4-benzyloxybenzene substituted barbituric acid derivative and preparation method thereof, 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal and preparation method and application thereof

Abstract

The invention provides a 4-benzyloxybenzene substituted barbituric acid derivative and a preparation method thereof, a 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal and a preparation method and application thereof, and belongs to the technical field of organic photoelectric materials. Under the stimulation of mechanical force, the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal is bent into a semi-ring without any fracture, and after the mechanical force is removed, the crystal is not fractured or fractured and quickly recovers to the original linear shape. The reversible bending-relaxation process can be repeated for multiple times, and the good elasticity of the flexible crystal is highlighted, which shows that the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal has excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of organic photoelectric materials, and in particular to a 4-benzyloxybenzene-substituted barbituric acid derivative and a preparation method thereof, a 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystal and a preparation method and application thereof. Background Art

[0002] Organic crystals have natural brittle / hard properties, which limits their potential for application in flexible fields. Fortunately, Ghosh and Reddy reported the first elastic crystal in 2012. They dissolved caffeine (CAF) and 4-chloro-3-nitrobenzoic acid (CNB) in methanol and prepared needle-shaped elastic crystals using a slow volatilization method. When tweezers were used to hold the two ends of the crystal and pressure was applied to the middle of the crystal using a needle (three-point test method), the crystal could bend into a semicircle and immediately return to its original straight position after the pressure was withdrawn, showing significant elastic bending behavior. This process can be repeated many times until the crystal breaks beyond the threshold limit. Single crystal data showed that CAF molecules form dimers with CNB molecules through OH...N and CH...O hydrogen bonds, and adjacent dimers are further connected by weak CH...O hydrogen bonds to form a one-dimensional network structure. These network structures further form two-dimensional or even three-dimensional network-like structures through π...π interactions. The above interactions can effectively buffer external mechanical forces and prevent crystals from breaking under force stimulation.

[0003] Although elastic crystals have been obtained by eutectic methods, the design strategy of elastic crystals remains elusive. It is a great challenge to simultaneously regulate flexibility and crystallinity in organic crystals. It is of great significance to study a 4-benzyloxybenzene-substituted barbituric acid derivative and its preparation method, and then prepare it into a 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystal. Summary of the invention

[0004] The purpose of the present invention is to provide a 4-benzyloxybenzene substituted barbituric acid derivative and a preparation method thereof, a 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal and a preparation method and application thereof, so as to solve the problem that the organic crystal in the prior art cannot simultaneously adjust the flexibility and crystallinity.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a 4-benzyloxybenzene-substituted barbituric acid derivative, wherein the 4-benzyloxybenzene-substituted barbituric acid derivative has a structure as shown in formula (I):

[0007]

[0008] The present invention provides a method for preparing the above-mentioned 4-benzyloxybenzene substituted barbituric acid derivative, comprising the following steps: mixing 1,3-dimethylbarbituric acid and 4-benzyloxybenzaldehyde in ethanol and performing a reflux reaction to obtain the 4-benzyloxybenzene substituted barbituric acid derivative.

[0009] Preferably, the molar ratio of 1,3-dimethylbarbituric acid to 4-benzyloxybenzaldehyde is 1:1.

[0010] Preferably, the molar volume ratio of the 4-benzyloxybenzaldehyde to ethanol is 5-8 mmol:40-60 mL.

[0011] Preferably, the reflux reaction time is 4 to 8 hours.

[0012] The present invention also provides a 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystal, wherein the 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystal is prepared from a 4-benzyloxybenzene-substituted barbituric acid derivative having a structure as shown in formula (I).

[0013] The present invention also provides a method for preparing the above-mentioned 4-benzyloxybenzene substituted barbituric acid derivative flexible crystals, comprising the following steps: dissolving the 4-benzyloxybenzene substituted barbituric acid derivative in a mixed solvent and allowing the mixture to stand to obtain the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystals.

[0014] Preferably, the mixed solvent consists of dichloromethane and ethanol, wherein the volume ratio of dichloromethane to ethanol is 1:2-6; and the mass volume ratio of the 4-benzyloxybenzene substituted barbituric acid derivative to the mixed solvent is 20-40 mg:10 mL.

