-14257), D102 (CAS no. 652145-28-3), D-149 (CAS no. 786643-20-7), D205 (CAS no. 936336-21-9), YD-2 as described in T. Bessho et al, Angew. Chem. Int. Ed. Vol 49, 37, 6646-6649, 2010, Y123 (CAS no. 1312465-92-1), bipyridin-Ruthenium dyes such as N3 (CAS no. 141460-19-7), N719 (CAS no. 207347-46-4), Z907 (CAS no. 502693- 09-6), C101 (CAS no. 1048964-93-7), C106 (CAS no. 1152310-69-4), K19 (CAS no. 847665-45-6) or terpyridine-Ruthenium dyes such as N749 (CAS no. 359415-47-7).

Particularly preferred dyes are Z907 or Z907Na which are both an amphiphilic ruthenium sensitizer or D205.

The structure of D205 is

Very particularly preferred dyes are Z907 or Z907Na.

In a preferred embodiment, the dye is coadsorbed with a phosphinic acid. A preferred example of a phosphinic acid is bis(3,3-dimethyl-butyl)-phosphinic acid (DINHOP) as disclosed in M. Wang et al, Dalton Trans., 2009, 10015- 10020.

The dye Z907Na means NaRu(2,2'-bipyridine-4-carboxylic acid-4'- carboxylate)(4,4'-dinonyl-2,2'-bipyridine)(NCS)₂. For example, a dye-sensitized solar cell comprises a photoelectrode, a counter electrode and, between the photoelectrode and the

counterelectrode, an electrolyte formulation or a charge transporting material, and wherein a sensitizing dye is absorbed on the surface of the photoelectrode, on the side facing the counter electrode.

According to a preferred embodiment of the device according to the invention, it comprises a semiconductor, the electrolyte formulation as described above and a counter electrode.

According to a preferred embodiment of the invention, the semiconductor is based on material selected from the group of Si, Ti0₂, Sn0₂, Fe₂O₃, W0₃, ZnO, Nb₂0₅, CdS, ZnS, PbS, Bi₂S₃, CdSe, GaP, InP, GaAs, CdTe, CulnS₂, and/or CulnSe₂. Preferably, the semiconductor comprises a mesoporous surface, thus increasing the surface optionally covered by a dye and being in contact with the electrolyte. Preferably, the semiconductor is present on a glass support or plastic or metal foil. Preferably, the support is conductive.

The device of the present invention preferably comprises a counter electrode. For example, fluorine doped tin oxide or tin doped indium oxide on glass (FTO- or ITO-glass, respectively) coated with Pt, carbon of preferably conductive allotropes, polyaniline or poly (3,4- ehtylenedioxythiophene) (PEDOT). Metal substrates such as stainless steel or titanium sheet may be possible substrates beside glass.

The device of the present invention may be manufactured as the

corresponding device of the prior art by simply replacing the electrolyte by the electrolyte formulation of the present invention. For example, in the case of dye-sensitized solar cells, device assembly is disclosed in numerous patent literature, for example WO 91/16719 (examples 34 and 35), but also scientific literature, for example in Barbe, C.J., Arendse, F., Comte, P., Jirousek, M., Lenzmann, F., Shklover, V., Gratzel, M. J. Am. Ceram. Soc. 1997, 80, 3157; and Wang, P., Zakeeruddin, S. M., Comte, P., Charvet, R., Humphry-Baker, R., Gratzel, M. J. Phys. Chem. B 2003, 107, 14336.

Preferably, the sensitized semiconducting material serves as a photoanode. Preferably, the counter electrode is a cathode.

The present invention provides a method for preparing a photoelectric cell comprising the step of bringing the electrolyte formulation of the invention in contact with a surface of a semiconductor, said surface optionally being coated with a sensitizer. Preferably, the semiconductor is selected from the materials given above, and the sensitizer is preferably selected from quantum dots and/or a dye as disclosed above, particularly preferably selected from a dye.

Preferably, the electrolyte formulation may simply be pured on the semiconductor. Preferably, it is applied to the otherwise completed device already comprising a counter electrode by creating a vacuum in the internal lumen of the cell through a hole in the counter electrode and adding the electrolyte formulation as disclosed in the reference of Wang et al., J. Phys. Chem. B 2003, 107, 14336.

Even without further comments, it is assumed that a person skilled in the art will be able to utilise the above description in the broadest scope. The preferred embodiments and examples should therefore merely be regarded as descriptive disclosure which is absolutely not limiting in any way.

The synthesized compounds are characterized through Raman spectroscopy, NMR spectroscopy or elemental analysis. The NMR spectrum is measured in acetone-D6 (Bruker Avance III with deuterium as lock). Used frequencies:: ¹H: 400,17 MHz, ¹⁹F: 376,54 MHz, ¹¹B: 128,39 MHz , ³¹ P: 161 ,99 MHz and ³C: 100,61 MHz, external references: TMS for ¹H and ¹³C ; CCI₃F - for ⁹F and BF₃ Et₂0 - for ¹¹B.

Example 1 : Preparation of Li[B(CN)₃OCH₃]:

A:

Li[BF₄] + 3 (CH₃)₃SiCN + (CH₃)₃SiOCH₃ Li[B(CN)₃(OCH₃)] + 4 (CH₃)₃SiF

Li[BF₄] (15.0 g, 160.1 mmol) is dissolved in (CH₃)₃SiCN (120.0 ml, 899.9 mmol) and (CH₃)₃SiOCH₃ (150 ml, 1092.3 mmol), and the reaction mixture is stirred at room temperature for two days. The resultant suspension is filtered, and the colourless solid is washed with CH₂CI₂ (20 ml) and subsequently dissolved in acetone (50 ml). CH₂CI₂ (350 ml) is added to the solution, and the precipitated Li[B(CN)₃OCH₃] is filtered off. Yield: 20.1 g (158.5 mmol, 99%). The product is characterized by means of NMR and Raman spectroscopy: 1B NMR (solvent: acetone-D₆), δ, ppm: -18.42 q, ³J_B-H = 3.7 Hz.

¹ B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.42 s.

¹H NMR (solvent: acetone-D₆), δ, ppm: 3.20 q (OCH₃), ³J_B-H = 4.1 Hz.

H{ ¹B} NMR (solvent: acetone-D₆), δ, ppm: 3.20 s (OCH₃).

¹³C NMR (solvent: acetone-D₆), δ, ppm: 128.56 q (3CN), ¹J_C-B = 70.3 Hz,

53.05 q,q (CH₃), ¹ J_C-H = 140.0 Hz, ²J_C-B < 1 Hz.

3C{¹H} NMR (solvent: acetone-D₆), <5, ppm: 128.50 q (3CN), ¹J_C-B = 70.3 Hz, 53.05 q (CH₃), ²J_C-B < 1 Hz.

Raman spectroscopy: v (CN) = 2245, 2240, 2233 cm^-1

Elemental analysis, found, %: C 37.96, H 2.18, N 33.50; calculated for

C₄H₃BLiN₃0: C 37.88, H 2.38, .N 33.13.

B

(CH₃)₃SiCN (75.0 ml, 562.4 mmol) is added to a solution of Li[BF₄] (15.0 g, 160.1 mmol) in acetonitrile (40 ml) with vigorous evolution of gas. After the evolution of gas has subsided, (CH₃)₃SiOCH₃ (25.0 ml, 182.1 mmol) is added. The reaction mixture is stirred at 40°C for 2 days, and all volatile constituents are subsequently thoroughly removed in vacuo. The residue is dissolved in acetone (25 ml), and Li[B(CN)₃OCH₃] is precipitated by slow addition of CHCI₃ (150 ml) and isolated by filtration. Yield: 20.2 g (159.3 mmol, 99%). The product is characterized by means of NMR and Raman spectroscopy. The spectra are identical to the spectra described in Example 1A.

C:

Li[B(OCH₃)₄] + 3 (CH₃)₃SiCN *^■ Li[B(CN)₃(OCH₃)] + 3 (CH₃)₃SiOCH₃

Li[B(OCH₃)₄] (20 mg, 0.141 mmol) is taken up in (CH₃)₃SiCN (0.3 ml, 2.2 mmol) in an NMR tube with glass valve and Teflon spindle. The suspension is heated at 80°C for two days. The formation of the [B(CN)₃OCH₃]^" anion (90%, based on the [B(OCH₃) ]^" anion employed) is detected by ¹¹B NMR spectroscopy. All volatile constituents are removed in vacuo, and CD₃CN is condensed onto the residue. This procedure is repeated twice, and the solid residue is dried at 100°C in vacuo, so that the (CH₃)₃SiCN and (CH₃)₃SiOCH₃ are removed completely, which is demonstrated by ¹H NMR spectra of a CD₃CN solution of the residue.

