AU2011346645A1

AU2011346645A1 - Naphtalene monoimide derivatives and use thereof as photosensitizers in solar cells and photodetectors

Info

Publication number: AU2011346645A1
Application number: AU2011346645A
Authority: AU
Inventors: Ingmar Bruder; Felix Eickemeyer; Neil Gregory Pschirer; Helmut Reichelt; Jan Schoneboom; Rudiger Sens
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2010-12-22
Filing date: 2011-12-16
Publication date: 2013-07-04
Anticipated expiration: 2031-12-16
Also published as: CN103261191A; ZA201305463B; AU2011346645B2; KR101823719B1; WO2012085803A1; EP2655366A4; JP5940089B2; JP2014507397A; EP2655366A1; EP2655366B1; CN103261191B; KR20130132534A

Abstract

Provided are compounds of the formulae la and lb, in which the variables R, n, A, B, R

Description

Naphthalene monoimide derivatives and use thereof as photosensitizers in solar cells and photodetectors Description 5 The present invention relates to compounds of the formulae ia and 1b A /A 0. NO IL

A

R~ R R R2 {0a) R'N 10 in which R are identical or different aryloxy, aryithia, hetaryloxy or hetarylthio radicals, n is 0, 1, 2, 3, 4 or 5, 15 B is Ci-Ci-akylene or 1,4-phenylene, where the phenylene radical may be mono- or polysubstituted by alkyl, nitro, cyano and/or halogen, A is -COOM, -SO 3 M or -PO 3 M, 20 M is hydrogen, an alkali metal cation or [NR']4 R' is hydrogen or aikyl, where the R' radicals may be the same or different, 25 L is a bridge of the formula -Ar- - -Ar-Ar-- O -Ar-Ar-Ar which may be mono- or polysubstituted by phenyl, alky alkoxy, alkylthto and/or 30 -NR 4 Rt and in which Ar is aryl or hetaryl which may be fused to saturated or unsaturated 5- to 18-membered rings which may comprise heteroators which may be the same or different in the case of two or three Ar, 2

R

4 , Ra are each independently hydrogen, alkyl whose carbon chain may be interrupted by one or more -0-, -3-, -CO-, -S0- and/or -SOr moieties, ary] or hetaryl, each of which may be mono- or polysubstituted by aikyl, alkoxy and/or alkyltho, 5 R'i R 2 are each independently radicals of the formula lla or lib R R ({ia) (lib) 10 Rs is phenyl, akyl, alkoxy, alkyithio or -NRR-. m is 0, 1, 2, 3 or4, X is C(R4R)q., NR, oxygen or sulfur and 15 Rl, R 7 , R8 are each independently hydrogen, alkyl whose carbon chain may be interrupted by one or more -0-, -S-, -CO-, -SO- and/or -S027 moieties, ary or hetaryl, each of which may be mono- or polysubstituted by alkyl, alkoxy and/or alkylthlo. 20 The present invention further relates to the use of compounds of the formula la or 1b or mixtures of compounds of the formulae la and lb and/or isomers or mixtures of the isomers of the compounds of the formulae la and Jb as photosensitizers in solar cells and photodetectors, and to solar cells and photodectors which comprise such compounds of the formula la or lb or mixtures of compounds of the formulae Ia and Ib and/or isomers or mixtures of the isomers of 25 the compounds of the formulae la and lb as photosensitizers. The direct conversion of solar energy to electrical energy in solar cells is based on the internal photoeffect of a semiconductor material, Le. the generation of electron-hole pairs by absorption of photons and the separation of the negative and positive charge carriers at a p-n junction or a 30 Schottky contact The photovoltage thus generated can bring about a photocurrent in an external circuit, through which the solar cell delivers its power. The semiconductor can absorb only those photons which have an energy which is greater than its band gap, The size of the semiconductor band gap thus determines the fraction of sunlight 35 which can be converted to electrical energy. Thin layers or films of metal oxides are known to constitute inexpensive solid semiconductor materials (n-semiconductors), but their absorption, owing to large band gaps, is typically not 3 within the visi be region of the electromagnetic spectrum. For use in solar cells, the metal oxides therefore have to be combined with a photosensitizer which absorbs in the wavelength range of sunlight, i.e. at from 300 to 2000 nm, and, in the electronically excited state, injects electrons into the conduction band of the semiconductor. With the aid of a redox system which is used 5 additionally in the cell and is reduced at the counterelectrode, electrons are recycled to the sensitizer which is thus regenerated. Of particular interest for use in solar cells are the semiconductors zinc oxide, tin dioxide and especially titanium dioxide, which are used in the form of nanocrystalline porous layers, These 10 layers have a large surface area which is coated with the sensitizer, so that high absorption of sunlight is achieved. Dye-sensitized solar celIs which are based on titanium dioxide as the semiconductor material are described, for example, in US-A-4 927 721, Nature 353, p, 737-740 (1991) and US-A-5 350 15 644, and also Nature 395, p. 583-585 (1998) and EP-A-1 176 646. These solar cells comprise monomolecular films of transition metal complexes, especially ruthenium complexes, which are bonded to the titanium dioxide layer via acid groups, as sensitizers and iodine/iodide redox systems present in dissolved form or amorphous organic p-conductors based on spirobifiuorenes 20 Also proposed repeatedly as sensitizers, not least for reasons of cost, have been metal-free organic dyes, For example, US-A-6 359 211 describes, for this purpose, cyanine, oxazine, thiazine and 25 acridine dyes which have carboxyl groups bonded via an aikylene radical for securing to the titanium dioxide semiconductor, Peryene-3,4:9,10-eracarboxyic acid derivatives as sensitizers are examined in Japanese documents JP-A-i0-189065, 2000-243463, 2001-093589, 2000-100484 and 10-334954, and in 30 New J. Chem, 26, p. 1155-1160 (2002). The liquid electrolyte solar cells based on these perylene derivatves, however, exhibited much lower efficiencies than a solar cell sensitized with a ruthenium complex for comparison. The most extensively examined sensitizers at present include dyes which possess a 35 cyanoacryIate anchor group, For example, Kim, S.; Lee, J.K. Kang, S.; Yum, jH.; Fantacci, S.; DeAngelis, F. Di Censo, D. Nazeerruddin, M.K; Gretzel, M. JACS 2006, 128, 16701 examines the compound 4 COOH ON S JK2 and Solar Energy Materials & Solar Cels 2009 93, 1143 examines the compound .5 N , N According to Solar Energy Materials & Solar Cells 2009, 93, 1143, however, the cyanoacrylate 10 anchor groups are not sufficiently stable; decarboxylation of these dyes was found and i was suspected that the anchor groups are unstable to light, Dyes wth naphthalene monoimide anchor groups are described in the document WO 2008/132103 Al, but these compounds absorb in the short-wave spectral region of sunlight 15 (absolute maximum at about 450 nm) and are therefore unsuitable for efficient absorption and conversion of sunlight.

