Method for synthesizing fullerene mono-addition derivative through constant-current electrolysis

Abstract

The invention discloses a method for synthesizing a fullerene mono-addition derivative through constant-current electrolysis, and relates to the technical field of fullerene derivative synthesis. The preparation method comprises the following steps: mixing C60, amino acid and glacial acetic acid in an electrolyte solution, and carrying out constant-current electrolysis by adopting an RVC electrode to obtain the fullerene mono-addition derivative. According to the method, the expected fullerene derivative is successfully synthesized in a constant-current electrolysis mode without adding aldehyde compounds for the first time, and the method has the advantages of being high in yield and easy to operate and has great technical breakthrough.

Description

Technical Field

[0001] The invention relates to the technical field of fullerene derivative synthesis, in particular to a method for synthesizing fullerene monoaddition derivatives by constant current electrolysis. Background Art

[0002] Functionalized fullerene (C 60 ) derivatives are important substances that play an important role in chemistry, medicine, pharmacy, biology, etc., and have attracted much attention from chemists. Chemists have been committed to its synthesis research in the past 30 years and have reported many synthetic methods for functionalized fullerene single-addition and multi-addition derivatives, most of which are chemical synthesis methods based on thermochemistry.

[0003] Chemical modification of monoaddition fullerene derivatives is generally divided into two types: one is to attach some groups to the outer layer of the fullerene sphere, and the other is to destroy the fullerene sphere to modify the spherical framework: external surface modification and skeleton modification. The modification methods on the fullerene sphere include cycloaddition, free radical addition, nucleophilic addition, dimerization reaction, transition metal catalysis / promoted reaction, aldehyde / amine participation reaction, asymmetric synthesis, reverse cycloaddition reaction, mechanochemical reaction, halogenation, hydrogenation, hydroxylation, addition of organic copper reagents, addition of peroxides, addition of amines, etc. Fullerene cycloaddition reaction is one of the most studied fullerene reactions, because this type of reaction can obtain monoaddition fullerene products that are easy to separate and have high yields, and most functional groups can be modified by cycloaddition methods. The most representative fullerene cycloaddition reactions include [2+1], [2+2], [3+2] and [4+2] cycloaddition reactions.

[0004] The fullerene [2+1] cycloaddition reaction is a three-membered ring fullerene derivative formed by connecting a carbon atom or other atom to the [5,6] or [6,6] bond of the fullerene. Generally, this reaction occurs on the [6,6] bond. The most commonly used atom to form the three-membered ring is the carbon atom, and the corresponding reaction is the Bingel reaction. In addition, there are other less commonly used methods, namely carbenes addition and thermal addition of diazo compounds. [2+2] cycloaddition compounds are generally formed by photochemical irradiation or thermal reaction with cycloalkenones, non-cyclic alkenones, alkenones, alkynes, benzenes, alkenes and cumulenes to form a cycloaddition reaction between fullerene and cyclobutane or cyclobutene fragments. The [2+2] cycloaddition reaction is also used to prepare fullerene dimers, that is, two or more fullerene cages connected by two CC bonds. [3+2] cycloaddition is another most commonly used method for preparing fullerene monoaddition five-membered ring derivatives, also known as the Prato reaction. This method can be used to prepare various fullerene five-membered heterocycles, such as fullertriazoles, fullerpyrazoles, fullerpyridines, fullerpyridines, fullerdihydrofurans, fullerenepyrazoles, fullereneisoxazoles, fullertetrahydrofurans, fullertetrahydrothiophenes, fulleroxazolidines, fuller2-imine-1,3-thiazolidines, etc. [4+2] cycloaddition Diels-Alder reaction is one of the earliest fullerene reactions studied. Six-membered carbocyclic or heterocyclic compounds fused with fullerenes are usually prepared by [4+2] cycloaddition. Many [4+2] cycloaddition products are usually generated by the reaction of fullerenes with in situ generated dienes.

