Sn-based organic-inorganic hybrid phase change material and preparation method and application thereof

Abstract

The present invention discloses an Sn-based organic-inorganic hybrid phase change material, its preparation method and application. The phase change material is an organic-inorganic hybrid crystal [3-Methoxyazetidine]2[SnCl6] with a central structure, and its molecular formula is C8N2O2Cl6Sn. This crystal crystallizes in the centrosymmetric space group Cmce (No. 64) of the orthorhombic system. The organic cation molecules pass through the mirror plane perpendicular to the a-axis direction, and the O atoms and C atoms vibrate back and forth at two symmetric positions of the mirror plane. As the temperature rises, the C on the ring begins to vibrate, and the order-disorder change of the ammonium cation causes the compound to undergo a phase change at 285K, which is manifested as a second-order isomorphic phase change. The preparation method of this crystal material is simple and easy to operate. In addition, the cultivation time is short, the preparation cost is low, and it has good stability at room temperature, and has potential application value in the fields of optoelectronic switches and other components.

Description

Technical Field

[0001] The present invention relates to a phase change material and a preparation method and application thereof, and in particular to a Sn-based organic-inorganic hybrid phase change material and a preparation method and application thereof. Background Art

[0002] Phase change materials can achieve changes in physical properties such as heat, sound, light, electricity, force, and magnetism when undergoing structural phase change, thereby obtaining various multifunctional materials, which are widely used in the fields of construction, textiles, and industry. In addition, phase change materials have broad application prospects in information storage, photoelectric switches, piezoelectric sensors, and biomedicine. Organic-inorganic hybrid phase change materials based on molecular design integrate flexible organic and inorganic units into the structure, so that it has both the advantages of organic compounds and the characteristics of inorganic compounds, showing many excellent application properties, including light weight, environmental friendliness (no lead element), high stability, etc. Among the many reported organic-inorganic hybrid materials, there are not many reports on Sn-based organic-inorganic hybrid materials, and even fewer reports on those showing secondary phase change behavior. Summary of the invention

[0003] Purpose of the invention: The present invention aims to provide a Sn-based organic-inorganic hybrid material with secondary isostructural phase transition behavior; another purpose of the present invention is to provide a method for preparing the Sn-based organic-inorganic hybrid material.

[0004] Technical solution: The Sn-based organic-inorganic hybrid material described in the present invention is an organic-inorganic hybrid crystal [3-Methoxyazetidine]2[SnCl6] (3-Methoxyazetidine is a 3-hydroxyazetidine cation) with a central structure, and its molecular formula is: C8N2O2Cl6Sn. The organic part of the crystal structure of the molecule passes through a mirror plane perpendicular to the a-axis direction, and O atoms and C atoms vibrate back and forth on both sides of the mirror plane, resulting in an order-disorder isomorphic phase transition, and has a secondary isomorphic phase transition behavior.

[0005] Furthermore, the Sn-based organic-inorganic hybrid phase change material is a crystal structure, which is crystallized in the central space group Cmce (No.64) of the orthorhombic system, and the unit cell parameters are α=γ=β=90°, Z=4,

[0006] The present invention also provides a method for preparing the Sn-based organic-inorganic hybrid phase change material, comprising the following steps:

[0007] (1) dissolving 3-hydroxy-N-heterocyclobutane hydrochloride in an appropriate amount of water, stirring at room temperature to fully dissolve it to obtain a colorless transparent solution;

[0008] (2) Add concentrated hydrochloric acid dropwise to the above colorless transparent solution to fully protonate it;

[0009] (3) adding tin tetrachloride to the solution obtained in step (2) and continuing to stir to obtain a colorless transparent solution;

[0010] (4) slowly volatilizing the colorless transparent solution obtained in step (3) under constant temperature conditions to obtain colorless transparent block crystals.

[0011] Further, in step (1), the concentration of the 3-hydroxy N-heterocyclobutane hydrochloride aqueous solution is 1-3 mmol ml -1 , dissolve 5-15 mmol of 3-hydroxyazetidine hydrochloride in every 5 ml of water.

[0012] Furthermore, in step (2), the volume ratio of the added concentrated hydrochloric acid to the above solution is 3-6:1.