D:

Na[B(CN)₃OCH₃] + LiCI >- Li[B(CN)₃(OCH₃)] + NaCI |

Aceton ¹

A solution of Na[B(CN)₃OCH₃] (1.0 g, 6.997 mmol) is added to a solution of LiCI (296 mg, 6.981 mmol) in acetone (150 ml) with vigorous stirring. The precipitate formed (NaCI) is filtered off and dried. Amount: 407 mg (6.964 mmol, 99.5%).

The filtrate is evaporated to a volume of 5 ml in a rotary evaporator at 40°C, and chloroform (100 ml) is added. The precipitate formed (Li[B(CN)₃OCH₃]) is filtered off and dried in vacuo. Yield: 883 mg (6.964 mmol, 99.5%). The product is characterized by means of NMR and Raman spectroscopy. The spectra are identical to the spectra described in Example 1A.

Example 2: Preparation of Na[B(CN)₃OCH₃]

A:

B(OCH₃)₃ + CH₃ONa + 3 (CH₃)₃SiCN _CH^_N» Na[B(CN)₃OCH₃] + 3 (CH₃)₃SiOCH₃

CH₃ONa (1.0 g, 18.5 mmol) is suspended in acetonitrile (5 ml). B(OCH₃)₃ (1.9 g, 2.1 ml, 18.5 mmol) and (CH₃)₃SiCN (9.0 ml, 67.5 mmol) are added, and the reaction mixture is stirred at 50°C for 4 days. All volatile constituents are subsequently removed in vacuo. The residue is taken up in H₂O₂ (30%, 10 ml), and Na₂C0₃ is added in portions. Peroxides are reduced using Na₂S₂05 until a test for peroxides (Merckoquant) is negative. The product is extracted from the aqueous phase with tetrahydrofuran (3 * 50 ml). The combined THF phases are dried using Na₂C0₃₎ filtered and evaporated to dryness in vacuo. The beige residue obtained is washed onto a frit (D4) using CH₂CI₂ (50 ml) and dried in vacuo. Yield: 1.8 g (12.6 mmol, 68%). The product is characterized by means of NMR, Raman spectroscopy and mass spectrometry (MS):

¹¹ B NMR (solvent: acetone-D₆), δ, ppm: -18.42 q, (³J_B-H = 3.8 Hz).

¹¹B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.42 s.

¹H NMR (solvent: acetone-D₆), δ, ppm: 3.21 q (OCH₃), ³J_B-H = 3.8 Hz.

¹H{¹¹B} NMR (solvent: acetone-D₆), δ, ppm: 3.21 s (OCH₃).

¹³C NMR (solvent: acetone-D₆), <5, ppm: 128.50 q (3CN), ¹J_C-B = 70.2 Hz,

52.97 q,q (OCH₃), ¹J_C-H = 139.6 Hz, ²J_C-B < 1 Hz.

3C{ H} NMR (solvent: acetone-D₆), <5, ppm: 128.50 q (3CN), ¹J_C-B = 70.2

Hz, 52.97 q (OCH₃), ²J_C-B < 1 Hz.

Raman spectroscopy: v (CN) = 2231 , 2217 cm^-1.

ESI-MS [B(CN)₃OCH₃V:

calculated: 120.0(100.0%), 119.0(24.5%), 121.0(5.7%). found: 120.4(100.0%), 119.4(21.5%), 121.4(5.0%). MALDI-MS [B(CN)₃OCH₃]^":

calculated: 120.0(100.0%), 119.0(24.5%), 121.0(5.7%).

found: 119.6(100.0%), 118.6(20.2%).

B:

Na[B(OCH₃)₄] + 3 (CH₃)₃SiCN *- Na[B(CN)₃OCH₃] + 3 (CH₃)₃SiOCH₃

Na[B(OCH₃)₄] (3.0 g, 18.9 mmol) is taken up in (CH₃)₃SiCN (100.0 ml, 749.9 mmol), and the mixture is stirred at 60°C for 2 days. Excess (CH₃)₃SiCN and (CH₃)₃SiOCH₃ formed are distilled off. The residue is dissolved in H₂0₂ (30%, 20 ml), and Na₂CO₃ is subsequently added. Na₂S₂0₅ is added to the mixture until the test for peroxides (Merckoquant) is negative. The solution is extracted with tetrahydrofuran (3 * 20 ml). The combined THF phases are dried using Na₂C0₃, filtered and evaporated to dryness in vacuo. The residue is dissolved in acetone (5 ml), and colourless Na[B(CN)₃OCH₃] is precipitated by addition of CH₂CI₂ (100 ml). This precipitate is filtered off and dried in vacuo. Yield: 2.5 g (17.5 mmol, 92%). A portion of the substance is recrystallized from acetone (contained water) and sent for elemental analysis.

Elemental analysis for Na[B(CN)₃OCH₃] · H₂0, found, %: C 29.94, H 2.79, N 26.22; calculated for C₄H₅BN₃NaO_2l %: C 29.86, H 3.13, N 26.12.

A structural analysis of a mono-crystal of the above described salt confirms that one molecule water is present per unit of the sodium salt.

C:

1) . + 4 CH3OH; - 4 H₂

2) . + 3 (CH₃)₃SiCN; - 3 (CH₃)₃SiOCH₃

Na[BH₄] *- Na[B(CN)₃(OCH₃)]

Na[BH₄] (10.0 g, 264.5 mmol) is dissolved in methanol (600 ml). When the exothermic reaction is complete, the reaction solution is evaporated to dry- ness at 70°C in a rotary evaporator. The residue is dried in vacuo, and (CH₃)₃SiCN (250 ml, 1874.7 mmol) is added. The reaction mixture is stirred at 60°C for 5 days. All volatile constituents are subsequently distilled off. The residue obtained is taken up in H₂O₂ (30%, 25 ml), and Na₂C0₃ is added in portions. Na₂S₂0₅ is added until the test for peroxides (Merckoquant) is negative. The product is extracted from the aqueous phase with tetrahydrofuran (5 * 100 ml). The combined THF phases are dried using Na₂C03, filtered and evaporated to dryness in vacuo. The beige residue obtained is washed with CH₂CI₂ (3 * 50 ml) until colourless and is dried in vacuo. Yield: 34.3 g (240.0 mmol, 91%). The product is characterized by means of NMR and Raman spectroscopy. The spectra are identical to the spectra described in Example 2A.

D:

Na[BF₄] + 3 (CH₃)₃SiCN + (CH₃)₃SiOCH₃ »^► Na[B(CN)₃(OCH₃)] + 4 (CH₃)₃S^'iF

Na[BF₄] (25.0 g, 227.6 mmol) is suspended in a mixture of (CH₃)₃SiCN and (CH₃)₃SiOCH₃ (200 ml, v/v -1/1 , 749.9 and 728.2 mmol respectively), and the mixture is stirred under reflux for 2 days. All volatile constituents are removed in vacuo, and the residue is washed with CH₂CI₂ (70 ml). The solid is subsequently taken up in acetonitrile (100 ml), and, after stirring for 5 minutes, undissolved Na[BF₄] is filtered off. The filtrate is evaporated to dryness in a rotary evaporator, and the residue is rinsed onto a frit (D4) using CH₂CI₂ and subsequently dried. Yield: 24.1 g (168.6 mmol, 74%).

The product comprises Na[BF ] (4%) and Na[BF₂(CN)₂] (9%).

Example 3: Preparation of Na[B(CN)₃OC₂H₅]

N(B)₃

Na[BF₄] + 4 (CH₃)₃SiCI + 3 NaCN + C₂H₅OH _n » Na[B(CN)₃(OC₂H₅)] + 3 NaCI + 4 (CH₃)₃SiF + HCI

NaCN (3.0 g, 61.2 mmol) is suspended in acetonitrile (10 ml), and

(CH₃)₃SiCI (7.0 ml, 55.3 mmol), C₂H₅OH (0.72 ml, 19.8 mmol) and a few drops of triethylamine, Et₃N, are added. Na[BF₄] (0.78 g, 7.1 mmol) is subsequently added, and the reaction mixture is stirred at room temperature for 2 days. The suspension is rendered alkaline using aqueous NaOH solution and evaporated to dryness in vacuo. The residue is extracted with tetrahydrofuran (5 x 5 ml), dried using MgS0₄ and filtered. The THF phase is evaporated to about 5 ml, and colourless Na[B(CN)₃OC₂H₅] is precipitated by addition of CH₂CI₂ (25 ml). The product is filtered off and dried in vacuo. Yield: 0.85 g (5.4 mmol, 76%). The product is characterized by means of NMR, Raman spectroscopy and mass spectrometry (MS):

¹¹ B NMR (solvent: acetone-D₆), o^~, ppm: -18.99 1, ³J_B-H = 1.7 Hz.

1¹B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.99 s.

1H NMR (solvent: acetone-D₆), <5, ppm: 3.42 q,q (2H, OCH₂), ³J_H-H = 7.0 Hz, ³J_B-H = -8 Hz, 1.09 t (3H, CH₃), ³J_H-H = 7.0 Hz.