[0005] Among the reported methods for chemically synthesizing fullerene polyaddition derivatives, there are mainly the localization method, template method, placeholder method, coordination chemistry method and other synthesis methods. The localization method reserves one or more redundant reaction sites when modifying the side chain of the fullerene derivative, so that the length of the chain can be controlled to synthesize fullerene polyaddition derivatives with certain specific addition modes; the template method is a synthesis method that uses certain special reactions for fixed-point addition to generate addition products at fixed sites; the placeholder method generally modifies two large steric groups on the fullerene carbon cage first, and uses the steric effect of the groups to synthesize polyaddition derivatives; the coordination chemistry rule is to mask certain areas on the fullerene carbon cage through the supramolecular interaction of the host-guest, thereby improving the regioselectivity of the polyaddition reaction.

[0006] The above-mentioned chemical method for synthesizing fullerene single-addition or multi-addition derivatives has advantages but also has some limitations, namely, the product is single, the reaction site of the multi-addition product is difficult to control, the reaction conditions are harsh, etc. Therefore, it is necessary to further develop a synthesis method for fullerene multi-addition derivatives with simple operation, novel addition mode, and flexible and controllable number of addition groups.

[0007] Electrochemical synthesis is considered to be a novel and efficient strategy for preparing various fullerene derivatives due to its mild reaction conditions, good regioselectivity and relatively high yield. In 1993, Kadish's research group first obtained C by constant-voltage electrolysis of fullerene. 60 2- Then add iodomethane to C 60 2- In 2007, Gao Xiang's research group reported a method for synthesizing fullerene derivatives based on constant-voltage electrolysis, namely the reaction of fullerene with benzyl bromide. They successfully prepared and separated four fullerene derivatives using electrochemical methods. Their work provided valuable experience for subsequent electrochemical synthesis of fullerene derivatives.

[0008] In 2008, Gao Xiang's research group reported the electrochemical generation of C 60 2- Reaction with benzyl bromide to reduce C in benzonitrile 60 When reacted with benzyl bromide, a C 60 A five-membered heterocyclic ring was attached to the [5,6] bond of the fullerene derivative. Later, in another electrochemical study on benzyl bromide and fullerene derivatives, they synthesized a variety of fused heterocyclic polyaddition derivatives. Since then, people have been exploring the electrochemical synthesis of fullerene derivatives more and more deeply. In 2014, Wang Guanwu's research group reported a C 60 The protonation reaction of the fused indoline dianion finally gave four tri-addition C 60 They subsequently reported various methods for the polyaddition synthesis of fullerene derivatives by constant-voltage electrolysis. In 2015, they C 60 After electroreduction of the fused oxazoline or imidazoline monoaddition fullerene derivative 17, they found that the reduction product would dissociate into fullerene derivatives 18 and 19. Fullerene derivative 18 then reacted with PhCH2Br to obtain fullerene derivative 19 and fullerene derivative 20, both of which are difficult to obtain by thermochemical reactions. In 2017, Wang Guanwu's research group reported a highly regioselective electrochemical carbonylation method that can directly obtain monocarbonylated C 60 In the same year, the research group also reported C 60 In the following years, they reported the electrochemical synthesis methods of various fullerene derivatives. These products are difficult to synthesize using thermochemical methods. It can be seen that electrochemical methods can play an irreplaceable role in the synthesis of fullerene products with special addition sites.

[0009] There are two ways of electrochemical synthesis, one is constant voltage electrolysis and the other is constant current electrolysis. Currently reported methods for electrochemical synthesis of fullerene derivatives are all constant voltage electrolysis, which is a more mature strategy than constant current electrolysis. However, there are basically no reports on the method of constant current electrolysis of fullerenes, because it is difficult to control the appropriate current to make fullerenes accurately add and obtain the expected addition product. Therefore, it is necessary to propose a method for constant current electrolysis to synthesize fullerene mono-addition derivatives, so as to obtain mono-addition fullerene derivatives with higher yield. Summary of the invention

[0010] The purpose of the present invention is to provide a method for synthesizing fullerene monoaddition derivatives by constant current electrolysis to solve the problems existing in the above-mentioned prior art.

