A diamondoid-modified fullerene (C 60 ) pyrrolidine, microcrystals thereof, and methods of making

Abstract

The application provides adamantane-modified fullerenes (C 60 ) pyrrolines with enhanced fluorescent properties. The application discloses adamantane-modified fullerenes pyrrolines with enhanced fluorescent properties, and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing and dispersing fullerenes, paraformaldehyde, 1-adamantane methylamine and o-dichlorobenzene, reacting, evaporating a solvent under reduced pressure, separating by column chromatography, and recrystallizing to obtain adamantane-modified fullerenes pyrrolines. The adamantane-modified fullerenes pyrrolines are dissolved in m-xylene, and a poor solvent, isopropanol, is slowly added dropwise to form a clear liquid-liquid interface. The reaction liquid is shaken until the liquid-liquid interface disappears, and then is subjected to ultrasonic treatment, standing, precipitation, washing, and drying to obtain microcrystals. The synthesis process is simple, and raw materials are cheap and easy to obtain. The crystallization method is simple and effective, and the crystallization is good, so that the crystal morphology and size can be controlled. The obtained adamantane-modified fullerenes pyrrolines and cubic crystals have good solubility in organic solvents, excellent fluorescent properties, and symmetrical structure, which is beneficial to subsequent application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanometer carbon material fluorescence, and particularly relates to a diamondane-modified fullerene (C 60 ) pyrrolidine with enhanced fluorescence properties. BACKGROUND

[0002] Due to the development of macro-scale preparation process of fullerene, chemical modification of fullerene has become one of the most promising fields in fullerene research, and a large number of interesting fullerene derivatives have been successfully prepared. Among them, fullerene pyrrolidine is the most widely studied class of fullerene derivatives. Due to its unique structure, it has applications in the fields of material science, biological applications, nanotechnology, etc. There are many synthesis methods of fullerene pyrrolidine, mainly including Prato reaction and newly developed aldehyde and amine-based reaction. As a traditional reaction type, Prato reaction has a mature process, but the obtained product has a chiral center, which is difficult to purify, affects the subsequent application, and greatly destroys the symmetry of fullerene, reducing its crystallinity. The newly developed aldehyde and amine-based reaction has the advantages of cheap raw materials, simple process, wide substrate replacement range and single product, and has broad application prospects.

[0003] In 2005, Pavel A. Troshin et al. used 2-, 3- and 4-pyridine methylamine and its various N-substituted derivatives as substrates to generate azomethine imine, which was used for [2+3] cycloaddition of fullerene (C 60 ) to synthesize a series of 2,5-disubstituted and 1,2,5-trisubstituted fullerene pyrrolidine (Formula 1).

[0004]

[0005] In 2017, Airat R. Tuktarov et al. reported that under the catalysis of Ti(Oi-Pr)4, fullerene (C 60 ) reacted with primary amine, paraformaldehyde and EtMgBr to generate N-hydrocarbon-2,5-unsubstituted fullerene (C 60 ) pyrrolidine derivative (Formula 2).

[0006]

[0007] In 2018, Li Fabao's research group of Hubei University synthesized a series of N-alkyl 2,5-unsubstituted / single-substituted fullerene pyrrolidine (Formula 3) by one-step thermal reaction of fullerene (C 60 ) and primary / secondary amine.

[0008]

[0009] In 2023, Liu Sijiang et al. used fullerene, aromatic alkylamine and o-phenylethynyl benzaldehyde as raw materials, o-dichlorobenzene as solvent, and obtained the target product fullerene pyrrolidine isoquinoline (formula 4) through one-step thermal reaction in air under light-proof conditions.

[0010]

[0011] The above reported fullerene pyrrolidine has its limitations. The fullerene pyrrolidine reported by Pavel A. Troshin and Liu Sijiang et al. has a chiral center, which is difficult to purify subsequently and affects application. The terminal group of the fullerene pyrrolidine reported by Airat R. Tuktarov and Li Fabao et al. is mostly asymmetric structure, which greatly destroys the symmetry of fullerene, and is not conducive to the formation of ordered micro-nano crystals through supermolecular self-assembly. Therefore, it is urgent to develop a kind of fullerene pyrrolidine with simple synthesis process, non-chirality, symmetric structure and conducive to subsequent application.

