KR20130102422A - Novel visible light active graphene-based photocatalyst, method for regeneration of oxidoreductase cofactor and method for enzymatic production of formic acid from carbon dioxide using the same - Google Patents

Abstract

PURPOSE: A novel graphene photocatalyst absorbing visible light, a regeneration method of oxidoreductase cofactor using the same, and a manufacturing method of formic acid from carbon dioxide with an enzyme reaction using the same are provided to be economic and environment-friendly, to enable the mass production and automation, and to be able to be usefully used in a novel manufacture industry in which artificial photosynthesis which selectively manufactures various compounds by fixing carbon dioxide which is global warming gas. CONSTITUTION: A novel graphene composite is represented by Chemical formula 1. The novel graphene composite is used as a photocatalyst absorbing visible light. A regeneration method of oxidoreductase cofactor comprises a step of inputting a phosphate buffer solution; oxidative oxidoreductase cofactor methyl viologen; at least one oxidation-reduction medium selected from the group consisting of a ruthenium (II) composite and a rhodium (III) composite; and the graphene photocatalyst absorbing visible light represented by Chemical formula 1 in a reactor, and stirring while applying light to produce a reductive oxidoreductase cofactor.

Description

Novel visible light active graphene-based photocatalyst, method for regeneration of oxidoreductase cofactor and method for enzymatic production of formic acid from carbon dioxide using the same}

The present invention relates to a novel visible light absorbing grepin-based photocatalyst, a method for regenerating oxidoreductase cofactors using the same, and a method for preparing formic acid from carbon dioxide by an enzymatic reaction using the same.

The development of a clean alternative energy source to replace fossil fuels such as petroleum and coal that causes global warming along with the limit of reserves is the most urgent task to solve for the future of mankind. In particular, the development of a new technology for manufacturing various chemical products using carbon dioxide, one of the main causes of global warming as infinite solar energy and representative greenhouse gases, is the most secure environmentally friendly energy utilization system to cope with global warming. This is one of the most urgent research and development areas.

As one of the methods using the solar energy and carbon dioxide, "artificial photosynthesis" method has attracted attention as the development of the next generation energy source.

Artificial photosynthesis focuses on the photosynthesis action of plants to obtain energy, and is a method of converting carbon dioxide into an energy source (for example, formic acid) using sunlight. Burning the manufactured energy source comes out of water and carbon dioxide, and the carbon dioxide can be made into an energy source again through photosynthesis, making it possible to create dream energy that does not cause environmental pollution.

Therefore, many approaches have been taken for artificial photosynthesis, and methods using dual molecular bioreactors and biocatalysts (enzymes) can be used to link human engineering with biological processes.

The enzyme is composed of a main enzyme (apoenzyme) and a coenzyme (protein), and the coenzyme is divided into a cofactor or a prosthetic group according to the presence of a metal ion. Coenzyme, which we usually refer to, refers strictly to a cofactor, which temporarily accepts atoms or groups of atoms released from a substrate and delivers them to other substances. Typically, nicotinamide cofactor NAD, NADP and flavin cofactors FAD and FMN.

The nicotinamide cofactors and flavin cofactors or their oxidized forms are used as cofactors essential in the redox biocatalysis carried out by many kinds of oxidoreductases. Such biocatalytic reactions are becoming increasingly important in laboratory organic synthesis and various industrial fields. However, the high cost of these cofactors prevents the development of an industry with many enzymatic processes. Therefore, in order to increase the efficiency of the biocatalytic reaction and to make an economical and industrially feasible process, cofactors for the continuous reaction of the enzyme need to be continuously regenerated. However, unlike hydrolytic enzymes that are widely used in various ways, a satisfactory cofactor regeneration method for the use of redox enzymes has not been established and is not widely commercialized.

Conventional electrochemical regeneration has been considered as an attractive alternative to existing second enzyme / substrate regeneration methods. However, in the electrochemical regeneration method, the reduction efficiency of NAD (P) ⁺ to NAD (P) H is poor due to the slow electron transfer rate between the electrode and NAD (P) ⁺ even under the thermodynamically preferred voltage condition.

In order to solve this problem, a method of transferring electrons between an electrode and NAD (P) ⁺ using a homogeneous redox mediator has been developed, and a typical rhodium (III) complex (pentamethylcyclopenta) has been developed. Dienyl-2,2'-bipyridinechloro) rhodium (III): [Cp * Rh (bpy) H ₂ O] ²⁺ (hereinafter M _ox ) using as a medium for electron transfer to NAD (P) ⁺ The method was developed.

The rhodium (III) complex M _ox in the electron transport medium is converted into M _red2 , an active reducing _agent , through electrochemical / chemical process and is involved in the regeneration of NADH. M _ox accepts two electrons and _becomes the state of M _red1 by an electrochemical change (E-step). The M _red1 is then converted to M _red2 through a chemical process by taking one proton in solution without changing the total amount of electrons (C-step). The active reductant M _red2 provides two electrons and one proton to NAD (P) ⁺ to convert to NAD (P) H, where it returns to its initial state, M _ox (see FIG. 1 ).

However, the electrochemical regeneration method using the electrode has a problem that the electrical energy must be injected from the outside.

On the other hand, in recent years, there is increasing interest in a method for generating formic acid from carbon dioxide by using the enzyme formate dehydrogenase by regenerating cofactors using photochemical energy as an alternative energy. The photochemical energy is clean and economical because it uses abundant solar energy.