¹H{ B} NMR (solvent: acetone-D₆), δ, ppm: 3.42 q (2H, OCH₂), ³J_H-H = 7.0 Hz, 1.09 t (3H, CH₃), ³J_H-H = 7.0 Hz.

¹³C NMR (solvent: acetone-D₆), δ, ppm: 128.82 q (3 CN), ¹J_C-B = 69.9 Hz; 61.12 t,q (OCH₂), J_C-H = 138.6 Hz, ³J_C-H = 4.6 Hz; 17.57 q,m (CH₃), ¹J_C-H = 126 Hz.

¹³C{¹H} NMR (solvent: acetone-D₆), <5, ppm: 128.82 q (3 CN), ¹J_C-B = 69.9 Hz; 61.12 s (OCH₂); 17.57 q (CH₃), ³J_C-B = 3.2 Hz.

Raman spectroscopy: v (CN) = 2238, 2227, 2219 cm^"1.

calculated: 134.1 (100.0%), 133.1(24.4%), 135.1(5.7%), 135.0(1.1%).

found: 134.1(100.0%), 133.3(29.0%).

MALDI-MS [B(CN)₃OC₂H₅]^":

calculated: 134.1(100.0%), 133.1(24.4%), 135.1(5.7%), 135.0(1.1 %).

found: 133.6(100.0%), 132.6(14.1%), 134.6(6.6%).

B:

Na[B(OC₂H₅)₄] + 3 (CH₃)₃SiCN Na[B(CN)₃(OC₂H₅)] + 3 (CH₃)₃SiOC₂H₅ Na[B(OC₂H₅) ] (2.0 g, 9.3 mmol) is taken up in (CH₃)₃SiCN (20.0 ml, 149.9 mmol), and the mixture is stirred at 60°C for 2 days. Excess (CH₃)₃SiCN and (CH₃)₃SiOC₂H₅ formed are distilled off. The slimy residue is taken up in H₂O₂, and Na₂C0₃ is added. Na₂S₂O₅ is subsequently added, and the mixture is extracted with tetrahydrofuran (4 * 50 ml). The combined THF phases are dried using Na2CO₃, filtered and evaporated in a rotary evaporator. The residue is dissolved in acetone, and CH₂CI₂/CHCI₃ (1 :1) is added. The precipitate formed is filtered off and dried in vacuo.

Yield: 0.8 g (5.1 mmol, 55%).

Elemental analysis, found, %: C 38.11 , H 3.03, N 26.77; calculated for C₅H₅BN₃NaO, %: C 38.27, H 3.21 , N 26.78.

1) . + 4 C₂H₅OH; - 4 H₂

2) . + 3 (CH₃)₃SiCI, + 3 NaCN, + Nal (cat.); - 3 (Ο^είΟΟ_ζΗ^ - 3 NaCI

Na[BH₄] - Na[B(CN)₃(OC₂H₅)]

Na[BH₄] (10.0 g, 264.5 mmol) is taken up in ethanol (600 ml). The reaction mixture is heated under reflux for 12 hours. Excess ethanol is removed at 70°C in a rotary evaporator. The residue is dried in vacuo and taken up in a suspension of NaCN (80.0 g, 1632.3 mmol), Nal (10.0 g, 66.7 mmol) and (CH₃)₃SiCI (200.0 ml, 1583.2 mmol) in acetonitrile (25 ml) which has previously been stirred for two days. The resultant suspension is stirred at 25°C for 6 days and freed from all volatile constituents in vacuo. The dark-brown residue is taken up in H₂0₂ (30%, 200 ml) with vigorous foaming, Na₂CO₃ is added in portions, and the mixture is stirred for one day. The peroxide fraction is reduced using Na₂S₂O₅. The aqueous phase is extracted with tetrahydrofuran (5 ^χ 100 ml). The yellow THF phases are dried using Na₂C0₃, filtered and evaporated to dryness in vacuo. The residue is dissolved in acetone at 60°C and subsequently precipitated using CH₂CI₂ (300 ml). The pale-yellow product is filtered off and dried in vacuo. Yield: 37.3 g (238.1 mmol, 90%). The product is characterized by means of NMR and Raman spectroscopy. The spectra are identical to the spectra described in Example 3A.

Example 4: Preparation of Na[B(CN)₃(OCH₂CF₃)]

Na[B(OCH₂CF₃)₄] + 3 (CH₃)₃SiCN *- Na[B(CN)₃(OCH₂CF₃)] + 3 (CH₃)₃SiOCH₂CF₃

Na[B(OCH₂CF₃)₄] (1.0 g, 2.4 mmol) is taken up in (CH₃)₃SiCN (15.0 ml, 112.5 mmol), and the mixture is stirred at 80°C for 2 days. The volatile constituents are subsequently removed, and the black residue is dissolved in H₂0₂ (30%, 20 ml). Na₂C0₃ is added to the solution. The peroxide fraction is reduced using Na₂S₂0₅, and the solution is extracted with tetrahydrofuran (3 χ 20 ml). The THF phases are dried using Na₂CO_3t filtered and evaporated to dryness in vacuo.

Yield: 443 mg (2.1 mmol, 87%). The product is characterized by means of

NMR, Raman spectroscopy and mass spectrometry (MS):

1B NMR (solvent: acetone-D₆), o^~, ppm: -19.03 t, ³J_B-H = 2.0 Hz.

¹¹B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -19.03 s.

¹⁹F NMR (solvent: acetone-D₆), 6, ppm: -76.08 1 (CF₃) ³J_F-H = 8.8 Hz.

¹H NMR (solvent: acetone-D₆), δ, ppm: 3.80 q,q (OCH₂), ³J_F-H = 9.1 Hz,

³JB-H = 2.0 Hz.

¹H{¹¹B} NMR (solvent: acetone-D₆), <5, ppm: 3.80 q (OCH₂), ³J_F-H = 9.1 Hz. 1³C{¹H} NMR (solvent: acetone-D₆), δ, ppm: 127.47 q (3 CN), ¹J_C-B = 71.7 Hz; 125.82 q,q (CF₃), ¹J_F-C = 277.2 Hz, ³J_C-B = 5.0 Hz; 64.21 q (OCH₂), ²J_F-C = 34.5 Hz.

MALDI-MS [B(CN)₃(OCH₂CF₃)V:

calculated: 188.0(100.0%), 187.0(24.4%), 189.0(6.7%).

found: 187.7 (100.0%), 186.7 (29.1 %), 188.7(10.2%).

Raman spectroscopy: v (CN) = 2227, 2236 cm^-1.

Example 5: Preparation of Na[B(CN)₂(OCH₂CF₃)2]

Na[B(OCH₂CF₃)₄] + 2 (CH₃)₃SiCN - Na[B(CN)2(OCH₂CF₃)2] + 2 (CH₃)₃SiOCH₂CF₃ Na[B(OCH₂CF₃)₄] (2.0 g, 4.7 mmol) is taken up in (CH₃)₃SiCN (20.0 ml, 149.9 mmol), and the mixture is stirred at room temperature for 2 days. All volatile constituents are distilled off, and the colourless residue is dried in vacuo. The solid is dissolved in acetone and precipitated using CHC , filtered and dried in vacuo. Yield: 1.2 g (4.2 mmol, 89%). The product is characterized by means of NMR, Raman spectroscopy and mass spectrometry (MS):

¹ B NMR (solvent: acetone-D₆), δ, ppm: -6.67 quin, ³J_B-H = 1.5 Hz.

1 B{ H} NMR (solvent: acetone-D₆), δ, ppm: -6.67 s.

1H NMR (solvent: acetone-D₆), δ, ppm: 3.78 q,q (4H, 2 OCH₂), ³JF-H = 9.4 Hz, ³JB-H = 1.6 Hz.

¹H{¹ B} NMR (solvent: acetone-D₆), δ, ppm: 3.78 q (4H, 2 OCH₂), ³J_F-H = 9.4 Hz.

¹⁹F NMR (solvent: acetone-D₆), <5, ppm: -76.11 t (6F, 2 CF₃), ³J_F._H = 9.3 Hz. ¹³C NMR (solvent: acetone-D₆), δ, ppm: 130.23 q (2 CN), J_C-B = 73.8 Hz; 126.40 q,m (2 CF₃), J_F-C = 280.9 Hz; 62.15 t,q (2 OCH₂), ¹J_C-H = 142.5 Hz, ²J_F-C = 34.1 Hz.

¹³C{¹H} NMR (solvent: acetone-D₆), δ, ppm: 130.23 q (2 CN), ¹J_{C B} = ^{73 8} Hz; 126.40 q,q (2 CF₃), ¹J_F-C = 280.9 Hz, ²J_C-B = 4.4 Hz; 62.15 q (2 OCH₂), ²J_F.c = 34.1 Hz.

