A Treatise on Furan Cored Schiff Base Cu(II), Ni(II) and Co(III) Complexes Accentuating Their Biological Efficacy: Synthesis, Thermal and Spectroscopic Characterization, DNA Interactions, Antioxidant and Antibacterial Activity Studies

Three metal complexes [Cu(FMIMDIP)2] (1), [Ni(FMIMDIP)2] (2) and [Co(FMIMDIP)3] (3) where, FMIMDIP=(((furan‐2‐yl)methylimino)methyl)‐4,6‐diiodophenol, were synthesized and characterized by various spectroscopy. The analytical data revealed a square planar geometry for 1 and 2 and an octahedral geometry for 3. The kinetic and thermodynamic parameters of the thermal decomposition steps were calculated from the thermograms. The quantum chemical parameters have been calculated using HOMO‐LUMO energies and reveal the stability of the complexes. The DNA interaction of 1–3 towards calf‐thymus DNA was investigated by absorption titration, fluorescence spectroscopy and gel electrophoresis. All the complexes bind to DNA via intercalation mode with binding constant (Kb) values of 4.17×103 M−1 to 5.9×104 M−1 and also effectively cleave pBR322 DNA by oxidative and photolytic techniques. The synergistic action of metal chelates with ascorbic acid induced the generation of free radicals. The antibacterial activity of 1–3 was tested against B. thuringiensis, S. pneumoniae, E. coli, and P. putida. Complex 3 has the best activity among all the complexes.