Specifically, as shown in FIG . 2 ,

The photocatalyst absorbs sunlight and electrons are _lifted to transfer electrons to M _ox to form M _red1 (step a); M _red1 of step a is oxidized to form M _red2 (step b); M _red2 of step b transfers electrons and protons to oxidative oxidoreductase cofactor (NAD ⁺ ) to form a reduced oxidoreductase cofactor (NADH) (step c); The NADH of step c gives promate (H ⁺ ) to formate dehydrogenase and returns to the oxidized form, and the formate dehydrogenase receives proton and converts carbon dioxide to formic acid by enzymatic action (step d). Form a cycle.

The role of the photocatalyst is important for this cycle to be effective. In particular, 46% of the total solar energy available on Earth is in the visible range and only 4% in the ultraviolet range. It is preferable that it is a substance which can be excited.

As a related art related to the visible light photocatalyst, Fujiwara researchers have reported the synthesis of formic acid directly from carbon dioxide using ZnS nanocrystals as a catalyst (Fujiwara, H. et al., Langmuir 14, 5154-5159 ( 1998)). However, the method has many problems such as conversion efficiency, long light exposure time, and photocatalyst stability.

Inoue and his colleagues also began experiments in which formic acid was prepared by placing TiO _{2 - x} N _x , ZnO, CdS, SiC and WO ₃ as photocatalysts in CO ₂ ^- saturated water and irradiating light with a xenon lamp. (Inoue, T. et al., Nature 277, 637-638 (1979)). However, this method has a problem in that a byproduct of formaldehyde, methanol and methane is produced in addition to formic acid.

As such, irradiation of donor-acceptor photocatalysts capable of producing formic acid under visible light with selective and high efficiency remains the most difficult task for artificial photosynthesis.

Accordingly, the present inventors have made a lot of efforts to develop an efficient regeneration method of cofactors of oxidoreductase using a new visible light photocatalyst, thereby producing a new grepin-based complex, and the new grepin-based complex is a visible light It can be used as a photocatalyst to absorb coenzyme of oxidoreductase with high efficiency without wasting additional energy costs. The present invention has been completed by developing a manufacturing method.

An object of the present invention is to provide a novel grepin-based complex.

Another object of the present invention is to provide a method for producing the novel grepin-based composite.

Still another object of the present invention is to provide a visible light absorbing photocatalyst containing the novel grepin-based composite as an active ingredient.

Another object of the present invention is to provide a method for regenerating cofactors of oxidoreductases without waste of additional energy costs by using solar energy by using novel visible light absorbing grepin-based photocatalysts instead of electrodes for redox mediators.

It is still another object of the present invention to provide a method for selectively preparing formic acid from carbon dioxide by an enzymatic reaction using a method of regenerating co-factors of oxidoreductase using the absorbing grepin-based photocatalyst.

In order to achieve the above object, the present invention provides a novel grepin-based complex represented by the following formula (1).

[Formula 1]

In addition, the present invention provides a method for producing the novel grepin-based composite.

Furthermore, the present invention provides a visible light absorption photocatalyst containing the novel grepin-based composite as an active ingredient.

In addition, the present invention is a phosphoric acid buffer solution in the reactor; Oxidoreductase cofactors of oxidized type; Any one or more redox mediators selected from the group consisting of methylbiologen, ruthenium (II) complexes and rhodium (III) complexes; And it provides a method for regenerating the oxidoreductase cofactor comprising the step of adding a visible light absorbing grepin-based photocatalyst represented by the formula (1) and stirring while applying light to produce a reduced oxidoreductase cofactor.

Furthermore, the present invention is a phosphate buffer solution in the reactor; Oxidoreductase cofactors of oxidized type; Any one or more redox mediators selected from the group consisting of methylbiologen, ruthenium (II) complexes and rhodium (III) complexes; Visible light absorbing grepin-based photocatalyst represented by Chemical Formula 1; By enzymatic reaction using a method of regenerating the cofactor of the oxidoreductase using the visible light absorbing grepin-based photocatalyst comprising the step of adding formate dehydrogenase and stirring with light under carbon dioxide atmosphere to produce formic acid Provided is a method for selectively preparing formic acid from carbon dioxide.

According to the present invention, by using a grepin-based photocatalyst that absorbs visible light instead of an electrode, solar energy can be used to reproduce cofactors of oxidoreductases without wasting additional energy costs, which is economical and environmentally friendly, and therefore mass production and automation. In addition, it can be usefully used in the new manufacturing industry applying artificial photosynthesis to selectively manufacture a variety of compounds by fixing the carbon dioxide is a warming gas.

1 is a diagram showing the electrochemical conversion of rhodium (III) complex M.
Figure 2 is a schematic diagram of a method for directly producing formic acid from carbon dioxide by the enzymatic reaction using the regeneration method of the cofactor of the oxidoreductase using a photocatalyst.
3 is a view showing a three-dimensional structure of a novel grepin-based photocatalyst according to the present invention.
4 is a graph showing the ultraviolet-visible light absorption spectrum of the novel grepin-based photocatalyst according to the present invention.
5 is a graph showing the FTIR spectrum of the novel grepin-based photocatalyst according to the present invention.
6 is a graph showing the X-ray diffraction spectrum of the novel grepin-based photocatalyst according to the present invention.
7 is a graph showing the amount of oxidoreductase cofactor production for photocatalyst type according to an embodiment of the present invention.
8 is a graph showing the amount of formic acid produced from carbon dioxide by photocatalytic reactions for photocatalyst types according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention provides a novel grepin-based complex represented by the following formula (1).

