JP2001510199A - Photosensitizer - Google Patents

Abstract

(57) Abstract: semiconductor, for example having an axial ligand capable of binding to TiO _2, and the novel transition metal phthalocyanine-type compound having at least one peripheral substituents effective photosensitizers for the dye solar cell Agent. Suitable compounds provide absorption of solar radiation in the near infrared and may be utilized in power windows.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to photosensitizers, and more particularly to novel transition metal photosensitizers.

[0002] Various metal-containing phthalocyanine derivatives have been proposed as potential photodynamic therapeutic agents, ie, photosensitizers in the treatment of tumors. For example, Rosenthal, Photoch
em Photobiol, 53 (6), 859-870 (1991) and our published international application WO 93/0.
See No. 9124. An interesting new field of photosensitization is the use of brighteners and phthalocyanines as photosensitizers in photocells based on TiO ₂ (WO 91).
/ 16719 (Graetzel) and WO 94/05025 (Sandoz)). We understand that many companies are developing photovoltaic cells based on this technology. The currently recommended dye-type sensitizer is cis-di (thiocyanato) bis (2,2'-bipyridine-4,4'-dicarboxylate) ruthenium (II), known as "RuN3 dye". It is. RuN ₃ dyes have excellent photoelectron-to-electron conversion and are very stable. Although certain metal-containing phthalocyanine is tested, its electrical output is not as high as RuN ₃ dye. Despite the high efficiency and power of optoelectronic devices based on RuN ₃ dyes, and their extremely useful properties of sustaining high power under cloudy conditions (unlike silicon-based photovoltaic cells),
They are purple. There remains a need for alternative photosensitizers for use in TiO ₂ -based photovoltaic devices, especially those that absorb wavelengths longer than RuN ₃ . Such sensitizers absorb in the near infrared region and are potentially used to make optically transparent photovoltaic devices useful, for example, in windows or other glossy regions. Visible spectrum light sensitizers customary, for example, when combined with RuN _3, more solar energy broad spectrum derived is converted into an electric, it should increase the efficiency of the device.

The present invention provides novel transition metal phthalocyanine-type derivatives of the following formula I:

Embedded image Wherein M is Ru, Rh, Os, Ir or Pt, and each X is hydrogen, alkyl, alkoxy, hydroxy, aryl, substituted aryl, alkylthio, ether, thioether, amino or mono- or di-substituted. -C ₄ H _4-amino or where adjacent X together (Y) _n - or

Embedded image Where Y is alkyl, alkoxy, hydroxy, aryl,
A substituted aryl, alkylthio, ether, thioether, amino or mono- or di-substituted amino, and n has a value from 0 to 4, and R and R 'are each independently a first binding ligand And contains a functional group that enables binding to TiO ₂ or other semiconductor to be sensitized, and when bound, the electrons are transferred from the phthalocyanine structure in an excited state to the conduction band of TiO ₂ or other semiconductor. Or a second ligand that does not destabilize the binding between M and the first binding ligand, provided that at least one of R and R 'is the first binding ligand. Ligand, and Q is nitrogen or -CZ-, wherein Z is independently hydrogen, alkyl, alkoxy, hydroxy, aryl, substituted aryl. To a substituted amino, provided that X, as at least one of Y and Z is other than hydrogen) - le, alkylthio, ether, thioether, amino or mono- - or di.

[0004] Preferably, M is Ru.

[0005] Suitable first binding ligands R or R 'comprise a phosphonic acid, a carboxylic acid or possibly a sulfonic acid group. When R or R 'comprises an amine, it may be a linear or branched amine, or a cyclic or aromatic amine such as pyridine, imidazole or triazole. The ligand may be mono- or poly-
It may be substituted. Suitable ligands include 4-pyridineethane-sulfonate,
3-pyridinesulfonate, pyridine-3-phosphonic acid, imidazole-4,5
-Dicarboxylic acid, 1,2,3-triazole-4,5-dicarboxylic acid, 4-diphenylphosphinobenzoic acid, tris (4-carboxyphenylphosphine), 4
-Isocyanobenzoate, nicotinic acid, and particularly preferred are pyridine-3,4-dicarboxylate and pyridine-4-phosphonic acid. Further, the TiO ₂ linking group may be a suitable linking group from the metal binding site,

Embedded image May be isolated by

[0006] It is believed that the ligand R or R ', when bound to TiO ₂ , is particularly desirable to provide a π-linked system.

