Synthesis And Liquid Crystal Properties Research On Long Chain Schiff Bases,Amino And Azo Porphyrin And Zinc Complexes

Porphyrins have large ring-plane conjugate systems,smaller HOMO-LUMO energy bands,and intense visible light absorption and luminescence properties.The D-A system,which is often related to various types of electron acceptors,has useful application prospects in the fields of organic photoelectric functional materials.Among the numerous connection,Imine bonds,amino and azo bonds can easily and efficiently link porphyrin rings with other functional groups.At the same time,long-chain alkyl groups can greatly improve the solubility of porphyrin functional molecules,and porphyrins with long-chain alkyl groups are also preferred liquid crystal materials.In this paper,four series of 29 long-chain Schiff bases,amino and azo porphyrin compounds and their zinc complexes were synthesized starting from tetraaminoporphyrin and tetrabromoporphyrin.The synthesized porphyrin ligands and zinc complexes were characterised by NMR spectroscopy,high resolution mass spectrometry(HRMS)and infrared spectroscopy(IR).UV-Vis spectroscopy(UV-vis),fluorescence spectroscopy,and cyclic voltammetry(CV)were utilized to investigate the spectral and electrochemical properties.The results showed that the meta-alkoxy Schiff-base porphyrins were blue shifted compared to the Soret band in the ultraviolet spectrum of the alkoxy Schiff-base porphyrins.The allomorphic are red-shifted relative to the Schiff-base porphyrins,and the long-chain aminophylline are red-shifted opposed to the azo-porphyrins.The fluorescence is demonstrated that the long-chain aminophylline undergo a larger red shift than the ozonosphere and the Schiff-base porphyrins.After the zinc was added,a significant blue shift occurred.Differential scanning calorimetry(DSC)and hot-stage polarizing microscopes were used to test the liquid crystallinity.Owing to the symmetry,the alkoxy Schiff-base porphyrins and azo-porphyrins have despotic liquid crystals,while the m-alkoxy Schiff-base porphyrins do not.Resulting from the influence of the terminal substituent,the long-chain actinomorphic has a liquid crystallinity of 16 C or more.