ESI-MS [B(CN)₂(OCH₂CF₃)₂]-:

calculated: 261.0(100.0%), 260.0(24.4%), 262.0(7.6%).

found: 261.3(100.0%), 260.3(25.3%), 262.3(1.0%).

MALDI-MS [B(CN)₂(OCH₂CF₃)₂]-:

calculated: 261.0(100.0%), 260.0(24.4%), 262.0(7.6%).

found: 260.7(100.0%), 259.7(22.1%), 262.3(0.5%).

Raman spectroscopy: v (CN) = 2229, 2215 cm^"1.

Example 6: Preparation of K[B(CN)₃OCH₃]

A 1) . + 4 CH3OH; - 4 H₂

2) . + 3 (CH₃)₃SiCN; - 3 (CH₃)₃SiOCH₃

K[BH₄] *- K[B(CN)₃(OCH₃)]

In the first step, K[BH₄] (10.0 g, 185.5 mmol) is taken up in methanol (500 ml, 12.3 mol) in a flask with magnetic stirrer bar (flask 1) with evolution of gas (H₂), and the mixture is heated under reflux for two hours. The reaction mixture is evaporated to dryness in a rotary evaporator, and the colourless residue is dried overnight in vacuo. In parallel, NaCN (60.0 g, 1224.5 mmol) and 1-ethyl-3-methylimidazolium chloride (10 g; serves as phase-transfer catalyst) are taken up in acetonitrile (20 ml) in a second flask with magnetic stirrer bar (flask 2), and trimethylsilyl chloride, (CH3)₃SiCI (140.0 ml, 1108.2 mmol), is added. The resultant suspension is stirred at room temperature for two days. All volatile constituents from this reaction (flask 2) are distilled at 150°C onto the colourless residue from the reaction of K[BH₄] with methanol (flask 1). The resultant suspension is stirred at room temperature for two days. All volatile constituents are then removed in vacuo, and the colourless residue is rinsed onto a frit using CH₂CI₂. Yield: 17.2 g (108.2 mmol, 58%). The product is characterized by means of NMR and Raman spectroscopy:

1¹B NMR (solvent: acetone-D₆), δ, ppm: -18.44 q, ³J_B-H = 3.8 Hz.

1B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.44 s.

H NMR (solvent: acetone-D₆), <5, ppm: 3.19 q (OCH₃), ³J_B-H = 3.8 Hz.

H{¹ B} NMR (solvent: acetone-D₆), δ, ppm: 3.19 (s, 3H) ppm.

1³C NMR (solvent: acetone-D₆), δ, ppm: 128.50 q (3 CN), J_C-B = 70.2 Hz; 52.97 q,q (OCH₃), ¹J_C-H = 140.0 Hz, ²J_C-B < 1 Hz.

¹³C{¹H} NMR (solvent: acetone-D₆), δ, ppm: 128.50 q (3 CN), J_C-B = 70.2

Hz; 52.97 q (OCH₃), ²J_C-_B < 1 Hz.

Raman spectroscopy: v (CN) = 2227, 2220 cm^"1

B: K[BF₂(CN)₂] + (CH₃)₃SiCN + (CH₃)₃SiOCH₃ *- K[B(CN)₃OCH₃] + 2 (CH₃)₃SiF

K[BF₂(CN)₂] (15 mg, 0.107 mmol) is taken up in (CH₃)₃SiCN and (CH₃)₃SiOCH₃ (0.5 ml, v/v -1/1 , 1.9 and 1.8 mmol respectively) in an NMR tube with glass valve and Teflon spindle. The reaction mixture is subsequently heated at 80°C for two days. The formation of the [B(CN)₃OCH₃]^" anion (94%, based on the [BF₂(CN)₂]^" anion employed) is detected by ¹¹B NMR spectroscopy.

Example 7: Preparation of 1-ethyl-3-methylimidazolium [B(CIM)₃OCH₃] + NaCI

Na[B(CN)₃OCH₃] (8.0 g, 55.9 mmol) is taken up in distilled water (10 ml) with 1-ethyl-3-methylimidazolium chloride, [EMIM]CI (8.2 g, 55.9 mmol), and the mixture is stirred vigorously. An emulsion of 1-ethyl-3-methyl- imidazolium [BOMe(CN)₃] in water forms. CH₂CI₂ (50 ml) is then added to the reaction mixture, and the emulsion is stirred for 15 minutes. The CH₂CI₂ phase is separated off, washed with distilled water (3 * 2-3 ml), subsequently dried using MgS0₄ and filtered. The solution is evaporated in vacuo, and the ionic liquid obtained is dried in vacuo. Yield of 1-ethyl-3- methylimidazolium [BOMe(CN)₃], which is liquid at room temperature: 9.1 g (39.4 mmol, 70%). Viscosity (20°C): 20 mPa s. The product is characterized by means of NMR and Raman spectroscopy:

1B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.48 s.

1H{¹¹B} NMR (solvent: acetone-D₆), δ, ppm: 8.95 br.s (1 H, CH); 7.72 d,d (1 H, CH), ³J_H-H = 1 -8 Hz; 7.65 d,d (1 H, CH), ³J_H-H = 1.7 Hz; 4.38 q (2H, CH₂), ³JH-H = 7.3 Hz; 4.04 s (3H, CH₃); 3.19 s (3H, OCH₃), 1.57 t (3H, CH₃), 3J_H-H = 7.3 Hz. ¹³C{¹H} NMR (solvent: acetone-D₆), <5, ppm: 136.91 s (CH), 128.60 q (3 CN), ¹JC-B = 70.0 Hz; 124.69 s (CH); 123.02 s (CH); 52.98 q (OCH₃), ²J_C-B < 1 Hz; 45.70 s (CH₂); 36.61 s (CH₃), 15.49 s (CH₃).

Raman spectroscopy: v (CN) = 2205, 2214 cm^-1.

Elemental analysis, found, %: C 51.35, H 6.35, N 30.76; calculated for C₁₀H₁₄BN₅O, %: C 51.98, H 6.11 , N 30.31

Example 8: Preparation of tetraethylammonium [B(CN)₃OCH₃]

[(C₂H₅)₄N]OH + Na[B(CN)₃OCH₃] -→ [(C₂H₅)₄N]⁺ [B(CN)₃OCH₃]- j + NaOH Tetraethylammonium hydroxide, [TEA]OH (solution in H₂0, 35% by weight, 20.2 g, 48.0 mmol), is added to Na[B(CN)₃OCH₃] (6.8 g, 47.6 mmol) in distilled water (5 ml), and the mixture is stirred. CH₂CI₂ (50 ml) is added to the resultant emulsion, and the organic phase is separated off. The CH₂CI₂ phase is subsequently washed with distilled water (3 x 5 ml), dried using MgSO₄, filtered and evaporated in a rotary evaporator. The ionic liquid obtained is subsequently dried at 60°C in vacuo. Yield of tetraethylammonium [B(CN)₃OCH₃], which is solid at room temperature: 10.0 g (39.9 mmol, 84%). Melting point: 33°C. The product is characterized by means of NMR and Raman spectroscopy:

1 B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.44 s.

1H{¹ B} NMR (solvent: acetone-D₆), δ, ppm: 3.44 q (8H, 4CH₂), ³J_H-H = 7.3 Hz; 3.20 s (3H, OCH₃); 1.38 t,t (12H, 4CH₃), ³J_H-H = 7.3 Hz.

1³C{ H} NMR (solvent: acetone-D₆), δ, ppm: 128.74 q (3 CN), ¹J_C-B = 70.1 Hz; 54.93 q (OCH₃), ²J_C-B < 1 Hz; 53.02 s (4CH₂); 7.66 s (4CH₃).

Raman spectroscopy: v (CN) = 2204, 2214 cm^-1.

Example 9: Preparation of tetrabutylammonium [B(CN)₃OCH₃]

A

[(C₄H₉)₄N]OH + Na[B(CN)₃OCH₃] [(C₄H₉)₄N]⁺ [B(CN)₃OCH₃]-J ₊ NaOH

Tetrabutylammonium hydroxide, [TBA]OH (-40% in water, -1.5 M, 25.0 ml, 37.5 mmol), is added to a solution of Na[B(CN)₃OCH₃] (5.2 g, 36.4 mmol) in distilled water (10 ml). CH₂CI₂ (50 ml) is added to the emulsion obtained, and the mixture is stirred for 10 minutes. The CH2CI₂ phase is then separated off, washed with distilled water (3 x 5 ml), dried using MgSO₄ and filtered. The solution is evaporated in vacuo, and the ionic liquid obtained is dried in vacuo. Yield of tetrabutylammonium [B(CN)₃OCH₃], which is liquid (highly viscous liquid) at room temperature: 11.6 g (32.0 mmol, 88%). The product is characterized by means of NMR and Raman spectroscopy:

1B{¹H} NMR (solvent: acetone-D₆), o^~, ppm: -18.40 s.