The compound of formula 1 of the present invention includes all salts, hydrates, and solvates that can be prepared by conventional methods.

The addition salt according to the present invention can be prepared by a conventional method, for example, by dissolving the compound of Chemical Formula 1 in a water-miscible organic solvent such as acetone, methanol, ethanol, acetonitrile, etc., And then precipitating or crystallizing the acid solution. Subsequently, in this mixture, a solvent or an excess acid is evaporated and dried to obtain an additional salt, or the precipitated salt may be produced by suction filtration.

In addition, the present invention provides a method for producing a novel grepin-based composite.

The compound of Chemical Formula 1 according to the present invention is chemically converted graphine (hereinafter referred to as CCG) and BODIPY (1-picoliamine-2-aminephenyl-3-oxy-phenyl-4,4-di Couplings commonly used in the art for fluoro-1,3,5,7-tetramethyl-2,6-diethyl-4-bora-3a, 4a-diaza-s-indacene-triazine) It can be prepared by synthesis using a reaction.

Specifically, chemically-converted graphene (CCG) is reacted with SOCl _{2 in} the presence of catalytic amount of DMF to prepare acyl chloride of CCG, and BODIPY is added to DCM in the presence of catalytic amount of triethylamine, argon, and acyl chloride of CCG It can be prepared by a method comprising the step of reacting with to produce a grepin-based complex.

In the production method according to the invention, the reaction is preferably carried out for 1 day or more, after the reaction may be further carried out the step of separation and purification.

Furthermore, the present invention provides a visible light absorption photocatalyst containing the novel grepin-based composite as an active ingredient.

The novel grepin-based composite according to the present invention absorbs visible light and moves the valence band filled with the electrons it possesses from the valence band to the empty conduction band, thereby allowing the redox mediator to move the electron well. It takes the role of performing a chemical reaction, and thus the photocatalyst (W ₂ Fe ₄ Ta ₂ O ₁₇ , BiVO ₄ -graphene oxide, conventionally used by the enzymatic reaction using the regeneration method of the cofactor of the oxidoreductase It was found that formic acid was produced 10 times or more from carbon dioxide than TiO ₂ -graphene oxide) for 2 hours (see Table 2 and FIG. 8 ). Therefore, the graphene-based composite according to the present invention can be usefully used as a visible light absorbing photocatalyst.

In addition, the present invention is a phosphoric acid buffer solution in the reactor; Oxidoreductase cofactors of oxidized type; Any one or more redox mediators selected from the group consisting of methylbiologen, ruthenium (II) complexes and rhodium (III) complexes; And it provides a method of regenerating oxidoreductase cofactor comprising the step of adding a visible light absorbing grepin-based photocatalyst and stirring while applying light to generate a reduced oxidoreductase cofactor.

In the present invention, The cofactor oxidoreductase of oxidation to be subjected to the electrochemical reduction nicotinamide cofactor design NAD ⁺ (nicotinamide adenine dinucleotide), NADP ⁺ (nicotinamide adenine dinucleotide phosphate) or a flavin cofactor design FAD ⁺ (flavin adenine dinucleotide), FMN ⁺ (flavin mononucleotide), preferably NAD ⁺ .

In the present invention, as the redox mediator, methylbiologen, ruthenium (II) complex and rhodium (III) complex are used as mediators for electron transfer to oxidative redox enzyme cofactors. .

Among the redox mediators, methyl viologen is an indirect electrochemical regeneration with Flavoenzyme (Ferredoxin reductase (FDR) or Lipoamide Dehydrogenase (LipDH)) as an electron transfer mediator for NAD (P) H. (Dicosimo et al. J Org Chem (1981) 46: 4622-4623), and the ruthenium (II) complex (hexamethylbenzene-2,2′-bipyridinechloro) ruthenium (II) is used in ketones. It has been used as a medium for electron transfer to the reduction to alcohol (Ogo S, Abura T, Watanabe Y (2002) Organometallics 21: 2964-2969; Yaw Kai Yan et al. J Biol Inorg Chem (2006) 11: 483 488), a (rhota (III)) complex (pentamethylcyclopentadienyl-2,2'-bipyridinechloro) rhodium (III): [Cp ^* Rh (bpy) H ₂ O] ²⁺ (hereinafter M _ox ) Are mediators for electron transfer to NAD (P) ⁺ (K. Vuorilehto, S. Lutz, C. Wandrey, Bioelectrochemistry 2004, 65, 1) and mediators for electron transfer to FAD ⁺ (F. Hollmann et al. Journal of Molecular Catalysis B: Enzymatic 19-20 (2003) 167-176). Thus, the redox mediator is used to improve the regeneration kinetics of oxidoreductase cofactors by delivering electrons and protons.

In this case, the ruthenium (II) complex may preferably be (hexamethylbenzene-2,2′-bipyridinechloro) ruthenium (II), and the rhodium (III) complex may be (pentamethylcyclopentadienyl-2 Preference is given to using, 2'-bipyridinechloro) rhodium (III), but not limited thereto.