[0013] Furthermore, in step (3), the molar ratio of the amount of tin tetrachloride added to the amount of 3-hydroxy N-heterocyclobutane hydrochloride in step (1) is about 1:1-3.

[0014] Furthermore, in step (4), the volatilization temperature is 20-40°C.

[0015] The Sn-based organic-inorganic hybrid phase change material of the present invention can be applied to photoelectric switches.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The phase change material has a secondary isomorphic phase change behavior. As the temperature rises, the C on the ring in the molecular structure begins to vibrate, and the ordered and disordered changes of the ammonium cations cause the compound to undergo a phase change at 285K, which can be applied to photoelectric switches near room temperature; (2) The phase change material has a simple structure, stable performance and is easy to synthesize. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 (a) Crystal structure stacking diagram of low temperature phase (LTP) and high temperature phase (HTP) of Sn-based organic-inorganic hybrid materials; (b) Crystal minimum asymmetric unit diagram of low temperature phase (LTP) and high temperature phase (HTP) of Sn-based organic-inorganic hybrid materials;

[0018] Figure 2 It is the differential scanning calorimetry characterization diagram (DSC) of Sn-based organic-inorganic hybrid materials;

[0019] Figure 3 This is the relationship between the dielectric constant and temperature of Sn-based organic-inorganic hybrid materials at a frequency of 100KHZ. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0021] Example 1

[0022] At room temperature, 5 mmol of 3-hydroxy N-heterocyclobutane hydrochloride was dissolved in 5 mL of distilled water, and stirred to fully dissolve to obtain a colorless transparent solution. 15 mL of 37% concentrated hydrochloric acid was added dropwise, and 5 mmol of tin tetrachloride was added. After stirring for 30 minutes, a colorless transparent solution was obtained. The solution was placed in an oil bath at a constant temperature of 40°C and slowly evaporated for 24-96 hours to obtain colorless transparent crystals, which is the compound C8N2O2Cl6Sn.

[0023] Example 2

[0024] At room temperature, 8 mmol of 3-hydroxy N-heterocyclobutane hydrochloride was dissolved in 5 mL of distilled water, and stirred to fully dissolve to obtain a colorless transparent solution. 15 mL of 37% concentrated hydrochloric acid was added dropwise, and 4 mmol of tin tetrachloride was added. After stirring for 30 min, a colorless transparent solution was obtained. The solution was placed in an oil bath at a constant temperature of 40 ° C and slowly evaporated for 24-96 h to obtain colorless transparent crystals, which is the compound C8N2O2Cl6Sn.

[0025] Example 3

[0026] At room temperature, 15 mmol of 3-hydroxy N-heterocyclobutane hydrochloride was dissolved in 5 mL of distilled water, and stirred to fully dissolve to obtain a colorless transparent solution. 15 mL of 37% concentrated hydrochloric acid was added dropwise, and 5 mmol of tin tetrachloride was added. After stirring for 30 minutes, a colorless transparent solution was obtained. The solution was placed in an oil bath at a constant temperature of 40°C and slowly evaporated for 24-96 hours to obtain colorless transparent crystals, which is the compound C8N2O2Cl6Sn.

[0027] The colorless and transparent crystal prepared in Example 1 was subjected to single crystal structure analysis. A single crystal of appropriate size was taken under a microscope and Mo Kα radiation was used to analyze the single crystal structure. The X-ray diffraction structure of the single crystal at 273K and 380K was characterized on a Rigaku Saturn 724diffractometer single crystal diffractometer, and the crystallographic parameters of the compound are shown in Table 1. The unit cell parameters were determined by the least squares method, the data structure analysis was completed using Olex2 software, and all non-hydrogen atoms were anisotropically refined using the full matrix least squares method.

[0028] Table 1 Main crystallographic data of compound C8Cl6N2O2Sn

[0029]

[0030]

[0031] [a] R1=Σ||F o |-|F c || / |F o |. [b] wR2=[Σw(F o 2 -F c 2 ) 2 ] / Σw(F o 2 ) 2 ] 1 / 2 .