When R or R ′ is said second ligand, it is CO or preferably a nitrogen donor, such as an aliphatic, especially a branched aliphatic amine, or a cyclic amine, especially an aromatic amine It may be. Such a second ligand may carry a substituent.

When X, Y or Z is alkyl or alkoxy, preferably each alkyl or alkoxy group has up to 8 carbon atoms and may be branched.

The compound may have a salt trait, in which case the counter ions are K ⁺ , N
Desirably, it is a ⁺ or quaternary ammonium.

The compounds of the formula I are new and the metal phthalocyanine compounds of the formula II

Embedded image Wherein M, Q and X are as described above, and A is an amine, preferably a pyridine group, CO (carbon monoxide) or a coordination catalyst, such as benzonitrile, reacting with a salt of ligand R And then isolating the resulting compound of Formula I.

The reactants of formula II and the salts of ligand R are known from the literature or can be prepared by analogous methods to those known.

Suitably, the starting metal phthalocyanine or naphthalocyanine is converted to an organic solvent such as toluene, ethanol or 2-methoxyethanol, or a mixture of a water-miscible organic solvent and water, such as aqueous tetrahydrofuran, or a mixture of immiscible solvents, For example, a mixture of chloroform and water is mixed with an excess, for example 2 to 10 times the stoichiometric amount of axial ligand, under an inert atmosphere, for example argon. The reaction is carried out, if desired, by heating, for example at reflux, for about 2 days. The product may be isolated by adding a co-solvent to the reaction mixture. If necessary, the solubility of this product can be increased by exchanging counterions by commonly known means.

When the axial ligands R in the compounds of the invention are not identical, it may be appropriate to prepare them starting from a compound of formula II where A is an amine suitable to act as a second ligand R . One of the ligands A may then be replaced with a salt of the first ligand R in a manner similar to that described above. Alternatively, a compound of Formula I may be prepared in which both ligands R are the same aromatic amine, and one ligand R may be displaced utilizing one equivalent of a non-aromatic amine.

The present invention relates to conventional substitutions around Pc (Sandoz WO 94/052).
5) has the advantage of incorporating a binding axial ligand instead of
And promote the synthesis of isomerically pure compounds. Experiments with RuN ₃ dye show that the purity of the dye is important and difficult to obtain. For optimum sensitization efficiency, the ground and excited state redox potentials, as well as the absorption λ _max , need to be carefully optimized. The present invention believes that substitution around the phthalocyanine structure allows for the selection of optimal photosensitization and improved "fine tuning" of properties. The incorporation of substrate binding groups around the ring is believed to hinder optimization of properties, and therefore, the design and preparation of the most efficient photosensitizers may be even more difficult. The novel compounds were found to be effective in photosensitizing activity for as TiO ₂ based photovoltaic device will be described later. In addition, at least some of the compounds have a pleasant green tinge, which increases the opportunities for commercial use of the compounds as photosensitizers.

The novel compounds of the present invention can be utilized in photovoltaic devices in a generally known manner.
The compounds show significantly improved performance over the previously detailed published phthalocyanines of Sandoz WO 94/05025 and our WO 93/09124, which are shown below.

[0016] Accordingly, the present invention further provides a photovoltaic device which is based the film of TiO _2, compounds of general formula I is placed on the TiO ₂ in it.

The present invention is further described by the following non-limiting examples.

Embodiment 1

Embedded image _{RuCl 3 · xH 2 O (43.37} % of Rh, 2.64g, 0.113mmol) and boiled until a solution deep purple in 1-pentanol (20ml). This one
3,6-dimethylphthalonitrile (8.85 g,
0.0566 mol) and a refluxing solution of hydroquinone (0.62 g, 0.0056 mol) were added under a nitrogen atmosphere. Ammonia gas is passed through the reaction flask and 3
Reflux continued for days. The cooled suspension was filtered and the purple solid was washed with pentanol (2 × 50 ml) then with methanol (3 × 25 ml) and dried to give α,
α′-Me ₈ PcRu (NH ₃ ) ₂ (4.81 g) was obtained. This was used without further purification.