In the present invention, the photocatalyst absorbs sunlight in place of the existing electrode to move the electron from the valence band filled with the electrons it possesses to the empty conduction band, thereby reducing the redox mediator. It accepts the former and plays a role in chemical reaction. At this time, since 46% of the total solar energy available on the earth is in the visible light region and only 4% is the ultraviolet light region, the photocatalyst used in the present invention is preferably a material capable of absorbing visible light to excite electrons. . As the visible light absorbing photocatalyst, preferably, the novel grepin-based photocatalyst according to the present invention may be used.

In the present invention, the light is preferably visible light, the wavelength is preferably 280 ~ 650 nm. If the wavelength is less than 280 nm, there is a problem in practicality because it does not exist in the sunlight on the surface of the surface, if the 650 nm or more there is a problem that the reaction is limited because the light energy is not enough.

The light source may be a sun, a lamp, or the like, but is not limited thereto, and may be any material that emits light having a wavelength of 280 to 650 nm.

The mechanism of the cofactor regeneration method of the oxidoreductase using the visible light photocatalyst according to the present invention is as follows.

Specifically, in the present invention, a rhodium (III) complex was used as a redox mediator. In this case, as shown in FIG . 2 , the photocatalyst grepin-based complex absorbs visible light to lift electrons to form M _ox . Transfer to form M _red1 (step a); M _red1 of step a is oxidized to form M _red2 (step b); M _red2 of step b transfers electrons and protons to oxidative oxidoreductase cofactors to form a reduced oxidoreductase cofactor (step c).

In addition, in the present invention, a reducing agent may be additionally used to stabilize holes (h + VB) generated in the valence band in the photocatalyst by the excitation of electrons. At this time, the reducing agent used is triethoxy arsine (TEOA), EDTA, triethylamine (TEA), NaBH ₄ , sodium citrate (sodium citrate) is preferable.

In this invention, it is preferable that the addition amount of the said reducing agent is 0.5-20 mM.

If the addition amount of the reducing agent is less than 0.5 mM there is a problem that the reaction system becomes unstable, if it exceeds 20 mM there is a problem that the yield is rather reduced.

As a result of measuring the NADH regeneration efficiency of the photocatalyst of Formula 1 according to the present invention, the conversion of NADH is 10.53% when BiVO ₄ -graphene oxide photocatalyst is used, W ₂ Fe ₄ Ta ₂ O ₁₇ In the case of using a photocatalyst, the conversion rate of NADH is 14.50%, but in the case of using the grepin-based photocatalyst according to the present invention, the conversion rate of NADH is 54.02%, which is 3.5 times better than other photocatalysts. .

Therefore, the graphene-based photocatalyst according to the present invention can reproduce cofactors of oxidoreductases with excellent conversion efficiency and thus can be mass-produced and automated, and it is economical and environmentally friendly because it does not incur additional energy costs using solar energy ( See Table 1 and FIG. 4 ).

In addition, the present invention is a phosphoric acid buffer solution in the reactor; Oxidoreductase cofactors of oxidized type; Any one or more redox mediators selected from the group consisting of methylbiologen, ruthenium (II) complexes and rhodium (III) complexes; Visible light absorbing grepin-based photocatalyst; By enzymatic reaction using a method of regenerating the cofactor of the oxidoreductase using the visible light absorbing grepin-based photocatalyst comprising the step of adding formate dehydrogenase and stirring with light under carbon dioxide atmosphere to produce formic acid Provided is a method for selectively preparing formic acid from carbon dioxide.

The present inventors measured the production of formic acid from carbon dioxide of the graphene-based photocatalyst, and showed a yield of 144 μmol for 2 hours. Thus, the conventional photocatalyst (W ₂ Fe ₄ Ta ₂ O ₁₇ : 14.25 μmol, BiVO ₄ -graphene oxide) Complex: 9.01 μmol) showed better production of formic acid (see Table 2 and Figure 8 ).

Therefore, the method used as a novel grepin-based photocatalyst according to the present invention can reproduce cofactors of oxidoreductases with excellent efficiency without additional energy costs using solar energy, so it is economical and environmentally friendly, thus allowing mass production and automation. In addition, it can be usefully used in the new manufacturing industry applying artificial photosynthesis to selectively prepare a variety of compounds by fixing the carbon dioxide which is a warming gas.

Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited to these Examples.

< Example  1> new Grepin system  Complex CCG - BODIPY Manufacturing

Graphite powder (Junsei Chemicals Co. Ltd. Lot.No. D12590-5) was purchased from Junsei Chemical. Analytical grade NaNO ₃ , KMnO ₄ and 98% H ₂ SO ₄ , 30% H ₂ O ₂ aqueous solutions were purchased from Samjeon Chem (Pyeongtaek, Gyeonggi-do) and used directly without further purification. Picolyl (CAS No. 1539-46-0), 2,4-dimethyl-3-ethyl-pyrrole (CAS No. 512-22-6 to 97%), cyanuric chloride (CAS No. 9550-1), Boron trifluoride etherate [(C ₂ H ₅ ) ₂ O. BF ₃ ] (Cat. No. 17550-1), DDQ (~ 98% purity), DIEA (Cat No. D12590-5), sodium phosphate buffer Sigma, triethanolamine ≥98% (Cas No. 102-71-6), formic acid dehydrogenase (Cas No. 9028-85-7), NAD ⁺ 99% purity (Cas No. 53-84-9) -Purchased from Aldrich. Aniline (Cat. No. 01384-01) was purchased from Kanto Chemical. Solvents used HPLC grade. Ultrapure water was prepared by the Millipore System (Tech Sinhan Science).