[0012] Fullerene has a high conjugated structure, and its band gap is 1.69 eV, which has potential application value in the field of light emission. However, due to the too large symmetry of fullerene molecules, the transition of electrons between its energy bands is prohibited, so the light emission intensity of fullerene crystal is often weak. In past studies, it was found that when organic solvents are doped into fullerene crystals, or fullerene structures with “geometric definition” are constructed, the light emission intensity will be greatly increased. For example, Choi et al. reported the first batch of highly crystalline C 70 cubes (P. Chibeam, et al. Angew. Chem. Int. Ed. 2010, 49, 9670-9675). Tsukagoshi and Lu et al. reported the polyhedral microcrystals of C 60 parallelepiped to octahedron, and also proved that up to 10wt% of n-heptanol molecules exist in the C 60 polyhedral crystals, which leads to a significant enhancement of fluorescence (S. Zheng, et al. Chem. Mater. 2018, 30, 7146-7153). Lu and Shen et al. used liquid-liquid interfacial precipitation (LLIP) to prepare cubic crystals of higher fullerene C 78 , and proved that the intercalation of trimethylbenzene molecules plays a key role in the formation of cubic crystals, compared with C 78 powder, the photocurrent density and light emission performance of the crystals are improved, which is conducive to its application in optoelectronic devices (N. Jannatun, et al. Chem. Eur. J. 2020, 26, 1-7). However, the research on C 60 and its derivatives with enhanced fluorescence properties is still in the blank stage. SUMMARY

[0013] In view of the deficiencies of the prior art, the present application provides adamantane-modified fullerene (C 60 ) pyrrolidine with enhanced fluorescent properties. The present application has simple synthesis process, cheap and readily available raw materials, simple and effective crystallization method, good crystallization, and controllable crystal morphology and size. The adamantane-modified fullerene (C 60 ) pyrrolidine and its cubic crystal have good solubility in organic solvents, excellent fluorescent properties, and symmetrical structure, which is beneficial for subsequent application.

[0014] The present application is realized by the following technical solutions.

[0015] In a first aspect, the present application provides adamantane-modified fullerene (C 60 ) pyrrolidine with enhanced fluorescent properties. The molecular formula of the adamantane-modified fullerene (C 60 ) pyrrolidine is C 73 H 21 N, and the molecular structure is as follows:

[0016]

[0017] In a second aspect, the present application provides a preparation method of adamantane-modified fullerene (C 60 ) pyrrolidine with enhanced fluorescent properties, which comprises the following steps: uniformly mixing and dispersing fullerene (C 60 ), paraformaldehyde, 1-adamantane methylamine and o-dichlorobenzene, reacting, then evaporating the solvent under reduced pressure, separating by column chromatography, and recrystallizing to obtain adamantane-modified fullerene (C 60 ) pyrrolidine.

[0018] According to the present application, the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantane methylamine is 1:10-20:15-25.

[0019] According to the present application, the molar amount of fullerene (C 60 ) and the volume of o-dichlorobenzene are in the ratio of 5-10 mmol / L.

[0020] According to the present application, the reaction is a reflux reaction, the reaction temperature is 160-200℃, and the reaction time is 10-30 min.

[0021] According to the present application, the eluent used for column chromatography separation is a mixed solvent of carbon disulfide and petroleum ether, wherein the volume percentage content of carbon disulfide is 15-25%.

[0022] According to the application, preferably, ethanol is used for recrystallization.

[0023] In a third aspect, the application provides a diamond-modified fullerene (C 60 ) pyrrolidine microcrystal having enhanced fluorescence properties, wherein the microcrystal is a cubic crystal with a length and width of 5-15 μm and a height of 1-5 μm.