[0015] Preferably, the standing temperature is room temperature and the time is 8 to 12 days.

[0016] The present invention also provides an application of the above-mentioned 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal in the preparation of organic optical fiber or waveguide material.

[0017] Beneficial effects of the present invention:

[0018] The 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal prepared by the present invention bends into a half ring under mechanical force stimulation without any breakage, and after the mechanical force is removed, the crystal does not break or crack, and quickly recovers to its original straight shape. This reversible bending-relaxation process can be repeated many times, highlighting its good elasticity, indicating that the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1is the hydrogen spectrum of BBDPT prepared in Example 1;

[0020] Figure 2 is the carbon spectrum of BBDPT prepared in Example 1;

[0021] Figure 3 The UV-visible absorption spectra and fluorescence emission spectra of the BBDPT in Example 1 and the 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystals prepared in Example 2;

[0022] Figure 4 This is a graph showing elastic bending test of the flexible crystal of the 4-benzyloxybenzene-substituted barbituric acid derivative prepared in Example 2;

[0023] Figure 5 The molecular stacking and crystal morphology of the flexible crystal of 4-benzyloxybenzene-substituted barbituric acid derivative prepared in Example 2, wherein a is the (100) plane, b is the (001) plane, d is the (010) plane, c is the crystal morphology, C, H, N and O correspond to blue, gray, purple and red atoms, respectively, and CH...π and CH...O correspond to green and orange dotted lines, respectively;

[0024] Figure 6 The Hirshfeld surface image, two-dimensional fingerprint points and the proportion of each interaction in the crystal to all interactions of the flexible crystal of 4-benzyloxybenzene substituted barbituric acid derivative prepared in Example 2, wherein a is the Hirshfeld surface image, b is the two-dimensional fingerprint points, and c is the proportion of each interaction in the crystal to all interactions. DETAILED DESCRIPTION

[0025] The present invention provides a 4-benzyloxybenzene-substituted barbituric acid derivative, wherein the 4-benzyloxybenzene-substituted barbituric acid derivative has a structure as shown in formula (I):

[0026]

[0027] The present invention provides a method for preparing the above-mentioned 4-benzyloxybenzene substituted barbituric acid derivative, comprising the following steps: mixing 1,3-dimethylbarbituric acid and 4-benzyloxybenzaldehyde in ethanol and performing a reflux reaction to obtain the 4-benzyloxybenzene substituted barbituric acid derivative.

[0028] In the present invention, the synthesis route of the 4-benzyloxybenzene-substituted barbituric acid derivative is as follows:

[0029]

[0030] In the present invention, the molar ratio of 1,3-dimethylbarbituric acid to 4-benzyloxybenzaldehyde is 1:1.

[0031] In the present invention, the molar volume ratio of 4-benzyloxybenzaldehyde to ethanol is 5-8 mmol:40-60 mL, preferably 6-7 mmol:45-55 mL, and more preferably 6.4 mmol:50 mL.

[0032] In the present invention, the reflux reaction time is 4 to 8 hours, preferably 5 to 7 hours, and more preferably 6 hours.

[0033] In the present invention, the product of the reflux reaction is filtered, precipitated and recrystallized in ethanol to obtain a 4-benzyloxybenzene-substituted barbituric acid derivative.

[0034] The present invention also provides a 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystal, wherein the 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystal is prepared from a 4-benzyloxybenzene-substituted barbituric acid derivative having a structure as shown in formula (I).

[0035] The present invention also provides a method for preparing the above-mentioned 4-benzyloxybenzene substituted barbituric acid derivative flexible crystals, comprising the following steps: dissolving the 4-benzyloxybenzene substituted barbituric acid derivative in a mixed solvent and allowing the mixture to stand to obtain the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystals.

[0036] In the present invention, the mixed solvent consists of dichloromethane and ethanol, wherein the volume ratio of dichloromethane to ethanol is 1:2-6, preferably 1:3-5, and more preferably 1:4; the mass volume ratio of the 4-benzyloxybenzene substituted barbituric acid derivative to the mixed solvent is 20-40 mg:10 mL, preferably 30 mg:10 mL.