5 It has now been found that, surprisingly, compounds of the formulae la and lb of the present invention which comprise naphthalene monoimide groups as anchor groups exhibit good to very good quantum efficiencies with very good stabilities in dye solar cells. 5 Accordingly, the compounds of the formulae la and lb detailed at the outset have been found, as has the use thereof as photosensitizers in solar cells and photodetectors. in the context of the present invention, aryl is an aryl radical, unit or group, especially a radical with a base skeleton of 6 to 30 carbon atoms, preferably 6 to 18 carbon atoms, which is formed 10 from one aromatic ring or a plurality of fused aromatic rings, Suitable base skeletons are, for example, phenyl, benzyl, naphthyl, anthracenyl or phenanthrenyL This base skeleton may be unsubstituted, which means that all carbon atoms which are substitutable bear hydrogen atoms, or substituted at one, more than one or all' substitutable positions of the base skeleton. Suitable substituents are, for example, alkyl radicals, preferaby alkyl radicals having 1 to 8 carbon 15 atoms, more preferably methyl, ethyl, i-propyl or t-butyl, ary. radicals, preferably Crvaryl radicals, which may in turn be substituted or unsubstituted, heteroaryl radicals, preferably heteroaryl radicals which comprise at least one nitrogen atom, more preferably pyridy radicals, alkenyl radicals, preferably alkenyl radicals which bear a double bond, more preferably alkenyl radicals with one double bond and 1 to 8 carbon atoms, or groups with donor or acceptor action. Groups 20 with donor action are understood to mean groups which have a +1 and/or +M effect, and groups with acceptor action are understood to mean groups which have a -l andor -M effect Suitable groups with donor or acceptor action are halogen radicals, preferably F, Cl, Br, more preferably F, alkyl radicals, aikoxy radicals, aryloxy radicals, carbonyl radicals, ester radicals, amine radicals, amide radicals, CH2F groups, CHF2 groups, CF groups, CN groups, thio groups or 25 SCN groups, The aryl radicals most preferably bear substituents selected from the group consisting of methyl. ethyl, iso-propyl, r-propy, ntbutyl, iso-buty, ertbuty, aryloxy, amine, thio groups and aikoxy, or the aryl radicals are unsubstituted. The aryl radical or the aryl group is preferably a phenyl radical which is optionally substituted by at least one of the aforementioned substituents. The phenyl radical more preferably has none, one, two or three of the 30 aforementioned substituents, In the context of the present invention, heteroaryl is a heteroaryi radical, unit or group, a radical which has 5 to 30, preferably 5 to 18, carbon atoms and/or heteroatoms and differs from the aforementioned aryl radicals in that at least one carbon atom in the base skeleton of the aryl 35 radicals is replaced by a heteroatom. Preferred heteroatoms are N, 0 and S. Most preferably, one or two carbon atonis of the base skeleton of the aryl radicals are replaced by heteroatoms. The base skeleton is especially preferably selected from systems such as pyridyi, pyrimidyl, pyrazyl and triazolyl, and five-membered heteroaromatlcs such as pyrrole, furan, thiophene, imidazole, pyrazole, triazole, oxazole and thiazole. The base skeleton may be substituted at 40 one, more than one or all substitutable positions of the base skeleton, Suitable substituents are the same as have already been mentioned for the aryl groups., a In the context of the present invenion, the aryloxy, arylthio, hetaryloxy and hetarylthio radicals derive in a formal sense from the aforementioned ary and heteroaryl radicals by attachment of an oxygen or sulfur atom to a carbon atom of the aryl or heteroaryl radical. 5 In the context of the present Invention, alkyl is an alky radical, unit or group, especially a radical having I to 20 carbon atoms, preferably 1 to 12 carbon atoms This alkyl radical may be branched or unbranched and optionally be interrupted by one or more -CO, - -, -SO and/or -S--r moieties, AIkyl is more preferably selected from the group consisting of methyl, ethyl, F-propyl, n-propy, i-butyt, n-but, t-butyl, sec-butyl, i-pentyl, n-pentyl, sec-pnty, 10 neopentyl, n-hexy,. -hexyl and sec-hexyl In the context of the present invention, alkoxy and alkylthio radicals derive in a formal sense from the aforementioned alkyl radicals by attachment of an oxygen or sulfur atom ho a carbon atom of the alkyl radical, 15 In the context of the present invention, hakagen is preferably F., Cl or Br, more preferably F In the context of the present invention, alkali metal cation is preferably Li, Na, Cs or K, more preferably Na. 20 When the bridge L is mono- or polysubstituted by phenyl, alkyl, alkoxy, aikyithio and/or -NR4R5, this means that these substituents are attached to suitable positions on the aromatic and heteroaromatic Ar groups. 25 When the bridge L comprises two or three Ar, they may be The same or different. Examples of suitable Ar include 1,4-, 1,3- and 1,2-phenyiene, 1,4- and 1,,8-naphthylene, 1,4 and 2-pyrryiene, 2,S, 2,4- and 2-thienylene, 2,5-, 2,4- and 2,3-furanyiene, 2,3-, 2,4-, 2,5, 2,6, 3,4- and 3,5-pyridinylene, 2,3-, 2,5-, 2,6-, 3,7-, 4,8-, 5,8- and 6,7-quinolinylene, 2,7-, 3,6, 30 4,5-, 2,8-, 3,7-, 4,7- and 4,S-isoquinolinylene, 1,4-{2,5-di(teitbutyi)jptienylene, 1 ,4-(25 dihexyl)phenylene, 1,4-[25di(tert-octyl)]ylenelene, 1,4-(25didodecyi)phenyiene and 1,4-[2,5 di(2-dodecyi)]phenylene. Especially useful as Ar are 1,4-phenylene and 2,5-thienylene. Suitable bridges L are, for example: 35 7 preferably: S 5 Preference is given to inventive compounds in which, in the formulae Ta and Ib; R are identical or different arytoxy or aryfthic, especiafly phenoxy or phenythbi, radicals, 10 n is 0, 1 or 2, B is Crraikylene, especially -Cr, -(H2)r and -(H2)r, 15 A is -COOM, M is hydrogen or an alkali metal cation, L is a bridge of the formula 20 -Ar-Ar- or -Ar-AT-Ara which may be mono- or polysubstituted by phenyl, Cr-Cjakyl, C,-Ciralkoxy, Cr

