A boc-l-phenylalanine dry gel, single crystal and preparation method and application thereof

Abstract

The application discloses a kind of Boc-L-phenylalanine xerogel, single crystal and its preparation method and application, it is related to cluster luminescent material technical field, the structure reorganization of Boc-L-phenylalanine from powder to xerogel is realized by solvent thermal induction method in the present application, and Boc-L-phenylalanine xerogel is obtained;And Boc-L-phenylalanine xerogel is cultivated into Boc-L-phenylalanine single crystal using crystallization method;And the Boc-L-phenylalanine xerogel and Boc-L-phenylalanine single crystal prepared by the application can be used as cluster luminescent material.

Description

Technical Field

[0001] The present invention relates to the technical field of cluster luminescent materials, and in particular to a Boc-L-phenylalanine xerogel, a single crystal, and a preparation method and application thereof. Background Art

[0002] Organic light-emitting materials based on valence bond conjugation (TBC) feature tunable emission colors, tunable structures, and high quantum efficiency. They are widely used in fields such as photoelectric sensors, information storage technologies, and biomedical treatments. Their luminescence mechanism originates from π-π* transitions. However, aromatic compounds often exhibit toxicity and resistance to biodegradation, posing a threat to human health and the ecological environment. In addition, problems such as high cost, complex synthetic routes, and aggregation-induced quenching effects also limit their application. Therefore, an increasing number of researchers are turning from traditional organic light-emitting groups to unconventional groups to overcome these challenges and explore safer, more stable, and more sustainable light-emitting materials.

[0003] In recent years, a new type of non-conjugated luminescent material has rapidly emerged. This material is different from the traditional TBC theory and its theoretical basis is transsteric interaction (TSI). Studies have shown that a short channel is formed between the isolated benzene ring and the heteroatom, resulting in orbital splitting and a reduction in the energy gap. Therefore, when aggregation occurs due to TSI, the emission will be red-shifted. These materials can emit visible light even if they only have one benzene ring, lack a large amount of aromatic structure or do not contain π-conjugated groups. These substances are called non-conjugated cluster luminogens (CLgens) and are usually composed only of electron-rich heteroatoms such as amino and carbonyl groups. Their luminescence originates from n-π* transitions. They usually show weak or no luminescence in dilute solutions, but show bright fluorescence in concentrated solutions or in aggregated states. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a Boc-L-phenylalanine xerogel, and to prepare a Boc-L-phenylalanine single crystal using the obtained Boc-L-phenylalanine xerogel. Boc-L-phenylalanine in the form of powder or dilute solution does not emit light, but Boc-L-phenylalanine in the form of a xerogel emits fluorescence, and Boc-L-phenylalanine in the form of a single crystal can emit brighter fluorescence. Therefore, the Boc-L-phenylalanine xerogel and Boc-L-phenylalanine single crystal prepared by the present invention can be used as cluster luminescent materials.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0006] One of the purposes of the present invention is to provide a method for preparing Boc-L-phenylalanine xerogel, which realizes the structural reorganization of Boc-L-phenylalanine from powder to xerogel by a solvent thermal induction method.

[0007] A second object of the present invention is to provide a Boc-L-phenylalanine xerogel obtained by the aforementioned method for preparing the Boc-L-phenylalanine xerogel.

[0008] The third object of the present invention is to provide a method for preparing Boc-L-phenylalanine single crystals, wherein the Boc-L-phenylalanine xerogel is cultured into Boc-L-phenylalanine single crystals by a crystallization method.

[0009] A fourth object of the present invention is to provide a Boc-L-phenylalanine single crystal obtained by the aforementioned method for preparing the Boc-L-phenylalanine single crystal.

[0010] A fifth object of the present invention is to provide the application of the Boc-L-phenylalanine xerogel and Boc-L-phenylalanine single crystal as cluster luminescent materials.

