CN110317471B - Agglomeration-free dyes with spiro-structure auxiliary units and methods for their synthesis - Google Patents

Abstract

The invention discloses a non-aggregation dye with a spiro structure auxiliary unit and a synthesis method thereof. On the basis of traditional D-π-A dyes, the present invention introduces an electron-deficient quinoxaline unit as an auxiliary electron acceptor, so that the electron donor part and the conjugated π-bridge are "isolated". A series of quinoxaline-based D-A-π-A dyes were designed and synthesized, which not only promoted the intramolecular charge Transport from the donor side to the acceptor side, and adjust the molecular energy level gap of the compound, increase the spectral response of the dye molecule to light, thereby significantly enhancing the efficiency of solar cells. New organic dyes, and these compounds have simple synthetic routes and reactions The conditions are mild, the post-processing is simple and convenient, and the yield is high.

Description

Agglomeration-free dyes with spiro-structure auxiliary units and methods for their synthesis

technical field

The invention belongs to the field of synthesis and application of dye-sensitized solar cell sensitizers, in particular to a non-aggregation dye with a spiro structure auxiliary unit and a synthesis method thereof.

Background technique

With the rapid growth of global population and economic development, the demand for energy continues to increase, and the search for clean and renewable energy has become a global concern. Among various renewable energy sources, compared with geothermal energy, wind energy and hydroelectric power, solar energy has the least pollution to the environment, the widest source, and the easiest access. Therefore, the development and utilization of solar energy have been paid more and more attention. The first laboratory-prepared higher-efficiency dye-sensitized solar cells were based on ruthenium-based complexes and black dyes, etc., used as dye-sensitizers. However, as a rare metal, ruthenium has less reserves on the earth and higher mining costs, which have affected the large-scale development of dye sensitizers containing ruthenium complexes, while pure organic sensitizer dyes have high molar extinction coefficients and easy structure design. , simple preparation and purification, low cost, and easy operation of battery cycling, so the research on pure organic sensitizing dyes has received extensive attention.

When the general dye molecules are adsorbed on the surface of the nanocrystalline semiconductor, intermolecular aggregation will occur to form aggregates. The dye molecules in the aggregates are rapidly deactivated due to intermolecular interactions, reducing the efficiency of electron injection. A co-adsorbent must be added to the dye solution. (CDCA) to prevent the aggregation of dyes on the surface of _TiO2 and improve the photoelectric conversion efficiency.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a non-aggregation dye with a spiro structure auxiliary unit and a preparation method.

The technical solution for realizing the object of the present invention is: a non-aggregating dye with a spiro structure auxiliary unit, and its general structural formula is as follows:

Wherein: R ₁ is selected from one of the following groups: triphenylamine, coumarin, tetrahydroquinoline, indoline, phenothiazine, etc.,

Ar is selected from one of the following groups: furan, benzene ring.

Preferably, R ₁ is triphenylamine.

The present invention provides a kind of synthetic method of above-mentioned target compound, comprises the following steps:

(1) the step of generating intermediate product c by Suzuki reaction of compound a and compound b in the presence of sodium carbonate

(2) the step of generating target product d by Knoevenagel reaction with compound c and cyanoacetic acid in the presence of ammonium acetate,

Further, in step (1), the catalyst of the reaction system is Pd(PPh ₃ ) ₄ ; the molar ratio of compound a and the catalyst Pd(PPh ₃ ) ₄ is 1:0.06.

Further, in step (1), the solvent of the reaction system is a mixed solution of water and tetrahydrofuran with a volume ratio of 1:1.5.

Further, in step (1), the molar ratio of compound a and compound b is 1:1.2, and the molar ratio of compound a and sodium carbonate is 1:3.

Further, in step (1), the reaction temperature is 50-60°C.

Further, in step (2), the solvent of the reaction system is a mixed solution of glacial acetic acid and toluene with a volume ratio of 1:3.

Further, in step (2), the molar ratio of compound c to cyanoacetic acid is 1:3, and the molar ratio of compound c to ammonium acetate is preferably 1:0.4.

Compared with the prior art, the present invention has the following advantages:

On the basis of traditional D-π-A dyes, the present invention introduces electron-deficient quinoxaline units (derivatives) as auxiliary electron acceptors, so that the electron donor part and the conjugated π-bridge are "isolated". Here, a series of quinoxaline-based D-A-π-A dyes were designed and synthesized by changing the conjugated π-bridge (i.e., furanyl, thienyl, and phenyl as π-bridges, respectively), which not only promoted Novel organic dyes that can significantly enhance the efficiency of solar cells by adjusting the energy level gap of compound molecules and increasing the spectral response of dye molecules to light, which can significantly enhance the efficiency of solar cells. The route is simple, the reaction conditions are mild, the post-processing is simple and convenient, and the yield is high.