[0011] To achieve the above object, the present invention provides the following solutions:

[0012] The present invention provides a method for synthesizing fullerene monoaddition derivatives by constant current electrolysis, comprising the following steps:

[0013] In an inert gas atmosphere, C 60 The fullerene mono-addition derivative is obtained by mixing with amino acid and glacial acetic acid in an electrolyte solution and performing constant current electrolysis using an RVC electrode (net-shaped glassy carbon electrode).

[0014] Furthermore, the current of the constant current electrolysis is 8-12 mA, more preferably 10 mA.

[0015] Furthermore, the amino acid includes sarcosine, N-(2-cyanoethyl)glycine, N-ethylglycine, N-benzylglycine or iminodiacetic acid.

[0016] Furthermore, the C 60 The molar ratio of amino acid to glacial acetic acid is 1:5-30:5-30.

[0017] Furthermore, the C 60 The molar ratio of amino acid to glacial acetic acid is 1:20:20.

[0018] Furthermore, the electrolyte solution uses tetrabutylammonium acetate as the solute and a mixture of o-dichlorobenzene and acetonitrile in a volume ratio of 1:1-4:1 as the solvent. More preferably, the volume ratio of o-dichlorobenzene to acetonitrile is 4:1.

[0019] Furthermore, the concentration of the electrolyte solution is 0.1-0.4M, more preferably 0.1M.

[0020] Furthermore, the constant current electrolysis time is 0.5-4h.

[0021] Furthermore, the temperature of the constant current electrolysis is 80-140°C, more preferably 120°C.

[0022] The present invention also provides a fullerene mono-addition derivative prepared by the above method.

[0023] The present invention discloses the following technical effects:

[0024] The present invention provides a method for synthesizing fullerene monoaddition derivatives by constant current electrolysis, which has the characteristics of high yield and simple operation. The present invention successfully synthesizes the expected fullerene derivatives by constant current electrolysis without adding aldehyde compounds for the first time, which is a great technical breakthrough. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 The UV-visible spectrum of the fullerene derivative prepared in Example 1 of the present invention (at around 430nm, there is obvious characteristic absorption of fullerene mono-addition derivative);

[0027] Figure 2 The nuclear magnetic resonance hydrogen spectrum of the fullerene derivative prepared in Example 1 of the present invention ( 1 H NMR) spectra;

[0028] Figure 3 The carbon NMR spectrum of the fullerene derivative prepared in Example 1 of the present invention ( 13 C NMR) spectra;

[0029] Figure 4 This is a mass spectrum (APCI-MS) of the fullerene derivative prepared in Example 1 of the present invention;

[0030] Figure 5 This is the UV-visible spectrum of the fullerene derivative prepared in Example 2 of the present invention (at around 430nm, there is obvious characteristic absorption of fullerene mono-addition derivative);

[0031] Figure 6 The nuclear magnetic resonance hydrogen spectrum of the fullerene derivative prepared in Example 2 of the present invention ( 1 H NMR) spectra;

[0032] Figure 7 The carbon NMR spectrum of the fullerene derivative prepared in Example 2 of the present invention ( 13 C NMR) spectra;

[0033] Figure 8 This is a mass spectrum (APCI-MS) of the fullerene derivative prepared in Example 2 of the present invention;

[0034] Fig. 9 This is the UV-visible spectrum of the fullerene derivative prepared in Example 3 of the present invention (at around 430nm, there is obvious characteristic absorption of fullerene mono-addition derivative);

[0035] Fig.10 The nuclear magnetic resonance hydrogen spectrum of the fullerene derivative prepared in Example 3 of the present invention ( 1 H NMR) spectra;

[0036] Fig.11 The carbon NMR spectrum of the fullerene derivative prepared in Example 3 of the present invention ( 13 C NMR) spectra;

[0037] Fig.12 This is a mass spectrum (APCI-MS) of the fullerene derivative prepared in Example 3 of the present invention;

