Synthesis, characterization, biological activity and DNA cleavage studies of tridentate Schiff bases and their Co(II) complexes

In the present study a series of Co(II) complexes of formyl chromone Schiff bases have been synthesized characterized by analytical, molar conductance, IR, electronic, magnetic susceptibility, thermal, fluorescence and powder XRD measurements and screened for various biological activities (antimicrobial, antioxidant, nematicidal, DNA cleavage and cytotoxicity). In all the Co(II) complexes 1:2 metal to ligand molar ratio was obtained from analytical data. The molar conductance data confirm that all complexes are non-electrolytic in nature. Based on the electronic and magnetic data, an octahedral geometry is ascribed for all the Co(II) complexes. Thermal behaviour of the synthesized complexes illustrates the general decomposition patterns of the complexes. The X-ray analysis data show that all the Co(II) complexes have triclinic crystal system with different unit cell parameters. Metal complexes have greater antimicrobial activity than ligands. Antioxidant and nematicidal activities indicate that the ligands exhibit greater activity when compared to their respective Co(II) complexes. All ligands and Co(II) complexes of HL1 and HL2 showed considerable anticancer activity against Raw, MCF-7 and COLO 205 cell lines. All ligands and their Co(II) complexes showed more pronounced DNA cleavage activity in the presence of H2O2.