Detailed ways

On the basis of traditional D-π-A dyes, the present invention introduces electron-deficient quinoxaline units (derivatives) as auxiliary electron acceptors, and uses triphenylamine, coumarin unit, tetrahydroquinoline, indole A series of new D-A-π-A structural dyes were designed and synthesized by changing the conjugated π-bridge with phenothiazine and phenothiazine as electron donors and cyanoacrylate as electron acceptors. The spiro ring structure designed by the present invention has two mutually perpendicular geometric skeletons. The spiro ring structure can effectively suppress strong intermolecular interactions, effectively suppress dye aggregation without the need for co-adsorbent (CADA), and reduce the emission of luminescent materials. Non-radiative transition to improve luminous efficiency.

The design and synthetic route of the dyestuff of the present embodiment are as follows:

The molecular structural formula of the target compound of the present invention is preferably as follows F1, F2:

Example:

All reactions were carried out under nitrogen atmosphere unless otherwise stated.

Example 1

Preparation of compound F1

Compound F1 was obtained according to Scheme 1 below:

plan 1

Synthesis of Intermediate 1

Intermediate a (1 mmol) and 5-formyl-2-furanboronic acid (1.2 mmol), tetrakistriphenylphosphine palladium (6 mol%) and sodium carbonate (3 mmol) were added to a two-necked flask, and tetrahydrofuran (45 mL) and Water (30 mL), under nitrogen protection, the reaction system was placed at 60°C for overnight reaction. After the reaction was completed, saturated NH ₄ Cl solution was added to the reaction system, extracted with CH ₂ Cl ₂ , the organic phase was dried over anhydrous magnesium sulfate, filtered, spin-dried, PE/DCM was used as the eluent, and the intermediate was obtained by column chromatography 1 (dark red solid) in 77% yield. The intermediate 1 was characterized by means of ¹ H NMR (500 MHz, CDCl ₃ ) and the following spectra were obtained: 9.74 (s, 1H), 8.68 (d, J=8.0 Hz, 1H), 8.44 (d, J=7.5 Hz, 1H), 8.29(d, J＝7.5Hz, 1H), 8.03(d, J＝8.0Hz, 1H), 7.99(d, J＝3.5Hz, 1H), 7.81(d, J＝8.5Hz, 2H) ,7.75(d,J＝8.0Hz,2H),7.49(t,J＝7.0Hz,1H),7.40(d,J＝3.5Hz,1H),7.38-7.15(m,19H),7.05(t, J=7.0Hz, 4H), 6.77 (br.s, 2H).

Synthesis of Compound F1

Intermediate 1 (1 mmol), cyanoacetic acid (3 mmol) and ammonium acetate (30 mg) were added to a two-necked flask, glacial acetic acid (16.7 mL) and toluene (50 mL) were added, and the reaction was refluxed overnight under nitrogen protection. After the reaction, a saturated NH ₄ Cl solution was added to the reaction system, extracted with CH ₂ Cl ₂ , the organic phase was dried over anhydrous magnesium sulfate, filtered, spin-dried, and eluted with DCM/MeOH (ie, dichloromethane/methanol) The target compound F1 (dark red solid, 242 mg) was obtained by column chromatography with a yield of 95%.

The compound F1 was characterized by means of ¹ H NMR (500 MHz, DMSO) and the following spectra were obtained: 13.77 (br.s, 1H), 8.62 (d, J=7.5Hz, 1H), 8.33 (t, J=8.0Hz, 2H), 8.14-8.16(m, 2H), 8.00(s, 1H), 7.96(d, J=6.5Hz, 2H), 7.88(d, J=8.0Hz, 2H), 7.60-7.63(m, 2H) ),7.27-7.42(m,9H),7.08-7.16(m,12H),6.63(br.s,2H).

Example 2

Preparation of compound F2

Compound F2 was obtained according to Scheme 2 below:

Scenario 2

Synthesis of Intermediate 2

Intermediate a (1 mmol) and 4-formylphenylboronic acid (1.2 mmol), tetrakistriphenylphosphine palladium (6 mol%) and sodium carbonate (3 mmol) were added to a two-necked flask, and tetrahydrofuran (45 mL) and water (30 mL) were added ), under nitrogen protection, the reaction system was placed at 60 °C for overnight reaction. After the reaction was completed, saturated NH ₄ Cl solution was added to the reaction system, extracted with CH ₂ Cl ₂ , the organic phase was dried over anhydrous magnesium sulfate, filtered, spin-dried, PE/DCM was used as the eluent, and the intermediate was obtained by column chromatography 2 (orange solid, 270 mg) in 85.2% yield.

