CN107540660B

CN107540660B - Iron complex with terpyridine derivative as ligand and synthesis method and application thereof

Info

Publication number: CN107540660B
Application number: CN201710840862.9A
Authority: CN
Inventors: 陈贵; 陈灵晶; 范洪波; 邱永福
Original assignee: Dongguan University of Technology
Current assignee: Dongguan University of Technology
Priority date: 2017-09-18
Filing date: 2017-09-18
Publication date: 2020-03-20
Anticipated expiration: 2037-09-18
Also published as: CN107540660A

Abstract

The invention discloses an iron complex taking terpyridine derivatives as ligands and a synthesis method and application thereof. The synthesis method of the iron complex taking the terpyridine derivative as the ligand comprises the steps of dissolving the ligand 6,6 '- (8-quinoline) -2, 2': 6 ', 2' -terpyridine in ethanol, adding ferrous perchlorate, stirring the obtained mixture for 2 hours at normal temperature, filtering to remove insoluble substances after the reaction is finished, removing the solvent by rotary evaporation, washing the obtained solid with ethanol, and drying to obtain the iron complex taking the terpyridine derivative as the ligand. The synthesis method has the advantages of simple process, high yield, mild reaction conditions, simple product purification treatment method and the like. The iron complex synthesized by the invention with the terpyridine derivative as the ligand has good catalytic activity on photocatalytic carbon dioxide reduction under the conditions of normal temperature and normal pressure in an air atmosphere, the TON (conversion number) can reach 500, and the iron complex has good industrial application prospect.

Description

Iron complex with terpyridine derivative as ligand and synthesis method and application thereof

Technical Field

The invention relates to an iron complex, in particular to an iron complex taking terpyridine derivatives as ligands, a synthesis method and application thereof.

Background

Carbon dioxide emitted by human beings in the production and living processes is partially absorbed by plants, and is also emitted to the atmosphere in a large amount to become a main greenhouse gas causing global environmental problems and also a main cause of the greenhouse effect. However, carbon dioxide is also an important carbon resource, and the conversion and fixation thereof are not only beneficial to alleviating the greenhouse effect, but also can obtain organic fuels or basic chemical raw materials. Therefore, the synthesis of organic chemicals by catalytic reduction of carbon dioxide has great significance in environmental protection and energy utilization. The most promising application prospect in the research of carbon dioxide catalytic reduction is the photocatalytic reduction reaction, so that the research and development of the catalyst capable of directly utilizing visible light to reduce carbon dioxide are of great significance.

Terpyridine and derivatives thereof are important ligands, and the terpyridine and the derivatives thereof have rich coordination capacity and can react with a plurality of transition metals (such as iron, cobalt, nickel, copper, ruthenium and the like) to generate a variety of metal complexes. The metal complex formed by terpyridine and derivatives thereof can be widely used in the fields of catalytic materials, luminescent materials, anti-tumor and the like, for example: cobalt complexes of tetrabipyridine (iron pyridine complex of terpyridine) can be used for water oxidation and hydrogen production (Energy & environmental science,2012,5, 7903-; penta-bipyridine (the bipyridine iron complex of terpyridine) is useful for antitumor (Chemistry-A European Journal,2015,21, 3062-. Therefore, the synthesis of iron complexes of terpyridine and derivatives thereof has been one of the hot points of attention of chemists. The synthetic method of the terpyridyl iron complex reported in the literature has long steps and harsh reaction conditions, and is not easy to purify. The invention provides a 6,6 '-di (8-quinolyl) -2, 2': 6 ', 2' -terpyridyl iron complex and a simple and efficient synthesis method thereof.

Disclosure of Invention

The invention aims to provide an iron complex taking a terpyridine derivative as a ligand, a synthesis method thereof and application thereof in photocatalytic carbon dioxide reduction.

