Crystal material based on b-n coordination bond, preparation, topological structure conversion method and application thereof

Abstract

The application discloses a kind of crystal materials based on B-N coordination bond, structural formula is as shown in following: the crystal material is obtained by 2,7-bis (4-pyridine) -9,9-dimethylfluorene and 2,2'-(1,1'-biphenyl)-4,4'-bis (1,3,2-ortho phenol borate) coordination.It is highly dynamic to utilize the material B-N coordination bond and the material is inclined to form different topological structures under the assistance of different solvents, realizes the reversible conversion between BN-R crystal with 0-dimensional topological structure and BN-P crystal with 1-dimensional topological structure, and has great application potential in intelligent response material.

Description

Technical Field

[0001] This invention relates to the fields of coordination chemistry and crystal chemistry, specifically to a crystal material based on BN coordination bonds, its preparation method, its topological transformation method, and its application in smart responsive materials. Background Technology

[0002] Compared to amorphous materials, crystalline materials possess a regular structure that extends in an ordered manner in three-dimensional space. Introducing response sites into the crystal structure allows for faster and more efficient energy transfer from external stimuli. Crystal transformations based on external stimuli, particularly single-crystal-to-single-crystal transformations, can be studied in situ at the molecular level using X-ray diffraction techniques, thus facilitating the elucidation of stimulus-response mechanisms and structure-activity relationships. In-depth research on crystal transformations also helps us overcome the challenges of achieving multifunctionality and the interrelationships between different properties, such as adsorption, magnetism, optical, or electrical properties, providing assistance for the future design of efficient sensors and molecular machines.

[0003] Single crystals are prone to loss of crystallinity or decomposition into small fragments under external stimuli, making efficient and mild single-crystal-to-single-crystal conversion a challenge. Coordination polymers, due to the highly dynamic nature of their coordination bonds, facilitate dynamic structural adjustments to complete single-crystal-to-single-crystal conversions (e.g., patents with publication numbers CN 111440329A and CN114702526A).

[0004] Compared to common metal-organic coordination bonds, BN organic coordination bonds exhibit higher dynamics, making them more conducive to achieving single-crystal-to-single-crystal transformations. Furthermore, organic coordination polymers are free of metal toxicity, have low density, and offer greater structural designability, making them more suitable for further applications in smart responsive materials.

[0005] Generally, the greater the change in the topological structure of a crystal, the more significant the change in its properties, and the more beneficial it is to realizing high-contrast smart response materials. Currently, there are few studies on single-crystal-to-single-crystal conversion based on organic coordination polymer crystals, and there are no reports of reversible conversion from 1D polymer single crystals to 0D macrocyclic single crystals. Summary of the Invention

[0006] To address the shortcomings in current technologies, particularly the challenge of crystal topological transformation, this invention provides a crystal material based on BN coordination bonds. The crystal material comprises a BN-R crystal with a 0-dimensional topological structure and a BN-P crystal with a 1-dimensional topological structure. This crystal material exhibits novel structure and reliable properties. The highly dynamic nature of BN coordination bonds in solvents enables reversible topological transformation between the two crystal materials.

[0007] This invention is achieved through the following technical solution:

[0008] A crystal material based on BN coordination bonds has the following structural formulas (1) and (2):

[0009]

[0010] Equation (1) is the structural formula of a BN-R crystal with a 0-dimensional topological structure;

[0011] Equation (2) is the structural formula of a BN-P crystal with a 1-dimensional topological structure, where n is an integer from 8000 to 12000.

[0012] Preferably, the BN-based crystal material is obtained by coordination with 2,7-bis(4-pyridine)-9,9-dimethylfluorene (N-2) and 2,2'-(1,1'-biphenyl)-4,4'-bis(1,3,2-catechol boronic acid ester) (B-2).

[0013] The structural formula of 2,7-bis(4-pyridine)-9,9-dimethylfluorene (N-2) is:

[0014]

[0015] The structural formula of 2,2'-(1,1'-biphenyl)-4,4'-bis(1,3,2-catechol borate) (B-2) is as follows:

[0016]

[0017] In this invention, the BN-R crystal and the BN-P crystal can be reversibly converted, and the topological structure can be converted simultaneously.

[0018] This invention also provides a method for preparing the aforementioned crystalline material. The preparation method is simple to operate, has a reliable route, and is low in cost.

[0019] A method for preparing the BN-R crystal, comprising: placing N-2 and B-2 in o-dichlorobenzene, reacting at 80-120°C, and recrystallizing after cooling to obtain the BN-R crystal.

[0020] The synthetic route for preparing the BN-R crystal is as follows:

[0021]

[0022] Preferably, in the method for preparing BN-R crystals, the reaction temperature is 90°C.