H{ B} NMR (solvent: acetone-D₆), δ, ppm: 3.39 m (8H, 4CH₂); 3.21 s (3H, OCH₃); 1.80 m (8H, 4CH₂); 1.44 m (8H, 4CH₂), 0.98 t (12H, 4CH₃), ³J_H-_H = 7.4.

¹³C{ H} NMR (solvent: acetone-D₆), δ, ppm: 128.84 q (3CN), J_C-B = 70.1 Hz; 59.48 (4NCH₂); 53.04 q (OCH₃), ²J_C-_B < 1 Hz; 24.47 s (4CH₂), 20.42 (4CH₂), 13.88 s (4CH₃).

Raman spectroscopy: v (CN) = 2202, 2212 cm^"1.

Elemental analysis, found, %: C 66.11 , H 9.74, N 15.44; calculated for C₁₀H₁₄BN₅O, %: C 66.29, H 10.85, N 15.46

B

1) . + 3 (CH₃)₃SiCN; - 3 (CH₃)₃SiOCH₃

2) . + [TBAJBr; - NaBr

Na[B(OCH₃)₄] ► [(C₄H₉)₄N]⁺[B(CN)₃(OCH₃)]-j

Na[B(OCH₃)₄] (300 mg, 1.9 mmol) is suspended in trimethylsilyl cyanide, (CH₃)₃SiCN (50.0 ml, 374.9 mol), and the mixture is stirred at 60°C for 2 days. All volatile constituents are removed in vacuo, and the residue is taken up in aqueous H₂0₂ (15%, 20 ml). K₂C0₃ is added to the solution, and the mixture is stirred at 50°C for 1 hour. Tetrabutylammonium bromide, [TBA]Br (806 mg, 2.5 mmol), is added, and the resultant emulsion is extracted with CH₂CI₂ (3 x 5 ml). The dichloromethane phase is separated off, washed with distilled water (2 ml), dried using MgS0 and subsequently removed in vacuo. The ionic liquid is dried in vacuo. Yield of tetrabutyl- ammonium [B(CN)₃0CH₃], which is liquid (highly viscous liquid) at room temperature: 600 mg (1.6 mmol, 84%). The product is characterized by means of NMR and Raman spectroscopy. The spectra are identical to the spectra described in Example 9A.

Example 10. Preparation of W-butyl-W-methylpyrrolidinium

Na[B(CN)₃OCH₃] (6.0 g, 41.9 mmol) and N-butyl-ZV-methylpyrrolidinium chloride, [BMPL]CI (7.5 g, 42.2 mmol), are taken up in distilled water (10 ml), and the mixture is stirred. The resultant emulsion is extracted with CH2CI2 (3 * 20 ml). The combined organic phases are washed with distilled water (3 ^χ 5 ml), dried using MgS0₄₎ filtered and evaporated in a rotary evaporator. The ionic liquid obtained is subsequently dried at 60°C in vacuo. Yield of A/-butyl-A/-methylpyrrolidinium [B(CN)₃OCH₃], which is liquid at room temperature: 9.1 g (34.7 mmol, 83%). Viscosity (20°C): 42 mPa-s. The product is characterized by means of NMR and Raman spectroscopy: 1 B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.44 (s, 1B) ppm.

H{¹¹B} NMR (solvent: acetone-D₆), δ, ppm: 3.68 m (4H, 2CH_2l); 3.49 m (2H, CH₂); 3.22 s (3H, CH₃), 3.20 s (3H, OCH₃); 2.31 m (4H, 2CH₂); 1.89 m (2H, CH₂); 1.43 m (2H, CH₂); 0.98 t (3H, CH₃), ³J_H,H = 7.4 Hz.

1³C{¹H} NMR (solvent: acetone-D₆), δ^~, ppm: 128.71 q (3CN), J_C-_B = 70.1 Hz; 65.20 s (2CH₂); 65.00 s (CH₂); 53.04 q (OCH₃), ²J_C-B = 0.8 Hz; 48.98 s (CH₃); 26.17 s (CH₂); 22.23 s (2CH₂); 20.30 s (CH₂); 13.64 s (CH₃) ppm. Raman spectroscopy: (CN) = 2204, 2214 cm^-1.

Elemental analysis, found, %: C 59.60, H 9.65, N 21.47; calculated for C₁₃H2₃BN₄0, %: C 59.56, H 8.84, N 21.37

Example 11 : Preparation of 1-ethyl-3-methylimidazolium [B(CN)₃OC₂H₅] C₂H5-N0N-CH₃ + Na[B(CN)₃OC₂H₅] -→ C₂H₅-N(^)N-CH₃ + NaCI

CI" ² [B(CN)₃OC₂H₅]-j

Na[B(CN)₃OC₂H₅] (7.0 g, 44.6 mmol) is dissolved in distilled water (10 ml), 1-ethyl-3-methylimidazolium chloride, [EMIM]CI (6.5 g, 44.3 mmol), in distilled water (10 ml) is added, and the mixture is stirred vigorously. CH₂CI₂ (50 ml) is then added, and the emulsion is stirred for 15 minutes. The CH₂CI₂ phase is separated off, washed with distilled water (3 * 2-3 ml), subsequently dried using MgS0₄ and filtered. The solution is evaporated in vacuo, and the ionic liquid is dried in vacuo. Yield of 1-ethyl-3- methylimidazolium [B(CN)₃OC₂H₅], which is liquid at room temperature: 7.8 g (31.8 mmol, 71 %). Viscosity (20°C): 27 mPa-s. The product is characterized by means of NMR and Raman spectroscopy:

1 B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -19.03 s.

1H{¹ B} NMR (solvent: acetone-D₆), <5, ppm: 8.97 s (1 H, CH); 7.73 d,d (1 H, CH), ³JH-H = 1.8 Hz; 7.66 d,d (1 H, CH), ³J_H-H = 1.7 Hz; 4.38 q (2H, CH₂), ³J_H- H = 7.3 Hz; 4.05 s (3H, CH₃); 3.43 q (2H, OCH₂), ³J_H-H = 7.0 Hz; 1.57 t (3H, CH₃), ³JH-H = 7.3 Hz; 1.10 t (3H, CH₃), ³J_H-H = 7.0 Hz.

1³C{¹H} NMR (solvent: acetone-D₆), δ, ppm: 137.00 s (CH), 129.01 q

(3CN), ¹ J_C-B = 69.8 Hz; 124.76 s (CH); 123.09 s (CH); 61.17 s (OCH₂), 45.75 s (CH₂); 36.66 s (CH₃); 17.73 q (CH₃), ³J_C-B = 3.2 Hz; 15.42 s (CH₃). Raman spectroscopy: v (CN) = 2204, 2216 cm^-1.

Elemental analysis, found, %: C 53.45, H 6.87, N 27.81 ; calculated for CnH^BNsO, %: C 53.91 , H 6.58, N 28.57.

Example 12: Preparation of tetrabutylammonium [B(CN)₃OC₂H₅]

[(C₄H₉)₄N]OH + Na[B(CN)₃OC₂H₅] -→ [(C₄H₉)₄N]⁺ [B(CN)₃OC₂H₅rj + NaOH Na[B(CN)₃OC₂H₅] (5.0 g, 31.9 mmol) is dissolved in distilled water (15 ml), and tetrabutylammonium hydroxide, [TBA]OH (-40% in water, -1.5 mol \^~ 22.0 ml, 33.0 mmol), is added. The suspension obtained is extracted with CH₂CI₂ (5 * 50 ml). The combined CH₂CI₂ phases are washed with distilled water (3 x 3 ml), dried using MgS0₄ and filtered. The solution is evaporated in vacuo, and the ionic liquid is dried in vacuo. Yield of tetrabutylammonium [B(CN)₃0C₂H₅], which is liquid (highly viscous liquid) at room temperature: 10.9 g (28.9 mmol, 91%). The product is characterized by means of NMR spectroscopy:

¹¹B{¹H} NMR (solvent: acetone-D₆), δ, ppm: -18.96 s.

H{¹ B} NMR (solvent: acetone-D₆), <5, ppm: 3.42 q (2H, OCH₂), ³J_H-H =

7.0 Hz; 3.39 m (8H, 4CH₂); 1.82 m (8H, 4CH₂); 1.44 m (8H, 4CH₂); 1.13 t

(3H, CH₃), ³J_H-H = 7.0 Hz; 0.99 t (12H, 4CH₃), ³J_H-H = 7.4 Hz.

¹³C{¹H} NMR (solvent: acetone-D₆), δ, ppm: 129.01 q (3CN), ¹J_C-B = 69.8

Hz; 61.17 s (OCH₂); 59.48 m (4NCH₂); 24.47 s (4CH₂), 20.39 (4CH₂); 17.78 q (CH₃), ³Jc-B = 3.2 Hz; 13.86 s (4CH₃).

