Synthesis And Photoelectromagnetic Properties Of Transition Metal Coordination Polymers Derived From Bisimidazolyl Benzothiadiazole Ligands

Coordination polymer is a new kind of organic-inorganic hybrid material.Metal nodes andligands are connected by different coordination modes to form a variety of network structure.Coordination polymer has broad applications in the fields of fluorescence,magnetism,conductivity,catalysis,nonlinear optics and so on,which attracts much attention from chemical researchers.In this paper,twelve new transition metal coordination polymers were successfully constructed by using the organic fluorescence compound4,7-bis(1H-imidazole-1-yl)-2,1,3-benzothiadiazole(BIBT)as the main ligand,various auxiliary carboxylate ligands and transition metal salts.X-ray single-crystal diffraction,infrared spectroscopy,and X-ray powder diffraction were used to characterize the structures of transition coordination polymers.The fluorescent,magnetic and conductive properties of partial coordination polymers were studied in detail.In addition,the synthetic strategy of coordination polymers and the structure-property relationship were summarized.The main contents are summarized as follows:1.By using the mixed-ligand strategy,five new transition metal coordination polymers based on fluorescent ligand BIBT,four straight type aromatic carboxylate ligands,and Cd(II),Co(II)and Zn(II)salts have been constructed.The crystal structure as well as fluorescence properties of some coordination polymers were studied in detail.Fluorescence measurements show that coordination polymer 1 takes excellent fluorescent properties and could be viewed as an effective fluorescent probe toward salicylaldehyde with high selectivity and sensitivity,strong anti-interference,and low detection limit.2.By using five kinds Y-shaped ligands such as 5-amino-phthalic acid(H₂AIPA),3,5-pyridine dicarboxylic acid(H₂PYDC),5-methyl-phthalic acid(H₂MIPA),5-tert-butyl-phthalic acid(H₂TBAIPA),and 5-methoxy-phthalic acid(H₂MOIPA),seven porous coordination polymers were successfully constructed by solvothermal reaction.The fluorescent studies indicate that coordination polymer 6 exhibits fluorescence quenching effects on nitrofurantoin(NFT)and 2.6-dichloro-4-nitroaniline(DCN)with high selectivity and sensitivity,strong anti-interference,and excellent circularity.The study of proton conduction shows that coordination polymers 7 and 8 display relatively good conductive properties,which ascribes to Vehicular mechanism.Magnetic investigation suggests that weak ferromagnetic and antiferromagnetic couplings between the adjacent Co ^IIions in the Co₂clusters exist in 9 and 11,respectively.