EP3174850A1

EP3174850A1 - Novel synthons for developing organic semiconductors

Info

Publication number: EP3174850A1
Application number: EP15749754.6A
Authority: EP
Inventors: Martial DEGBIA; Bruno SCHMALTZ; François TRAN-VAN
Original assignee: Universite Francois Rabelais de Tours
Current assignee: Universite de Tours
Priority date: 2014-07-28
Filing date: 2015-07-28
Publication date: 2017-06-07
Also published as: KR20170040301A; JP2017523196A; WO2016016221A1; FR3024144B1; FR3024144A1; US20170213652A1; US10403445B2

Abstract

A method for synthesising ττ-conjugated materials comprising a step of implementing a synthon of formula (I) comprising a carbazole or fluorine ring.

Description

The present invention relates to novel synthons, to a process for their preparation and to their use in the preparation of various materials, in particular organic semiconductors and dyes. BACKGROUND OF THE INVENTION

Dye-sensitized solar cells (DSSCs) are a promising photovoltaic technology for the production of renewable and low-cost energy. These cells consist of a nanocrystalline oxide with a large energy gap, for example TiO ₂ deposited on a transparent conductive oxide glass support. Molecular sensitizers, bonded through wide-gap oxide anchoring groups, inject electrons into the conduction band of the semiconductor under solar exposure. Usually, a liquid electrolyte comprising a redox system provides regeneration of the photoexcited dye.

Today, liquid electrolyte based DSSCs achieve conversion efficiencies of more than 12%. However, they can cause problems of leakage and corrosion of the electrodes.

A strategy that was developed a few years ago, consists in the manufacture of "solid state" DSSC (ssDSSC) obtained by replacing the liquid electrolyte with a p-type organic semiconductor or an associated polymer matrix. to a redox couple. For this purpose, various pi-conjugated compounds such as triphenylamine derivatives, carbazole derivatives or conjugated polymers such as poly (3,4-ethylenedioxythiophene) (PEDOT) or poly-3-hexylthiophene (P3HT) have been proposed. Currently, one of the most studied materials is 2,2,7,7-tetrakis- (N, N-di-p-methoxyphenylamine) -9,9-spirobifluorene or spiro-OMeTAD which has become the reference molecule for an organic semiconductor carrier of holes. The results obtained with this type of molecular glass exceed those obtained with liquid cells, since the use of type sensitizers perovskites that achieved conversion efficiencies of over 15%.

Recently, the inventors have synthesized new di-substituted carbazole-based organic hole-transporting materials at the 3- and 6-positions useful for the manufacture of molecular glasses (Martial Degbia et al., Carbazole-based molecular glasses for 3, 44% efficient solid-state dye-sensitized solar cells Journal of Power Sources, 233 (2013) 86-92); among the compounds described, 3,6-di (4,4-dimethoxydiphenylaminyl) -9-phenylcarbazole has been shown to be very promising since it gives results almost as high as the Spiro-OMeTAD conventionally used with conversion efficiencies of the order of 3.44% under conditions of realization of non-optimized PV devices.

Although these all-solid dye devices can be easily made, thus making it possible to overcome the problems of electrolyte corrosion, leakage and temperature limitation, the processes making it possible to access these molecules, in particular to the molecule of reference (spiro-OMeTAD) are still very expensive.

Also it is necessary to find new synthons to easily prepare a range of high performance low cost molecular glasses, modular chemical structures and having a common core suitable for the realization of DSSC any solid high efficiency of solar energy conversion. .

However, the inventors have discovered that, from particular synthons, in particular carbazole or fluorene-based synthons that can be chemically modified in an easy manner, it is possible to prepare a wide range of amorphous molecules, carrier of holes, having good mobility. , energy levels suitable for regeneration of the photooxidized dye, and having optical and semiconductor properties suitable for use in DSSCs. The interest of these synthons is the possibility of developing many π-conjugated organic materials, in particular thanks to the reactivity of the 9-position on the carbazole or fluorene ring. The synthesis of these π-conjugated materials if they present complex structures can be carried out in a single step from said synthons and a well-chosen connector center.

These π-conjugated materials have applications in optoelectronics, especially for charge transport and / or photon absorption. OLEDs, organic transistors and organic and hybrid photovoltaic cells can be mentioned as examples.

Thus the invention aims to provide a process for preparing π-conjugated materials from new synthons.

The invention also aims to provide new synthons and their manufacturing process.

Also the present invention relates to a process for synthesizing π-conjugated materials comprising a step of implementing a synthon of formula (I)

in which

W represents either a group -CH R ₅ -, or a group -N (H) -,

R 1 and R ₂ , identical or different, are respectively in position 3 and 6 or in position 2 and 7 of the ring and are chosen independently of each other in the group comprising

i. hydrogen,

ii. monocyclic or polycyclic aromatic groups, said groups may be substituted by at least one alkyl group-Ci ₂ straight or branched, in particular methyl, or by alkoxy, Ci-Ci ₂ straight or branched, in particular methoxy,

iii. the groups

where Ari and Ar ₂ , which are identical or different, each independently represent an aryl group, optionally substituted with one or more identical or different substituents chosen from:

at. the hydrogen atom,

b. straight or branched Ci-Ci ₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

vs. the alkoxy-Ci ₂ straight or branched, said alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S,

d. oligoethers and

e. oligothioethers,

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

R ₃ and R _{4, which are} identical or different, occupy the positions left free by R 1 and R ₂ and are chosen from:

at. hydrogen

b. halogens

vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

boy Wut . mono or polycyclic aromatic groups h. straight or branched Ci-Ci ₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and which may comprise one or more heteroatoms chosen from O and S,

i. straight or branched C ₁ -C ₁₂ alkoxy radicals, which alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S,

j. oligoethers and

k. oligothioethers.

R ₅ is chosen from:

at. straight or branched C ₁ -C ₁₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

b. oligoethers and

vs. oligothioethers.

In an advantageous embodiment of the process of the invention, R 1 and R ₂ , which are identical or different, are respectively in position 3 and 6 or in position 2 and 7 of the ring and are chosen independently of each other in the group including

i. hydrogen,

iii. the groups

^Ar i where Ari and Ar ₂ , which are identical or different, each independently represent an aryl group, optionally substituted with one or more identical or different substituents chosen from:

at. the alkoxy-Ci ₂ straight or branched, said alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S,

b. oligoethers and

vs. oligothioethers,

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

When W represents a group -CR ₅ -, then the synthon is derived from fluorene of formula (la)

and when W represents a group -N (H) -, then the synthon is a carbazole derivative of formula (Ib)

When R 1 and R ₂ are in position 3 and / or 6 or 2 and / or 7 of the carbazole ring, then R ₃ and R ₄ are in position 1 and 5 or 4 and 8 of said ring.

