DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: synthesis and spectral approach.

The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, (1)H NMR, (13)C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.

Crystal structure of 3-[(E)-2-(4-phenyl-1,3-thia-zol-2-yl)hydrazin-1-yl-idene]indolin-2-one.

In the title mol-ecule, C17H12N4OS, the thia-zole ring forms a dihedral angle of 10.8 (2)° with the phenyl ring and an angle of 3.1 (3)° with the indole ring system [which has a maximum deviation of 0.035 (2) Å]. The dihedral angle between the planes of the phenyl ring and the indole ring system is 11.5 (1)°. An intra-molecular N-H⋯O hydrogen bond is observed. In the crystal, pairs of N-H⋯O hydrogen bonds form inversion dimers with an R (2) 2(8) graph-set motif.