(1) 1- Chloro -2- Aminobenzene -3- Oxy - Benzaldehyde - Triazine  Produce

1-chloro-2-aminobenzene-3-oxy-benzaldehyde-tree according to Hu YH, Wang H, Hu B. Thinnest Two-Dimensional Nanomaterial-Graphene for Solar Energy.ChemSusChem 2010; 3: 782-796. A azine was prepared.

Specifically, cyanuric chloride (2.206 g, 12.0 mmol) was dissolved in 100 ml of methylene chloride in a cold water bath at 0 ° C., where 4-hydroxybenzaldehyde (1.620 g, 13.2 mmol) and diisopropylethylamine (2.52 ml, 14.4 mmol) was added to a solution of DCM (50 ml). The mixture was stirred at 0 ° C for an additional 40 minutes. Reaction completion was monitored by TLC (ethyl acetate / hexane = 5/40). A solution of aniline (1.227 g, 13.2 mmol) and DIPEA (2.52 ml, 14.4 mmol) in 30 ml of DCM was added at the same temperature followed by the cold water bath. After stirring for 2 hours, TLC (ethyl acetate / hexane = 25/75) was monitored at room temperature, the reaction was passed through a silica gel column (about 120 g) and then washed with ethyl acetate. After concentration in vacuo, the crude product was purified by flash chromatography (ethyl acetate / hexane = 1/6 to 1/4) to convert 1-chloro-2-aminobenzene-3-oxy-benzaldehyde-triazine to a white solid. Obtained (2.96 g, yield 76%).

¹ H NMR (CDCl ₃ ): δ 7.00-7.99 (m, 7H), 8.02 (d, 2H, J = 8.6 Hz), 10.04 (s, 1H);

¹³ C NMR (CDCl ₃ ): δ 120.5, 121.02, 122.63, 125.11, 128.93, 129.21, 131.29, 134.30, 136.21, 156.31, 190.76 .;

EI ⁺ mass spectrometry, m / z 326.0 (M + H) ⁺ and R _f = 0.39.

(2) 1- Picolylamine -2- Aminobenzene -3- Oxy - Benzaldehyde - Triazine  Produce

1-Picolylamine-2-aminobenzene-3-oxy-benzaldehyde according to Hu YH, Wang H, Hu B. Thinnest Two-Dimensional Nanomaterial-Graphene for Solar Energy.Chem Sus Chem 2010; 3: 782-796. Triazine was prepared.

Specifically, K ₂ CO ₃ 1-chloro-2-aminobenzene-3-oxy-benzaldehyde-triazine prepared above in the presence of aqueous solution (1.104 g / 12 ml water), di- (2-picolyl) amine (400 mg, 4.0 mmol) (2.0 mmol) was dissolved in THF (70 ml). The reaction was refluxed for 5 hours and then the mixture was concentrated to about 15 ml, after which 100 ml of chloroform were added. The organic layer was washed with water and dried over anhydrous magnesium sulfate. After concentration in vacuo the crude product was purified by flash chromatography (ethyl acetate / hexane = 75/25) to afford the desired compound in 88% yield.

¹ H NMR (CDCl ₃ ): δ 4.82 (s, 2H), 4.99 (s, 2H), 6.92-7.09 (m, 2H), 7.11-7.50 (m, 9H), 7.54-7.77 (m, 2H), 7.83 (d, 2H, J = 8.50 Hz), 8.42 (d, 1H, J = 4.5 Hz), 8.54 (d, 1H, J = 4.5 Hz), 9.96 (s, 1H);

¹³ C NMR (CDCl 3): δ 53.87, 120.83, 121.38, 121.75, 122.20, 122.49, 123.38, 128.73, 130.90, 133.42, 136.49, 136.70, 138.91, 149.42, 157.17, 157.36, 165.37, 167.20, 190.97.

EI ⁺ mass spectrometry, m / z 489.0 (M + H) ⁺ .

(3) Triazine Tripod BODIPY Manufacturing

A catalytic amount of tree in a solution of 1-picolylamine-2-aminobenzene-3-oxy-benzaldehyde-triazine (1.20 mmol) and 2, 4-dimethylpyrrole (0.24 g, 2.56 mmol) in 60 ml of dry THF Fluoroacetic acid was added under argon and at room temperature. After stirring for 20 hours, a solution of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (1.20 mmol) in 30 ml of anhydrous THF was slowly added to the mixture for 10 minutes, followed by reaction. The solution was further stirred for 2 hours at room temperature. The mixture was then passed through an aluminum oxide column (˜40 g) to remove impurities and eluted with MC / MeOH (97.5 / 2.5) solvent to give a dark brown solution. After concentration the residue was dried under vacuum overnight and used directly without further purification steps.

Anhydrous THF (60 ml) and triethylamine (6.0 ml) were added repeatedly to the flask containing crude product with stirring under argon atmosphere and room temperature followed by boron trifluoride-diethrate (6.0 ml) for 20 minutes. It was dripped using the dropping funnel. The mixture was stirred overnight then passed through an Al ₂ O ₃ column (˜40 g) and washed with MC / MeOH (98.03 / 1.97) mixed solvent. After concentration of the solvent the residue was redissolved in DCM (100 ml), washed well with 15% K ₂ CO ₃ aqueous solution (3 × 200 ml) and water (160 ml), dried over magnesium sulfate, concentrated under vacuum The crude product was purified by flash chromatography (DCM / MeOH = 98/2) to afford the desired compound in 30% yield.