For the purposes of the present invention, the mono or polycyclic aromatic groups comprise from 6 to 50 carbon atoms. In a way Advantageously, they comprise from 6 to 18 carbon atoms and are mono-, bi- or tricyclic. When the carbocyclic group comprises more than one ring nucleus, the cyclic rings can be fused two by two or attached in pairs by σ bonds. Two fused rings may be ortho-condensed or pericondensed. The carbocyclic radical may comprise a saturated part and / or an aromatic part and / or an unsaturated part. There may be mentioned as examples the (C ₆ -C ₈₎ aryl including phenyl, benzyl, tolyl, xylyl, naphthyl, anthryl, phenanthryl, biphenyl, terphenyl, tetrahydronaphthyl, fluorene and carbazole. These mono- or polycyclic radicals, and especially mono-, bi- or tricyclic radicals may comprise one or more heteroatoms chosen from O, S and / or N, preferably 1 to 4 heteroatoms. Preferably, the monocycles or the monocycle constituting the heterocycle, has from 5 to 12 ring members, more preferably from 5 to 10 ring members, for example from 5 to 6 ring members. By way of example, mention may be made of mono- or polycyclic, unsaturated or aromatic heterocycles, pyridine, furan, thiophene, pyrrole, pyrrazole, imidazole, thiazole, isoxazole and isothiazole. , pyridazine, pyrimidine, pyrazine, triazines, indolizine, indole, isoindole, benzofuran, benzothiophene, indazole, benzimidazole, benzothiazole, purine, quinoline, isoquinoline , cinnoline, phthalazine, quinazoline, quinoxaline, pteridine, naphthyridines, carbazole, phenothiazine, phenoxazine, acridine, phenazine, oxazole, pyrazole, oxadiazole, triazole, thiadiazole and their unsaturated derivatives. Other examples are the unsaturated derivatives of pyrrolidine, dioxolane, imidazolidine, pyrazolidine, piperidine, dioxane, morpholine, dithiane, thiomorpholine, piperazine and trithiane.

According to the invention, the term C ₁ -C ₁₂ or straight or branched (C ₁ -C ₂ ) alkyl, said alkyl group may be saturated or unsaturated and may comprise one or more heteroatoms chosen from O and S , a saturated or unsaturated linear or branched chain of 1 to 15 carbons said carbon atoms may be replaced by one or more heteroatoms selected from O and S. Examples may be mentioned by way of example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, 2-methylbutyl, 1-ethylpropyl, hexyl, isohexyl, neohexyl, 1-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 1,3-dimethylbutyl, 2-ethylbutyl, 1-methyl-1-ethylpropyl, heptyl, 1-methylhexyl, 1-propylbutyl, 4,4-dimethylpentyl, octyl, 1-methylheptyl, 2-ethylhexyl, 5,5-dimethylhexyl, nonyl, decyl, 1-methylnonyl, 3,7-dimethyloctyl and 7,7-dimethyloctyl.

According to the invention, alkoxy groups C ₁ -C ₁₂ alkyl or (Ci-Ci ₂₎ alkoxy straight or branched, represent an alkoxy group comprising 1 to 12 carbon atoms, said alkoxy groups may be saturated or unsaturated and may comprise one or more heteroatoms selected from O and S. By way of example, mention may be made of methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy and tert-butoxy groups.

According to the invention, the term oligoether group is understood to mean oligomers whose organic repeating units are held together by ether functions (C-O-C). Advantageously, the oligoethers according to the invention comprise two to five ether groups and from 2 to 4 repeating units. As an example of oligoethers, there may be mentioned diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol.

According to the invention, the term "oligothioether group" means oligomers whose organic repeating units are held together by thioether (C-S-C) functions. Advantageously, the oliothioethers according to the invention comprise two to three thioether groups and from 2 to 4 repeating units. As an example of oligothioethers, mention may be made of ethanedithiol.

According to the invention, halogen is understood to mean an atom chosen from the group comprising bromine, chlorine, fluorine and iodine.

According to the invention, the term nitro group, a group -NO ₂ and sulfonate group, a group -S0 ₂ . According to the invention, the term "amine groups" means primary (-NH ₂ ), secondary or tertiary amines.

According to the invention, the term "carbonyl groups" means the groups = C = O, -CHO, -COR, R being a C 1 -C ₂ alkyl group.

As examples of particularly advantageous groups for Ri and

R ₂ may be mentioned:

In an advantageous embodiment of the process of the invention, a compound of formula (I) in which R 1 and R ₂ are each independently of one another is chosen from:

i. phenyl, naphthyl, anthracenyl, indenyl, biphenyl, terphenyl and carbazolyl groups, said groups possibly being substituted with at least one straight or branched C ₁ -C 12 alkyl group, especially a methyl group,

ii. the groups

where Ra and Rb, identical or different, each represent independently of each other:

at. either a hydrogen atom,

b. is a straight or branched C ₁ -C 12 alkyl group, said alkyl group possibly being saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

vs. or alkoxy Ci-Ci ₂ straight or branched, said alkoxy group may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S, in particular methoxy,

d. an oligoether,

e. an oligothioether.

In a more advantageous embodiment of the process of the invention, a compound of formula (I) in which R 1 and

R ₂ are each independently of one another, a group selected from the groups:

at. is a straight or branched C ₁ -C ₁₂ alkoxy group, said alkoxy group may be saturated or unsaturated and may comprise one or more heteroatoms chosen from O and S, in particular a methoxy group,

b. an oligoether,

vs. an oligothioether.

In an even more advantageous embodiment of the process of the invention, compounds of formula (I) in which R ₃ and R ₄ each represent a hydrogen atom are used; these compounds therefore correspond to the formula (Γ)

wherein R 1 and R ₂ are as previously defined.

The process of the invention makes it possible to prepare a wide range of π-conjugated materials of different structure and properties, in particular compounds of formula (Ib ')

(Ib ') in which

i. hydrogen,

ii. the aryl groups, said aryl groups possibly being substituted with at least one straight or branched C ₁ -C ₅ alkyl group, in particular a methyl group,

iii. the groups

at. the hydrogen atom,

b. straight or branched Ci-Ci ₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S, vs. straight or branched C1-C12 alkoxy, said alkoxy groups being saturable or unsaturated and may comprise one or more heteroatoms selected from O and S,

d. oligoethers and

e. oligothioethers,

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen,

b. halogens,

vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

boy Wut . mono or polycyclic aromatic groups h. straight or branched Ci-Ci ₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

i. the alkoxy-Ci ₂ straight or branched, said alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S,

j. oligoethers and

k. oligothioethers.

and

- R ₆ represents either an alkyl group _Ci-2 straight or branched, or an aryl group of C ₆ -C _8, in particular a benzene group or methoxybenzene (anisole), or an amine protecting group, in particular a group benzyl, optionally substituted by an alkoxy group C1-C5 or an aryl group of C ₆ -C ₈ alkyl by a halogen, in particular fluorine or substituted by a straight or branched fluorinated C ₁ -C ₁₂ alkyl group, in particular trifluoromethyl (CF 3), or a bicyclic or tri-tetracyclic group comprising from 10 to 18 carbon atoms such as, for example, naphthyl, tetrahydronaphthyl, anthracenyl or pyrenyl.