In order to achieve the purpose, the invention adopts the following technical scheme:

an iron complex taking terpyridine derivatives as ligands has the following structure:

the invention also discloses a synthesis method of the iron complex with the terpyridine derivative as the ligand, which comprises the following steps: dissolving ligand 6,6 '-di (8-quinolyl) -2, 2': 6 ', 2' -terpyridine in ethanol, adding ferrous perchlorate, stirring the obtained mixture for 2h at normal temperature, filtering to remove insoluble substances after the reaction is finished, performing rotary evaporation to remove the solvent, washing the obtained solid with ethanol, and drying to obtain the iron complex taking the terpyridine derivative as the ligand.

The ratio of the amounts of the reactants in the reaction system can affect the utilization rate of the reactants, and preferably, the mass ratio of the 6,6 '-di (8-quinolyl) -2, 2': 6 ', 2' -terpyridine to the ferrous perchlorate is 1: 10; this ensures that the reactants in the reaction system are in appropriate concentrations, and in particular the ligand can react completely, thereby achieving the best reactant utilization.

The invention also discloses an application of the iron complex taking the terpyridine derivative as the ligand in photocatalytic carbon dioxide reduction, which comprises the following specific steps: 6,6 '-bis (8-quinolyl) -2, 2': 6 ', 2' -terpyridine derivative iron complex (0.05mmol), organic dye rhodopsin (0.05mmol), 1, 3-dimethyl-2-phenyl-2, 3-dihydro-1H-benzimidazole (0.1mmol) and carbon dioxide (10mL, 1atm) were added to a solution of 5% trifluoroethanol in N, N-dimethylformamide (5mL), respectively, and the resulting mixture was stirred uniformly and then irradiated under natural light for 15 hours.

The invention has the beneficial effects that:

1) the synthesis method is simple and efficient, only needs one-step reaction, and the yield can reach 90 percent (calculated according to the content of the terpyridine derivative ligand).

2) The synthesis method used in the invention has mild reaction conditions, does not need high temperature and high pressure, does not need special equipment, and is suitable for large-scale industrial production.

3) The purification method of the synthetic method product is simple, and the final product with high purity can be obtained only by washing the product with ethanol.

4) The iron complex synthesized by the invention with the terpyridine derivative as the ligand has good catalytic activity on photocatalytic carbon dioxide reduction under the conditions of normal temperature and normal pressure in an air atmosphere, TON (conversion number) can reach 500, carbon dioxide recycling and reasonable energy utilization can be realized, an ideal artificial photosynthesis simulation system is provided as a reference, and the iron complex has good industrial application prospect.

Drawings

FIG. 1 is a structural formula of an iron complex with terpyridine derivatives as ligands.

Detailed Description

Example 1:

the synthesis of the iron complex with the terpyridine derivative as the ligand comprises the following steps:

1. the ligand 6,6 '-bis (8-quinolyl) -2, 2': 6 ', 2' -terpyridine was synthesized as follows: dissolving 8-quinolineboronic acid (2.0mmol, 342mg), 6,6 '-dibromo-2, 2': 6 ', 2' -terpyridine (1.0mmol, 390mg), palladium tetraphenylphosphine (0.05mmol, 57.8mg) and sodium carbonate (10.0mmol, 1.06g) in 20ml of a mixed solvent of isopropanol and water in a volume ratio of 10:1, heating and refluxing for 24h, cooling, removing the solvent by rotary evaporation, washing the obtained solid with water and methanol respectively to obtain the ligand 6,6 '- (8-quinoline) -2, 2': 6 ', 2' -terpyridine with a yield of 94% having the following chemical structural formula:

characterization of the ligand 6,6 "-bis (8-quinolyl) -2,2 ': 6', 2" -terpyridine:¹H NMR(400MHz,CDCl₃,ppm):δ9.01(s,2H),8.72(d,2H),8.63(d,2H),8.39(d,2H),8.26(d,4H),8.02(d,2H),7.94(d,3H),7.74(d,2H),7.74-7.45(m,2H)。¹³C NMR(100MHz,CDCl₃,ppm):δ156.14,156.02,155.67,150.25,146.00,138.99,137.59,136.46,136.26,131.59,128.79,128.71,127.1`5,126.55,121.03,120.99,119.62。