[0023] A method for preparing the BN-P crystal, comprising: placing N-2 and B-2 in toluene or chlorobenzene, reacting at 80-120°C, and recrystallizing after cooling to obtain the BN-R crystal.

[0024] The synthesis route a of the method for preparing the BN-R crystal is as follows:

[0025]

[0026] The synthesis route b of the method for preparing the BN-R crystal is as follows:

[0027]

[0028] Preferably, in the method for preparing BN-P crystals, the reaction temperature is 90°C.

[0029] Preferably, in the preparation method of the BN-R crystal or the BN-P crystal, the molar ratio of N-2 to B-2 is 1:0.9 to 1.1.

[0030] This invention also provides a method for topological transformation of the aforementioned crystal material. The topological transformation method is simple to operate and has a reliable approach.

[0031] The topological transformation path of the crystal material is as follows:

[0032]

[0033] A method for topological transformation of the BN-R crystal to the BN-P crystal, comprising: placing the BN-R crystal in toluene or chlorobenzene, reacting at 60-80°C, and then recrystallizing at a lower temperature to obtain the BN-P crystal.

[0034] With the assistance of chlorobenzene, coordination polymer single crystals tend to form, and finally recrystallization yields the BN-P crystals.

[0035] Preferably, the method for topological transformation of the BN-R crystal to the BN-P crystal is as follows: placing the BN-R crystal in chlorobenzene, reacting at 70°C for at least 4 hours, and then recrystallizing at a lower temperature to obtain the BN-P crystal.

[0036] A method for topological transformation of the BN-P crystal to the BN-R crystal, comprising: placing the BN-P crystal in o-dichlorobenzene, reacting it at 60-80°C, and then recrystallizing it after cooling to obtain the BN-R crystal.

[0037] With the assistance of o-dichlorobenzene, it tends to form a coordinated macrocyclic single crystal, which is eventually recrystallized to obtain the BN-R crystal.

[0038] Preferably, the method for topological transformation of the BN-P crystal to the BN-R crystal is as follows: placing the BN-P crystal in o-dichlorobenzene, reacting at 80°C for at least 4 hours, and then cooling and recrystallizing to obtain the BN-R crystal.

[0039] The topology conversion method provided by this invention utilizes the highly dynamic nature of the BN coordination bonds in the crystal material and its tendency to form different topologies under different solvent assistance to achieve reversible conversion between coordination polymer single crystals (BN-P) and coordination macrocyclic single crystals (BN-R).

[0040] The present invention also provides the application of the crystal material in smart responsive materials.

[0041] Compared with the prior art, the present invention has at least the following advantages:

[0042] 1. The crystal materials provided by the present invention include BN-R crystals with 0-dimensional topology and BN-P crystals with 1-dimensional topology. The above two crystal materials have novel structures and reliable properties.

[0043] 2. The method for preparing crystal materials provided by this invention is simple to operate, reliable in its route, and low in cost.

[0044] 3. The topology transformation method provided by this invention utilizes the highly dynamic nature of BN coordination, which tends to form different topologies under the assistance of different solvents, realizing the reversible transformation between coordination polymer single crystals (BN-P) and coordination macrocyclic single crystals (BN-R), and simultaneously realizing the transformation of topology between 0-dimensional and 1-dimensional.

[0045] 4. The crystal material provided by this invention has great application potential in smart response materials. Attached Figure Description

[0046] Figure 1 This is diagram A, showing the synthetic route of BN-P in Example 1;

[0047] Figure 2 This is diagram B, showing the synthetic route of BN-P in Example 2;

[0048] Figure 3 This is a synthetic route diagram of BN-R in Example 3;

[0049] Figure 4 This is a single-crystal structure diagram of the converted BN-R in Example 4;

[0050] Figure 5 This is a single-crystal structure diagram of the converted BN-P in Example 5;

[0051] Figure 6This is a roadmap for the interconversion of BN-P and BN-R single crystals;

[0052] Figure 7 The XRD diffraction results of BN-P and BN-R in Example 6 are shown.

[0053] Figure 8 The graph shows the thermal performance test results in Example 7. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer.

[0055] Example 1

[0056] Preparation of BN-P (Route A):

[0057] 10.5 mg of 2,7-bis(4-pyridine)-9,9-dimethylfluorene (N-2) and 11.9 mg of 2,2'-(1,1'-biphenyl)-4,4'-bis(1,3,2-catechol borate) (B-2) were weighed and placed in 15 mL of chlorobenzene at 110 °C for 4 hours. Recrystallization after cooling yielded yellow single crystals of BN-P. The synthetic route is as follows. Figure 1 As shown.