In an advantageous embodiment, the compounds prepared according to the process of the invention correspond to formula (Ib ')

in which

i. hydrogen,

ii. the aryl groups, said aryl groups possibly being substituted with at least one straight or branched C ₁ -C ₅ alkyl group, especially a methyl group,

iii. the groups

b. oligoethers and

vs. oligothioethers, with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen,

b. halogens,

vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

j. oligoethers and

k. oligothioethers.

and

- R ₆ represents either an alkyl group _Ci-2 straight or branched, or an aryl group of C ₆ -C _8, in particular a benzene group or methoxybenzene (anisole), or an amine protecting group, in particular a group benzyl, optionally substituted alkoxy C ₁ -C 5 or an aryl group of C ₆ -C _{8 alkyl} substituted by halogen, in particular fluorine or substituted by an alkyl group Ci-Ci ₂ straight or branched fluorinated, in especially trifluoromethyl (CF3), or bistral, tri or tetracyclic group comprising from 10 to 18 carbon atoms, such as for example a naphthyl, tetrahydronaphthyl, anthracenyl or pyrenyl group. The process of the invention also makes it possible to prepare π-conjugated materials corresponding to formula (Ia) or (Ib)

(la) (lb) in which represents a polyfunctional central unit. By ~ ~ polyfunctional unit means a unit carrying functions for grafting in position 9 of the carbazole ring or the fluorene ring. As examples of functions that allow grafting, mention may be made of iodine, bromine, chlorine atoms, tosylates, mesylates, etc. By way of example of polyfunctional central units, it may be noted - C ₆ H ₄ -, biphenylene, terphenyl, fluorenyl, carbazolyl, oligooxyethylene derivative, these polyfunctional central units may or may not be substituted by one or more linear or branched C1-C12 alkyls.

n is an integer equal to or greater than 2, advantageously between 2 and 6, R 1 and R ₂ , identical or different, are respectively in position 3 and 6 or in position 2 and 7 of the ring and are chosen independently of each other in the group comprising

i. hydrogen,

iii. the groups

at. the hydrogen atom,

d. oligoethers and

e. oligothioethers,

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom, R ₃ and R ₄ identical or different occupy the positions left free by Ri and R ₂ and are chosen from:

at. hydrogen

b. halogens

vs. the nitro group,

d. the sulphonate group

e. amino groups,

f. the carbonyl groups,

j. oligoethers and

k. oligothioethers

R ₅ represents:

a) is a straight or branched C ₁ -C 12 alkyl group, said alkyl groups may be saturated or unsaturated and may comprise one or more heteroatoms selected from O and S,

(b) oligoethers and

or (c) oligothioethers.

By way of example, compounds of formula (Ial) and

(Lbl) - 21 -

The interest of the various synthons used in the process according to the invention is the possibility of elaboration of many π-conjugated organic materials, in particular thanks to the reactivity of the 9-position of the carbazole ring and the 9-position of fluorene. The π-conjugated organic materials derived from said synthons may be polyfunctional, ie they have a center connected to several synthons. Also the process according to the invention gives a wide possibility of synthesis of new π-conjugated organic materials. In addition, the synthesis of these π-conjugated materials is made easy by the use of the synthon since one can have access to certain π-conjugated materials of complex structures in a single step from this synthon.

These π-conjugated materials have applications in optoelectronics, especially for charge transport and / or photon absorption. Examples that may be mentioned include OLEDs, organic transistors, organic photovoltaic cells, hybrid cells and perovskites cells.

The compounds of formula (Ia), (Ib) and (Ib ')

(the)

(Ib)

(Ib ') in which

i. hydrogen, halogens,

the aryl groups, said aryl groups possibly being substituted with at least one straight or branched C1-C5 alkyl group, in particular a methyl group,

the groups

at. the hydrogen atom,

d. oligoethers and

e. oligothioethers,

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen,

b. halogens, vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

boy Wut . mono or polycyclic aromatic groups

h. straight or branched C ₁ -C ₁₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

j. oligoethers and

k. oligothioethers

R ₅ is chosen from:

b. oligoethers,

vs. oligothioethers,

R ₆ is alkyl C ₁ -C ₁₂ straight or branched, or an aryl group of C ₆ -C _8, in particular a benzene group or methoxybenzene (anisole), or an amine protecting group, in particular a group benzyl, optionally substituted alkoxy C ₁ -C 5 or an aryl group of C ₆ -C _{8 alkyl} substituted by halogen, in particular fluorine or substituted with alkyl C ₁ -C ₁₂ straight or branched fluorinated, in particular, trifluoromethyl (CF 3), or bistral, tri or tetracyclic group comprising from 10 to 18 carbon atoms, for example a naphthyl, tetrahydronaphthyl, anthracenyl or pyrenyl group are new and form part of the invention. There may be mentioned in particular the compound of the following formula:

The compounds of formula (I) may be prepared by any technique known to those skilled in the art from compounds available commercially or which may be prepared according to techniques known to those skilled in the art or described in the literature.

Thus, the method illustrated in the following diagram 1 can be used:

Diagram 1

The first step (ii) is the iodination of positions 3 and 6 of carbazole in acetic acid at 85 ° C in the presence of potassium iodide and potassium iodate as described by Tucker, SHJ Chem. Soc. 1926, 129, 546. It is followed by a second step (i) which consists in protecting the amine at position 9 of the diiodocarbazole with a benzyl group in the presence of sodium hydride in anhydrous tetrahydrofuran (THF) at room temperature (Estrada, LA; Neckers, DC Organic Letters 2011, 13, 3304). In a third step, a CN coupling makes it possible to fix the bis (4-methoxyphenyl) amine group at the 3 and 6 positions of the carbazole unit; this step is carried out in toluene at 110 ° C. in the presence of a palladium catalyst, tris-terbutylphosphine and sodium butyloxate (Yamamoto, T., Nishiyama, M., Koie, Y. Tetrahedron Letters 1998, 39, 2367). The last step is a deprotection reaction to remove the benzyl group from the 9-position of the carbazole core to make the amine function available for later use; it is carried out in THF and dimethylsulfoxide (DMSO) in the presence of potassium and oxygen terbutylate (Haddach, AA, Kelleman, A. Deaton-Rewolinski, MV Tetrahedron letters 2002, 43, 399). The compounds of formula (I) as defined above can also be prepared by a process comprising:

a) a step of protecting W when W represents a group -N (H) - in the compound of formula (II)

and

R ₃ and R _{4, which are} identical or different, are chosen from

hydrogen,

halogens,

the nitro group,

the sulphonate group,

amino groups,

the carbonyl groups,

mono or polycyclic aromatic groups,

viii. straight or branched C ₁ -C ₁₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S, ix. straight or branched C ₁ -C ₁₂ alkoxy radicals, which alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S,

x. oligoethers and

xi. oligothioethers,

provided that if R ₃ is in position 2 then R ₄ is not in position 7 and if R ₃ is in position 3 then R ₄ is not in position 6,

to give a compound of formula (III)

where GP is an amine protecting group, and wherein R 1 and R ₂ are hydrogen. b) treating the compound of formula (II) wherein W represents a group -CHR ₆ - or a compound of formula (III) with a halogenated derivative, to give a compound of formula (IVa) or (IVb)

