Synthesis, Structural, DNA Binding and Cleavage Studies of Cu(II) Complexes Containing Benzothiazole Cored Schiff Bases.

Novel benzothiazole Schiff bases L1 [1-((4,6-difluorobenzo[d]thiazol-2-ylimino)methyl) naphthalen-2-ol], L2 [3-((4,6-difluorobenzo[d]thiazol-2-ylimino) methyl)benzene-1,2-diol], L3 [2-((4,6-difluorobenzo[d]thiazol-2-ylimino)methyl)-5-methoxyphenol], L4 [2-((4,6-difluorobenzo[d]thiazol-2-ylimino)methyl)-4-chlorophenol] and their binary Cu(II) complexes were synthesized. The structures of all the compounds have been discussed on the basis of elemental analysis, FT-IR, NMR, UV-Visible, ESI-Mass, TGA, ESR, SEM, powder XRD and magnetic moments. Based on the analytical and spectral data a square planar geometry has been assigned to all complexes in which the Schiff bases act as monobasic bidentate ligands, coordinating through the azomethine nitrogen and phenolic oxygen atom. DNA binding ability of these complexes was studied on CT-DNA by using UV-Vis absorption, fluorescence and viscometry. DNA cleavage ability of the complexes was examined on pBR322 DNA by using gel electrophoresis method. All the DNA binding studies reveal that they are good intercalators. The bioefficacy of the ligands and their complexes was examined against the growth of bacteria and fungi in vitro to evaluate their antimicrobial potential. The screening data revealed that the complexes showed more antimicrobial activity than the corresponding free ligands.