Synthesis Of Biphenylene-Bridged Silane, Self-assembly Behaviour And Functional Hybrid Materials

Bridged silsesquioxanes are a new class of hybrid network materials that have organic and inorganic domains dispersed at the molecular level. The polysiloxane-bridged monomer is generally prepared by functional organic bridge molecules and silanes. Organic bridged units can be connected with three ethoxy groups through Si-C bond. So, the structure and function of the organic bridged silanes can be tailored. The bridged silsesquioxanes can be widely used in photoelectric, catalysis, separation medium, adsorbent, and other eareas. Therefore, the study of bridged silsesquioxanes is significant and pocesses of application prospects.Benzidine, as an important intermediate of synthetic dyes, is widely used in various dyes preparation and production. They are deemed to be carcinogens and pose a great danger to human health. So the benzidine dyes are used with a strict management in order to protect the circumstance. Performance analysis of DCB and its congener in matrices often requires some clean-up and preconcentration steps. Traditionally, sample preparation is performed extraction with low selectivity. Consequently, there is considerable interest in developing a selective and sensitive method for extracting and isolating DCB from complex matrices.In this study, isocyanatetriethoxysilanes and benzidines were used as reactants to prepare a biphenyl-bridged silane monomer which containing alkoxy, urea and biphenyl groups. The monomer can be used to prepared hybrid materials by hydrolysis and polycondensation reaction.The self-assembly behavior of the biphenyl-bridged silanes in organic solution was studied. The biphenyl-bridged silanes tend to self-organize because of the hydrogen bonding andπ-πinteractions. The binding energy of two silane molecules and their hydrolyzates, which were calculated by using molecular computation simulation, are-52.8 kJ/mol.Ordered biphenyl-bridged silsesquioxanes were prepared by interfacial polymerization under acid and alkaline conditions. The biphenyl-bridged silsesquioxanes was characterized by X-ray powder diffraction, scanning electron microscopy, optical microscopy, infrared spectrum, fluorescence spectrum etc.. The X-ray powder diffraction indicated biphenyl-bridged silsesquioxanes had a certain long-range order structure. Scanning electron microscopy showed ordered biphenyl-bridged silsesquioxanes were a buildup of around 100 nm wide rods. The hydrogen bonding andπ-πof biphenyl bridged were study by infrared spectrum and fluorescence spectrum.The molecularly imprinted polysiloxane microspheres were prepared by using biphenyl-bridged silane monomers.3,3-dichlorobenzidine was used as template molecule. TEM shows that the diameter of microspheres prepared is in the range of 100-200 nm. The selectivity and adsorption of the molecularly imprinted polysiloxane microspheres were studied by using UV and HPLC methods. The molecularly imprinted polysiloxane microspheres showed good adsorption and selectivity towards 3,3-dichlorobenzidine. Furthermore,47.5% polychorinated biphenyls (PCB) in water can be absorbed by the molecularly imprinted polysiloxane microspheres.