(IVa) (IVb) in which

R ₃ and R ₄ are as defined in claim 1 and

X, at position 2 and 7 of the fluorene or 3 and 6 carbazole represents a halogen atom, especially an iodine or bromine atom,

c) a coupling reaction of said compound of formula (IVb) or (IVa) to give a compound of formula (Vb) or (la)

(la) (Vb) in which R 1, R ₂ , R 3 and R ₄ are as defined above and

d) if necessary the deprotection of the compound of formula (Vb) to give a compound of formula (Ib).

In an advantageous embodiment, the amine protecting group GP is chosen from: a benzyl group, optionally substituted by a C1-C5 alkoxy group, acetyl groups, tert-butyloxycarbonyl (Boc) and carbamate.

The compounds of formula (Ib ') in which R ₆ represents a polycyclic group, in particular a bicyclic tri- or tetracyclic group comprising from 10 to 18 carbon atoms, for example a naphthyl, tetrahydronaphthyl, anthracenyl or pyrenyl group, are prepared from the corresponding compounds of formula (Ib) according to techniques known to those skilled in the art. The subject of the invention is also π-conjugated materials of formula (Ibl)

(Ibl)

in which

- Ri and R ₂ , identical or different, are respectively in position

3 and 6 or in position 2 and 7 of carbazole and are selected independently of each other in the group comprising

i. the aryl groups, said aryl groups possibly being substituted with at least one straight or branched C ₁ -C ₅ alkyl group, in particular a methyl group,

ii. the groups

at. the hydrogen atom, b. straight or branched C ₁ -C ₁₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

vs. straight or branched C ₁ -C ₁₂ alkoxy radicals, which alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S,

d. oligoethers and

e. oligothioethers

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen,

b. halogens,

vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

boy Wut . mono or polycyclic aromatic groups, h. straight or branched Ci-Ci ₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

j. oligoethers and

k. oligothiethers

and

Q represents a spacer selected from the group consisting of: at. C1-C12 alkylenyl groups,

b. arylenyl groups,

vs. oligoethers and

d. oligothioethers.

By "arylènyles groups" is meant a arylènyle C ₆ -C _8, unsubstituted or substituted with one or more C ₁ -C _12. In a particular embodiment of the invention, the arylenyl group represents a fluorenyl group substituted with one or more C ₁ -C ₁₂ alkyls at the 9-position of fluorenyl.

By way of example of compound (Ibl), mention may be made of the following compounds 4 to 11:

The compounds of formula (Ibl) may be prepared by any technique known to those skilled in the art from the synthons of the invention, using products which are commercially available or which may be prepared according to techniques known to man of the art or described in the literature.

Thus it is possible to prepare the compounds of formula (Ibl) by reacting a synthon of formula (I)

in which

W, Ri, R ₂ , R 3, and R ₄ are as previously defined

with a compound of formula

X-Q-X

where X represents a halogen atom, especially an iodine or bromine atom to obtain a compound of formula (Ibl)

A very promising application of the present invention is the field of organic photovoltaics and particularly photovoltaic cells with dye or dye sensitized solar cell (DSSC). The process according to the invention has already allowed the synthesis of a number of π-conjugated organic molecules, semiconductors whose use instead of the liquid electrolyte in the DSSC has given preliminary results very promising. The best materials used under the same conditions as the market's reference molecule (spiro-OMeTAD), give comparable photovoltaic performances. These results demonstrate the strong potential of the present invention in this field since it will make it possible to develop many organic semiconductors to manufacture DSSC solid electrolyte.

Furthermore, the synthon may also be used to develop dyes having similarities of chemical structures with the semiconductors derived from this same synthon. Having strong affinities between the semiconductor and the dye will increase the dye / semiconductor interactions, which is favorable for the pore filling of the sensitized Ti0 ₂ .

Examples 1 to 11 which follow and FIGS. 1 and 2 illustrate the invention.

Figure 1 shows dark-current-voltage (J-V) curves of devices using semiconductors comprising compounds 4-7 synthesized according to Examples 2-5 in combination with D102 dye according to Example 11.

Figure 2: Current-voltage (VV) curves under illumination of devices using semiconductors comprising compounds 4 to 7 synthesized according to Examples 2 to 5 in combination with dye D102 according to Example 11. Example 1 Synthesis of VV ³ , VV ³ , VV ⁶ , VV ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine (brick 3.6)

It is carried out according to diagram 1.

Diagram 1

The first step is a protection of the 9-position amine of carbazole with a benzyl group according to Estrada, L.A. Neckers, D. C. Organic Letters 2011, 13, 3304. The second step consists of the iodization of the 3 and 6 positions of the carbazole core according to Tucker, S.H. J. Chem. Soc. 1926, 129, 546. In a third step, a C-N coupling makes it possible to bind the bis (4-methoxyphenyl) amine group to the 3 and 6 positions of the carbazole unit according to Yamamoto, T.; Nishiyama, M. ; Koie, Y. Tetrahedron Letters 1998, 39, 2367. The last step is a deprotection reaction to remove the benzyl moiety from the 9-position of the carbazole core to make the amino function available for later use according to Haddach, A.A. Kelleman, A.; Deaton-Rewolinski, M. V. Tetrahedron letters 2002, 43, 399.

1.1. Synthesis of 9-benzyl-9H-carbazole (1)

In a solution of carbazole (10 mmol, 1.7 g, leq) in anhydrous tetrahydrofuran (about 30 mL) at room temperature, sodium hydride (20 mmol, 0.7 g, 2 eq) is added slowly. There is a gas evolution (H ₂ which is released) and the solution changes color from yellow to whitish. The mixture is left stirring at room temperature for one hour when the solution becomes light brown. Benzyl bromide (1.8 mL, 1.5 eq) is added dropwise stirring at room temperature. The mixture is left stirring for about 3 hours and TLCs are made to check if the reaction is complete. At the end of the reaction, water is added to the reaction mixture which is extracted with diethyl ether. The combined organic phases were dried with MgSO ₄ and the solvent was then evaporated. The solid obtained is washed with n-hexane.

The product is obtained in the form of a low-density white solid.