[0038] Fig.13 This is the UV-visible spectrum of the fullerene derivative prepared in Example 4 of the present invention (at around 430nm, there is obvious characteristic absorption of fullerene mono-addition derivative);

[0039] Fig.14 The nuclear magnetic resonance hydrogen spectrum of the fullerene derivative prepared in Example 4 of the present invention ( 1 H NMR) spectra;

[0040] Fig.15 The carbon NMR spectrum of the fullerene derivative prepared in Example 4 of the present invention ( 13 C NMR) spectra;

[0041] Fig.16 This is a mass spectrum (APCI-MS) of the fullerene derivative prepared in Example 4 of the present invention;

[0042] Fig.17 This is the UV-visible spectrum of the fullerene derivative prepared in Example 5 of the present invention (at around 430nm, there is obvious characteristic absorption of fullerene mono-addition derivative);

[0043] Fig.18 The H NMR spectrum of the fullerene derivative prepared in Example 5 of the present invention ( 1 H NMR) spectra;

[0044] Fig.19 The carbon NMR spectrum of the fullerene derivative prepared in Example 5 of the present invention ( 13 C NMR) spectra;

[0045] Fig. 20 This is the mass spectrum (APCI-MS) of the fullerene derivative prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0047] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0048] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0049] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0050] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0051] The raw materials and reagents used in the experiments of the present invention are shown in Table 1.

[0052] Table 1

[0053]

[0054]

[0055] o-Dichlorobenzene, toluene and chlorobenzene were all dehydrated with anhydrous calcium chloride before use.

[0056] TBAA is used as the supporting electrolyte for the electrochemical constant current electrolysis synthesis of fullerene derivatives. The concentration of the TBAA electrolytic solution used is 0.1M, and the solvent composition is o-DCB (V): acetonitrile (V) = 4:1. After preparation, add clean anhydrous Molecular sieve, and use bubbling method to deoxygenate the solution.

[0057] The method for synthesizing fullerene monoaddition derivatives by constant current electrolysis of the present invention comprises the following steps:

[0058] Two bare carbon rod RVC electrodes were used as positive and negative electrodes for constant current electrolysis. 60 Cyanoethyl amino acid (20 eq.) and glacial acetic acid (20 eq.) were added to the solution, 0.1 M TBAA (tetrabutylammonium acetate) was selected as the supporting electrolyte, and the solvent was o-DCB:MeCN = 4:1 (volume ratio). Constant current electrolysis was performed at 120°C under inert gas conditions and a current of 10 mA. During the electrolysis process, the reaction results were monitored using a thin layer chromatography column. The results showed that when the reaction was carried out for 30 minutes, in addition to the unreacted C 60 In addition, obvious reaction product spots appeared. After the reaction time was extended, the product spots were found to be the most concentrated when the reaction was carried out for 3.5 hours. After the reaction was stopped, the samples were separated for characterization. Through ultraviolet monitoring, it was found that there was a very obvious single addition characteristic peak of fullerene derivatives at 431nm, such as Figure 1 The obtained product was subjected to mass spectrometry test, and the results were as follows Figure 2 shown.

[0059] Based on the above experiments (standard conditions) of the present invention, the conditions shown in Table 2 were screened.

[0060] Table 2 Condition screening

[0061]

[0062]

[0063] Note: "nd" in the table means no product was found.