[0037] In the present invention, the standing temperature is room temperature, preferably 20 to 30° C., more preferably 25° C., and the time is 8 to 12 days, preferably 9 to 11 days, more preferably 10 days.

[0038] The present invention also provides an application of the above-mentioned 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal in the preparation of organic optical fiber or waveguide material.

[0039] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0040] Example 1

[0041] 1,3-Dimethylbarbituric acid (1.00 g, 6.4 mmol) and 4-benzyloxybenzaldehyde (1.36 g, 6.4 mmol) were mixed in anhydrous ethanol (50 mL), and the mixture was refluxed at room temperature for 6 h. The reaction product was filtered and precipitated and recrystallized from ethanol to obtain 1.84 g of a 4-benzyloxybenzene-substituted barbituric acid derivative (denoted as BBDPT) as shown in formula (I) as a yellow solid with a yield of 82%. 1 H NMR (600 MHz, DMSO-d 6 )δ8.34-8.32(m,3H),7.48(d,J=7.2Hz,2H),7.42(t,J=7.5Hz,2H),7.36(t, J=7.3Hz,1H),7.15(d,J=8.9Hz,2H),5.25(s,2H),3.23(s,3H),3.21(s,3H). 13 C NMR (151 MHz, CDCl 3 )δ163.46,163.12,161.00,158.83,151.42,137.97,135.88,128.77,128.39,127.53,125.73,114.80,114.40,70.32,29.09,28.41.

[0042] Example 2

[0043] 30 mg of BBDPT was dissolved in 10 mL of a mixed solvent of dichloromethane and anhydrous ethanol (the volume ratio of dichloromethane to anhydrous ethanol was 1:4), and allowed to stand at 25° C. for 10 days to obtain flexible crystals of a 4-benzyloxybenzene-substituted barbituric acid derivative, which were yellow needle-shaped crystals.

[0044] Example 3

[0045] The difference from Example 2 is that the added amount of BBDPT is 40 mg, and other conditions are the same.

[0046] Example 4

[0047] The difference from Example 2 is that the added amount of BBDPT is 20 mg, and other conditions are the same.

[0048] The UV-visible absorption spectra and fluorescence emission spectra (λ) of the flexible crystals of the 4-benzyloxybenzene-substituted barbituric acid derivative of Example 1 and the 4-benzyloxybenzene-substituted barbituric acid derivative of Example 2 were tested. ex =404 nm), the 4-benzyloxybenzene-substituted barbituric acid derivative of Example 1 was dissolved in acetonitrile to form an acetonitrile solution of the 4-benzyloxybenzene-substituted barbituric acid derivative, the concentration of which was 1.0×10 -5M, the test results are as follows Figure 3 As shown, Figure 3 Wherein Acetonitrile represents the acetonitrile solution of the 4-benzyloxybenzene-substituted barbituric acid derivative, and Microcrystal represents the flexible crystal of the 4-benzyloxybenzene-substituted barbituric acid derivative of Example 2 (the flexible crystal of the 4-benzyloxybenzene-substituted barbituric acid derivative of Example 2 is slightly ground and then tested for UV-visible absorption spectrum and fluorescence emission spectrum). Figure 3 It can be seen that in acetonitrile solution, the compound BBDPT shows two main absorption peaks at 265nm (π-π* transition) and 404nm (π-π* transition). Compared with the absorption of the compound in solution, the absorption peak of the flexible crystals of the 4-benzyloxybenzene-substituted barbituric acid derivative is red-shifted to 421nm, indicating the presence of J aggregation. Similarly, compared with the emission peak of the acetonitrile solution, the emission peak of the flexible crystals of the 4-benzyloxybenzene-substituted barbituric acid derivative is red-shifted by 28nm from 479nm to 507nm.

[0049] The 4-benzyloxybenzene substituted barbituric acid derivative flexible crystals prepared in Example 2 were subjected to a bending performance test using a three-point bending test. The results are as follows: Figure 4 As shown in the figure, it can be seen that: under mechanical force stimulation, the crystal bends into a half ring without any fracture. After the mechanical force is removed, the crystal does not break or crack, and quickly returns to its original straight shape. This reversible bending-relaxation process can be repeated many times, highlighting its good elasticity and indicating that the crystal has excellent mechanical properties.