The intermediate product 2 was characterized by means of ¹ H NMR (500 MHz, CDCl ₃ ) and the following spectra were obtained: 10.10 (s, 1H), 8.37 (d, J=8.0 Hz, 1H), 8.21 (d, J=7.5 Hz, 1H), 8.08(d, J＝8.0Hz, 2H), 8.02(s, 2H), 8.01(d, J＝8.5Hz, 2H), 7.81(d, J＝8.5Hz, 2H), 7.73(d, J=7.5Hz, 2H), 7.26-7.37 (m, 8H), 7.14-7.22 (m, 10H), 7.05 (t, J=7.0Hz, 4H), 6.79 (br.s, 2H).

Synthesis of Compound F2

Intermediate 2 (1 mmol), cyanoacetic acid (3 mmol) and ammonium acetate (30 mg) were added to a two-necked flask, glacial acetic acid (16.7 mL) and toluene (50 mL) were added, and the reaction was refluxed overnight under nitrogen protection. After the reaction, saturated NH ₄ Cl solution was added to the reaction system, extracted with CH ₂ Cl ₂ , the organic phase was dried over anhydrous magnesium sulfate, filtered, and spun dry, DCM/MeOH was used as the eluent, and the target compound was obtained by column chromatography F2 (orange-yellow powder), 80% yield.

The compound F2 was characterized by means of ¹ H NMR (500 MHz, DMSO) and the following spectra were obtained: 13.97 (br.s, 1H), 8.42 (s, 1H), 8.34 (d, J=7.5 Hz, 1H), 8.28 ( d, J=8.0Hz, 1H), 8.21 (d, J=8.5Hz, 2H), 8.19 (d, J=8.0Hz, 1H), 8.13-8.15 (m, 3H), 7.95 (d, J=7.5 Hz, 2H), 7.89(d, J＝8.5Hz, 2H), 7.44(t, J＝7.5Hz, 2H), 7.37-7.39(m, 2H), 7.34(t, J＝8.0Hz, 4H), 7.26-7.30(m, 2H), 7.07-7.14(m, 12H), 6.63(br.s, 2H).

Example 3

Determination of Photovoltaic Properties of Compounds F1 and F2

The corresponding photoelectrode chemical properties of F1 and F2: short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF) and power conversion efficiency (η) data are listed in Table 1.

In many cases, the addition of CDCA improves the photovoltaic performance because CDCA acts as an auxiliary to hinder the intermolecular aggregation of dyes on _TiO films. Through comparative analysis of the above data, the observed effects of DSSC on photovoltaic performance based on F1 and F2 are different after the addition of CDCA. F1-based DSSCs showed little change with or without the addition of CDCA. For the F2-based DSSC, the power conversion efficiency decreased from 3.72% to 3.43% after the addition of CDCA. Therefore, quinoxaline-based organic dyes with spiro structural auxiliary units can effectively inhibit dye aggregation without the need for co-adsorbents.

Claims (9)

1. The aggregation-free dye with the spiral structure auxiliary unit is characterized in that the spiral structure auxiliary unit has two mutually perpendicular geometrical skeletons, and the structural general formula is as follows:

wherein R is₁Selected from one of the following groups: triphenylamine, coumarin, tetrahydroquinoline, indoline, phenothiazine; ar is selected from one of the following groups: furan, benzene rings.

2. The non-aggregating dye of claim 1, wherein R is₁Is triphenylamine.

3. The method of synthesizing an aggregation-free dye having a spiro structural assist unit as set forth in claim 1, comprising the steps of:

(1) a step of carrying out Suzuki reaction on the compound a and the compound b in the presence of sodium carbonate to generate an intermediate product c,

(2) a step of reacting the compound c with cyanoacetic acid in the presence of ammonium acetate to generate a target product d,

4. the synthesis method according to claim 3, wherein in the step (1), the catalyst of the reaction system is Pd (PPh)₃)₄(ii) a Compound a and catalyst Pd (PPh)₃)₄Is 1: 0.06.

5. The method according to claim 3, wherein in the step (1), the solvent of the reaction system is a mixture of tetrahydrofuran and water.

6. The synthesis method according to claim 3, wherein in step (1), the molar ratio of the compound a to the compound b is 1:1.2, and the molar ratio of the compound a to sodium carbonate is 1: 3.

7. The synthesis method according to claim 3, wherein in the step (1), the reaction temperature is 50-60 ℃.

8. The synthesis method according to claim 3, wherein in the step (2), the solvent of the reaction system is a mixture of glacial acetic acid and toluene.

9. The method of claim 3, wherein in step (2), the molar ratio of compound c to cyanoacetic acid is 1:3 and the molar ratio of compound c to ammonium acetate is 1: 0.4.