[0064] It is found that the current has a certain influence on the final yield of the reaction when the current is 8mA, the yield of the expected product is only 34.10%, and when the current is increased to 12mA, the yield of the expected product is only 29.50%. Compared with condition 1, the change of current in condition 2 and condition 3 will reduce the yield of the product. Adjust the electrolyte solution, replace acetonitrile with an equal amount of methanol, and the result shows that the yield is reduced to 25.4% (condition 4), and obvious insoluble matter can be observed in the solution during the electrolysis process. When glacial acetic acid is not added (condition 5) or glacial acetic acid is replaced by other organic acid MSA (methylsulfonic acid) (condition 6), the yield of the target product is more obviously reduced, and the yield is only 26.20% when glacial acetic acid is not added, and when glacial acetic acid is replaced by MSA, the yield is only 17.5%. It can be seen that the presence of glacial acetic acid plays a very important role in the reaction process. The present invention further sets up experiments under conditions 10, 11 and 12. By comparing the differences between the several groups of experiments, it is found that when the electrolyte TBAA (tetrabutylammonium acetate) is replaced with TBAP (tetrabutylammonium perchlorate) or replaced with TBAPF6 (tetrabutylammonium hexafluorophosphonate) or TBACl (tetrabutylammonium chloride) without adding glacial acetic acid, the expected product is not detected in the reaction. - The presence of is particularly important in the reaction, and even affects whether the product can be produced. - The presence of AcO promoted the reaction. The present invention also tried to add TBACl and glacial acetic acid without adding TBAA (condition 13), creating a - There is [(CH2)3CH3]4N + The conditions for the existence of TBAA were created, and the production of the target product was monitored again in the reaction. Although the yield of the target product was 7% under the artificially created conditions similar to those for the existence of TBAA, this verified a very critical issue, that is, the presence of acetate does promote the production of the target product.

[0065] In addition to the screening of current and electrolyte solution, temperature, electrode and gas conditions were also screened. By comparing conditions 8 and 9, it can be found that 120°C is the optimal reaction temperature condition for this reaction. Replacing the RVC electrode with a platinum electrode will lead to a significant decrease in the yield of the target product (condition 7), and the reaction can only obtain the target product under inert gas protection conditions (condition 14). In the absence of current, the reaction was carried out for 5 hours, but the yield of the target product was only 17% (condition 15). It can be seen that the presence of current is also crucial.

[0066] As shown in Table 3, after screening the conditions, the corresponding amino acid substrates were expanded. It was found that conditions a to d all generated the corresponding fullerene monoaddition products in a relatively short time, especially condition a, which only took 2.5 h to electrolyze to obtain the corresponding structural fullerene derivative with a yield of 52%. Condition e may be that the carboxyl group fell off during the heating process to generate CO2.

[0067] Table 3 Electrochemical reactions of fullerenes with different amino acids

[0068]

[0069]

[0070]

[0071] In the present invention, the specific examples of constant current electrolysis of fullerene and different amino acids are as follows:

[0072] Example 1 Electrochemical Synthesis of Fullerene Derivative EP-Me

[0073]

[0074] Wash the 25mL four-necked flask, stirring rod, condenser, RVC electrode, and graphite electrode to be used, and put them in a 60℃ oven to dry for 1h. Cut the RVC electrode into a cylindrical shape and the graphite electrode into a pencil shape. Then insert the graphite electrode into the RVC electrode, leaving some of the graphite electrode slightly exposed at the bottom of the RVC electrode. Finally, install the two electrodes connected in this way on the four-necked flask and seal them. Weigh C 60 (0.1mmol, 1eq), sarcosine (2mmol, 20eq) were added to a four-necked flask equipped with a graphite electrode and an RVC electrode, and a closed reaction device with a reflux condenser was built. A vacuum double-row tube was used to evacuate and replace with argon three times, and finally an appropriate amount of argon was filled as the reaction gas condition. 10mL of the prepared 0.1M TBAA solution was added, the reaction temperature was set to 120°C, a constant current electrolyzer was connected, and the electrolysis current was set to 10mA. When the temperature reached the set value, AcOH (2mmol, 20eq) was added, and then the constant current electrolyzer was started for electrolysis. The reaction progress was monitored by thin layer chromatography, and the reaction was stopped when the reaction reached the best. The crude product was concentrated in vacuo and then separated and purified on a chromatographic column using toluene as the eluent to obtain the desired product EP-Me. The product was dissolved with carbon disulfide, precipitated once by adding n-hexane, and then precipitated twice by adding methanol. The solution was removed by suction to obtain a solid product. The product was placed in a vacuum drying oven at 100°C and vacuum dried for 24 hours to obtain a brown solid product with an isolated yield of 52.0%.