[0058] Example 2

[0059] Preparation of BN-P (Route B):

[0060] 10.5 mg N-2 and 11.9 mg B-2 were weighed and placed in 15 mL of toluene. The mixture was kept at 90 °C for 6 hours, and then recrystallized at a lower temperature to obtain yellow single crystals of BN-P. The synthetic route is as follows: Figure 2 As shown.

[0061] Example 3

[0062] Preparation of BN-R:

[0063] 21 mg N-2 and 23.8 mg B-2 were weighed and placed in 15 mL of o-dichlorobenzene at 90 °C for 4 hours. Recrystallization after cooling yielded pale yellow single crystals of BN-R. The synthetic route is as follows: Figure 3 As shown.

[0064] Example 4

[0065] Conversion from BN-P to BN-R:

[0066] Weigh 20 mg of the prepared BN-P single crystal and keep it in 15 mL of o-dichlorobenzene at 70 °C for 4 hours. After cooling and recrystallization, yellow single crystal BN-R is obtained.

[0067] The obtained BN-R single crystal structure is as follows: Figure 4 As shown.

[0068] Example 5

[0069] Conversion from BN-R to BN-P:

[0070] Weigh 15 mg of the prepared BN-R single crystal and keep it in 15 mL of chlorobenzene at 60 °C for 4 hours. After cooling and recrystallization, a pale yellow single crystal BN-P is obtained.

[0071] The single crystal structure of the obtained BN-P is as follows: Figure 5 As shown.

[0072] The interconversion pathway between BN-R crystals and BN-P crystals is shown in the diagram below. Figure 6 As shown.

[0073] Example 6

[0074] X-ray diffraction analysis was performed on the prepared BN-R and BN-P:

[0075] The significant differences in the crystal structures of BN-R and BN-P lead to substantial differences in their diffraction patterns, such as... Figure 7 As shown.

[0076] Example 7

[0077] Thermal properties of the prepared BN-R and BN-P were analyzed:

[0078] Because BN-P forms a one-dimensional polymer structure, it exhibits higher heat resistance than the zero-dimensional small-molecule BN-R, as shown in the corresponding thermogravimetric (Tg) test. Figure 8 As shown.

[0079] Generally, the temperature at which a material loses 10% of its mass is taken as its thermal decomposition temperature.

[0080] from Figure 8 In the study, we found that the thermal decomposition temperature of BN-P crystal is 247℃, which is much higher than that of BN-R crystal at 141℃. This significant thermal performance paves the way for the application of smart crystal materials.

[0081] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A crystal material based on BN coordination bonds, characterized in that, The structural formula is shown in equation (1) or equation (2) below: （1）； （2）； Equation (1) is the structural formula of a BN-R crystal with a 0-dimensional topological structure; Equation (2) is the structural formula of a BN-P crystal with a 1-dimensional topological structure, where n is an integer from 8000 to 12000.

2. The crystal material according to claim 1, characterized in that, The crystalline material was obtained by coordination of 2,7-bis(4-pyridine)-9,9-dimethylfluorene and 2,2'-(1,1'-biphenyl)-4,4'-bis(1,3,2-catechol boronic acid ester).

3. The crystal material according to claim 1, characterized in that, The BN-R crystal and the BN-P crystal can be reversibly converted, and the topological structure can be transformed simultaneously.

4. A method for preparing the crystalline material according to any one of claims 1 to 3, characterized in that, The preparation method of the BN-R crystal is as follows: N-2 and B-2 are placed in o-dichlorobenzene and reacted at 80~120℃, and the BN-R crystal is obtained by cooling and recrystallization. The BN-P crystal is prepared by placing N-2 and B-2 in toluene or chlorobenzene, reacting at 80~120 °C, and then recrystallizing after cooling to obtain the BN-P crystal.

5. The preparation method according to claim 4, characterized in that, The molar ratio of N-2 to B-2 is 1:0.9~1.

1.

6. The method for topological transformation of crystal materials according to any one of claims 1 to 3, characterized in that, The method for topological transformation of the BN-R crystal to the BN-P crystal is as follows: the BN-R crystal is placed in toluene or chlorobenzene, reacted at 60-80 °C, and then recrystallized after cooling to obtain the BN-P crystal.

7. The method for topological transformation of crystal materials according to any one of claims 1 to 3, characterized in that, The method for topological transformation of the BN-P crystal to the BN-R crystal is as follows: the BN-P crystal is placed in o-dichlorobenzene and reacted at 60-80 °C, and then recrystallized after cooling to obtain the BN-R crystal.

8. The application of the crystal material according to any one of claims 1 to 3 in smart responsive materials.

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