Studies On3,5-Dibromosalicylaldehyde Bis-Schiff Base And Its Transition Metal Complexes

(1) L1and its transition metal (Co(Ⅱ), Ni(Ⅱ))complexes were synthesized and characterized by ’HNMR, IR spectra, elemental analysis, molar conductivity and TG-DSC. The Schiff base L1and its complex L’Ni(Ⅱ) were calculated by full-optimized molecular geometry with GaussianO3program,the structure was the same as the the experimental results,We found that L1was the asymmetry compound,but L’Ni(Ⅱ) was symmetrical compound;L’Ni(II) was more stable than L1but the biological activity was weaker than it, and3,5-diiodo salicylaldehyde was the biological activity center of the complex L’Ni(Ⅱ).(2) L2and its transition metal (Co(Ⅱ)、Ni(Ⅱ))complexes were synthesized and characterized by ’HNMR, IR spectra, elemental analysis, molar conductivity and TG-DSC. The interaction of L2, M2+(M=Co(Ⅱ)、Ni(Ⅱ))and complexes with BSA was studied by fluorescence spectrum in Tris-Hcl buffer solution(pH=7.30) and they all caused the fluorescence quenching BSA through a static quenching procedure by1:1. L22Co2has influenced on the conformation of BSA and other substances that have no effect on the conformation of BSA,so L22Co2is likely to be a kind of antimicrobial, antiviral activity, promote blood clotting drug.The binding constants (Ka) was L22Co2>L22Ni2> L2> Co2+>Ni2+.(3)L3and its transition metal (Cu (Ⅱ) and Mn(Ⅱ)complexes were synthesized and characterized by1HNMR, IR spectra, elemental analysis, molar conductivity and TG-DSC. The coordination reaction of the Schiff based with Cu(Ⅱ) and M n(Ⅱ) was investigated via Molar ratio and the equivalent molarity method,The composition of the complexes was proved to be M2L2(M=Cu (Ⅱ) and Mn(Ⅱ)).The binding mode between complexes and DNA was investigated by UV spectra,cyclic voltammetry and fluorescent spectra. The results showed that the mode between DNA and complexes is intercalative binding, the Cu(Ⅱ) complex affinity is bigger than the M n(Ⅱ) complex.