Α, α′-Me ₈ PcRu (NH ₃ ) ₂ (4.8 in benzonitrile (50 ml)
1 g) was refluxed for 24 hours under a nitrogen atmosphere. The purple solid was filtered, washed with methanol (4 × 25 ml), and α, α′-Me ₈ PcRu (PhCN) ₂ was obtained (
3.80 g).

Experimental values: C 69.74%, H 4.58%, N 15.10%; C ₅₄ H ₄₂ N ₁₀ Ru has C 69.6%, H 4.54%, N 15.0%. Requirements.

Α, α′-Me ₈ PcRu (PhCN) ₂ (0.58 g, 0.6 mmol) and pyridine-3,4-dicarboxylic acid (0.45 g, 2.7 mmol) were added under nitrogen and:
Reflux in 1 of tetrahydrofuran (THF) / water (190 ml) without light for 80 hours. During that time, additional THF was added as needed to maintain capacity. Then T
The HF was removed under a stream of nitrogen, and the product was collected by filtration. It is washed well with water and dried in vacuo to give a purple α, α′-Me ₈ PcRu (pyridine-3,4
-Dicarboxylic acid) ₂ crystals were obtained. Yield: 0.41 g (IR C = O stretch 1734, 1708 cm ^-1 ; HPLC analysis using reverse phase chromatography, purity 95%).

[0022]Example 2 α, α '-(n-octyl)₈PcRu (pyridine-3,4-dicarboxylic acid) _Two α, α '-(n-octyl)₈PcRu (PhCN)_TwoWith excess pyridine-3
, 4-dicarboxylic acid in 1: 1 THF / water. This mixture overnight
Reflux. The solvent is removed by evaporation and the residue is
F / Petroleum and filtered through silica. Extract the silica with THF and add
The product was recovered as purple crystals by evaporation of the extract. (
IR C = O stretch 1720cm^-1).

The compound α, α ′-(n-decyl) ₈ PcRu (pyridine-3,4-dicarboxylic acid) ₂ is prepared in a similar manner.

Example 3 α, α′-Me ₈ PcRu (pyridine-3,5-dicarboxylic acid) ₂ α, α′-Me ₈ PcRu (PhCN) ₂ (0.2 g, 0.2 mmol) and pyridine-3 , 5-Dicarboxylic acid (0.14 g, 0.8 mmol) was refluxed in 1: 1 THF / water (190 ml) under nitrogen and without light for 80 hours. The THF was boiled off leaving a viscous blue / green residue in the water. The solid was collected by filtration, then placed in a Soxhlet apparatus, and the excess ligand was extracted overnight. The resulting solid was collected by filtration and washed with water (4 × 20 ml), then with diethyl ether (3 × 5 ml) and purple α, α′-Me ₈ PcRu (pyridine-3,5).
-Dicarboxylic acid) ₂ crystals were obtained. Yield: 0.21 g. (IR C = O stretch 1724 cm ^-1 ).

Example 4 α, α′-Me ₈ PcRu (pyridine-4-hydroxamic acid) ₂ α, α′-Me ₈ PcRu (PhCN) ₂ (0.2 g, 0.2 mmol) and pyridine-4-hydroxamine The acid (0.5 g, 3.7 mmol, 17 equiv.) Was refluxed in 1: 1 ethanol / toluene (60 ml) under nitrogen and without light for 48 hours.
The solvent was removed in vacuo, then the blue / green residue was stirred with water (20 ml) for 1 hour to remove excess ligand. The resulting solid was collected by filtration and water (4 × 20 ml)
Then, it was washed with hexane (2 × 20 ml) to obtain α, α′-Me ₈ PcRu (pyridine-4-hydroxamic acid) ₂ . Yield: 0.19 g. IR 1741, 17
02,1606 cm ^-1 ; HPLC analysis using reverse phase chromatography, purity 9
2%.

