Study On Preparation And Performance Of Light Control Materials Based On Diarylethylene

With the development of society,people have put forward higher requirements for materials,especially high expectations for functional materials.Porous materials are characterized by large specific surface area,controllable pore size,novel and diverse structures,and have potential applications in catalytic reactions,adsorption desorptions,environmental treatment,energy supply,luminescent materials and drug delivery.Under the efforts of Yaghi et al.,metal coordination polymers(Coordination polymers)and covalent organic frameworks(COFs)were reported for the first time,and various COFs materials with abundant bridging groups,metal ligands and COFs have been reported successively.In addition,diarylvinyl is a class of compound that can be subjected to UV/visible light stimulation to open the closed loop of the molecule and undergo structural isomerization.In this process,the open ring of the molecule presents different color changes.Diarylenes have excellent thermal stability and fatigue resistance in photochromic process.It is these unique and excellent properties that have attracted the attention of many scientists.With the deepening of the research on diarylene,it is found that it has attractive potential applications in the fields of optically controlled gas absorption and desorption,sensing and molecular wiring.Based on this,the research carried out in this paper is as follows:(1)Photochromic 1,2-2[2-methyl-5-(4-carboxyl-phenyl)-3-base]thiophene ring of perfluorinated pentene(1 b)as the organic ligand,ligand for the center with Cd²⁺ions,the design and synthesis of diaromatic Cd(II)complexes,through red outside and X-ray single crystal diffraction,structural characterization,structure of complexes single-crystal X-ray crystallography determination results showed that Cd(II)complexes 1h in monoclinic P2(1)/c crystal,a=26.737(3)(?);b=7.9659(10)(?);c=13.2624(16)(?);?/(?)=92.061(2);Volume/(?)3=2822.9(6),and the calculated density is 1.776Mg·m^-3.The structural unit of the complex 1h contains one Cd(II)ion,two diarylcarboxylic acid ligands 1b and two water molecules.The seven-coordination Cd(II)is coordinated with six surrounding oxygen atoms,two of which are from two coordination water molecules,and five of which are from carboxylic acid ligand 1b,the bond length of Cd-O ranges from 2.215(4)-2.575(4)(?).The coordination geometry of Cd(II)ion is a twisted quadrilateral,and the diarylene behaves parallel structure in the crystal,thus inhibiting its photochromic properties.When 1H is dissolved in DMSO,the diarylene in the complex is not affected by the crystal space structure,and can show good photochromic properties.Under the irradiation of ultraviolet light at 365nm,the solution of the colorless complex turns to blue,and the maximum absorption wavelength is 592nm.When irradiated with white light,the blue complex turns to colorless again.(2)1,2-2[2-methyl-5-(6-aldehyde group-phenyl)alkynyl-3-base]thiophene ring of perfluorinated pentene,3,6,8(TL-2)and 1-4(of benzene amino)pyrene(TL-3)of the organic structure unit,The COF-2 is designed and synthesized by the film-forming method,and the structure of the compound is characterized by FT-IR,XRD,etc.,and its gas adsorption is determined-Desorption performance.The material contains diarylene structural units,which can exhibit reversible photochromism.When irradiated with a 365nm UV lamp,the material turns green,with a maximum absorption wavelength of 411 nm.When irradiated with visible light(?>500 nm),It can be restored to the original yellow.At the same time,the light control material we synthesized can obviously find obvious changes in the gas adsorption capacity and specific surface area through the effect of light switching.During the adsorption and desorption of N₂ by COF-2,the specific surface of the open-closed loop structure changes from 285.1796 m²/g When it reaches 140.2729 m²/g,its specific surface is reduced to about 50%of the original,and the adsorption capacity changes from 166.64 m³/g to 121.39 m³/g,reduced to about 75%.These results indicate that the open and closed loop of Co F-2 material can significantly control the gas adsorption amount and specific surface size,which indicates that COF-2 has a good channel controllable switching effect and can be used for the photocontrolled adsorption separation of N₂.The read-write cycle of the material was completed by UV-Vis experiment.These results indicate that COF-2 material has potential application value in information reading and writing,material reuse and confidential information transmission.