¹ H NMR (CDCl ₃ ): δ 0.93 (t, 6H, J = 7.5 Hz, CH 3 of ethyl group), 1.30 (s, 6H, CH 3 on BODIPY), 2.25 (q, 4H, J = 7.5 Hz, CH 2 of ethyl group), 2.53 (s, 6H, CH3 on BODIPY closest to N), 4.85 (s, 2H), 4.94 (s, 2H), 6.99 (s, 2H), 7.01 (m, 1H), 7.11-7.22 ( m, 10H), 7.24 (m, 2H), 7.59 (m, 2H), 8.53 (d, 1H, J = 4.5 Hz), 8.54 (d, 1H, J = 4.5 Hz).

¹³ C NMR (CDCl ₃ ): δ 8.97, 12.46, 14.57, 17.00, 30.91, 46.14, 120.20, 121.44, 121.43, 122.21, 122.33, 122.82, 123.39, 128.81, 129.08, 136.52, 136.63, 138.22, 149.28, 149.44. , 157.30;

¹ B NMR (CDCl ₃ ): -2.234-3.124 (D, 1B) .;

EI ⁺ mass spectrometry, m / z 707.0 (M + H) ⁺ .

(4) chemically converted graphene ( chemically converted graphene ; CCG Manufacturing

Graphene oxide was prepared from natural graphite by the Hemmers method (Jr WSH, Offeman RE, J. Am. Chem. Soc 1958; 80 (6): 1339.).

Specifically, 5.0 g of powdered flake graphite (325 mesh) and 2.5 g of sodium nitrate were placed in 1.15 liters of sulfuric acid. The ingredients were placed in an ice bath for safety purposes. 15.0 g of potassium permanganate was added to the suspension while maintaining vigorous stirring. The addition rate was adjusted with care not to exceed the temperature of the suspension above 20 ° C. The ice bath was then removed and the temperature of the suspension was raised to 35 ° C. for 30 minutes. As the reaction proceeded the mixture gradually thickened and stopped foaming. After 20 minutes the mixture became a slightly brownish gray paste with only a small amount of gas. After 30 minutes, 1.0 liter of water was added to the paste with slow stirring to induce an explosive bubble and the temperature was raised to 98 ° C. The diluted suspension was kept at this temperature for 15 minutes. Next, the suspension was further diluted with about 2.0 liters of warm water and treated with hydrogen peroxide to reduce the residual permanganate and manganese dioxide to a clear soluble manganese sulfate. The suspension turned pale yellow during the treatment of hydrogen peroxide. The suspension was filtered to give a yellowish brown, ie cake form. Filtration was carried out while the suspension was warm to avoid precipitation of slightly soluble melic acid salts formed by side reactions. The slightly yellow brown filter cake was washed three times with a total of 2.0 liters of hot water and then the graphite oxide residue was dispersed in 4.0 liters of water to yield about 0.0285 g of solid. The remaining salt impurities were removed by treatment with an anion and cation exchanger of resin. After centrifugation, dehydration was performed with phosphorus pentoxide at 40 ° C. to obtain a dry form of graphite oxide.

CCG was prepared by the method of Pulickel M. Ajayan (Gao W, Alemany LB, Ci L, Ajayan PM, Nature Chemisty 2009; 1: 403-408.). Specifically, dry graphite oxide (GO) was dispersed in deionized water to obtain a colloidal solution. The pH of this solution was adjusted to 9-10. Sodium borohydride was added directly to the GO solution with magnetic stirring to disperse, and the mixture was kept at 80 ° C. for 1 hour with constant stirring. The reduced product was filtered and washed several times with large amounts of water to remove most of the residual ions. This suitably reduced GO was placed in a vacuum desiccator containing phosphorus pentoxide and maintained for 2 days, then redispersed in concentrated sulfuric acid, warmed to 180 ° C. and stirred for 12 hours. After cooling the dispersion was diluted with deionized water. The final product was isolated by filtration.

(5) CCG - BODIPY Manufacturing

The CCG-BODIPY was synthesized by applying the method reported in Zhang X, Huang Y, Wang Y, Ma Y, Liu Z, Chen Y, Carbon 2008; 47: 313-347.

Specifically, chemically converted graphene (CCG, 50 mg) was reacted with SOCl ₂ (25 ml) at 70 ° C. for 24 hours in the presence of catalytic amount of DMF to obtain acyl chloride of CCG. Excess SOCl ₂ was evaporated under reduced pressure and residual SOCl ₂ was washed with toluene. Next, BODIPY (150 mg) was added to DCM (50 ml) in the presence of catalytic amount of triethylamine (1 ml), argon and the residue and stirred at 130 ° C. for 3 days. After the reaction was completed, the solution was poured into acetone. The resulting suspension was filtered through a membrane filter of 0.1 μm pore size and 47 mm diameter. The crude product was washed again several times using the same procedure using CHCl ₃ / CH ₂ Cl ₂ . UV spectroscopy and thin layer chromatography confirmed the absence of BODIPY in the filtrate upon final wash. Next, CCG-BODIPY was washed with a small amount of water to remove acid-amine impurities and finally dried under vacuum to obtain a hybrid CCG-BODIPY (40 mg) which is a grepin-based photocatalyst.