synthesis of 6,6 '-bis (8-quinolyl) -2, 2': 6 ', 2' -terpyridyl iron complex: the ligand 6,6 '-bis (8-quinolyl) -2, 2': 6 ', 2' -terpyridine (0.1mmol, 48.7mg) was dissolved in 15ml ethanol under nitrogen, ferrous perchlorate (1.0mmol,274.7mg) was added, the resulting mixture was stirred at room temperature for 2h, filtered to remove insoluble matter, the solvent was removed by rotary evaporation, the resulting solid was washed with ethanol and dried to give the 6,6 '-bis (8-quinolyl) -2, 2': 6 ', 2' -terpyridine iron complex 68.5mg in 90% yield (based on the content of terpyridine derivative ligand) according to the following reaction formula:

the resulting 6,6 '-bis (8-quinolinyl) -2, 2': 6 ', 2' -terpyridyl iron complex was characterized by elemental analysis as follows: experimental values of C, 52.32; h, 3.18; n,9.12, theoretical value: c₃₃H₂₃Cl₂FeN₅O₉C, 52.13; h, 3.05; n, 9.33; the theoretical value of element analysis is consistent with the experimental value, which shows that the synthesized compound has high purity and the synthesis and purification method is feasible.

The experimental procedure for 6,6 '-bis (8-quinolinyl) -2, 2': 6 ', 2' -terpyridyl iron complex photocatalytic carbon dioxide reduction was as follows: 6,6 '-bis (8-quinolyl) -2, 2': 6 ', 2' -terpyridine derivative iron complex (0.05mmol), organic dye rhodopsin (0.05mmol), 1, 3-dimethyl-2-phenyl-2, 3-dihydro-1H-benzimidazole (0.1mmol) and carbon dioxide (10mL, 1atm) were added to a solution of 5% trifluoroethanol in N, N-dimethylformamide (5mL), respectively, and the resulting mixture was stirred uniformly, then irradiated under natural light for 15 hours, and then the final reaction was taken for gas chromatography, and as a result, it was confirmed that: the final product is carbon monoxide and the TON (conversion number) can reach 500.

Claims

1. An iron complex with terpyridine derivatives as ligands is characterized by having the following structure:

。

2. the method for synthesizing an iron complex with a terpyridine derivative as a ligand in claim 1, comprising the steps of: dissolving ligand 6,6 '-di (8-quinolyl) -2, 2': 6 ', 2' -terpyridine in ethanol, adding ferrous perchlorate, stirring the mixture at normal temperature for 2h, filtering to remove insoluble substances after the reaction is finished, removing the solvent by rotary evaporation, washing the obtained solid with ethanol, and drying to obtain the iron complex taking the terpyridine derivative as the ligand, wherein the mass ratio of the ligand 6,6 '-di (8-quinolyl) -2, 2': 6 ', 2' -terpyridine to the ferrous perchlorate is 1: 10.

3. The use of an iron complex of claim 1 with a terpyridine derivative as ligand in photocatalytic carbon dioxide reduction: the method is characterized by comprising the following specific steps: respectively adding 0.05mmol of 6,6 '' -di (8-quinolyl) -2,2 ': 6', 2 '' -terpyridine derivative iron complex, 0.05mmol of organic dye rhodopsin, 0.1mmol of 1, 3-dimethyl-2-phenyl-2, 3-dihydro-1H-benzimidazole and 10mL of 1atm carbon dioxide into 5mL of N, N-dimethylformamide solution containing 5% of trifluoroethanol, stirring uniformly, and irradiating for 15 hours under natural light.