[0075] 1 H NMR (600MHz, CDCl3 / CS2=1 / 2): δ (ppm) 4.41 (s, 4H), 3.02 (s, 3H). 13 C NMR (151MHz, CDCl3 / CS2=1 / 2): δ154.62,147.12,146.09,145.91,145.84,145.52,145.32,145.13,1 44.40,142.97,142.50,142.08,141.94,141.76,140.06,136.13,70.98,69.87,41.38.APCI-MS:m / z calcd for C 65 H8N2:777.1[M] - ,found:777.0.

[0076] Example 2 Electrochemical Synthesis of Fullerene Derivative EP-CN

[0077]

[0078] Wash the 25mL four-necked flask, stirring rod, condenser, RVC electrode, and graphite electrode to be used, and put them in a 60℃ oven to dry for 1h. Cut the RVC electrode into a cylindrical shape and the graphite electrode into a pencil shape. Then insert the graphite electrode into the RVC electrode, leaving some of the graphite electrode slightly exposed at the bottom of the RVC electrode. Finally, install the two electrodes connected in this way on the four-necked flask and seal them. Weigh C 60 (0.1mmol, 1eq), N-(2-cyanoethyl)glycine (2mmol, 20eq) were added to a four-necked flask equipped with a graphite electrode and an RVC electrode, and a closed reaction device with a reflux condenser was built. A vacuum double-row tube was used to evacuate and replace with argon three times, and finally an appropriate amount of argon was filled as the reaction gas condition. 10mL of the prepared 0.1M TBAA solution was added, the reaction temperature was set to 120°C, a constant current electrolyzer was connected, and the electrolysis current was set to 10mA. When the temperature reached the set value, AcOH (2mmol, 20eq) was added, and then the constant current electrolyzer was started for electrolysis. The reaction progress was monitored by thin layer chromatography, and the reaction was stopped when the reaction reached the best. The crude product was concentrated in vacuo and then separated and purified on a chromatographic column with toluene as the eluent to obtain the desired product EP-CN. The product was dissolved with carbon disulfide, precipitated once by adding n-hexane, and then precipitated twice by adding methanol. The solution was removed by suction to obtain a solid product. The product was placed in a vacuum drying oven at 100°C and vacuum dried for 24 hours to obtain a brown solid product with an isolated yield of 42.4%.

[0079] 1H NMR (600MHz, CDCl3 / CS2=1 / 2): δ (ppm) 4.55 (s, 4H), 3.50 (t, J = 7.0Hz, 2H), 3.00 (t, J = 7.0Hz, 2H). 13 C NMR (151MHz, CDCl3 / CS2=1 / 2): δ154.00,147.16,146.14,145.94,145.65,145.46,145.40,145.16,144.39, 142.99,142.54,142.01,141.95,141.79,140.11,136.14,117.45,70.21,67.48,50.22,17.89.APCI-MS:m / z calcd for C 65 H8N2:816.1[M] - ,found:816.0.

[0080] Example 3 Electrochemical Synthesis of Fullerene Derivative EP-Et

[0081]