Yield: 80% 1.2. Synthesis of 9-benzyl-3,6-diiodo-9H-carbazole (2)

9-benzyl-9H-carbazole of the step obtained in step 1.1 in a flask. (16 mmol, 4.1 g, leq) is dissolved in glacial acetic acid (40-50 mL) at 80 ° C. After complete dissolution of 9-benzyl-9H-carbazole, potassium iodide (KI, 20.8 mmol, 3.5 g, 1.3 eq) and potassium iodate (KI0 ₃ , 12.8 mmol, 2.75 g, 0.8 eq) are then added. The temperature is maintained at 80 ° C until the complete consumption of I ₂ formed. The mixture is then left stirring at 80 ° C. until a white precipitate appears. After the appearance of the precipitate, TLCs are made to check if the reaction is complete. A solution of sodium thiosulfate at 5% is then added to the reaction mixture after returning to ambient temperature and the precipitate is recovered by filtration and then washed several times with water. The solid obtained is dried.

The product is obtained in the form of a white solid.

Yield: 98%

1.3. 9-Benzyl- / V ^{: 3} _/ / V ^{: 3} _/ / V ⁶ _/ / V ⁶ _/ tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine (3)

In a schlenk, diphenylamine (10 mmol, 2.3 g, 1 eq), the diiodinated carbazole obtained in step 1.2. (5 mmol, 2.54 g, 0.5 eq), tristbutylphosphine (0.2 mmol, 0.1 mL, 0.2 eq) and palladium acetate (Pd (OAc) ₂ ; 0.2 mmol, 5 mg, 0.2 eq) are added. After having adapted the bicol to a refrigerant, the mixture is placed under an argon atmosphere. Toluene (80 mL) is then added to the reagent mixture. After agitation for 15 minutes, at room temperature, sodium terbutoxylate (13 mmol, 1.25 g, 1.3 eq) is added to the reaction mixture. After adding the base, the mixture is refluxed at 110 ° C for one day. TLCs are made to check the end of the reaction. Once the reaction is complete, the crude is filtered with celite. The filtrate obtained is purified by column chromatography (eluent = petroleum ether / ethyl acetate 8: 2).

The product is obtained in the form of a yellow powder

Yield: 93% 1.4. / V ^{: 3} _/ / V ^{: 3} _/ / V ⁶ _/ / V ⁶ _/ tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine (brick 3.6)

The benzylcarbazole derivative obtained at step 1.3. (2 mmol, 1.45 g, 1 eq) is added to a flask and the medium is then placed under an argon atmosphere. Dimethylsulfoxide (DMSO) is then added and the reaction mixture is stirred at room temperature. A solution of potassium tert-butoxide (KO'Bu) at 1M in THF (12 mmol, 1.4 g, 6 eq, ie 12 mL of a solution of KO'Bu at 1M in THF) is then added to the mixture. The argon inlet is stopped and oxygen is bubbled into the reaction medium which remains stirred at room temperature for about 3 hours. TLCs are made to see the progress of the reaction. At the end of the reaction, water is added to the mixture and the crude is extracted with acetate. The organic phase is washed with a saturated solution of NaHCO ₃ to remove the benzoic acid formed and then with salt water. The organic phase is then dried with MgSO ₄ and the solvent is evaporated. After purification by chromatographic column (eluent = petroleum ether / ethyl acetate 7: 3), the product is obtained in the form of a light yellow powder.

Yield: 80% Example 2 Synthesis of 9 '- (14-phenylene) bis (v ³ , v ³ , v ⁶ , v ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine) (compound 4)

In a microwave reaction tube were added / V ^{: 3} _/ / V ^{: 3} _/ / V ⁶ _/ / V ⁶ _/ tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine (brick 3.6 ) prepared in Example 1 (0.48 mmol, 300 mg, 1 eq), 4,4'-diiodophenyl (0.24 mmol, 81 mg, 0.5 eq), potassium carbonate (K ₂ CO ₃₎ 3.84 mmol, 540 mg, 8 eq), copper (1.92 mmol, 120 mg, 4 eq) and ether 18-crown-6 (0.03 mmol, 10 mg, 0.06 eq) . After placing the tube containing the reagents under an inert atmosphere, 3 to 5 ml of orthodichlorobenzene are added thereto. The reaction medium is heated by microwave at 210 ° C for about 1 hour. TLCs are performed to see the progress of the reaction and at the end of the reaction, the reaction mixture is filtered to remove the remainder of the inorganic reagents. The filtrate obtained is concentrated in the evaporator (by evaporating a portion of ortho-dichlorobenzene).

The crude obtained is purified by precipitation in acetone to obtain a pale green solid.

Yield: 50% Example 3 Synthesis of 9,9 '- ([1 _/ l-biphenyl] -4,4'-diyl) bis (VV ³ , VV ³ , VV ⁶ , VV ⁶ , tetrakis (4-methoxyphenyl) -9H- carbazole-3,6-diamine) (compound 5)

In a tube for microwave reaction were added the brick [3,6] prepared in Example 1 (0.48 mmol, 300 mg, 1 eq), 4,4 'diiodobiphenyl (0.24 mmol, 98 mg, 0.5 eq), potassium carbonate (K ₂ CO ₃ , 3.84 mmol, 540 mg, 8 eq), copper (1.92 mmol, 120 mg, 4 eq) and ether 18- crown-6 (0.03 mmol, 10 mg, 0.06 eq) are added. After having placed the tube containing the reagents under an inert atmosphere, 3 to 5 ml of ortho-dichlorobenzene are added thereto. The reaction medium is heated by microwave at 210 ° C. for about 1 hour. TLCs were performed to see the progress of the reaction. At the end of the reaction, the reaction mixture is filtered to remove the remainder of the inorganic reagents. The filtrate obtained was concentrated in the evaporator (by evaporating a portion of ortho-dichlorobenzene). The crude obtained is purified by precipitation in acetone to obtain a pale green solid.

Yield: 43% Example 4 Synthesis of 9,9 '- (9,9-dihexyl-9H-fluoren-2,7-diyl) bis (VV ³ , VV ³ , VV ⁶ , VV ⁶ , tetrakis (4-methoxyphenyl) -9H -carbazole-3,6-diamine) (compound 7)

4.1. Synthesis of 9,9'-dihexyl-2,7-diiodo-9H-fluorene

4.1.1. Synthesis of 2,7-diiodo-9H-fluorene

Fluorene (4 g, 24 mmol, 1 eq) is dissolved in a mixture containing acetic acid (60 ml), water (13 ml) and sulfuric acid (2 ml) at 95 ° C. vs. After reducing the temperature to 80 ° C., the diiodine (4.2 g, 16.6 mmol, 0.7 eq) and the periodic acid (1.85, 8 mmol, 0.33 eq) are then added to the mixture. reaction which is then left stirring for about 1h. TLCs were performed to follow the evolution of the reaction. The precipitate formed was recovered by filtration and then washed with a saturated solution of NaHCO ₃ and water. The crude solid obtained was recrystallized from n-hexane.

The product is obtained in the form of a white solid.