[0011] The beneficial effects of the present invention are:

[0012] 1. The preparation methods of the Boc-L-phenylalanine xerogel and Boc-L-phenylalanine single crystal provided by the present invention are not only environmentally friendly but also cost-effective;

[0013] 2. The Boc-L-phenylalanine xerogel and Boc-L-phenylalanine single crystal prepared by the present invention can be used as cluster luminescent materials and have a wide range of applications, including biology, display, lighting and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the preparation process of Boc-L-phenylalanine xerogel;

[0015] Figure 2 Boc-L-phenylalanine xerogel 1 H NMR spectrum;

[0016] Figure 3 Fluorescence images of Boc-L-phenylalanine in four forms: powder, large crystals, crystal particles, and single crystals.

[0017] Figure 4 The UV-visible absorption spectra of Boc-L-phenylalanine in three forms: powder, solution, and xerogel;

[0018] Figure 5 The fluorescence spectra of Boc-L-phenylalanine xerogel at different wavelengths;

[0019] Figure 6 is the fluorescence lifetime of Boc-L-phenylalanine in the form of powder, solution and xerogel;

[0020] Figure 7 CD spectra of Boc-L-phenylalanine in powder, dilute solution, and xerogel forms;

[0021] Figure 8 2D NOESY spectrum of Boc-L-phenylalanine xerogel;

[0022] Figure 9 XRD patterns of Boc-L-phenylalanine in powder, xerogel and single crystal forms;

[0023] Figure 10 FT-IR images of Boc-L-phenylalanine in powder, xerogel and single crystal forms;

[0024] Figure 11 The concentrations of Boc-L-phenylalanine solution 1 H NMR spectrum. DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific embodiments and illustrations.

[0026] like Figure 1 As shown, the present invention provides a method for preparing Boc-L-phenylalanine xerogel, which realizes the structural reorganization of Boc-L-phenylalanine from powder to xerogel by solvent thermal induction method.

[0027] The structural formula of Boc-L-phenylalanine is shown below:

[0028]

[0029] Furthermore, the solvent includes but is not limited to at least one of dichloromethane, chloroform, ethanol, ethyl acetate, and tetrahydrofuran.

[0030] Furthermore, the solvent thermal induction temperature is 50 to 80° C., the pressure is -0.08 to -0.05 MPa, and the time is 2 to 6 hours.

[0031] Furthermore, the solvent thermal induction is carried out in a vacuum drying oven.

[0032] Furthermore, the usage ratio of the solvent to the Boc-L-phenylalanine powder is (1-3) mL: (3-6) g.

[0033] The present invention provides a Boc-L-phenylalanine xerogel obtained by the above-mentioned preparation method of Boc-L-phenylalanine xerogel.

[0034] The present invention also provides a method for preparing a Boc-L-phenylalanine single crystal, which comprises cultivating the Boc-L-phenylalanine xerogel into the Boc-L-phenylalanine single crystal by a crystallization method.

[0035] Furthermore, the crystallization method is a low-temperature crystallization method.

[0036] The present invention provides a Boc-L-phenylalanine single crystal obtained by the above-mentioned method for preparing the Boc-L-phenylalanine single crystal.

[0037] The present invention also provides the use of the Boc-L-phenylalanine xerogel and Boc-L-phenylalanine single crystal as cluster luminescent materials.

[0038] Example 1

[0039] 6 g of Boc-L-phenylalanine powder was ultrasonically dissolved in 2 mL of dichloromethane to obtain a mixed solution; the mixed solution was then placed in a vacuum drying oven at a temperature of 50°C and a pressure of -0.05 MPa for 4 hours to obtain a colorless and transparent Boc-L-phenylalanine xerogel.

[0040] Example 2

[0041] 3 g of Boc-L-phenylalanine powder was ultrasonically dissolved in 1 mL of chloroform to obtain a mixed solution; the mixed solution was then placed in a vacuum drying oven at a temperature of 60°C and a pressure of -0.08 MPa for 2 h to obtain a colorless and transparent Boc-L-phenylalanine xerogel.