C

2 -alkylfthio and/or -NR4R%, and in which Ar is identical or different aryl or hetaryl which may be fused to saturated or unsaturated 5- to I 8-rnembered rings which may comprise heteroatoms, 5 R, R6 are each independently hydrogen, C-Cr2-aIkyI whose carbon chain may be interrupted by one or more -0-, -S-, -CO-, -SO- and/or -SOr moieties, R, R 2 are each independently radicals of the formulae Ia and IWb 10 3 x (Ira) (irt) Ris CeCeakoxy, 15 M is 0 or 1, X is C(RR7) 2 NRt oxygen or sulfur and R6, R, R6 are each independently hydrogen, Ce-C 1 aIkyi whose carbon chain may be 20 interrupted by one or more -0-, -S-, -CO-, -SO- and/or -30- moieties. Particular preference is given to Inventive compounds in which, in the formulae [a and Ib, n is 0, 25 B is Ci-Cralkyene, especially -CH- and -(CH 2

)

2 -, A is -COOM, 30 M is hydrogen or an alkali metal cation, L is a bridge of the formula -Ar-Ar or -Ar-A-Ar 35 in which Ar is identical or different aryl or hetaryl, RX R 2 are each independently radicals of the formulae W~a and 1I'b 9' X (il'a) (lih) RF3 iS-C1 2 -alkoxy, 5 m [secr1, X is C(RPR2 and 10 R, R' are each independently hydrogen or Ci-C*ralkyl. The invention shall encompass not only the compounds of the formulae Ia and Ib and the preferred embodiments thereof, but also mixtures thereof, the isomers thereof and the mixtures of the isomers. 15 For example, the invention aLso includes isomeric compounds of the formula I*b shown below: A N. L (1*b) 20 Examples Example 1: 10 COOH 0 N 0 The preparation (according to Ko et at Chemical Comm unrloations, 2004, 6B-69) proceeded from (4-bromopheny!)bis(9,90-dimeth-y -9H-fluioreni-2-yl)am ine, which was first reacted with 5thiophene-2,5-diboronic ester O- O (step a). This was flowed by the coupling with the methyl ester of N-(2-carboxyethyl)-4 hchporonaphthalimide and deprotection of the ester group (step b). Step a): A mixture of 1 y66 g (298 mmo) of (4romophAeny2)bis(99-dimethyH-fluorre-2-y)amie, 2,00 g (5,96 mmol) of thiophne-25-diboronic ester, 0,82 g (5.96 mmol) of K2CO dissolved in 155.2 mL of 10:1V H20/ethanol, 92 mg (0.06 miml) of Pd(PPhs1)4 and 10 m L of toluene was heated to 85"C under nftrogen anid stirred at this temperature for 4 h. After cooling, the reaction mixture was filtered off with suction. The mother liquor was extracted by shaking with dihooehn/zThe so.Nvent was removed f-rom the organic phase and 20the residue was dried, The crude product iwas used unpurified mn the next reaction step. Step b); A mxturep of 200 g of stage a crude product, 33 g (4.38 mmo) t of the m ethylt N-(2 carbxyethyl)-4-chloronaphthaimide, 504 mg (0.055 mmol) of Pd2(dba)3, 1,43 gj (4.38 mal) 11i of Cs2C03, 26.3 mg (0.13 mmol) of tributylphosphine and dioxane was heated to 90*C and stirred at this temperature for 6 h..After cooling, the reaction mixure was filtered off with suction and then the solvent was removed from the mother liquor The crude product was purified by column chromatography with n-hexane/ethyl acetate (2:1). 70 mg of the protected compound 5 were obtained, The latter was stirred with 200 mg of KOH in 10 mL of 1:1 demineralized water:THF at 60*C for one day. After cooling, 10 mL of conc., HCI were added and the mixture was stirred for I h. Then the reaction mixture was added to demineralized water The solid was filtered off with suction, 10 washed with hot demineralized water and dried, The purfication was effected by column chromatography with the eluent 10:1 dich loromethane:ethanol + 2% trimethylamine, The solid obtained was extracted by stirring with 50% acetic acid at 60C, flltered off with suction and washed with hot demineralzed water, After 15 drying, 1.2 g af a red solid were obtained. Analytical data IH NMR (500MHz, CDCI3, 25*C): = 879 (d, 1H); &68 (d,1H); 8.63 (d, 1H); 7.88 (d, IH):; 7.80 (q, 1 H), 766 (d, 2H); 7.63 (d, 2H); 7.58 (d, 2H); 740 (t, 3H); 7.33 (m, 3H); 7.27 (m, 4H-); 7.23 (d, 20 2H); 7.15 (d, 2H); 5.02 (s, 2H); 1A3 (s, 12H) 12 Example 2: COOH QN 0 4 N 0 2a 5The preparation (according to Ko et aW, Chemical Comnmunfications, 2004, 68-69) Proceeded from (4-bromopheniy. )bi s(9,9-d~jinethyi-9H-fluoren-2-,y1)aminte., which was first reacted with 2,2 bisthiloph ene- 5 bronic ester (step a). Thisww allowed -by the brom ination (step b) and then the coupling wIth the 4-boronic ester naphthalimide of the structure COOMe O NQ O) o 10 a nd deprotection of the ester group p (step c).