[0024] In a fourth aspect, the application provides a method for preparing a diamond-modified fullerene (C 60 ) pyrrolidine microcrystal having enhanced fluorescence properties, comprising the steps of:

[0025] The diamond-modified fullerene (C 60 ) pyrrolidine is dissolved in m-xylene, and then a poor solvent, isopropanol, is slowly added dropwise to form a clear liquid-liquid interface, the reaction solution is shaken until the liquid-liquid interface disappears, and then is subjected to ultrasonic treatment, left to stand, and the precipitate is collected, washed and dried to obtain the diamond-modified fullerene (C 60 ) pyrrolidine microcrystal.

[0026] According to the application, preferably, the mass of the diamond-modified fullerene (C 60 ) pyrrolidine and the volume of m-xylene are in a ratio of 3-5 mg / mL. If the concentration is too low, no crystal can be obtained, and if the concentration is too high, amorphous solid particles can be produced. Moreover, only m-xylene according to the application can be used to obtain the crystal structure according to the application; if an o-xylene or the like having a similar structure is used, the crystal structure according to the application cannot be obtained.

[0027] According to the application, preferably, the isopropanol is added at a rate of 2-3 mL / min.

[0028] According to the application, preferably, the volume ratio of m-xylene to isopropanol is 1:4-13. As the volume of the isopropanol introduced increases, the size of the crystal gradually decreases. If a poor solvent such as methanol, ethanol or tert-butanol is used instead, no cubic block crystal can be formed.

[0029] According to the application, preferably, the ultrasonic treatment is performed at room temperature for 1-5 min. If no ultrasonic treatment is performed, the crystal morphology can be irregular.

[0030] According to the application, preferably, the standing temperature is 20-25 °C, and the standing time is 12-48 h. If the standing time is too short, too little crystal can be deposited and collected, and if the standing time is too long, flocculent substances can be produced at the bottom and mixed with impurities.

[0031] The synthesis reaction formula of the diamond-modified fullerene (C 60 ) pyrrolidine according to the application is as follows:

[0032]

[0033] The technical features and beneficial effects of this invention are as follows:

[0034] 1. This invention provides an adamantane-modified fullerene (C 60 The synthesis method of pyrrolidine, using fullerene (C 60 Using paraformaldehyde and 1-adamantane methylamine as raw materials, a one-step reaction is carried out to generate adamantane-modified fullerene pyrrolidine derivatives. The synthesis process is simple, the raw materials are inexpensive and readily available, the products are easy to separate and purify, and the cost is low.

[0035] 2. The method for preparing adamantane-modified fullerene (C60) pyrrolidine in this invention has simple reaction conditions, adopts a one-pot synthesis, and does not require light protection or inert gas protection. The reaction time is short, which is convenient for mass production. The preparation method of this invention, as a whole, enables the target product to be obtained smoothly, with high yield and purity.

[0036] 3. The crystallization method of this invention is simple, effective, and produces good crystallinity, allowing for control over crystal morphology and size. The preparation method of this invention, as a whole, enables the obtaining of the target product with the structure and properties of this invention.

[0037] 4. The adamantane-modified fullerene (C) prepared by the method of the present invention 60 Pyrrolidines possess axisymmetric properties and good crystallinity; compared to primitive fullerenes (C... 60 It has a significantly improved solubility in organic solvents.

[0038] 5. The material obtained by the crystallization method of this invention is a cubic crystal material; compared with fullerenes, the linked adamantyl group disrupts the continuous and closed conjugated π system of fullerenes, which allows electrons to transition between energy bands. Moreover, the crystals prepared by the method of this invention have good crystallinity and a "geometrically defined" structure. These factors, combined with the adamantyl-modified fullerene (C1) with the specific structure of this invention, result in a cubic crystal material. 60 Pyrrolidine significantly increases the fluorescence intensity of the crystal, with the emission wavelength located in the red and near-infrared regions. Attached Figure Description

[0039] Figure 1 Example 1 of this invention is an adamantane-modified fullerene (C 60 )pyrrolidine derivatives 1 H nuclear magnetic resonance spectrum.

[0040] Figure 2 Example 1 of this invention is an adamantane-modified fullerene (C 60 )pyrrolidine derivatives 13 C10 NMR spectrum.