[0042] Example 3

[0043] 5 g of Boc-L-phenylalanine powder was ultrasonically dissolved in 3 mL of ethanol to obtain a mixed solution; the mixed solution was then placed in a vacuum drying oven at a temperature of 80°C and a pressure of -0.06 MPa for 6 h to obtain a colorless and transparent Boc-L-phenylalanine xerogel.

[0044] Example 4

[0045] The Boc-L-phenylalanine xerogel prepared in Example 1 was rapidly crystallized (placed in a sealed container at room temperature for one week) to obtain large Boc-L-phenylalanine crystals. The large Boc-L-phenylalanine crystals were crushed to obtain Boc-L-phenylalanine crystal particles.

[0046] Example 5

[0047] The Boc-L-phenylalanine xerogel prepared in Example 1 was slowly crystallized (placed in a sealed container at 2-6° C. for two months) to obtain Boc-L-phenylalanine single crystals.

[0048] Structural characterization:

[0049] Figure 2 This is the H NMR spectrum of Boc-L-phenylalanine xerogel ( 1 H NMR spectrum); (a) is the Boc-L-phenylalanine xerogel in a deuterated chloroform dilute solution (ρ = 10 mg / mL) 1 H NMR spectrum; (b) Boc-L-phenylalanine xerogel in deuterated chloroform concentrated solution (ρ = 500 mg / mL) 1 H NMR spectrum. Figure 2 It can be seen that the structural reorganization of Boc-L-phenylalanine from powder to xerogel achieved by the solvothermal induction method did not destroy the molecular structure of Boc-L-phenylalanine.

[0050] Performance testing:

[0051] Figure 3 Fluorescence images of Boc-L-phenylalanine in four forms: powder, large-size crystal, crushed grains, and single crystal. Figure 3 It can be seen that Boc-L-phenylalanine powder does not emit light; the large-sized crystals obtained by rapid crystallization emit weak blue fluorescence, and the crystal particles obtained by further crushing partially emit blue fluorescence; the single crystals obtained by slow crystallization emit bright blue fluorescence. This is because through the slow crystallization process, the molecular arrangement is more compact and orderly, and can emit brighter fluorescence.

[0052] Figure 4 The UV-visible absorption spectra of Boc-L-phenylalanine in three forms: powder, solution (Solution) and dry gel (X-Gel). The solution is DCM solution (c = 10 -5 M). By Figure 4 It can be seen that the absorption at a wavelength of 250-280 nm comes from a single benzene ring, and the absorption at a wavelength of 300-400 nm is caused by TSI; compared with solutions and powders, the TSI effect of dry gel is stronger.

[0053] Figure 5 The fluorescence spectra of Boc-L-phenylalanine xerogel at different wavelengths. Figure 5 The photoluminescence spectrum of the xerogel can be observed within the excitation wavelength range (λex) of 250 to 390 nm. The emission peak corresponding to the benzene ring appears at 302 nm, while the emission peak in the range of 320 to 390 nm corresponds to TSI. This luminescence clearly exhibits a pronounced excitation-dependent effect (EDE), a characteristic of cluster luminescence (CL).

[0054] Figure 6 is the fluorescence lifetime (λex = 373 nm) of Boc-L-phenylalanine in the form of powder, solution and xerogel, where the solution is DCM solution (c = 10 -3 M). By Figure 6 It can be seen that the fluorescence lifetime of Boc-L-phenylalanine powder is only 2.5×10 -3 ns; the fluorescence lifetime of Boc-L-phenylalanine in DCM solution is 6.81×10 -2 The fluorescence lifetime of Boc-L-phenylalanine xerogel was extended to 2.59 ns, which was significantly longer than that of Boc-L-phenylalanine powder and its solution.