Yield: 50%

4.1.2. Synthesis of 9,9'-dihexyl-2,7-diiodo-9H-fluorene

In a flask, the diiodinated fluorene obtained in the preceding step, (4.2 g, 10 mmol, leq), n-bromo-hexane (3.63 g, 22 mmol, 2.2 eq) and potassium tertbutoxide ( 3.36 g, 30 mmol, 3 eq) are dissolved in anhydrous THF (30 mL). After placing the medium under an inert atmosphere under argon, the reaction mixture is brought to 40 ° C and then left stirring overnight. TLCs were performed to follow the evolution of the reaction. At the end of the reaction, the reaction mixture is allowed to come to room temperature then poured into cold water. The resulting crude was extracted with diethyl ether, the combined organic phases were washed with brine and dried with MgSO ₄ . After evaporation of the solvent, the crude was purified by chromatographic column with eluent petroleum ether / ethyl acetate (9.5: 0.5).

The product is obtained in the form of a white solid.

Yield: 78% 4.2. Synthesis of 9,9 '- (9,9-dihexyl-9H-fluorene-2,7-diyl) bis (N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole-3 , 6-diamine)

In a tube for microwave reaction were added the brick [3,6] prepared in Example 1 (0.48 mmol, 300 mg, 1 eq), the diiodinated derivative of the fluorene prepared in the previous step (0). , 24 mmol, 141 mg, 0.5 eq), potassium carbonate (3.84 mmol, 540 mg, 8 eq), copper (1.92 mmol, 120 mg, 4 eq) and ether 18- crown-6 (0.03 mmol, 10 mg, 0.06 eq) are added. After having placed the tube containing the reagents under an inert atmosphere, 3 to 5 ml of ortho-dichlorobenzene are added thereto. The reaction medium is heated by microwave at 210 ° C. for approximately 2 hours. TLCs were performed to see the progress of the reaction. At the end of the reaction, the reaction mixture is filtered to remove the remainder of the inorganic reagents. The filtrate obtained was concentrated in the evaporator (by evaporating a portion of ortho-dichlorobenzene). The crude product obtained is purified by chromatographic column using the eluent: petroleum ether / ethyl acetate 7: 3.

The product is obtained in the form of a light yellow powder.

Yield: 44% Example 5 Synthesis of 9 '- ((((((oxybis (ethane-2-diyl)) bis (oxy) bis (ethane-2-diyl) bis (4-phenylene) bis (N ³ N ³

IM ⁶ , IM ⁶ , Tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine)

(compound 6)

5.1. Synthesis of 4,4 '- (((((oxybis (ethane-2,1-diyl)) bis (oxy) bis (ethane-2,1-diyl) bis (oxy) bis (iodobenzene)

5.1.1. Synthesis of ((oxybis (ethane-2, 1-diyl)) bis (oxy) bis (ethane-2, 1-diyl) bis (4-methylbenzenesulphonate) or ethylene glycol ditosylate

In a flask, ether glycol (10 mmol, 1 eq) is dissolved in tetrahydrofuran (20 ml), tosyl chloride (25 mmol, 2.5 eq) is then added and an aqueous solution of Potassium hydroxide (4ml, 16M, 64mmol, 6.4 eq) is then added dropwise to the reaction mixture. After stirring for about 7 hours at room temperature, TLCs were performed to follow the evolution of the reaction. At the end of the reaction, the reaction mixture is poured into a cold water solution and the precipitate formed is recovered by filtration.

The product is obtained in the form of a white solid

Yield: 85%

5.1.2. Synthesis of 4,4 '- ((((oxybis (ethane-2,1-diyl)) bis (oxy) bis (ethane-2,1-diyl) bis (oxy) bis (iodobenzene)

In a flask iodophenol (3.8 g, 17 mmol, 1 eq) is dissolved in dimethylformamide (60 ml), potassium terbutylate (2.9 g, 26 mmol, 1.5 eq) is then slowly added. . Ditosylate derived from ether glycol obtained in the previous step (4.3 g, 8.5 mmol, 0.5 eq) is then added to the reaction mixture which is left stirring overnight at room temperature. During the addition of the ditosylate, the formation of a white precipitate is observed. TLCs were performed to check the progress of the reaction. At the end of the reaction, water is added to the reaction mixture. The crude product obtained is then extracted with ethyl acetate and the combined organic phases are washed with saturated NaHCO ₃ solution and dried with MgSO ₄ .

The product is obtained in the form of a white solid.

Yield: 95%

5.2. Synthesis of 9,9 '- ((((((oxybis (ethane-2,1-diyl)) bis (oxy) bis (ethane-2,1-diyl) bis (4,1-phenylene) bis ( N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine)

In a tube for microwave reaction were added brick

[3.6] prepared according to Example 1 (0.48 mmol, 300 mg, 1 eq), the diiodinated derivative of ethylene glycol prepared in the previous step (0.24 mmol, 98 mg, 0.5 eq. ), potassium carbonate (3.84 mmol, 540 mg, 8 eq), copper (1.92 mmol, 120 mg, 4 eq) and ether 18-crown-6 (0.03 mmol, 10 mg) , 0.06 eq) are added. After having placed the tube containing the reagents under an inert atmosphere, 3 to 5 ml of ortho-dichlorobenzene are added thereto. The reaction medium is heated by microwave at 210 ° C. for about 1 hour. TLCs were performed to see the progress of the reaction. At the end of the reaction, the reaction mixture is filtered to remove the remainder of the inorganic reagents. The filtrate obtained was concentrated in the evaporator (by evaporating a portion of ortho-dichlorobenzene). The crude product obtained is purified by chromatographic column using the eluent: petroleum ether / ethyl acetate 7: 3.

The product is obtained in the form of a green powder

Yield: 45%. Example 6 Synthesis of N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9- (2-naphthalene) -carbazole-3,6-diamine (compound A), N ³ N ³ N ⁶ N ⁶ Tetrakis (4-methoxyphenyl) -9- (1-pyrene) -carbazole-3-diamine (Compound B) and N ³ , N ³ , N ⁶ , N ⁶ , Tetrakis (4-methoxyphenyl) ) -9- (4-fluorobenzene) carbazole-3,6-diamine

(compound C)

(Compound A) Compound (B) Compound (C)

Obtaining Compound A:

In a microwave tube, the synthon N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine (brick 3.6) obtained in Example 1 (1 g, 1 eq), NaOtBu (7 eq), 2-bromonaphthalene (1 eq) then Pd (OAc) ₂ (10%), tri-tert-butylphosphine (20%) and toluene (2 ml) are added under controlled atmosphere. The solution is heated with microwaves at 200 ° C. for 20 min then in an oil bath at reflux for 48 h. The solution is filtered on celite then purified by chromatographic column on silica gel. The yield is 87%.

Obtaining Compounds B and C: Compounds B and C are obtained according to the same protocol using respectively 1-bromopyrene or 1-fluoro-4-iodobenzene.