3 shows a three-dimensional structure of the prepared grepin-based photocatalyst.

<Analysis>

(1) ultraviolet-visible absorption spectrum

The ultraviolet-visible spectrum of CCG, BODIPY and the compound of formula 1 according to the present invention is shown in FIG. 4 .

As shown in FIG . 4 , CCG did not show a conventional BODIPY absorption band, but BODIPY dissolved in a CH3CN: DMSO (4.5: 0.5, v / v) solvent showed a strong soret band near about 500 nm. The compound according to the invention showed two bands at about 465 nm and 600 nm, which was observed with covalently linked BODIPY.

Therefore, it can be seen that the compound of Formula 1 according to the present invention contains BODIPY and absorbs light in the visible light region.

(2) FTIR  spectrum

The FTIR spectra of the CCG and the compound of formula 1 according to the invention are shown in FIG. 5 .

As shown in FIG . 5 , the CCG spectrum is 1060 cm ⁻¹ ( ^ν CO), 1210-1225 cm ⁻¹ ( ^ν phenol), 1370 cm ⁻¹ (OH bending in ^ν tertiary alcohol), 1620 cm ^{− 1} (bending HOH in ^ν water), and an important band of 1720 cm ⁻¹ ( ^ν C═O). The peak of 1720 cm ⁻¹ contributes to the C═O stretching of the —COOH group. A strong broad band of about 3400-3500 cm ⁻¹ indicates the presence of carboxyl groups.

In the spectrum of the compound of formula 1 according to the present invention, no peak at 1720 cm ⁻¹ was observed, but a new wide band appeared at 1613 cm ⁻¹ , which corresponds to the C = O stretching band of the amide carbonyl group. The tertiary-N-stretch band is at 3053 cm ⁻¹ . Bands at 2864 cm ⁻¹ , 1512-1613 cm ⁻¹ , 1981 cm ⁻¹ and 1084 cm ^{−1 show} stretching of the CH ₂ , —C═C—, —CH ₂ CH ₃ and BN groups. In addition, the new CN stretching band of the amide group appearing at 1206-1299 cm ⁻¹ clearly shows the presence of the amide carbonyl linking group —CON— in the structure, thereby indicating the coupling of CCG and BODIPY.

Therefore, it can be seen that the compound of Formula 1 according to the present invention is a complex in which CCG and BODIPY are coupled.

(3) X-ray diffraction  spectrum

X-ray diffraction spectra of CCG, BODIPY and the compound of formula 1 according to the invention are shown in FIG. 6 .

As shown in FIG. 6, the compound of formula 1 according to the present invention had a new peak formed at 2θ = 17.9400 and 2θ = 25.8590 compared to BODIPY, and was shown to be lower than BODIPY by exhibiting d-spaced at 0.494 nm. It also showed a new peak at 2θ = 25.8590 when compared to CCG, showing a d-spaced of 0.345 nm. This means that CCG is covalently bound to BODIPY.

From this, it was confirmed that the compound of Formula 1 according to the present invention is a complex in which CCG and BODIPY are coupled.

< Manufacturing example > Preparation of Rhodium (III) Composite

Rhodium (III) complex (pentamethylcyclopentadienyl-2,2'-bipyridinechloro) rhodium (III) (hereinafter referred to as M) as an organometallic medium for transferring electrons between NAD ⁺ and a grepin-based photocatalyst M = [Cp ^* Rh (bpy) H ₂ O] ⁺ ; Cp ^* = C ⁵ Me ⁵ , bpy = 2,2′-bipyridine). The rhodium (III) complex M was synthesized by Kelle and Gratzel's method (F. Hollmann, B. Witholt, A. Schmid, J. Mol . Catal . B 2002, 19-20 , 167).

< Example  2> Using Grephin Photocatalyst and Rhodium (III) Composite NADH How to play

Phosphoric acid buffer solution (100 mM, pH 7.0) was added to the quartz cuvette reactor, 10 μmol of the grepin-based composite prepared in Example 1 as a photocatalyst, and 0.2 mmol of the rhodium (III) complex prepared in Preparation Example 2 as an electron carrier. , 0.4 mmol of NAD and 400 mmol of triethanolamine (TEOA) were added and stirred at room temperature. The reaction was carried out using a 450 W xenon lamp (λ ≧ 420 nm) under argon atmosphere. Since the concentration of NADH was measured at 340 nm using a spectrophotometer (UV-1800, Shimadzu).

< Example  3> grepin-based photocatalyst and Formate Dehydrogenase  Conversion of Carbon Dioxide Using Formic Acid

For the catalytic reaction, 100 mM phosphate buffer solution (pH 7.0) was placed in a reactor, 10 μmol of the grepin-based complex prepared in Preparation Example 1 as a photocatalyst, and rhodium (III) prepared in Preparation Example 2 as an electron transporter. 0.2 mmol of the complex, 0.4 mmol of NAD, 400 mmol of triethanolamine (TEOA) and 3 units of Formate Dehydrogenase as a biocatalyst (enzyme) were added and stirred at room temperature. The reaction was carried out using a 450 W xenon lamp (λ ≧ 420 nm) under CO ₂ atmosphere. Since the concentration of NADH was measured at 340 nm using a spectrophotometer (UV-1800, Shimadzu), the formic acid produced by the reaction was quantitatively analyzed by gas chromatography (GC, 5890 Series II, HP).