Elemental analysis, found, %: C 66.63, H 12.34, N 13.78; calculated for C₂iH₄iBN₄O, %: C 67.01 , H 10.98, N 14.89.

Example 13: Synthesis of Na[B(O e)₂(CN)2]

Na[B(OCH₃)₄] + 2 (CH₃)₃SiCN _ _{2 (CHafaSi0C}, » Na[B(CN)₂(OCH₃)₂]

Trimethylsilylcyanide, TMSCN (1.0 mL, 7.499 mmol) is added to a suspension of Na[B(OMe)₄] (592 mg, 3.749 mmol) in dry acetonitrile (30 mL) and stirred for further 12 hours at room temperature in dry atmosphere. The stirring is stopped and the solid material is allowed to settle. The clear liquid phase is transferred into a second flask and all volatiles are removed under reduced pressure. The yield of the white solid Na[B(OMe)₂(CN)₂] is 440 mg (3.08 mmol, 82 % related to Na[B(OMe) ].)

The product is characterized by means of NMR spectroscopy:

1 B NMR (CD₃CN): δ = -5.40 (q, ³J_B-H = 3.2 Hz, 1 B) ppm.

1 B{ H} NMR (CD₃CN): δ = -5.40 (s, 1 B) ppm.

H NMR (CD₃CN): δ = 3.21 (q, ³J_B-H = 3.3 Hz, 6H) ppm.

1H{ ¹B} NMR (CD₃CN): <5 = 3.21 (s, 6H) ppm. ¹³C NMR (CD₃CN): δ = 131.85 (q, J_C-B = 68.4 Hz, 2C, CN), 50.91 (q, ¹J_C-H = 139.5 Hz, 2C, CH₃) ppm.

¹³C{¹H} NMR (CD₃CN): δ = 131.85 (q, _c-B = 68.4 Hz, 2C, CN), 50.91 (s, 2C, CH₃) ppm.

Example A: Formulations and device

The following electrolyte formulations are synthesized to demonstrate the advantage of electrolyte formulations according to the invention relative to electrolyte formulations of the prior art containing EMIM TCB.

Example A:

1. Electrolyte preparation

The ionic liquids used are summarized in Table 1.

Table 1. The ionic liquids in this study

The following electrolyte mixtures are prepared containing in addition 10 molar amounts of NBB, 5 molar amounts of Iodine and 2 molar amounts of guanidinium thiocyanate.

Electrolyte 1 given in the molar ratio:

36 mmim I, 36 pmim I, 72 emim TCB

Electrolyte 2 given in the molar ratio: 36 mmim I, 36 emim I, 72 emim TCB

Electrolyte 3 given in the molar ratio:

36 mmim I, 36 amim I, 72 emim TCB

Electrolyte 4 given in the molar ratio:

72 emim I, 72 emim TCB

Electrolyte 5 given in the molar ratio:

36 mmiml, 36 mohmim I, 72 emim TCB

Electrolyte 6 given in the molar ratio:

36 mmim I, 36 mmpl I, 72 emim TCB

Electrolyte 7 given in the molar ratio:

36 mmim I, 36 sm3 I, 72 emim TCB

Electrolyte 8 given in the molar ratio:

36 mmim I, 8 pmim I, 12 amim I, 8 hmim I, 8 mmpl I, 72 emim TCB

Electrolyte 9 given in the molar ratio:

36 mmim I, 36 pmim I, 72 emim tricyanomethoxyborate

Electrolyte 10 given in the molar ratio:

36 mmim I, 36 emim I, 72 emim tricyanomethoxyborate

Electrolyte 11 given in the molar ratio:

36 mmim I, 36 amim I, 72 emim tricyanomethoxyborate

Electrolyte 12 given in the molar rato:

72 emim I, 72 emim tricyanomethoxyborate

Electrolyte 13 given in the molar ratio:

36 mmiml, 36 mohmmim I, 72 emim tricyanomethoxyborate

Electrolyte 14 given in the molar ratio:

36 mmim I, 36 mmpl I, 72 emim tricyanomethoxyborate

Electrolyte 15 given in the molar ratio:

36 mmim I, 36 sm3 I, 72 emim tricyanomethoxyborate

Electrolyte 16 given in the molar ratio:

36 mmim I, 8 pmim I, 12 amim I, 8 hmim I, 8 mmpl I, 72 emim tricyanomethoxyborate The compounds pmim I, amim I, hmim I, mmim I, emim I, l₂, N- butylbenzimidazole and guanidinium thiocyanate are commercially available from Merck, Darmstadt or are synthesized according to known literature.

emim I = 1-ethyl-3-methylimidazolium iodide

mmim I = 1 ,3-dimethylimidazolium iodide

pmim I = 1-propyl-3-methylimidazolium iodide

amim I = 1-allyl-3-methylimidazolium iodide

mohmim I = 1-hydroxymethyl-3-methylimidazolium iodide

mmpl I = 1 ,3-dimethylpyrrolidinium iodide

sm3 I = trimethylsulfonium iodide.

2: The fabrication of the dye sensitized solar cell (DSSC):

The dye sensitized solar cells are fabricated as disclosed in US 5,728,487 or WO 2007/093961:

A double-layer, mesoporous TiO₂ electrode was prepared as disclosed in Wang P et al., J. Phys. Chem. B 2003, 107, 14336, in particular page 14337, in order to obtain a photoanode consisting of a double layer structure. To prepare a transparent nanoporous T1O2 electrode, a screen printing paste containing terpineol solvent and nanoparticulate T1O2 of anatase phase with 20 nm diameter was deposited on a transparent conductive substrate to 5 mm x 5 mm squared shape by using a hand printer. The paste was dried for 10 minutes at 120 degrees Celsius.

Another screen printing paste containing T1O2 with 400 nm diameter was then deposited on top of the nanoporous layer to prepare an opaque layer. The double layer film was then sintered at 500 degrees Celsius for an hour with the result of an underlying transparent layer (7 microns thick) and a top opaque layer (4 microns thick). After sintering, the electrode was immersed in 40 mM aqueous solution of TiCI₄ (Merck) for 30 minutes at 70 degrees Celsius and then rinsed with pure water sufficiently. Thus TiCI₄-treated electrode was dried at 500 degrees Celsius for 30 minutes just before dye sensitization. The electrode was dipped into a 0.3 mM Z907 dye solution of acetonitrile (Merck HPLC grade) and tert-butyl alcohol (Merck), v:v = 1 :1 for 60 hours at 19 degrees Celsius. The counter electrode was prepared with thermal pyrolysis method as disclosed in the reference above. A droplet of 5 mM solution of platinic acid (Merck) was casted at 8 μΙ/οητι2 and dried on a conductive substrate. The dye sensitized solar cell was assembled by using 30 micron thick Bynel (DuPont, USA) hot-melt film to seal up by heating. The internal space was filled with each of the electrolyte

formulations as described above to produce the corresponding devices.

The dye Z907 is an amphiphilic ruthenium sensitizer Ru(2,2'-bipyridine 4,4'- dicarboxylic acid) (4,4'-dinonyl-2,2'-bipyridine)(NCS)2 or synonymously

[Ru(H2dcbpy)(dnbpy)(NCS)₂].

In order to obtain accurate light intensity level, Air Mass 1.5 Global (AM 1.5G) simulated sunlight is calibrated spectrally according to Seigo Ito et al, "Calibration of solar simulator for evaluation of dye-sensitized solar cells", Solar Energy Materials & Solar Cells, 82, 2004, 421.

3. The DSSC characteristics at varied temperature.

The measurements of photocurrent-voltage curves are carried out under Air Mass 1.5 simulated sunlight (AM 1.5) with temperature control for devices fabricated as described above containing electrolytes 1 to 4 placed on a black plate chilled down to 25°C under 1 Sun illumination. A photomask of 4 mm x 4 mm is placed on top of the devices to define the light projection area. The cell gap is around 20 micron. Characteristic photovoltaic parameters are summarized in table 2.

Energy conversion efficiency is generally the ratio between the useful output of an energy conversion machine and the input of light radiation, in energy terms, determined by using adjustable resistant load to optimize the electric power output. Table 2 shows detailed photovoltaic parameters of the devices made according to example A represented by the short-circuit photocurrent density (Jsc), the open-circuit photovoltage (V_oc), the fill factor (FF) and the power conversion efficiency (η)

* not according to the invention

Claims

Patent Claims

An electrolyte formulation comprising at least one compound containing borate anions of formula la

[B(CN)_4-x(OR^*)_x]- la

Hal denotes F, CI, Br or I.

An electrolyte formulation according to claim 1 , characterised in that the compound conforms to the formula I

[Kt]^z+ z[B(CN)₄._x(OR^*)_x]- I

in which [Kt]^z+ denotes an inorganic or organic cation or H⁺ z is 1 , 2, 3 or 4 and x and R^* have a meaning as indicated in claim 1.