[0032] The molecular formula of the compound is C8Cl6N2O2Sn, the crystal space group at 273K is Cmce, and the unit cell parameters are α=γ=β=90°, Z=4, V= The crystal space group at 380K is Cmce, and the unit cell parameters are α=γ=β=90°, Z=4, Indicates that the structure has changed.

[0033] like Figure 1 As shown in (a), the organic part of the compound of Example 1 can be seen to pass through the mirror plane perpendicular to the a-axis; Figure 1 As shown in (b), as the temperature increases, the C atoms and O atoms vibrate back and forth on both sides of the mirror.

[0034] like Figure 2 As shown, differential scanning calorimetry (DSC) analysis was performed on the compound of Example 1, and it can be seen that a pair of reversible thermal anomaly peaks appeared under heating (285K) and cooling (286K), with a thermal hysteresis of 1K, indicating that a reversible secondary phase transition occurred.

[0035] The colorless transparent block crystals prepared in Example 1 were ground into powder, and an appropriate amount of the powder was pressed into a sheet with a thickness of about 5 mm. The slices were fixed on a small electrode by silver glue copper wire, and the relationship between temperature and dielectric constant at different frequencies was measured. Figure 3 As shown, at a frequency of 100KHZ, obvious dielectric anomalies appear in the heating and cooling processes, further indicating that a reversible phase change occurs.

Claims

1. A Sn-based organic-inorganic hybrid phase change material, characterized in that: The material is an organic-inorganic hybrid crystal with a central structure, and its molecular formula is: C8N2O2Cl6Sn. In the crystal structure of the molecule, the organic part passes through the mirror plane perpendicular to the a-axis direction, and the O atoms and C atoms vibrate back and forth on both sides of the mirror plane, resulting in an ordered-disordered isomorphic phase transition; the material has a crystal structure, belongs to the orthorhombic crystal system, and crystallizes in the central space group Cmce The unit cell parameters are a = 7.535(3) Å, b = 14.8932(7) Å, c = 16.9764(7) Å, α = γ = β = 90 ° , Z = 4, V = 1905.10(14) Å 3 The preparation method of the Sn-based organic-inorganic hybrid phase change material comprises the following steps: (1) Dissolve 3-methoxy-azetidine hydrochloride in an appropriate amount of water and stir at room temperature to fully dissolve it to obtain a colorless transparent solution; (2) Add an appropriate amount of hydrochloric acid dropwise to the above colorless transparent solution and continue stirring to fully protonate it; (3) adding tin tetrachloride to the solution obtained in step (2) and continuing to stir to obtain a colorless transparent solution; (4) The colorless transparent solution obtained in step (3) is slowly evaporated under constant temperature conditions to obtain colorless transparent block crystals.

2. A method for preparing the Sn-based organic-inorganic hybrid phase change material according to claim 1, characterized in that: The steps include: (1) Dissolve 3-methoxy-azetidine hydrochloride in an appropriate amount of water and stir at room temperature to fully dissolve it to obtain a colorless transparent solution; (2) Add an appropriate amount of hydrochloric acid dropwise to the above colorless transparent solution and continue stirring to fully protonate it; (3) adding tin tetrachloride to the solution obtained in step (2) and continuing to stir to obtain a colorless transparent solution; (4) The colorless transparent solution obtained in step (3) is slowly evaporated under constant temperature conditions to obtain colorless transparent block crystals.

3. The method for preparing the Sn-based organic-inorganic hybrid phase change material according to claim 2, characterized in that: In step (1), the concentration of the aqueous solution of 3-methoxy-azetidine hydrochloride is 1-3 mmol ml -1 .

4. The method for preparing the Sn-based organic-inorganic hybrid phase change material according to claim 2, characterized in that: The volume ratio of the hydrochloric acid in step (2) to the colorless transparent solution in step (1) is 3-6:

1.

5. The method for preparing the Sn-based organic-inorganic hybrid phase change material according to claim 2, characterized in that: The molar ratio of the tin tetrachloride to the 3-methoxy-azetidine hydrochloride is 1:1-3.

6. The method for preparing the Sn-based organic-inorganic hybrid phase change material according to claim 2, characterized in that: In step (4), the volatilization temperature is 20-40 °C.

7. Use of the Sn-based organic-inorganic hybrid phase change material according to claim 1 as a photoelectric material.

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