13 Step a: A mixture of 1,67 g (3,00 mmol) of (4-bromophery)bis(9;9-dimethyL9H-fioren-2-yi~amine, 1,80 mL (9,00 mmol) of 5 molar NaOH and 10 mL of dioxane was degassed with argon for 30 mir. Then 54 mg (0.160 mo) of Pd[P(tBu)Kh and 1.00 g (3.42 mmo[) of 2,2-bisthiophene-5 5 boronic ester were added, and the mixture was heated to 85*C and stirred over the weekend. After cooling, 10 the reaction mixture was added to ice-water. Subsequently, it was extracted with dichioromethane and the solvent was removed from the organic phase. The residue was dissolved in a little tetrahydrofuran. Methanol was added thereto until a solid precipitated out. The latter was filtered off with suction, washed with a little methanol and dried. 1.40 g of a yellow solid were obtained, which corresponds to a yield of 73%, 15 Analytical data: 'H NMR (500MHz, DMSO, 25*C): $ -7.77 (m, 4H); 7.62 (d, 2H); 7.51 (d, 3H); 7,41 (d. 1H); 7.31 (m, 8H); 7.11 (m, 3H); 7.05 (d, 2H); 1.37 (a, 12H) 20 Step b: A solution of 466 mg (2,62 mmol) of Nbromosuccimide and 10 mL of DMF was added dropwise at 0-5SC to a mixture of 1.40 g (2.18 mmod) of stage a and 20 mL of dimethylformamide (DMF). Stirring was then continued at this temperature for 15 min and then 10 rmL of dilute sodium thiosulfate solution were added. The reaction mixture was added to 150 mL of demineralized 25 water and extracted with methyl tert-butyl ether (MTBE). The solvent was removed from the organic phase and the residue was dried. 1.20 g of a yellow solid were obtained, which corresponds to a yield of 76%. Analytical data: 30 'H NMR (500MHz, DMSO, 25'C); 6 = 7.77 (m, 4H); 7.62 (d, 2H); 7.51 (d, 2H); 742 (d, 1H); 7.31 (m; 7H); 7.23 (d, 1H); 7.17 (d, 1H); 7.11 (d, 2H); 7,06 (d, 1H); 1,37 (s, 12H) Step c: A mixture of 1.00 g (1.4 mmol) of stage b, 0.84 mL (4.2 mmol) of 5 molar NaOH and 15 mL of 35 dioxane was degassed with argon fbr 30 mm, Then 24 mg (0.05 mmol) of Pd{P(tiBU)z and 0.97 p (1 mmol) of the 4-boronic ester naphthalimide (65%) shown above were added, and the mixture was heated to 85*C and stirred for I day. After cooling, the reaction mixture was added to ice-water and extracted with dichloromethane. The solvent was removed from the 14 organic phase. The residue was purified by means of column chromatography with the eluent 4:1 dichioromethane:methanoL Protected target product was obtained, which was stirred with 1:1 THFwater and I g of KOH at 5 65*C ovemight, After cooling, the reaction mixture was added to water, and 15 mL of conc. HCI were added. The mixture was stirred at room temperature for I h. Then the solid was filtered oIf with suction, washed and dried. The crude product was purified by means of column chromatography with the eluent 4:1 dichloromethane:mehant This gave 330 mg of a red soid, which corresponds to a yield of 26%. 10 Analytical data: IH NMR (500MHz, DMSO, 25C): S = 8.80 (d 1 H); 861 (r, 1 H); 8-55 (d, I H); 7-99 (q, 2H); 7,76 (g, 4H); 7-65 (d, 2H); 7.55 (q, 2H); 7.51 (d, 2H); 7.47 (d, 2H); 7.30 (m, H); 7.12 (d, 2H); 7.06 (d, 2H); 4.75 (s, 2H); 1.34 (s, 12H) 1.5 Example 3: COO IN 4 N MeO~ / 3a The preparation proceeded from diarylamine, which was fis reacted with bisthiophene-5 20 boronic ester (step a). This was followed by brominaton (step b) and then coupling with 2-boronic ester naphthalimide (slep c): 15 Step a: A mixture of 1.80 g (2.9 mmol) of diarylamine, 15 mL of dioxane and 1.74 mL (8,7 mmol) of 5 molar NaGH was degassed with argon ror 30 min, Then 1 mg (0,I mmOl) of Pd(P(tBU)J 2 and 0.91 g (3.11 mmol) of bisthiophene-5-boronic ester were added, and the mixture was heated to 5 85C and stirred over the weekend. After cooling, the reaction mixture was added to ice-water and extracted with dichloromethane, The sdvent was removed from the organic phase, and the residue was dissolved in a little THF and methanol was added. The precipitated solid was filtered off with suction and dried, The purification was effected by means of column chromatography with the eluent ni.hexane + 2% ethyl acetate. This gave 1,70 g of a yellow solid, 10 which corresponds to a yield of 85%. Analytical data: 1H: NMR (500MHz, DMSO, 25 *C). = 741 (d 4H), 7,34 (d, 2H); 7.26 (d, 1H); 7,14 (d, 11); 7-08 (d. 1H); 7.04 (d, 1H); 6.99 (d, 2H); 6,86 (d, 3H); 6.81 (d, 2H); 6.76 (d, 2H); 6.65 (d, 2H); 356 (S 15 6H); 1.11 (s, 12H) Step b: A solution of 490 mg (2.40 mmol) of N-bromosuccimide and 10 mL of DMF was added dropwise at 0-5*C to a mixture of 1,6 g (2.3 mmol) of stage a and 30 m L of DMF. Stirring was then 20 continued at this tempernature for 15 min and then 10 mL of dilute sodium thiosulfate solution were added. The reaction mixture was added to 150 mL of demineralized water- The solid was filtered off with suction, washed and dried. 