[0082] Wash the 25mL four-necked flask, stirring rod, condenser, RVC electrode, and graphite electrode to be used, and put them in a 60℃ oven to dry for 1h. Cut the RVC electrode into a cylindrical shape and the graphite electrode into a pencil shape. Then insert the graphite electrode into the RVC electrode, leaving some of the graphite electrode slightly exposed at the bottom of the RVC electrode. Finally, install the two electrodes connected in this way on the four-necked flask and seal them. Weigh C 60 (0.1mmol, 1eq), N-ethylglycine (2mmol, 20eq) were added to a four-necked flask equipped with a graphite electrode and an RVC electrode, and a closed reaction device with a reflux condenser was built. A vacuum double-row tube was used to evacuate and replace with argon three times, and finally an appropriate amount of argon was filled as the reaction gas condition. 10mL of the prepared 0.1M TBAA solution was added, the reaction temperature was set to 120°C, a constant current electrolyzer was connected, and the electrolysis current was set to 10mA. When the temperature reached the set value, AcOH (2mmol, 20eq) was added, and then the constant current electrolyzer was started for electrolysis. The reaction progress was monitored by thin layer chromatography, and the reaction was stopped when the reaction reached the best. The crude product was concentrated in vacuo and then separated and purified on a chromatographic column with toluene as the eluent to obtain the desired product EP-Et. The product was dissolved with carbon disulfide, precipitated once by adding n-hexane, and then precipitated twice by adding methanol. The solution was removed by suction to obtain a solid product. The product was placed in a vacuum drying oven at 100°C and vacuum dried for 24 hours to obtain a brown solid product with an isolated yield of 37.3%.

[0083] 1 H NMR (600MHz, CDCl3 / CS2=1 / 2): δ (ppm) 4.43 (s, 4H), 3.18 (q, J = 7.2Hz, 2H), 1.59 (t, J = 7.2Hz, 3H). 13 C NMR (151MHz, CDCl3 / CS2=1 / 2): δ154.80,147.09,146.07,145.88,145.86,145.50,145.30,145.10,144. 40,142.95,142.48,142.07,141.92,141.74,140.05,136.15,70.40,67.64,49.28,14.27.APCI-MS:m / z calcd for C 65 H8N2:791.1[M] - ,found:791.0.

[0084] Example 4 Electrochemical Synthesis of Fullerene Derivative EP-Ph

[0085]

[0086] Wash the 25mL four-necked flask, stirring rod, condenser, RVC electrode, and graphite electrode to be used, and put them in a 60℃ oven to dry for 1h. Cut the RVC electrode into a cylindrical shape and the graphite electrode into a pencil shape. Then insert the graphite electrode into the RVC electrode, leaving some of the graphite electrode slightly exposed at the bottom of the RVC electrode. Finally, install the two electrodes connected in this way on the four-necked flask and seal them. Weigh C 60 (0.1mmol, 1eq), N-benzylglycine (2mmol, 20eq) were added to a four-necked flask equipped with a graphite electrode and an RVC electrode, and a closed reaction device with a reflux condenser was built. A vacuum double-row tube was used to evacuate and replace with argon three times, and finally an appropriate amount of argon was filled as the reaction gas condition. 10mL of the prepared 0.1M TBAA solution was added, the reaction temperature was set to 120°C, a constant current electrolyzer was connected, and the electrolysis current was set to 10mA. When the temperature reached the set value, AcOH (2mmol, 20eq) was added, and then the constant current electrolyzer was started for electrolysis. The reaction progress was monitored by thin layer chromatography, and the reaction was stopped when the reaction reached the best. The crude product was concentrated in vacuo and then separated and purified on a chromatographic column using toluene as the eluent to obtain the desired product EP-Ph. The product was dissolved with carbon disulfide, precipitated once by adding n-hexane, and then precipitated twice by adding methanol. The solution was removed by suction to obtain a solid product. The product was placed in a vacuum drying oven at 100°C and vacuum dried for 24 hours to obtain a brown solid product with an isolated yield of 32.7%.

[0087] 1 H NMR (600MHz, CDCl3 / CS2=1 / 2): δ (ppm) 7.68 (d, J = 7.6 Hz, 2H), 7.45 (t, J = 7.5, 2H), 7.36 (t, J = 7.4, 1H), 4.45 (s, 4H), 4.32 (s, 2H). 13 C NMR (151MHz, CDCl3 / CS2=1 / 2): δ154.71,147.13,146.11,145.92,145.89,145.53,145.34,145.14,144.42,142.97,1 42.51,142.11,141.95,141.77,140.08,137.75,136.18,128.70,128.67,127.61,70.50,67.49,58.91.APCI-MS:m / z calcd for C 65 H8N2:853.1[M] - ,found:853.1.