[0041] Figure 3The adamantane-modified fullerene (C 60 UV-visible absorption spectrum of the pyrrolidine derivative.

[0042] Figure 4 The adamantane-modified fullerene (C 60 SEM images of the pyrrolidine cubic crystal at different magnifications.

[0043] Figure 5 The adamantane-modified fullerene (C 60 Infrared spectrum of the pyrrolidine powder and the crystal prepared in Example 13.

[0044] Figure 6 The adamantane-modified fullerene (C 60 XRD pattern of the pyrrolidine powder and the crystal prepared in Example 13.

[0045] Figure 7 Emission spectrum of the original C 60 powder, the pyrrolidine powder of the adamantane-modified fullerene (C 60 The crystal prepared in Example 13, and the crystal prepared in Comparative Example 1-2 under excitation at a wavelength of 470 nm.

[0046] Figure 8 SEM images of the pyrrolidine spherical crystal of the adamantane-modified fullerene (C 60 prepared in Comparative Example 1 at different magnifications.

[0047] Figure 9 SEM images of the pyrrolidine lamellar crystal of the adamantane-modified fullerene (C 60 prepared in Comparative Example 2 at different magnifications. DETAILED DESCRIPTION

[0048] In order to better understand the present application, the following further describes in conjunction with specific examples.

[0049] The experimental methods used in the examples are all conventional methods unless otherwise specified.

[0050] The materials, reagents, etc. used in the examples can be obtained from commercial channels unless otherwise specified.

[0051] Example 1

[0052] Preparation of the adamantane-modified fullerene (C 60 pyrrolidine:

[0053] The molecular structure of the adamantane-modified fullerene (C 60 pyrrolidine is as follows:

[0054]

[0055] The specific preparation method is:

[0056] C 60 (360 mg, 0.5 mmol), paraformaldehyde (225 mg, 7.5 mmol), 1-adamantylamine (2.062 g, 12.5 mmol) and o-dichlorobenzene (60 mL) were added into a 250 mL round bottom flask, and the reaction was completely dissolved by ultrasonic, then the round bottom flask was placed in a preheated 180 °C oil bath, and heated to reflux for 15 min. After the reaction was completed, the solvent was evaporated under reduced pressure using a rotary evaporator, and the residue was separated by column chromatography with carbon disulfide / petroleum ether (1:4 (v / v)) as the eluent. The first purple solution separated was unreacted fullerene (C 60 ), followed by a brown-black solution, which was adamantane-modified fullerene (C 60 ) pyrrolidine. The product was further purified by recrystallization with ethanol to obtain a brown-black solid. The yield of adamantane-modified fullerene (C 60 ) pyrrolidine in this example was 25%.

[0057] The molecular structure and 1 H nuclear magnetic resonance spectrum of the product obtained above are shown in Figure 1 , 13 C nuclear magnetic resonance spectrum is shown in Figure 2 , and the ultraviolet-visible absorption spectrum is shown in Figure 3 .

[0058] Figure 1 1 The H nuclear magnetic resonance spectrum, the chemical positions of the main hydrogen can be corresponded.

[0059] Figure 2 13 The C nuclear magnetic resonance spectrum, the chemical shift of the spectrum further proves that the target molecule has been successfully synthesized.

[0060] Figure 3 The ultraviolet-visible absorption spectrum, the characteristic absorption peak of the single addition derivative of the molecule appears at 434 nm, which further proves the successful preparation of the target molecule.

[0061] Example 2

[0062] The preparation of adamantane-modified fullerene (C 60 ) pyrrolidine is as described in Example 1, except that the reaction time is changed to 10 min, and the other conditions remain unchanged.

[0063] Example 3

[0064] The preparation of adamantane-modified fullerene (C 60The preparation of pyrrolidine was carried out as described in Example 1, except that the reaction time was changed to 20 min, and other conditions were unchanged.

[0065] Example 4

[0066] adamantane-modified fullerene (C 60 The preparation of pyrrolidine was carried out as described in Example 1, except that the reaction time was changed to 25 min, and other conditions were unchanged.