1. 62 g of a yellow solid were obtained, which corresponds to a yield of 90%. 25 Analytical data: 1H NPR (500MHz, DMSO, 25'C): 8 = 7.66 (d, 4H); 7. 58 (d, 2H); 7.40 (d, IH); 7.30 (d, 1H); 7.26 (d, 2H); 723 (d, 1H); 7.16 (d, 1H; 711 (d, 2H); 7,07 (d, 2H); 7.01 (d, 2H); 6.90 (d, 2H); 3,81 (s, 6H); 1 36 (s, 12H) 30 Se: A mixture of 1,00 g (1,3 mmol) of stage b, 0.78 mL (3.9 mmol) of 5 molar NaOH and 15 mL of dioxane was degassed with argon for 30 min. Then 26 nig (0,05 mmol) of Pd[P(tBu)]2 and 0,59 g (1.5 mmol) of the compound 16 ,C0OMe N ,,0 0B were added, and the mixture was heated to 85*C and stirred for 1 day. After coolrg, the reaction mixture was added to ice-water and extracted with dichloromethans, The solvent was removed from the organic phase. The residue was purified twice by means of column S chromatography with the eluent 4:1 dichloromethane:methanol This gave 630 mg of a red soid, which corresponds to a yield of 68%. Analytical data; ,H NMR (500MHz, DMSO, 25"C): = &,75 (d, 1H); 8.58 (d, 1H); 8.51 (d, 1H): 7.96 (m, 2H); 7.65 10 (d, 4H); 7,62 (d, 2H); 7,53 (s, 2H); 7AS (a, 2H); 7.26 (d, 2H); 7.11 (d, 2H); 7.07 (d, 2H); 7,2 (d, 2H); 6.90 (d, 2H); 4,51 (s, 2H); 3.81 (s 6H) 136 (s, 12H) Example 4: COOH o N ~ S O N Hg~~e 4aCH 17 The preparation proceeds from 4-hexyloxybromoberizene, which was reacted with p-hexyloxybronobenzene (step a). The resulting amine was reacted further with 1,4 dibromobenzene (step b), This was followed by coupling with 2,2-bisthiophene-S-boronic aster (step c) and bromination (step d). Finaly, coupling was effected with 2-boronic ester 5 naphthalimide and the ester group was deprotected (step e), Step a: A rnixture of 20 g (78 mmol) of 4-hexyloxybromobenzene, 18 g (93 mmol) of p-hexyloxybromobenzene, 037 g (3.9 mmol) of pailadium(li) acetate, 3.1 g (5.8 mmol) of 10 0PEphos, 12 g (125 mmol) of sodium tert-butoxi de and 100 mL of toluene was heated to I 00"C and stirred for one day. After coolng, the solvent was removed from the reaction mixture. The crude product was purified by means of column chromatography with the iMuent 2:1 dichloromethanethexane. 19. g of a white solid were obtained, which corresponds to a yield of 68%. 15 Analytical data: 'H NMR (500 MHz, CD2C12, 25"C): 5 = 6,91 (d, 4H): 679 (d, 4H); 5.35 (s, 1H); 3.90 (t, 4H); 174 (m, 4H); 1.45 (m, 4H); 1 34 (m, 6H); 0,91 (t,6H) 20 Step b: A mixture of 54 g (14.6 mmol) of stage a, 6.9 g (29.2 mmol) of 1,4-dibromobenzene, 275 mg (0.30 mmol) of Pd2(dba)s, 405 mg (0.73 mmi) of DPPF, 2.80 g (29.2 mmol) of sodium tert butoxide and 40 mL of toluene was heated to 90*C and stirred for 2 days. After cooling, the solvent was removed from the reaction mixture, The purification was effected by means of 25 column chromatography with the eluent 4:1 hexane:dichloronethane. 5.6 g of a light-colored oil were obtained, which corresponds to a yield of 72%. Analytical data: IH NMR (500MHz, DMSO, 25*C): 8:= 7.29 (d, 2H): 6,99 (d, 4H); 6.89 (d, 41); 6,66 (d, 2H); 3.92 30 (t, 4H); 1.69 (m, 4H); 1.40 (m, 4H); 1,30 (mn SH); 88 (t, 6H) Step c: A mixture of 1.6 g of stage b (3.1 mmoi), 15 mL of dioxane and 1.86 mL (9.3 mmol) of 5 molar NaOH was degassed with argon for 30 min. Then 51 mg (0.1 mmol) of Pd(P(tBu)] and 0,98 g 35 (3.31 mmd) of 2,2- bisthiophene-b-boronic ester were added, and the mixture was heated to 85C and stirred over the weekend After cooling, the reaction mixture was added to ice-water and extracted with dichloromethane, The solvent was removed from the organic phase The purification was effected by means of column chromatography with the eiuent n-hexane + 2% ethyl acetate. This gave 1,62 g of a yellow solid, wh[ch corresponds to a yield of 86%. 40 18' Analytical data: IH NMR (500MHz, DMSO, 25*C): = 7.48 (m, 3H); 7,30 (M, 2H); 7.25 (d, 1H); 7.09 (q, 1H); 7.03 (q, 4H); 6.92 (q, 4H); 676 (q, 2H); 3.94 (1, 4H); 1.70 (m, 4H); 1 -41 (m, 4H); 1.31 (m, BH); 0.88 (t, 6H) Step d: A solution of 430 mg (2.40 nmol) of N-bromosuccimnide and 10 rnL of DMF was added dropwise at 0-.5"C to a mixture of 1.2 g (2.00 mnol) of stage c and 30 mL of DMF. Stirring was then continued at this temperature for 15 min and then 10 mL of dilute sodium thiosulfate solution 10 were added. The reaction mixture was added to 150 mL of demineralized water and extracted with MTBE, and dhe solvent was removed from the organic phase. 