Example 5 α, α'-Me ₈ PcRu (pyridine-3-phosphonic acid) ₂ Pyridine-3-phosphonic acid (0.4 g, 2.1 mmol) and aqueous solution of tetra-n-butylammonium hydroxide ( (3.7 ml, 5.5 mmol, 1.48 M, 2 eq) were refluxed in ethanol (25 ml) for 30 min. The solvent was removed under reduced pressure and pyridine-3
-Tetra-n-butylammonium phosphonate was obtained.

Α, α′-Me ₈ PcRu (PhCN) ₂ (0.2 g, 0.2 mmol) and pyridine-3-tetra-n-butylammonium phosphonate (0.34 g, 0.8
mmol, in 3.1 ml of ethanol) under nitrogen and without light with 1: 1 ethanol /
Refluxed in toluene (30 ml) for 48 hours. The solvent was removed under reduced pressure and blue /
The green residue was washed with 10 ml of 0.2 M HCl. The solid is filtered and
. Washing with 2M HCl (10 ml) and 80-100 petroleum ether (2 × 10 ml) gave α, α′-Me ₈ PcRu (pyridine-3-phosphonic acid) ₂ . Yield: 0
. 19g.

Example 6 α, α′-Me ₈ PcRu (pyridine-3-diethylphosphonate) ₂ α, α′-Me ₈ PcRu (PhCN) ₂ (0.2 g, 0.2 mmol) and pyridine-3- Diethylphosphonic ester (0.2 g, 0.8 mmol, 16 ml of 1: 1
In toluene / ethanol) was refluxed for 60 hours in 1: 1 ethanol / toluene (40 ml) under nitrogen and without light. The solvent was removed under reduced pressure to give a blue / green residue. The solid was dissolved in chloroform (50 ml) and 0.1 M HCl (
2 × 50 ml) and then hexane (250 ml) was added to the blue / green chloroform solution to precipitate a purple crystalline solid. The solid was filtered off and washed with hexane (2 × 20 ml) and dried to give α, α′-Me ₈ PcRu (pyridine-3-diethylphosphonate) ₂ . Yield 0.21 g, IR 1
730 cm ^-1 .

Example 7 α, α ′-(octyl) ₈ PcRu (CO) (pyridine-3,4-dicarboxylic acid) α, α ′-(octyl) ₈ PcH ₂ (0.6 g, 0.39 mmol) and Ru ₃ (
(CO) ₁₂ (0.32 g, 0.5 mmol) was refluxed with benzonitrile (15 ml) for 3 hours. Methanol was added and the mixture was filtered over silica gel. The gel is washed with methanol and the product is petroleum ether (bp 4
0 to 60 ° C) / THF (4: 1). This is because α, α '-(octyl) ₈ PcRu (CO) (PhCN) and α, α'-(octyl) ₈ PcR
u (PhCN) ₂ .

The eluate was evaporated and the solid was petroleum ether (bp 40
６０60 ° C.). The solution was heated to reflux and CO was bubbled in until the reaction was complete as indicated by tlc (1 hour). The solution is then evaporated to dryness and α, α '-(octyl) ₈ PcRu (CO) (
PhCN) was obtained.

Α, α ′-(octyl) ₈ PcRu (CO) (PhCN) is added to an excess amount of 3,4-
Heat to reflux in 1: 1 THF / water with potassium carbonate with little addition of pyridine-dicarboxylic acid. After 3 days, the solvent was evaporated and the mixture was filtered over silica, eluting with petroleum ether (bp 40-60 <0> C) / THF. This elutes unreacted starting material. This silica was extracted using a Soxhlet apparatus. The resulting solution is evaporated to give the product α, α'-
(Octyl) ₈ PcRu (CO) (pyridine-3,4-dicarboxylic acid) was obtained.
^{_{1 H NMR (C 6 D 6}} ) δ3.56 (s), 6.02 (d) pyridine dicarboxylic acid ligand δ4.65 (m), 5.04 (m ) PC-C H 2 - C 7 H 5 (Pyridine dicarboxylate and other phthalocyanine ligands are not shown due to spectral complexity).