3. An electrolyte formulation according to claim 2, characterised in that [Kt]^z+ is an organic cation selected from the group comprising

sulfonium, oxonium, ammonium, phosphonium, uronium, thiouronium, guanidinium cations or heterocyclic cations.

An electrolyte formulation according to claim 2 or 3, characterised in that [Kt]^z+ is an oxonium cation of formula [(R°)30]⁺ (1) or a sulfonium cation of formula [(R°)3S]⁺ (2), where R° independently of each other denotes straight-chain or branched alkyl groups having 1-8 C atoms, or nonsubstituted phenyl or phenyl which is substituted by R°, OR⁰,

N(R°)2, CN or halogen and in case of sulfonium cations of formula (2) additionally denotes each independently (R"')2N and R'" is

independently of each other straight-chain or branched C-i to C₆ alkyl; or characterised in that [Kt]^z+ is an ammonium cation, which conforms to the formula (3) [NR₄]⁺ (3),

where

R in each case, independently of one another, denotes

H, OR', NR'2, with the proviso that a maximum of one substituent R in formula (3) is OR'or NR'_2l

straight-chain or branched alkyl having 1-20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two R may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -CN, -NR'₂, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -NO₂, -SR', -S(O)R', -SO₂R' and where one or two non-adjacent carbon atoms in R which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N+R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or periiuorinated straight-chain or branched C-r to C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non- substituted or substituted phenyl and X each independently is halogen; or characterised in that [Kt]^z+ is a phosphonium cation, which conforms to the formula (4)

where

R² in each case, independently of one another, denotes

H, OR' or NR'₂,

straight-chain or branched alkyl having 1-20 C atoms, straight-chain or branched alkenyl having 2-20 C atoms and one or more double bonds,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two R² may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -CN, -NR'₂, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -NO₂, -SR\ -S(O)R', -SO₂R' and where one or two non-adjacent carbon atoms in R² which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)RO-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to Ci₈-alkyl, saturated C₃- to C₇-cycloalkyl, non- substituted or substituted phenyl and X each independently is halogen; or characterized in that [Kt]^z+ is a uronium cation, which conforms to the formula (5)

[C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺ (5),

where

R³ to R⁷ each, independently of one another, denote

H, where H is excluded for R⁵,

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R³ to R⁷ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'_2> -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂₎ -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R³ to R⁷ which are not in the oc-position may be replaced by atoms and/or atom groups selected from the group -O-, -S- , -S(O)-, -SOr, -SO2O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(0)RO-, -C(O)NR'-, -SO₂NR'-, -OP(O)RO-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to Ci₈-alkyl, saturated C₃- to C7-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or characterised in that [Kt]^z+ is a thiouronium cation, which conforms to the formula (6)

[C(NR³R⁴)(SR⁵)(NR⁶R⁷)]⁺ (6),

where

R³ to R⁷ each, independently of one another, denote

H, where H is excluded for R⁵,

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R³ to R⁷ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R³ to R⁷ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S- , -S(O)-, -SOz- -SO2O-, -C(O)-, -C(0)0-, -N⁺R'₂-, -P(0)RO-, -C(O)NR'-, -SO2NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(0)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to de-alkyl, saturated C3- to C7-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or characterised in that [Kt]^z+ is a guanidinium cation, which conforms to the formula (7)

[C(NR⁸R⁹)(NR¹⁰R¹¹)(NR¹²R¹³)]⁺ (7),

where

R⁸ to R¹³ each, independently of one another, denote

H, -CN, NR'₂₎ -OR',

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyi having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R⁸ to R¹³ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'_2l -SO₂NR'_2l -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R⁸ to R¹³ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S- , -S(O)-, -SO₂-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO2NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'-, where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to Cie-alkyl, saturated C3- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or characterised in that [Kt] conforms to the formula (8)

[HetNJ z+

(8)

where

HetNT denotes a heterocyclic cation selected from the group imidazolium 1 H-pyrazolium 3H-pyrazolium 4H-pyrazolium 1-pyrazolinium

2-pyrazolinium 3-pyrazolinium 2,3-dihydroimidazolinium 4,5-dihydroimidazolinium

2,5-dihydroimidazolinium pyrrolidinium

1 ,2,4-triazohum 1 ,2,4-triazolium

pyridinium pyridazinium pyrimidin

razinium thiazolium

where the substituents

R^1, to R⁴' each, independently of one another, denote

H;

F, CI , Br, I, -CN, -OR', -NR'₂, -P(O)R'₂, -P(O)(OR')₂, -P(O)(NR'₂)₂, -C(O)R', -C(O)OR', -C(O)X, -C(O)NR'₂, -SO₂NR'₂, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R' and/or NO₂, with the proviso that R¹', R³', R⁴' are H and/or a straight-chain or branched alkyl having 1-20 C atoms; straight-chain or branched alkyl having 1-20 C atoms, which optionally may be fluorinated or perfluorinated;

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms; saturated, partially or fully unsaturated heteroaryl, heteroaryl-C-i-C₆- alkyl or aryl-Ci-C₆-alkyl;

where the substituents R¹ , R² , R³ and/or R⁴ together may also form a ring system,

where one, two or three substituents R¹ to R⁴ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, - OR', NR'₂, -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, - SO₂X, -SR', -S(O)R', -SO₂R', -NO₂, but where R^r and R^4' cannot simultaneously be fully substituted by halogens and where, in the substituents R¹ to R⁴ , one or two non-adjacent carbon atoms which are not bonded to the heteroatom may be replaced by atoms and/or atom groups selected from the -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-, - C(O)O-, -N⁺R'₂-, -P(O)RO-, -C(O)NR'-, -SO₂NR'-, -OP(O)RO-,

-P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'-, where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched C-i- to Ci₈-alkyl, saturated C3- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen.

An electrolyte formulation according to claim 2, characterised in that [Kt]^z+ is a lithium cation.

An electrolyte formulation according to claim 1 comprising the compound containing the borate anion of formula la in molar

concentrations from 0.1 to 5 M.

An electrochemical and/or optoelectronic device comprising an electrolyte formulation according to one or more of claims 1 to 6.

A device according to claim 7 which is a photovoltaic cell, a light emitting device, an electrochromic or photo-electrochromic device, an electrochemical sensor, a biosensor, a primary battery, a secondary battery, a capacitor or a supercapacitor.

Compounds of formula

[Kt]^z+ z[B(CN)₂(OR^*)₂r I*,

in which R* denotes in each case, independently of one another, straight-chain or branched alkyl groups having 1 to 12 C atoms which can be partially subsituted by Hal and

Hal denotes F, CI, Br or I, z is 1 , 2, 3 or 4,

[Kt]^z+ denotes H⁺; an inorganic or organic cation selected from the group of NO⁺, H⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, or Mg²⁺, Cu⁺, Cu²⁺, Zn²⁺, Ag⁺, Ca²⁺, Y⁺³, Yb⁺³, La⁺³, Sc⁺³, Ce⁺³, Nd⁺³, Tb⁺³, Sm⁺³ or complex (ligands containing) metal cations which include rare-earths, transitions or noble metals like rhodium, ruthenium, iridium, palladium, platinum, osmium, cobalt, nickel, iron, chromium, molybdenum, tungsten, vanadium, titanium, zirconium, hafnium, thorium, uranium, gold; or an oxonium cation of formula [(R°)3O]⁺ (1) or a sulfonium cation of formula [(R°)3S]⁺ (2), where R° independently of each other denotes straight-chain or branched alkyl groups having 1-8 C atoms, or nonsubstituted phenyl or phenyl which is substituted by R°, OR⁰, N(R°)2, CN or halogen and in case of sulfonium cations of formula (2) additionally denotes each independently (R"')2 and R'" is

independently of each other straight-chain or branched Ci to C₆ alkyl; or an ammonium cation, which conforms to the formula (3) [NR₄]⁺ (3),

where

R in each case, independently of one another, denotes

H, OR', NR'₂, with the proviso that a maximum of one substituent R in formula (3) is OR'or NR'_2>

straight-chain or branched alkyl having 1-20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two R may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -CN, -NR'_2> -C(O)OH, -C(O)NR'₂, -SO2NR 2, -C(O)X, -SO2OH, -SO2X, -NO2, -SR', -S(O)R', -SO₂R' and where one or two non-adjacent carbon atoms in R which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-,

-C(O)O-, -N+RV, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to ds-alkyl, saturated C₃- to C₇-cycloalkyl, non- substituted or substituted phenyl and X each independently is halogen; or

a phosphonium cation, which conforms to the formula (4)

where

R² in each case, independently of one another, denotes

H, OR' or NR'₂,

straight-chain or branched alkyl having 1-20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two R² may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -CN, -NR'_2l -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -NO₂, -SR', -S(O)R", -SO₂R' and where one or two non-adjacent carbon atoms in R² which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S-, -S(O)-, -SO₂-, -SO₂O-, -C(O)-,