1.0 g of a yellow solid was obtained, which corresponds to a yield of 73%. Analyhcal data: 15 1 H NMR (500MHz, DMSO, 25*C): = 7.46 (d, 2H); 7.29 (d, 1H); 7.27 (d, 1H); 7.21 (d, 1H); 7.14 (d, IH); 7,03 (d, 4H); 6.92 (d, 4H); 6,75 (d, 2H); 3.94 (t, 4H); 170 (m, 4H); 1.41 (m, 4H); 1.31 (n, 8H); O 98 (t 6H) Step e: 20 A mixture of 0,90 g (1.3 mmol) of stage d, 0,78 mL (3.9 mmol) of 5 molar NaOH and 15 mL of dioxane was degassed with argon for 30 min Then 22 mg (0.04 mmol) of Pd[P(tBu)] and 0,91 g (1.5 mmol) of the compound CO OMe O N-- 0 0 0 25 were added, and the mixture was heated to 850C and stirred for I day. After cooling, the reaction mixture was added to ice-water and extracted with dichloromethane, and the solvent was removed from the organic phase. The residue was purified twice by means of column chromatography with the eluert 4:1 dichloriomethane:iethanoi + 1% triethylamine. Protected 30 target product was obtained, which was stirred with 1:1 THF:water and 1 g of KOH: at 65*C overnight. After cooling, the reaction mixture was added to water and 15 mL of conc, HCI were added. The mixture was stirred at room temperature for I h. Then the mixture was extracted 19 with dichloromethane and the sovent was then removed from the organic phase. The crude product was purfied by means of column chromatography with the eluent 4:1 dichloromethane:methanoi + 2% triethylamine. This gave 610 mg of a red solid, which corresponds to a yield of 54%. 5 Analytical data: 1H NMR (50MHz, DMSO, 25"C): = 8.78 (d, 1H); 80 (d, 1H)i 8.53 (d, 1H); 797 (m, 2H); 7.53 (m, 4H); 7.41 (d, IH); 7,34 (d, 1H); 7.03 (d, 4H); 6.92 (d, 4H); 6 77 (d, 2H); 412 (s, 2H); 3.93 (t, 4H); 1.70 (n, 4H); 1.41 (m, 4H); 1.31 (m, 8H); 0.88 (t, 6h) 10 Example 5 (compound occurred as a mixture of the isomers 5a and Sb): /COON OH Ni , aq 15 [r y)amine (450 mg, 0.62 mmi) was dissolved in dioxane (15 ml), 5 molar NaOH (0,4 mL, 1,9 mmoi4) was added and the mixture was degassed with argon for 30 min, Then Pd[P(tBu ]2 (10 mg, 0.02 mmona) and 20 1 mmoi) were introduced and the mnixture- was stirred at 8WC overnight. Mter cooling, the mixture was added to ic-water and extracted with dichloromnethane, and the organic phase was concentrated. This gae490 mg of an orange solid, 20 Maldi-MS; M+ = 837,27 6S(5'44[B is-(9,9-dimethy9H-fluoren-2-.yiaminopheny2;2']bitiophenyv5-yi) benzotdetscchromene-1 &dione (400 mg, 0.48 mmo), zinc acetate (88 mg, 0.22 mmol) and 5 3,4-diaminobenzoic acid (220 mg, 1.44 mmol) were introduced into quinoline (40 ml). The mixture was heated to 220 C and stirred for 7 h, After coohng, precipitation was effected with 6% HCl, and the solid was filtered off with suction and washed with hot water and a little ethanoL, Column chromatography with 5:1 dichoriomethane:methanol gave 98 mg (21%) of an orange solid. 10 Maldi-MS: M+ = 953.24 Use Exanples: 15 The substrates used were glass plates which had been coated with fluorine-doped tin oxide (FTO) and had dimensions of 25 mm x 15 mm x 3 mm (Nippon Sheet Glass), which had been treated successively with glass cleaner (RBS 35), dernineralized water and acetone, in each case for 5 min in an ultrasound bath, then boiled in isopropanol for 10 minutes and dried in a nitrogen stream. 20 To produce the solid TiQ2 barrier layer, a spray pyrolysis process as described in Peng et aL, Coord. Chaim, Rev. 248 (2004), 1479, was used. The TiO 2 paste DSL 18NR-T (Dyssol) was printed onto the solid TiC 2 barrier layer in a screenprinting process. The paste consisted of TKX particles with a diameter of approx, 25 nm, which were dispersed in a terpineollethylcellulose 25 mixture, After the printing process, the paste was dried at 80'C for 5 minutes. This was followed by sintering at 450'C for 30 mInutes. The resulting nanoporous TiC 2 layer had a layer thickness of 1.8 pm. For electrical insullation between metal back electrodes and working electrodes, as well as the 30 TiO 2 layer, strips of polyimide (Pyrolin Polyimide Coating, Supelco) were placed along each longitudinal side and cured in a drying cabinet at 200CC for 15 mir, After removal from the drying cabinet, the sample was cooled to 80*C, immersed into a 5 x 104 molar ethanolic solution of hydroxamic acid sat (the salt was obtained by reacting the 35 commercially available hydroxamic acid with sodium hydroxide solution) H N, , O' -'N'a for 16 h, then removed, washed briefly with EtCH and then placed into a 5 x 104 molar solution 40 of the inventive dye or a solution of the comparative compound JK2 in dichoromethane for I K.