[0050] from Figure 5 a It can be seen that the flexible crystal molecules of the 4-benzyloxybenzene-substituted barbituric acid derivative prepared in Example 2 of the present invention exist on the (100) plane. interaction; from Figure 5 b It can be seen that the molecule exists on the (001) plane force; from Figure 5 d It can be seen that the molecule exists on the (010) plane Three kinds of forces. Under mechanical stimulation, the above interactions can effectively relieve pressure and thus prevent crystal breakage.

[0051] from Figure 6c It can be seen that HH, OH, CC and CH interactions account for 50.8%, 20.5%, 11.0% and 10.9% of all interactions in the crystal, respectively, and these interactions account for about 93.2% of all interactions in the crystal. Although HH interactions account for 50.8% of the total interactions, they contribute little to the stability of the crystal. These results further illustrate that van der Waals interactions (CH…π) and hydrogen bonds (CH…O) account for a large proportion in the crystal, forming a structural buffer zone, which has an important influence on the elasticity of the crystal.

[0052] As can be seen from the above embodiments, the present invention provides a 4-benzyloxybenzene substituted barbituric acid derivative and a preparation method thereof, a 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal and a preparation method and application thereof, wherein the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal bends into a half ring under mechanical force stimulation without any breakage, and after the mechanical force is removed, the crystal does not break or crack, and quickly recovers its original straight shape. This reversible bending-relaxation process can be repeated many times, highlighting its good elasticity, indicating that the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal has excellent mechanical properties.

[0053] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A 4-benzyloxybenzene-substituted barbituric acid derivative, characterized in that: The 4-benzyloxybenzene-substituted barbituric acid derivative has a structure as shown in formula (I):

2. The method for preparing the 4-benzyloxybenzene-substituted barbituric acid derivative according to claim 1, characterized in that: The method comprises the following steps: mixing 1,3-dimethylbarbituric acid and 4-benzyloxybenzaldehyde in ethanol for reflux reaction to obtain a 4-benzyloxybenzene-substituted barbituric acid derivative.

3. The method for preparing a 4-benzyloxybenzene-substituted barbituric acid derivative according to claim 2, characterized in that: The molar ratio of the 1,3-dimethylbarbituric acid to 4-benzyloxybenzaldehyde is 1:

1.

4. The method for preparing a 4-benzyloxybenzene-substituted barbituric acid derivative according to claim 2 or 3, characterized in that: The molar volume ratio of the 4-benzyloxybenzaldehyde to ethanol is 5-8 mmol:40-60 mL.

5. The method for preparing a 4-benzyloxybenzene-substituted barbituric acid derivative according to claim 4, characterized in that: The reflux reaction time is 4 to 8 hours.

6. A 4-benzyloxybenzene-substituted barbituric acid derivative flexible crystal, characterized in that: The 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal is prepared from the 4-benzyloxybenzene substituted barbituric acid derivative having a structure as shown in formula (I) of claim 1.

7. The method for preparing the flexible crystal of 4-benzyloxybenzene-substituted barbituric acid derivative according to claim 6, characterized in that: The method comprises the following steps: dissolving the 4-benzyloxybenzene substituted barbituric acid derivative of the structure shown in formula (I) of claim 1 in a mixed solvent and allowing the mixture to stand to obtain a flexible crystal of the 4-benzyloxybenzene substituted barbituric acid derivative.

8. The method for preparing the flexible crystal of 4-benzyloxybenzene-substituted barbituric acid derivative according to claim 7, characterized in that: The mixed solvent consists of dichloromethane and ethanol, wherein the volume ratio of dichloromethane to ethanol is 1:2-6; the mass volume ratio of the 4-benzyloxybenzene substituted barbituric acid derivative to the mixed solvent is 20-40 mg:10 mL.

9. The method for preparing the flexible crystal of 4-benzyloxybenzene-substituted barbituric acid derivative according to claim 7 or 8, characterized in that: The temperature of the static state is room temperature, and the time is 8 to 12 days.

10. Use of the 4-benzyloxybenzene substituted barbituric acid derivative flexible crystal according to claim 6 in the preparation of organic optical fiber or waveguide material.

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