The yield obtained for compounds B and C are respectively 83% and 91%. Example 7 Synthesis of 9,9 '- (9-dodecanyl-9H-carbazole-3,6-diyl) bis (IM ³ , IM ³ , IM ^e , IM ^e , tetrakis (4-methoxyphenyl) -9H-carbazole 3,6-diamine) (compound 8)

In a microwave tube, the synthon N3, N3, N6, N6, tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine (brick 3.6) obtained in Example 1 (lg, léq ), NaOtBu (7eq), 3,6-dibromo-9-dodecylcarbazole (0.5eq) then Pd (OAc) 2 (10%), tri-tert-butylphosphine (20%) and toluene (2ml) are added under controlled atmosphere. The solution is heated with microwaves at 200 ° C. for 20 min then in an oil bath at reflux for 48 h. The solution is filtered on celite then purified by chromatographic column on silica gel. The yield is 35%.

Example 8: Synthesis of 9,9 '- (propyl) bis ⁽³ IM, IM ^3, ^an IM, IM ^e, tetrakis (4-methoxyphenyl) -9H-carbazol-3,6-diamine) (compound 9)

In a 100ml Schlenk, the synthon N ³ , N ³ , N ⁶ , N ⁶ , tetrakyl (4-methoxyphenyl) -9H-carbazole-3,6-diamine (brick 3.6) obtained in Example 1 (1 g, 2, 1 eq) and NaH (4 eq) are dissolved in 10 ml of DMF. The solution is stirred for one hour at room temperature. 1,3-Dibromopropane (léq) is added dropwise and the solution is stirred overnight. The reaction is quenched with 5 mL of MeOH. After evaporation of the solvent, the precipitate is solubilized in CHCl ₃ . The organic phase is washed and then dried over MgSO ₄ . The reaction crude is purified by chromatographic column on silica gel with a solvent mixture: petroleum ether / ethyl acetate. The yield is 35%.

Example 9 Synthesis of 9,9 '- (hexyl) bis (N3, N3, N6, N6, tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine) (compound 10)

Compound 10 was obtained according to the same protocol as that used in Example 8 using respectively 1,6 dibromohexane.

The yield obtained for the compound is 60%.

Example 10 Synthesis of 9,9 '- (dodecyl) bis (IM3, IM3, IM6, IM6, Tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine) (Compound 11)

Compound 11 was obtained according to the same protocol as that used in Example 8 using respectively 1,12 dibromododecane.

The yield obtained for the compound is 84%.

Example 11: Efficiency of molecular glasses of Examples 2 to 5 as organic semiconductors in ssDSSC devices.

The development of solid photovoltaic cells sensitized with dye is done in several steps. It begins with the preparation of the fluorine substrate doped with tin oxide (Sn0 ₂ : F or FTO) and ends with the deposition of the gold or silver electrode. The different stages of this manufacture will be described successively.

Manufacture of all-solid photovoltaic devices DSSC.

The four molecular glasses:

Compound 4: 9,9 '- (1,4-phenylene) bis (N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine), (obtained according to the method of Example 2);

Compound 5: 9,9 '- ([1,1'-biphenyl] -4,4'-diyl) bis (N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole -3,6-diamine), (obtained according to the method of Example 3);

Compound 6: 9,9 '- (((((oxybis (ethane-2,1-diyl)) bis (oxy) bis (ethane-2,1-diyl) bis (4,1-phenylene)) bis (N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole-3,6-diamine), (obtained according to the method of Example 5);

Compound 7: 9,9 '- (9,9-dihexyl-9H-fluorene-2,7-diyl) bis (N ³ , N ³ , N ⁶ , N ⁶ , tetrakis (4-methoxyphenyl) -9H-carbazole -3,6-diamine), (obtained according to the method of Example 4), have been used as organic semiconductors for DSSC devices in combination with D102 dye which is a commercial product, the chemical structure of which is shown below.

The manufacture of all solid DSSC photovoltaic devices (ssDSSC) was carried out according to the protocol well known to those skilled in the art and in particular described in the publication of Puckyte et al ("Carboazole-based molecular glasses for efficient solid-state dye-sensitized"). solar cells, Journal of Power Sources, 2013, vol 233, p86-92). Device performance measurements are made in the dark and under illumination (AM 1.5 G). The composition of the cell is as follows: FTO / TiO ₂ / D102 / HTM / Ag. Semiconductors are represented by hole transporting materials (HTM). The solutions used for the development of the hole transport layer have a concentration of HTM of 200 mg / mL in chlorobenzene, in the presence of additives commonly used for DSSC namely lithium bis (trifluoromethane) sulfonimide (LiTFSI ) and 4-tert-butylpyridine. The results obtained are shown in Figures 1 and 2 and summarized in Table 1 below.

Table 1: Photovoltaic parameters of devices using HTMs including compounds 4, 5, 6 and 7 in combination with D102 dye (in the dark and under illumination) Definitions of the abbreviations used in Table 1:

Jsc: surface density of current (m A. cm ^'2 )

Voc: open circuit voltage (V)

FF: form factor (%)

Conclusion

The characterizations were performed in the dark and under illumination (AM 1.5 G). The four devices show a diode characteristic in the dark and a photovoltaic effect under illumination by the appearance of a photogenerated current (see Figures 1 and 2). The short-circuit current densities obtained are between 4.17 mA.cm ^-2 and 7.45 mA.cm ^-2 and the values of the open circuit voltages are between 0.73V and 0.82V. Photovoltaic conversion efficiencies range from 1.34% to 2.36%. Compound 5 is the one which made it possible to obtain the best conversion yield which is 2.36%.

Claims

1. Process for synthesizing π-conjugated materials comprising a step of implementing a synthon of formula (I)

in which

W represents either a -C (HR ₅ ) - group or a -N (H) - group,

i. hydrogen,

ii. monocyclic or polycyclic aromatic group which groups may be substituted with at least one alkyl group in Ci-Ci ₂ straight or branched, in particular methyl, or by alkoxy, Ci-Ci ₂ straight or branched, in particular methoxy,

iii. the groups

vs. straight or branched C ₁ -C ₁₂ alkoxy radicals, which alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S, and

d. oligoethers,

e. oligothioethers, with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen

b. halogens

vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

i. the alkoxy-Ci ₂ straight or branched, said alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S, and

j. oligoethers

R ₅ is chosen from: d. straight or branched C ₁ -C ₁₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

e. the (C ₆ -C ₈₎ aryl,

f. oligoethers,

boy Wut . oligothioethers,

h. heterocycles and

i. heteroaryls.