21 The sample removed from the solution was subsequently rinsed with pure solvent (here dichloromethane) and dried in a nitrogen stream. A p-conductor solution was spun onto the dried sample. The solution consisted of 0.16 M spiro 5 MeOTAD (Merck) in chlorobenzene and 0.3 M LiN(SO2CF)2 (Aldrich) in cyclohexanone in a ratio of 15:1 and 2.5 percent by weight of V) 5 based on spiro-MeOTAD. 125 p; of this solution were applied to the sample and allowed to act for 60 s. Thereafter, The excess solution was spun off at 2000 rpn for 30 sa 10 The rmetal back electrode was applied by thermal metal vaporization under reduced pressure, For this purpose, the sample was provided with a mask, in order to apply 8 separate back electrodes with dimensions of 0.13 cm' to the active region. For this purpose, Ag was vaporized at a rate 3.0-3.15 nm/s at a pressure of approx. 5*1WY mbar, so as to result in a layer thickness of 200 nrn. 15 The quantum efficiency (IPCE = Incident Photonto-current Conversion Efficiency) was measured vith a 75 watt xenon arc lamp (LOT-Oriel), a 1/8 m monochromator (SpectraPro 21501; Acton Research Corporation), a transimpedance amplifier (Aescusoft GmbH Automation) and a lockin amplifier 7265 (Signal Recovery). 20 Current/voltage characteristics were obtained at an illumination intensity of 100 mW/crn2 (xenon lamp (LOT-Oriel) with AM11.5 filter) by varying the voltage between -0.6 V and +1.0 V and measuring the resuLting short circuit current. The data for different inventive compounds and the prior art compound JK2 are shown in Table 1 (Isc: short circuit current, Voe: open circuit voltage; 25 FF: fill factor; ETA: efficiency). Table I Dye IsmAlm ] %[VmV] FF[%] ETA[%] 2a 7.8 820 63 3.9 4a -7,5 840 61 18 31 -7.4 840 59 36 32 ,touene) -7.7 860 64 41 5a/b -7.8 900 42 2.9 JK2- - 9 - - 4 - 6 30 * "3a (toluene) means that the dye was not applied as usual from dichtlromethane solution, but from toluene solution, Figure 1 shows the EQE values of the inventive compounds and of the prior art compound JK2 as a function of wavelength.

