Synthesis And Properties Of Schiff Base Complexes With Thiosemicarbazone

Thiosemicarbazone ligands and their metal complexes are favored by researchers both at home and abroad because of their wide application prospects in the fields of biological antibacterial,anti-tumor and functional materials.O-vanillic aldehyde thiosemicarbazone ligand and 2-hydroxy-1-naphthalene benzaldehyde thiosemicarbazide ligands and their metal complexes were designed and synthesized in this paper,and their crystal structure,biological activity,and its magnetic were studied in detail.The detailed works are summarized as follows.?1?O-vanillic aldehyde thiosemicarbazone ligand?L¹?has been synthesized with O-vanillic aldehyde and thiosemicarbazide as starting materials,which react withlanthanides metal-based nitrate to form four dual-core rare earth complexes[Ln?L¹?₂?phen??OH?]₂·2C₃H₇NO·4H₂O?1-4??Ln=Dy?1??Tb?2??Ho?3??Er?4??with solvothermal method.At the same time,four tri-nuclei rare earth complexes[Ln₃?L¹?₅?phen?₂O₂]·2H₂O?5-8??Ln=Dy?1??Tb?6??Ho?7??Er?8??were obtained by controlling the solvent.A series of techniques,such as single crystal diffraction,infrared spectrum,thermogravimetric analysis and powder diffraction were employed to characterize these complexes.Single crystal diffraction tests show that the complexes 1-4 are isomorphic compounds,all of which have a monoclinic system with eight coordination while the crystal of the complexes 5-8 belongs to the triangle ring spiral structure of the monoclinic C2/c space group.The thermogravimetric analysis reveals that the stable temperature of the compound 1-4 is around 190?,while the temperature of 5-8 is about 205?.?2?Seven complexes?9-13?have been synthesized by the reaction of ligand L¹with Cu²⁺?Co²⁺?Cr²⁺?Cd²⁺?Zn²⁺?Ni²⁺respectively.In addition,2-hydroxy-1-naphthalene benzaldehyde thiosemicarbazone ligand L² can be obtained from 2-hydroxy-1-naphthalene benzaldehyde and thiosemicarbazide,which react with the nitrate oftransition metal-based Cu and Zn to form four transition metal complexes 14-17.Apart from infrared,powder diffraction,thermogravimetric analysis and single crystal diffraction,the spatial structure of these complexes was analyzed.In the simulated physiological condition,the mechanism of the combination of the partial metal complexes with bovine serum albumin?BSA?/DNA was studied by UV and fluorescence spectrometry.Experimental results show that quenching of this kind of compound is static quenching.At the same time,binding-site numbers of complexes with BSA,binding constant,and combined with distance were calculated.Thermodynamic parameters of?G was also tested and?G values are below zero,showing the process of the combination of metal complexes with BSA/DNA are spontaneous.