[0067] Example 5

[0068] adamantane-modified fullerene (C 60 The preparation of pyrrolidine was carried out as described in Example 1, except that the reaction time was changed to 30 min, and other conditions were unchanged.

[0069] Example 6

[0070] adamantane-modified fullerene (C 60 The preparation of pyrrolidine was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantane methylamine was changed to 1:10:15, and other conditions were unchanged.

[0071] Example 7

[0072] adamantane-modified fullerene (C 60 The preparation of pyrrolidine was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantane methylamine was changed to 1:10:20, and other conditions were unchanged.

[0073] Example 8

[0074] adamantane-modified fullerene (C 60 The preparation of pyrrolidine was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantane methylamine was changed to 1:10:25, and other conditions were unchanged.

[0075] Example 9

[0076] adamantane-modified fullerene (C 60 The preparation of pyrrolidine was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantane methylamine was changed to 1:15:15, and other conditions were unchanged.

[0077] Example 10

[0078] adamantane-modified fullerene (C 60The preparation of pyrrolidine was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantylmethylamine was changed to 1:15:20, and other conditions were unchanged.

[0079] Example 11

[0080] The preparation of pyrrolidine of adamantyl-modified fullerene (C 60 ) was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantylmethylamine was changed to 1:20:20, and other conditions were unchanged.

[0081] Example 12

[0082] The preparation of pyrrolidine of adamantyl-modified fullerene (C 60 ) was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantylmethylamine was changed to 1:20:25, and other conditions were unchanged.

[0083] Example 13

[0084] The preparation of pyrrolidine of adamantyl-modified fullerene (C 60 ) was carried out as described in Example 1, except that the molar ratio of fullerene (C 60 ), paraformaldehyde and 1-adamantylmethylamine was changed to 1:20:30, and other conditions were unchanged.

[0085] In 1 mL of m-xylene was added 4 mg of adamantyl-modified fullerene (C 60 ) pyrrolidine prepared by the method of Example 1, the above solution was mixed uniformly under ultrasonic treatment at room temperature for 20 min, and then was transferred into a 20 mL glass bottle. 7 mL of poor solvent isopropyl alcohol was slowly added along the inner wall of the bottle at a rate of 2-3 mL / min to form a clear liquid-liquid interface. The reaction solution was shaken until the liquid-liquid interface disappeared, and then was ultrasonically treated at room temperature for 5 min. The color of the solution in the vial became turbid dark brown, and the vial was placed in a constant temperature incubator at 20°C for 48 h. The black precipitate at the bottom was collected by centrifugation at 8000 g for 5 min, and the supernatant was removed. The precipitate was washed with 5 mL of m-xylene / isopropyl alcohol (1:7 (v / v)), and this step was repeated 3 times. Then the precipitate was washed with 5 mL of isopropyl alcohol, and this step was repeated 3 times. The product was dried in vacuum at 45°C for 72 h to obtain adamantyl-modified fullerene (C 60 ) pyrrolidine microcrystals.

[0086] The SEM images of the adamantyl-modified fullerene (C 60 ) pyrrolidine microcrystals obtained in this example at different magnifications are shown in Figure 4 The obtained crystals were cubic crystals with a length and width of 7-10 μm and a height of 3-4 μm.

[0087] Figure 5Preparation of adamantane-modified fullerene (C 60 The infrared spectra of the powder (powder) and the crystal (cubic) prepared in this example were as shown in the figure. The corresponding characteristic absorption peaks of fullerene (C 60 ), C-N, and adamantane, etc. were found, further indicating the successful preparation of the target molecule.

[0088] Figure 6 Preparation of adamantane-modified fullerene (C 60 The XRD patterns of the powder (powder) and the crystal (cubic) prepared in this example were as shown in the figure. It can be seen from the figure that the structure of the crystal is more regular and the crystallinity is higher than that of the powder.