Process according to Claim 1, characterized in that in the compound of formula (I), R 1 and R ₂ each independently represent a group selected from:

i. phenyl, naphthyl, anthracenyl, indenyl, biphenyl, terphenyl and carbazolyl groups, said groups possibly being substituted with at least one straight or branched C ₁ -C 12 alkyl group, especially a methyl group, ii. the groups

at. either a hydrogen atom,

b. is alkyl Ci-Ci ₂ straight or branched, said alkyl group may be saturated or unsaturated and may have one or more heteroatoms selected from O and S,

vs. is a straight or branched C ₁ -C ₁₂ alkoxy group, said alkoxy group may be saturated or unsaturated and may comprise one or more heteroatoms chosen from O and S, in particular a methoxy group,

d. an oligoether,

e. an oligothioether.

Process according to any one of the preceding claims, characterized in that in the compound of formula (I), R ₃ and R ₄ each represent a hydrogen atom.

Process according to any one of the preceding claims, characterized in that the π-conjugated materials correspond to formula (Ib ')

(Ib ') in which

i. hydrogen,

ii. aryl groups, said aryl groups being able to be substituted by at least one alkyl group Straight or branched C ₁ -C ₁₂ , especially a methyl group,

iii. the groups

at. the hydrogen atom,

vs. the alkoxy-Ci ₂ straight or branched, said alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and

S

d. oligoethers and

e. oligothioethers

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen

b. halogens

vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups, boy Wut. mono or polycyclic aromatic groups

h. straight or branched C1-C12 alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

i. straight or branched C1-C12 alkoxy, said alkoxy groups being saturable or unsaturated and may comprise one or more heteroatoms selected from O and S,

f. oligoethers and

boy Wut. oligothioethers

and

R ₆ represents either a straight or branched C 1 -C 12 alkyl group or a C ₆ -C 18 aryl group, especially a benzene or methoxybenzene (anisole) group, or an amine protecting group, in particular an optionally substituted benzyl group; with a C ₁ -C ₅ alkoxy group, a C ₆ -C ₁₈ aryl group substituted by a halogen, in particular fluorine or substituted by a straight or branched fluorinated C 1 -C 12 alkyl group, in particular trifluoromethyl (CF 3) or a bi-, tri- or tetracyclic group comprising from 10 to 18 carbon atoms, for example a naphthyl, tetrahydronaphthyl, anthracenyl or pyrenyl group.

Process according to any one of the preceding claims, characterized in that the π-conjugated materials correspond to formula (Ia) or (Ib)

represents a polyfunctional central unit, that is to say a unit carrying functions for grafting in the 9-position of the carbazole ring or the fluorene ring.

n is an integer equal to or greater than 2, advantageously between 2 and 5,

i. hydrogen,

iii. the groups

at. the hydrogen atom,

d. oligoethers and

e. oligothioethers,

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen

b. halogens

vs. the nitro group,

d. the sulphonate group

e. amino groups,

f. the carbonyl groups,

j. oligoethers and

k. oligothioethers

I. oligothioethers

R ₅ is chosen from:

b. oligoethers and

vs. oligothioethers.

Compounds of formula (Ia), (Ib) and and (Ib ')

(Ib ') in which

i. hydrogen, halogens,

the groups

at. the hydrogen atom,

d. oligoethers and

e. oligothioethers,

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen,

b. halogens,

vs. the nitro group, d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

boy Wut . mono or polycyclic aromatic groups

j. oligoethers and

k. oligothioethers,

R ₅ is chosen from:

b. oligoethers and

vs. oligothioethers and

R ₆ is alkyl C ₁ -C ₁₂ straight or branched, or an aryl group of C ₆ -C _8, in particular a benzene group or methoxybenzene (anisole), or an amine protecting group, in particular a group benzyl, optionally substituted alkoxy C ₁ -C 5 or an aryl group of C ₆ -C _{8 alkyl} substituted by halogen, in particular fluorine or substituted with alkyl C ₁ -C ₁₂ straight or branched fluorinated, in particular trifluoromethyl (CF3), either bicyclic tri or tetracyclic group comprising from 10 to 18 carbon atoms, for example a naphthyl, tetrahydronaphthyl, anthracenyl or pyrenyl group.

7. Process for the preparation of the compounds of formula (I) according to claim 1, characterized in that it comprises:

and

R ₃ and R _{4, which are} identical or different, are chosen from

i. hydrogen,

ii. halogens,

iii. the nitro group,

iv. the sulphonate group,

v. amino groups,

vi. the carbonyl groups,

vii. mono or polycyclic aromatic groups,

viii. straight or branched C ₁ -C ₁₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

ix. the alkoxy-Ci ₂ straight or branched, said alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S,

x. oligoethers and

xi. oligothioethers,

provided that if R ₃ is in position 2 then R ₄ is not in position 7 and if R ₃ is in position 3 then R ₄ is not in position

6

to give a compound of formula (III) where GP is an amine protecting group,

b) treating the compound of formula (II) wherein W represents a group -CHR ₅ - or a compound of formula (III) with a halogenated derivative, to give a compound of formula (IVa) or (IVb)

(IVa) (IVb)

in which

R ₃ and R ₄ are as defined in claim 1 and

X, in position 2 and 7 of fluorene or 3 and 6 of carbazole represents a halogen atom, especially an iodine or bromine atom,

c) a coupling reaction of said compound of formula (IVa) or (IVb) to give a compound of formula (Vb) or (la)

(la) (Vb) in which R 1, R ₂ , R 3 and R ₄ are as defined in claim 1 and

d) if necessary the deprotection of the compound of formula (Va) to give a compound of formula (la).

8. π-conjugated materials of formula (Ibl)

in which

R 1 and R ₂ , which are identical or different, are respectively in position 3 and 6 or in position 2 and 7 of the carbazole and are chosen independently of each other in the group comprising

i. aryl groups, said aryl groups being able to be substituted by at least one alkyl group Straight or branched C1-C5, especially a methyl group,

the groups

at. the hydrogen atom,

S and

d. oligoethers

with the proviso that R 1 and R ₂ are not simultaneously a hydrogen atom,

at. hydrogen,

b. halogens,

vs. the nitro group,

d. the sulphonate group,

e. amino groups,

f. the carbonyl groups,

boy Wut . mono or polycyclic aromatic groups, h. straight or branched C ₁ -C ₁₂ alkyl groups, said alkyl groups being able to be saturated or unsaturated and possibly containing one or more heteroatoms chosen from O and S,

i. straight or branched C ₁ -C ₁₂ alkoxy radicals, which alkoxy groups may be saturated or unsaturated and may contain one or more heteroatoms selected from O and S, and

j. oligoethers,

and

Q represents a spacer selected from the group consisting of: a. C1-C12 alkylenyl groups,

b. arylenyl groups,

vs. oligoethers and

d. oligothioethers

9. Process for the preparation of the compounds of formula (Ibl), characterized in that a synthon of formula (I) is reacted

in which

W, R 1, R ₂ , R 3, and R ₄ are as defined in claim 1 with a compound of formula

X-Q-X

where X represents a halogen atom, especially an iodine atom to obtain a compound of formula (Ibl)