[0088] Example 5 Electrochemical Synthesis of Fullerene Derivative EP-COOH

[0089]

[0090] Wash the 25mL four-necked flask, stirring rod, condenser, RVC electrode, and graphite electrode to be used, and put them in a 60℃ oven to dry for 1h. Cut the RVC electrode into a cylindrical shape and the graphite electrode into a pencil shape. Then insert the graphite electrode into the RVC electrode, leaving some of the graphite electrode slightly exposed at the bottom of the RVC electrode. Finally, install the two electrodes connected in this way on the four-necked flask and seal them. Weigh C 60(0.1mmol, 1eq), iminodiacetic acid (2mmol, 20eq) were added to a four-necked flask equipped with a graphite electrode and an RVC electrode, and a closed reaction device with a reflux condenser was set up. A vacuum double-row tube was used to evacuate and replace with argon three times, and finally an appropriate amount of argon was filled as the reaction gas condition. 10mL of the prepared 0.1M TBAA solution was added, the reaction temperature was set to 120°C, a constant current electrolyzer was connected, and the electrolysis current was set to 10mA. When the temperature reached the set value, AcOH (2mmol, 20eq) was added, and then the constant current electrolyzer was started for electrolysis. The reaction progress was monitored by thin layer chromatography, and the reaction was stopped when the reaction reached the best. The crude product was concentrated in vacuo and then separated and purified on a chromatographic column with toluene as the eluent to obtain the desired product EP-COOH. The product was dissolved with carbon disulfide, precipitated once by adding n-hexane, and then precipitated twice by adding methanol. The solution was removed by suction to obtain a solid product. The product was placed in a vacuum drying oven at 100°C and vacuum dried for 24 hours to obtain a brown solid product with an isolated yield of 17.1%.

[0091] 1 H NMR (600MHz, CDCl3 / CS2=1 / 2): δ (ppm) 4.41 (s, 4H), 3.02 (s, 3H). 13 C NMR (151MHz, CDCl3 / CS2=1 / 2): δ154.66,147.13,146.11,145.92,145.86,145.53,145.33,145.14,1 44.42,142.98,142.51,142.09,141.95,141.77,140.07,136.15,71.01,69.90,41.37.APCI-MS:m / z calcd for C 65 H8N2:777.1[M] - ,found:777.0.

[0092] The present invention adopts specific electrolysis conditions and selects different amino acid substrates to prepare fullerene monoaddition products. Although the fullerene monoaddition products of the present invention can be synthesized in one step by Prato reaction, the present invention successfully synthesizes the expected fullerene derivatives for the first time by constant current electrolysis without adding aldehyde compounds, which is a great technical breakthrough.

[0093] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for synthesizing fullerene monoaddition derivatives by constant current electrolysis, characterized in that: The following steps are involved: In an inert gas atmosphere, C 60 The fullerene mono-addition derivative is obtained by mixing with amino acid and glacial acetic acid in an electrolyte solution and performing constant current electrolysis using an RVC electrode.

2. The method according to claim 1, characterized in that The current of the constant current electrolysis is 8-12 mA.

3. The method according to claim 1, characterized in that The amino acid includes sarcosine, N-(2-cyanoethyl)glycine, N-ethylglycine, N-benzylglycine or iminodiacetic acid.

4. The method according to claim 1, characterized in that The C 60 The molar ratio of amino acid to glacial acetic acid is 1:5-30:5-30.

5. The method according to claim 1, characterized in that The electrolyte solution uses tetrabutylammonium acetate as a solute and a mixed solution of o-dichlorobenzene and acetonitrile in a volume ratio of 1:1-4:1 as a solvent.

6. The method according to claim 1, characterized in that The concentration of the electrolyte solution is 0.1-0.4M.

7. The method according to claim 1, characterized in that The constant current electrolysis time is 0.5-4h.

8. The method according to claim 1, characterized in that The temperature of the constant current electrolysis is 80-140°C.

9. A fullerene monoaddition derivative prepared by the method according to any one of claims 1 to 8.

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