Synthesis, spectroscopic characterization, antimicrobial, antitubercular and DNA cleavage studies of 2-(1H-indol-3-yldiazenyl)-4, 5, 6, 7-tetrahydro-1, 3-benzothiazole and its metal complexes

In the present work, the bioactive metal complexes were synthesized from 2-(1H-indol-3-yldiazenyl)-4, 5, 6, 7-tetrahydro-1, 3-benzothiazole (HL). All the newly synthesized compounds were characterized by spectral (IR, UV-Visible, NMR, Mass, ESR, powder XRD), elemental, magnetic susceptibility and molar conductivity studies. Conductivity data indicated the non-electrolytic nature of the complexes. From the spectroscopic data, distorted square planar geometry was deduced for Cu (II) and Ni (II) complexes, octahedral geometry for Co (II) and Fe (III) complexes and tetrahedral geometry for Zn (II) complex. Electron paramagnetic resonance spectra of the Cu (II) complex was studied in dimethyl sulphoxide at 77 K and it showed mononuclear nature of the complex. The redox behaviour of the Cu (II) complex was also studied in the solution of N, N-dimethyl formamide. All the synthesized compounds exhibited potential antimicrobial activity against tested pathogens. The antimycobacterial activity of the synthesized compounds was studied and all the metal chelates exhibited higher activity than the free ligand. The DNA cleavage ability of the synthesized compounds was studied by using calf thymus DNA (CT-DNA) and among the studied compounds, only ligand (HL), Cu (II) and Fe (III) complexes cleaved completely.