[0089] Figure 7 The emission spectra of the original C 60 powder, the adamantane-modified fullerene (C 60 ) pyrrolidine powder (derivative powder), and the crystal (cubic) prepared in this example under 470nm wavelength excitation were as shown in the figure. It can be seen from the figure that the adamantane-modified fullerene (C 60 ) pyrrolidine powder and the crystal prepared in this example have double-peak emission at 738nm and 820nm, and their emission intensities are higher than that of the original C 60 powder. Among them, the emission intensity of the crystal prepared in this example is twice that of the adamantane-modified fullerene (C 60 ) pyrrolidine powder due to its higher crystallinity. Moreover, the crystal prepared in this example can emit red fluorescence under 470nm wavelength excitation.

[0090] Example 14

[0091] The preparation method of the adamantane-modified fullerene (C 60 ) pyrrolidine microcrystal was as described in Example 13, except that the amount of isopropanol added was replaced with 4mL, and other conditions were unchanged.

[0092] Example 15

[0093] The preparation method of the adamantane-modified fullerene (C 60 ) pyrrolidine microcrystal was as described in Example 13, except that the amount of isopropanol added was replaced with 10mL, and other conditions were unchanged.

[0094] Example 16

[0095] The preparation method of the adamantane-modified fullerene (C 60 ) pyrrolidine microcrystal was as described in Example 13, except that the amount of isopropanol added was replaced with 13mL, and other conditions were unchanged.

[0096] Example 17

[0097] adamantyl modified fullerene (C 60 The preparation method of pyrrolidine microcrystal was as described in Example 13, except that the ultrasonic time was changed to 1 min, and other conditions were unchanged.

[0098] Example 18

[0099] adamantyl modified fullerene (C 60 The preparation method of pyrrolidine microcrystal was as described in Example 13, except that the ultrasonic time was changed to 2 min, and other conditions were unchanged.

[0100] Example 19

[0101] adamantyl modified fullerene (C 60 The preparation method of pyrrolidine microcrystal was as described in Example 13, except that the ultrasonic time was changed to 3 min, and other conditions were unchanged.

[0102] Example 20

[0103] adamantyl modified fullerene (C 60 The preparation method of pyrrolidine microcrystal was as described in Example 13, except that the ultrasonic time was changed to 4 min, and other conditions were unchanged.

[0104] Example 21

[0105] adamantyl modified fullerene (C 60 The preparation method of pyrrolidine microcrystal was as described in Example 13, except that the mass of adamantyl modified fullerene (C 60 ) pyrrolidine added in 1 mL m-xylene was changed to 3 mg, and other conditions were unchanged.

[0106] Example 22

[0107] adamantyl modified fullerene (C 60 The preparation method of pyrrolidine microcrystal was as described in Example 13, except that the mass of adamantyl modified fullerene (C 60 ) pyrrolidine added in 1 mL m-xylene was changed to 5 mg, and other conditions were unchanged.

[0108] Comparative Example 1

[0109] adamantyl modified fullerene (C 60 The preparation method of pyrrolidine microcrystal was as described in Example 13, except that m-xylene was replaced by o-xylene, i.e., 4 mg of adamantyl modified fullerene (C 60 ) pyrrolidine prepared by the method of Example 1 was added in 1 mL o-xylene, and other conditions were unchanged.

[0110] The adamantane-modified fullerene (C 60 ) pyrrolidine microcrystal prepared in this comparative example was subjected to SEM observation at different magnifications, and the SEM images are shown in Fig. 2. As shown in Fig. 2, the obtained crystal is a spherical crystal with a size of 7-8 μm. Figure 8

[0111] The emission spectrum of the crystal (spheres) prepared in this comparative example under excitation at a wavelength of 470 nm is shown in Fig. 3. The fluorescence intensity of the crystal (spheres) prepared in this comparative example is lower than that of the crystal prepared in Example 13. Figure 7

[0112] Comparative Example 2

[0113] The adamantane-modified fullerene (C 60 ) pyrrolidine microcrystal was prepared according to the method described in Example 13, except that m-xylene was replaced by p-xylene, i.e., 4 mg of the adamantane-modified fullerene (C 60 ) pyrrolidine prepared according to the method described in Example 1 was added to 1 mL of p-xylene, and other conditions were not changed. In the experiment, the adamantane-modified fullerene (C 60 ) pyrrolidine was not completely dissolved in p-xylene.