Other complexes PcRu (CO) R containing phthalocyanine and R ligand can be obtained in a similar manner.

Complexes containing different ligands R ′ (eg, where R ′ is a different pyridine ligand than R) can be obtained according to known methods by displacement of carbonyl ligands by photolysis in the presence of excess ligand R ′. (D Dolphin, BR James, AJ Murr
ay and JR Thornback, Can J Chem (1980), 58, 1125].

The following compounds were prepared analogously to Example 1:

[0035]

[Table 1]

The actual performance of this new compound was tested as follows. An alcoholic solution of Compound A was prepared. The visible absorption band has a maximum at 650 nm (e49'000
M ^-1 cm ^-1 ), and that of phosphorescence is at 895 nm, the triplet state lifetime is 474 ns under anaerobic conditions. All luminescence disappeared when Compound A was adsorbed on the nanocrystalline TiO ₂ film. J. Am. Chem. Soc. 1993, 115, 6382, a mesoscopic anatase film (about 10μ thick, conductive glass LOF TEC).
10. Fluorine-doped SnO ₂ sheet (coating on resistance 10 ohm / sq) was coated with 50 mM 3α, 7α-dihydroxy-5β-cholic acid (Cheno) and 2.5 mM
The compound was deposited by immersion in a 3 × 10 ⁻⁴ M solution in ethanol containing% DMSO for several hours. The presence of Cheno is necessary to avoid surface aggregation of the sensitizer. The visible band of the absorption spectrum of Compound A is red, and the absorption spectrum was shifted by 10 nm.

The very efficient extinction of the emission of Compound A was found to be due to electron emission from the excited triplet state of phthalocyanine to the conduction band of TiO ₂ . The photocurrent action spectrum is shown in FIG. 1, where the incident photon versus current conversion efficiency (IPCE) is plotted as a function of wavelength. The undulation has sufficiently extended to the near IR region where the IPCE has a maximum value near 660 m exceeding 50%. Although the pyridyl orbitals do not appear to be involved in the π, π ^* excitation responsible for the 650 nm absorption band of compound A, the electronic binding to the Ti (3d) conduction band manhold in its excited state, through this additional mode, is Strong enough to make the injection very effective.

Electron transfer was further confirmed by a time-resolved nanosecond Nd-YAG laser experiment shown in the insert of FIG. The top of the transient spectrum of the pulse indicates the brown color of the ground state absorption of Compound A and the appearance of new undulations in the 700-800 nm and 480-580 nm wavelength ranges. These bands are due to the formation of the phthalocyanine cationic group. The return of the ground state spectrum by charge recombination was observed on a time scale of several hundred microseconds, suggesting that the recapture of conduction band electrons by the oxidative dye is a relatively slow process.

Our results establish a new route for phthalocyanine grafting to oxide surfaces through axially attached ligands. 1M LiI /
Utilizing a sandwich-type battery-shaped film described in J. Am. Chem. Soc. Together with a 0.05 M LiI ₃ redox electrolyte, the photocurrent reaching 10 mA / cm ² can be simulated AM1.5 solar radiation. Obtained easily below. These show the highest conversion efficiency ever observed among phthalocyanine-type sensitizers.

The standard tests described in the dissertation were carried out on Compound A and Compounds BE above and are summarized below.

[0041]

[Table 2]

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, GM, HU, ID, IL, IS, JP, KE, KG, KP, KR , KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW (72) Inventor Mahler, Barry Anthony United Kingdom, Reading RGS 15 SBS, Carnarvon Road 17 (72) Inventor Gretzel, Michael, Switzerland, Seash-1025 San Sul Pis, Shman du Marxa 7a (72) Inventor Nazerudin Mohamed Kahaya, Switzerland, Seash-1024 Eckbran, Shman de la Shesa 9F Term (reference) 4H050 AA01 AA02 AB92 BB11 BB14 BB31 BB46 BB47 BB61 WB11 WB14 WB21 5F051 AA12 BA05

Claims (16)