-C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to Ci₈-alkyl, saturated C₃- to C₇-cycloalkyl, non- substituted or substituted phenyl and X each independently is halogen; or a uronium cation, which conforms to the formula (5)

[C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺ (5),

where

R³ to R⁷ each, independently of one another, denote

H, where H is excluded for R⁵,

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R³ to R⁷ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'₂₎ -SO₂NR'₂, -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R³ to R⁷ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -0-, -S- , -S(O)-, -SO₂-, -S0₂O-, -C(O)-, -C(0)0-, -N⁺R'₂-, -P(O)RO-, -C(O)NR'-, -SO2NR'-, -OP(O)R'0-, -P(0)(NR'₂)NR'-, -PR'₂=N- or -P(0)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to Cis-alkyl, saturated C3- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or a thiouronium cation, which conforms to the formula (6)

[C(NR³R⁴)(SR⁵)(NR⁶R⁷)]⁺ (6),

where

R³ to R⁷ each, independently of one another, denote

H, where H is excluded for R⁵,

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyi having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R³ to R⁷ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'_2> -SO₂NR'₂₎ -C(O)X, -SO₂OH, -SO₂X, -SR\ -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R³ to R⁷ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S- , -S(O)-, -SO2-, -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'- where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched Ci- to Ci₈-alkyl, saturated C₃- to C7-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or a guanidinium cation, which conforms to the formula (7)

[C(NR⁸R⁹)(NR ⁰R ¹)(NR¹²R¹³)]⁺ (7),

where

R⁸ to R¹³ each, independently of one another, denote

H, -CN, NR'₂, -OR',

straight-chain or branched alkyl having 1 to 20 C atoms,

saturated, partially or fully unsaturated cycloalkyi having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms, where one or two of the substituents R⁸ to R¹³ may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, -OR', -NR'₂, -CN, -C(O)OH, -C(O)NR'_2l -SO₂NR'₂₎ -C(O)X, -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R', -NO₂ and where one or two non-adjacent carbon atoms in R⁸ to R¹³ which are not in the a-position may be replaced by atoms and/or atom groups selected from the group -O-, -S- , -S(O)-, -SO₂- -SO₂O-, -C(O)-, -C(O)O-, -N⁺R'₂-, -P(O)R'O-, -C(O)NR'-, -SO₂NR'-, -OP(O)R'O-, -P(O)(NR'₂)NR'-, -PR'₂=N- or -P(O)R'-, where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched C-i- to Ci₈-alkyl, saturated C₃- to C7-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen; or [Kt]^z+ conforms to the formula (8)

[HetN]²⁺ (8)

where

HetN^z+ denotes a heterocyclic cation selected from the group imidazolium 1 H-pyrazolium 3H-pyrazolium 4H-pyrazolium 1-pyrazolinium

2-pyrazolinium 3-pyrazolinium 2,3-dihydroimidazolinium 4,5-dihydroimidazolinium

2,5-dihydroimidazolinium pyrrolidine ·, ₂,_4-t_riazolium 1.2,4-triazolium

pyridinium pyridazinium pyrimidinium

pyrazinium thiazolium oxazoium

quinolinium isoquinolinium quinoxalinium

where the substituents

R¹' to R⁴' each, independently of one another, denote

H;

F, CI , Br, I, -CN, -OR', -NR'₂₎ -P(O)R'₂, -P(O)(OR')₂, -P(O)(NR'₂)₂, -C(O)R', -C(O)OR', -C(O)X, -C(O)NR'₂₎ -SO₂NR'_2> -SO₂OH, -SO₂X, -SR', -S(O)R', -SO₂R' and/or NO₂, with the proviso that R¹', R³', R⁴' are H and/or a straight-chain or branched alkyl having 1-20 C atoms;

saturated, partially or fully unsaturated cycloalkyi having 3-7 C atoms, which may be substituted by alkyl groups having 1-6 C atoms;

saturated, partially or fully unsaturated heteroaryl, heteroaryl-CrCe- alkyl or aryl-Ci-C₆-alkyl;

where the substituents R , R² , R³ and/or R⁴ together may also form a ring system,

where one, two or three substituents R¹ to R may be partially or fully substituted by halogens, in particular -F and/or -CI, or partially by -OH, - OR', NR'₂, -CN, -C(O)OH, -C(O)NR'₂, -SO₂NR'₂, -C(O)X, -SO₂OH, - S0₂X, -SR'. -S(0)R', -SO₂R', -N0₂, but where R^1' and R^4' cannot simultaneously be fully substituted by halogens and where, in the substituents R¹ to R⁴ , one or two non-adjacent carbon atoms which are not bonded to the heteroatom may be replaced by atoms and/or atom groups selected from the -0-, -S-, -S(O)-, -S0₂-, -S0₂O-, -C(O)-, - C(0)0-, -N⁺R'₂-, -P(O)RO-, -C(0)NR'-, -S0₂NR'-, -OP(0)RO-, -P(0)(NR'₂)NR'-, -PR'₂=N- or -P(0)R'-, where where R' each independently is H, non-fluorinated, partially fluorinated or perfluorinated straight-chain or branched to Ci₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X each independently is halogen.

10. Process for the preparation of a compound of formula I as described in claim 2in which [Kt]^z+ is an alkali metal cation and x denotes 1 which denotes a compound of formula 1-1

[Me]⁺ [B(CN)₃(OR*)r 1-1

and R* has a meaning as indicated in claim 1 or 2

comprising the reaction of a compound of formula II

[Me]⁺ [B(OR^*)₄]^~ II

in which [Me]⁺ denotes an alkali metal cation and R^* denotes in each case, independently of one another, straight-chain or branched alkyl groups having 1 to 12 C atoms with at least three equivalents of trialkylsilylcyanide in which the alkyl groups independently denotes straight-chain or branched alkyl groups having 1 to 4 C atoms.

11. Process according to claim 10, characterised in that the reaction

temperature is between 10°C and 150°C.

12. Process for the preparation of a compound of formula I according to claim 2 in which [Kt]^z+ is an alkali metal cation and x denotes 1 which denotes a compound of formula 1-1 [Me]⁺ [B(CN)₃(OR*)r 1-1

and R* has a meaning as indicated in claim 1 or 2

comprising the reaction of a compound of formula III

[Me]⁺ [BF₄]^" III

in which [Me]⁺ denotes an alkali metal cation with trialkylsilylcyanide and with alkoxytrialkylsilane in which alkoxy means OR* and R* has a meaning as indicated in claim 1 or 2 and in which the alkyl groups of the silyl compounds independently denotes straight-chain or branched alkyl groups having 1 to 4 C atoms.

13. Process for the preparation of a compound of formula I according to claim 2 in which [Kt]^z+ is an alkali metal cation and x denotes 2 which denotes a compound of formula I-2

[Me]⁺ [B(CN)₂(OR^*)₂]^" I-2

and R* has a meaning as indicated in Claim 1 or 2

comprising the reaction of a compound of formula II

[Me]⁺ [B(OR^*)₄]^' II

14. Process for the preparation of a compound of formula I as described in one or more of claims 2 to 6 in which [Kt]^z+ is another cation than the used alkali metal cation in the starting material in a salt-exchange reaction, characterized in that an alkali metal salt of formula 1-1

[Mef [B(CN)₃(OR*)r 1-1 or of formula I-2

[Me]⁺ [B(CN)₂(OR^*)₂]- I-2

in which Me is an alkali metal cation or H[B(CN)₃(OR^*)] or

H[B(CN)₂(OR^*)₂] and R* has a meaning as indicated in claim 1 or 2 is reacted with a compound of formula V

KtA V,

in which

Kt has a meaning of an organic cation or a metal cation other than the alkali metal cation of the compound of formula 1-1 or formula I-2 and A denotes F^", CI^", Br^", I ^", OH^" (merely for the synthesis of compounds of formula 1-1), [HF₂] ^~ [CN] ^" [SC ]^", [RiC(O)O]^" [^00(0)0]^"

[R1SO3] - [R₂C(O)O]-, [R₂SO₃]- [R1OSO3] - [SiF₆] ²- [BF₄] ^~ [HOCO2] - [HSO₄] - [N0₃]-, [(Ri)₂P(0)0]-, [R RiOJPiOJO]-, [(R₂)₂P(O)O]-,

[R₂P(O)O₂]^2", tosylate, malonate which may be substituted by straight- chain or branched alkyl groups having 1 to 4 C atoms, [SO₄] ^2~ or

[CO3] ^2" (merely for the synthesis of compounds of formula I with a metal cation),

in which Ri is each independently of another a straight-chain or branched alkyl group having 1 to 12 C atoms and

R₂ is each independently of one another a straight-chain or branched perfluorinated alkyl group having 1 to 12 C atoms and where

electroneutrality should be taken into consideration in the formula of the salt KtA.