< Experimental Example  1> Photocatalyst  Following NADH  Production measurement

In the NADH regeneration method according to the present invention, the following experiment was performed to determine the effect of the photocatalyst.

In the photocatalyst, W ₂ Fe ₄ Ta ₂ O ₁₇ instead of the grepin-based photocatalyst and the grepin-based photocatalyst Except that the catalyst and BiVO ₄ -graphene oxide was used, the reaction was carried out for 2 hours in the same manner as in Example 2 to determine the amount of NADH produced over time.

The measurement results are shown in Table 1 and FIG. 7 .

NADH conversion rate (%) The compound of formula (1) 54.02 W ₂ Fe ₄ Ta ₂ O ₁₇ 14.50 BiVO ₄ -graphene oxide 10.53

As shown in Table 1 and FIG. 4 , when BiVO ₄ -graphene oxide photocatalyst was used, the conversion rate of NADH was 10.53%, and W ₂ Fe ₄ Ta ₂ O ₁₇ In the case of using a photocatalyst, the conversion rate of NADH is 14.50%, but in the case of using the grepin-based photocatalyst according to the present invention, the conversion rate of NADH is 54.02%, which is 3.5 times better than other photocatalysts. .

Therefore, the graphene-based photocatalyst according to the present invention can reproduce the cofactor of the oxidoreductase with excellent conversion efficiency and thus can be mass-produced and automated, and it is economical and environmentally friendly since it does not incur additional energy costs using solar energy.

< Experimental Example  2> Photocatalyst  Formic acid conversion of carbon dioxide according to

In order to examine the effect of the grepin-based photocatalyst used in the present invention on the biocatalytic reaction through the production of NADH, the following experiment was performed.

In the photocatalyst, W ₂ Fe ₄ Ta ₂ O ₁₇ instead of the grepin-based photocatalyst and the grepin-based photocatalyst Except that the catalyst and BiVO ₄ -graphene oxide was used, the reaction was carried out for 2 hours in the same manner as in Example 3 to determine the formic acid production of carbon dioxide over time.

The measurement results are shown in Table 2 and FIG. 8 .

catalyst Formic acid production amount of carbon dioxide (μmol) The compound of formula (1) 144.22 W ₂ Fe ₄ Ta ₂ O ₁₇ 14.25 BiVO ₄ -graphene oxide 9.01

As shown in Table 2 and FIG. 8 , when W ₂ Fe ₄ Ta ₂ O ₁₇ absorbing visible light was used as the photocatalyst, formic acid production of carbon dioxide was found to be 14.25 μmol, and other graphene-based catalysts (BiVO ₄ -graphene) were used. Fin oxide), the amount of formic acid produced in carbon dioxide was 9.01 μmol, but in the case of using the graphene photocatalyst according to the present invention, The amount of formic acid produced in carbon dioxide was 144 μmol, which was 10 times better than other photocatalysts.

Therefore, the photocatalyst used in the method for regenerating the oxidoreductase cofactor according to the present invention and the method for producing formic acid from carbon dioxide through the present invention is preferably to use the compound of formula 1 according to the present invention.

Claims (10)

New grepin-based complex represented by the formula (1):
[Formula 1]

.
The novel grepin-based composite according to claim 1, which is used as a visible light absorbing photocatalyst.
Phosphoric acid buffer solution in the reactor; Oxidoreductase cofactors of oxidized type; Any one or more redox mediators selected from the group consisting of methylbiologen, ruthenium (II) complexes and rhodium (III) complexes; And adding a visible light absorbing grepin-based photocatalyst represented by Chemical Formula 1 and stirring while applying light to generate a reduced oxidoreductase cofactor.
The method of claim 3, wherein the oxidoreductase cofactor of the oxidized type is any one selected from the group consisting of NAD ⁺ , NADP ⁺ , FAD ^+, and FMN ⁺ .
The ruthenium (II) complex is (hexamethylbenzene-2,2'-bipyridinechloro) ruthenium (II), and the rhodium (III) complex is (pentamethylcyclopentadienyl-2, A method of regenerating oxidoreductase cofactors, characterized in that 2'-bipyridinechloro) rhodium (III).
The method of claim 3, wherein the light has a wavelength of 280 ~ 650 nm.
Phosphoric acid buffer solution in the reactor; Oxidoreductase cofactors of oxidized type; Any one or more redox mediators selected from the group consisting of methylbiologen, ruthenium (II) complexes and rhodium (III) complexes; Visible light absorbing grepin-based photocatalyst represented by Chemical Formula 1 of claim 1; Selectively preparing formic acid from carbon dioxide by enzymatic reaction using a co-regeneration method of the redox enzyme of claim 1 comprising the step of adding formate dehydrogenase and stirring with light under a carbon dioxide atmosphere to produce formic acid. How to.
The method according to claim 7, wherein the oxidoreductase oxidoreductase cofactor is any one selected from the group consisting of NAD ⁺ , NADP ⁺ , FAD ⁺ and FMN ⁺ .
The method of claim 7, wherein the ruthenium (II) complex is (hexamethylbenzene-2,2'-bipyridinechloro) ruthenium (II), and the rhodium (III) complex is (pentamethylcyclopentadienyl-2, A process for selectively preparing formic acid from carbon dioxide, characterized in that it is 2'-bipyridinechloro) rhodium (III).
8. The method of claim 7, wherein said light has a wavelength of 280-650 nm.

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