[0055] Figure 7 The circular dichroism (CD) spectra of Boc-L-phenylalanine in three forms: powder, dilute solution (Dilut Solution) and dry gel. Figure 7 It can be seen that the powder and solution have basically no CD signal, while the dry gel shows an obvious CD signal.

[0056] Figure 8 2D NOESY spectrum of Boc-L-phenylalanine xerogel. Figure 8 It can be seen that the two-dimensional NOESY spectrum of Boc-L-phenylalanine xerogel in CDCl3 solution shows the correlation signal between the protons on the carboxyl group and the protons on the amide group, indicating the existence of CH···π interaction. Theoretical calculation of the single crystal structure of Boc-L-phenylalanine shows that the d(H a -H b ) Shorter distance This indicates that there is a stronger cross-space n-π* interaction in the crystal.

[0057] Figure 9 The X-ray diffraction patterns (XRD patterns) of Boc-L-phenylalanine in three forms: powder, dry gel and single crystal. Figure 9 It can be seen that the position of the diffraction peak undergoes an obvious red shift from powder to dry gel, accompanied by a sharpening of the peak, which is due to the formation of stronger intermolecular interactions in the dry gel; in addition, a further position red shift is observed in the crystal structure, which is because the rigid environment provided by the crystal can effectively maintain the excited state of the molecule, which is conducive to efficient emission.

[0058] Figure 10 The following are Fourier infrared spectra (FT-IR spectra) of Boc-L-phenylalanine in three forms: powder, dry gel and single crystal. Figure 10 It can be seen that the 1712 and 1649 cm-1-1 The bands correspond to the C=O stretching vibrations of the carboxyl group and the amide bond, respectively, at 3320 cm -1 Compared with the powder, the FT-IR spectrum of the crystal showed that the C=O stretching vibration peaks at 3 and 5 cm -1 The blue shift at 3310 cm -1 The NH vibration peak at 10 cm -1 The xerogel also exhibited a blue shift compared to the powder. Regardless of whether the shift is red or blue, any shift change indicates the influence of intermolecular interactions. These results indicate that more hydrogen bonds are formed in the xerogel and crystals.

[0059] Figure 11 The concentrations of Boc-L-phenylalanine solution 1 H NMR spectrum. Figure 11 As the concentration increases from 100 mg / mL to 500 mg / mL, the peak corresponding to the carboxyl protons (blue line) and the signal corresponding to the amide protons (yellow line) gradually red-shift. As the concentration increases, the peaks corresponding to the carboxyl and amide bonds gradually red-shift. At a concentration of 500 mg / mL, the peaks become sharper, indicating the formation of larger and more compact clusters in the concentrated solution.

[0060] In summary, compared with powder and solution, the cross-space interaction force of dry gel is further enhanced, and the fluorescence shows the characteristics of cluster luminescence.

[0061] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a Boc-L-phenylalanine xerogel, characterized in that: The structural reorganization of Boc-L-phenylalanine from powder to xerogel was achieved by solvothermal induction. The solvent is one of dichloromethane, chloroform and ethanol; The solvothermal induction temperature is 50-80°C, the pressure is -0.08-0.05 MPa, and the time is 2-6 h; The solvent thermal induction was carried out in a vacuum drying oven.

2. The preparation method according to claim 1, wherein: The ratio of the solvent to the Boc-L-phenylalanine powder is (1-3) mL: (3-6) g.

3. Boc-L-phenylalanine xerogel obtained by the preparation method according to claim 1 or 2.

4. A method for preparing Boc-L-phenylalanine single crystals, comprising: cultivating the Boc-L-phenylalanine xerogel according to claim 3 in a sealed container at 2-6°C for two months to form Boc-L-phenylalanine single crystals by a crystallization method.

5. Use of the Boc-L-phenylalanine xerogel according to claim 3 or the Boc-L-phenylalanine single crystal obtained by the preparation method according to claim 4 as a cluster luminescent material.

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