[Claims] 1. A transition metal phthalocyanine type derivative of the following formula I: Wherein M is Ru, Rh, Os, Ir or Pt, and each X is hydrogen, alkyl, alkoxy, hydroxy, aryl, substituted aryl, alkylthio, ether, thioether, amino or mono- or di-substituted. amino or where adjacent X is -C ₄ H ₄ together (Y) _n - or ## STR2 ## Where Y is alkyl, alkoxy, hydroxy, aryl,
A substituted aryl, alkylthio, ether, thioether, amino or mono- or di-substituted amino, and n has a value from 0 to 4, and R and R 'are each independently a first binding ligand And contains a functional group that enables binding to TiO ₂ or other semiconductor to be sensitized, and when bound, the electrons are transferred from the phthalocyanine structure in an excited state to the conduction band of TiO ₂ or other semiconductor. Or a second ligand that does not destabilize the binding between M and the first binding ligand, provided that at least one of R and R 'is the first binding ligand. Ligand, and Q is nitrogen or -CZ-, wherein Z is independently hydrogen, alkyl, alkoxy, hydroxy, aryl, substituted aryl. To a substituted amino, provided that X, as at least one of Y and Z is other than hydrogen) - le, alkylthio, ether, thioether, amino or mono- - or di. 2. The derivative according to claim 1, wherein said M is Ru. 3. The derivative according to claim 1, wherein said R or R ′ is a binding ligand and comprises one or more phosphonic acid, carboxylic acid or sulfonic acid functional groups. 4. The derivative according to claim 1, wherein said R or R ′ is a straight-chain or branched amine or a cyclic or aromatic amine. 5. The method according to claim 1, wherein R or R ′ is 4-pyridineethanesulfonate, 3-pyridinesulfonate, pyridine-3-phosphonic acid, imidazole-4,5-dicarboxylic acid, 1,2,3-triazole-4,5- Claims selected from dicarboxylic acids, 4-diphenylphosphinobenzoic acid, tris (4-carboxyphenylphosphine), 4-isocyanobenzoate, nicotinic acid, pyridine-3,4-dicarboxylate and pyridine-4-phosphate. Item 5. The derivative according to any one of Items 1 to 4. 6. The derivative according to claim 1, wherein one of R and R ′ is CO. 7. The method according to claim 1, wherein one or more of X, Y or 2 is alkyl or alkoxy having up to 8 carbon atoms, and the alkyl group is linear or branched. A derivative according to any one of the preceding claims. 8. The method for producing a derivative according to claim 1, wherein R = R ′,
Metal phthalocyanine compound of the following formula II Wherein M, Q and X are as defined in claim 1 and A is an amine, is reacted with a salt of ligand R as defined in claim 1 and the resulting derivative of formula I is simply A method comprising releasing. 9. In an organic solvent, a mixture of a water-miscible organic solvent and water, or a mixture of an immiscible organic solvent and water, in the presence of a stoichiometric excess of a salt of a ligand R, 9. The method according to claim 8, which is performed under an inert atmosphere. 10. A process for the preparation of a derivative of the formula I as defined in claim 1, wherein R is not the same as R ′, wherein the corresponding nonmetallated phthalocyanine is
reacting with u ₃ (CO) ₁₂ and a binding ligand to produce a derivative of Formula I wherein R or R ′ is CO and the other of R and R ′ is a binding ligand, and if desired, converting the carbonyl ligand to A method comprising substituting with another ligand. 11. A photosensitizer for semiconductors in dye solar cells as claimed in claim 1.
Use of the derivative according to any one of claims 1 to 7. 12. Use of a derivative of any one of claims 1 to 7 in combination with RuN ₃ as photosensitizer for semiconductors in the dye solar cell. 13. An optically transparent device incorporated in a dye solar cell, wherein the dye comprises a derivative according to any one of claims 1 to 7. 14. A dye solar cell, wherein the dye comprises the derivative according to any one of claims 1 to 7. 15. A window for a building, comprising a dye solar cell according to claim 14. 16. A photosensitizer for a semi-derivative in a dye solar cell.
A method for generating electricity from sunlight comprising the use of a derivative according to any one of claims 7 to 7.