[0114] The adamantane-modified fullerene (C 60 ) pyrrolidine microcrystal prepared in this example was subjected to SEM observation at different magnifications, and the SEM images are shown in Fig. 4. As shown in Fig. 4, the obtained crystal is a lamellar crystal with a size of 20-30 μm. Figure 9

[0115] The emission spectrum of the crystal (lamellae) prepared in this comparative example under excitation at a wavelength of 470 nm is shown in Fig. 5. The fluorescence intensity of the crystal (lamellae) prepared in this comparative example is lower than that of the crystal prepared in Example 13. Figure 7

[0116] Test Example

[0117] The solubility of the adamantane-modified fullerene (C 60 ) pyrrolidine (C 60 derivative) prepared in Example 1 in different organic solvents was tested, and the test data are shown in Table 1.

[0118] Table 1

[0119]

[0120] As can be seen from the above, the adamantane-modified fullerene (C 60 ) pyrrolidine prepared in Example 1 has a large solubility in different organic solvents, and the solubility is greatly improved compared with C 60 .​​​​

Claims

1. An adamantane-modified fullerene (C2) with enhanced fluorescence properties 60 )pyrrolidine, characterized in that, The adamantane-modified fullerene (C 60 The molecular formula of pyrrolidine is: C 73 H 21 N; the molecular structure is as follows: 。 2. The adamantane-modified fullerene (C1) with enhanced fluorescence properties as described in claim 1 60 A method for preparing pyrrolidine includes the following steps: reacting fullerene (C...) with... 60 Paraformaldehyde, 1-adamantane methylamine, and o-dichlorobenzene were thoroughly mixed and dispersed, reacted, and then the solvent was removed under reduced pressure, separated by column chromatography, and recrystallized to obtain adamantane-modified fullerene (C14). 60 )pyrrolidine; fullerene (C 60 The molar ratio of paraformaldehyde and 1-adamantane methylamine is 1:10-20:15-25; the reaction is a reflux reaction at a temperature of 160-200℃ for 10-30 min; the eluent used for column chromatography is a mixed solvent of carbon disulfide and petroleum ether. The volume percentage of carbon disulfide is 15-25%.

3. The adamantane-modified fullerene (C1646) with enhanced fluorescence properties according to claim 2. 60 The method for preparing pyrrolidine is characterized in that, Fullerene (C 60 The molar ratio of α-dichlorobenzene to o-dichlorobenzene is 5-10 mmol / L.

4. The adamantane-modified fullerene (C1646) with enhanced fluorescence properties according to claim 2. 60 The method for preparing pyrrolidine is characterized in that, Recrystallization was performed using ethanol.

5. The adamantane-modified fullerene (C1) with enhanced fluorescence properties as described in claim 1 60 ) Pyrrolidine microcrystals, characterized in that, The microcrystals are cubic crystals, with a length and width of 5-15 μm and a height of 1-5 μm.

6. The adamantane-modified fullerene (C1646) with enhanced fluorescence properties as described in claim 5 60 The method for preparing pyrrolidine microcrystals includes the following steps: The above-mentioned adamantane-modified fullerene (C 60 Pyrrolidine was dissolved in m-xylene, and then isopropanol, a poor solvent, was slowly added dropwise to form a clear liquid-liquid interface. The reaction mixture was shaken until the liquid-liquid interface disappeared, then sonicated, allowed to stand, and the precipitate was collected. The precipitate was washed and dried to obtain adamantane-modified fullerene (C164- ... 60 )pyrrolidine microcrystals; adamantane-modified fullerene (C 60 The mass ratio of pyrrolidine to m-xylene is 3-5 mg / mL; the volume ratio of m-xylene to isopropanol is 1:4-13; the ultrasonic temperature is room temperature, and the ultrasonic time is 1-5 min; the standing temperature is 20-25℃, and the standing time is 12-48 h.

7. The adamantane-modified fullerene (C6) with enhanced fluorescence properties according to claim 6 60 A method for preparing pyrrolidine microcrystals, characterized in that, The dropping rate of isopropanol is 2-3 mL / min.

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