22 Figure 2 shows a comparison of the lightfastness of the invenfrve dye of compound 2a compared to the prior art dye JK2, in each case on T10 2 . The irradiation series was commenced after 2 h of "light soaki ng" in the sun tester. 5 Figure 3 shows the efficiency of a short-circuited solar cell with dye 2a as a function of time. To determine the efficiency, the current/voitage characteristic was recorded in a Source Meter Model 2400 (Keithley Instruments Fnc.) with irmdiation using a power of 100 mV/crn 2 (xenon iamp (LOT-Oriel) with AM 1.5 filter),

Claims

1. A om pound of the formula la or lb A o G N 0 L 4 N R L 5 (b) in which R are ident ical or different aryloxy, arylthio, hetaryloxy or hetarylthio radicals, 10 n is 0, 1, 2, 3, 4 or 5, B is CrCralkylene or 1,4-phenylene, where the phenyleno radical may be mono- or polysubstituted by alky, nitro, cyano and/or halogen, 15 A is -COOM, -SO 3 M or -PO0M, M is hydrogen, an alkali metal cation or [NRi 4 t 20 R' Is hydrogen or alkyl, where the R' radicals may be the same or different, L is a bridge of the formula Ar- ' -Ar-Ar- or -Ar-Ar-Ar 25 which may be mono- or polysubstituted by phenyl, alkyl, alkoxy, alkylthic and/or -NR 4 R, and in which Ar is aryl or hetaryl which may be fused to saturated or unsaturated 5- to 18-mnembered rings which rnay comprise heteroatoms which may be the same or different in the case of two or three Ar 30 R4 R 5 are each independeny hydrogen, alkyl whose carbon chain may be interrupted by one or more -0-, -S-, -CO-, -SO- and/or -S02- moieties. aryl or 24 hetaryl, each of wNch may be mono- or polysubstituted by alkyl, aikoxy and/or al kyithio, R1, R 2 are each independently radicals of the formta lIa or lIb 5 RR (la) (Fib) R 3 is phenyl, alky, alkoxy, alkylthio or -NR7R% 10 m Is 0, 1, 2, 3 or 4, X is C(RR) 2 , NR8, oxygen or sulfur and RE, R 7 , Ra are each independently hydrogen, aikyl whose carbon chain may be 15 interrupted by one or more ~O -S, -CO-, -S&- and/or -SOr moieties, aryl or hetaryl, each of which may be mono- or polysubstituted by alky, alkoxy and/or alkyithio.

2. A compound according to claim 1, wherein, in the formulae la and ib, 20 R are identical or different aryloxy or arylthio radicals, n is 0, 1 or 2, 25 B is CiCa-kylene, A is -COOM, M is hydrogen or an a lkali metal cation, 30 L is a bridge of the formula Ar-Ar-- or 'Ar-Ar-Ar 35 which may be mono- or polysubstituted by pheny, CrC4ralkyl, Ce 1 -alkoxy, CrC iralkythio and/or -NR 4 R 6 , and in which Ar is idenical or different aryl or hetaryl which may be fused to saturated or unsaturated 5- to 18-mem bered rings which may comprise heteroatoms, 1 25 R4 R5 are each independently hydrogen, CeCj-alky whose carbon chain may be interrupted by one or more -0-, -3-, -CO-, -SO- and/or -$02- moeties, 5 RR 2 are each independently radicals ot the formulae Ira and 111 x R (Wa)(]Ib) Ra is C-Cralkoxy, 10 m is 0 or 1, X is C(RQR) 2 , NRe, oxygen or sulfur and 15 R6, R1, R8 are each independently hydrogen, Ci-Ce-alkyl whose carbon chain may be interrupted by one or more -0-, -S-, -CO-, qSO- and/or -SO2- moieties.

3. A compound according to claim 1, wherein, in the formuflae la and ib, 20 n is 0, is ,-Cralkylene, A is -COOM, 25 M Is hydrogen or an alkali metal cation, L is a bridge of the formula 30 -'Ar-Ar or -- Ar-Ar- in which Ar is identical or different ary or hetaryl, R, R2 are each independently radicals of the fornulae lla and 11 b 26 X (Ira) (Nb RAis (t-12askoxy, 5 m is0or1, X is C(R3R) 2 and 10 R R are each independently hydrogen or CrC2-alkylt

4. The use of compounds of the formula ia or ib or mixtures of compounds of the formulae la and lb according to claim 1, 2 or 3 and/or isomers or mixtures of the isomers of the compounds of the formulae la and Ib according to claim 1, 2 or 3 as photosensitizers in 15 solar cells and photodetectors.

5. A solar cell or photodetector comprising compounds of the formula Ia or Ib or mixtures of compounds of the formulae la and Ib according to claim 1, 2 or 3 and/or isomers or mixtures of the isomers of the compounds of the formulae Ia and 1b according to claim 1, 20 2 or 3 as photosensitizers.