Synthesis and characterization, antimicrobial activity, DNA binding and DNA cleavage studies of new 5-chloro-2-[4-phenylthiazol-2-yl-iminomethyl]phenol metal complexes

New Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Cd(II) complexes derived from bidentate Schiff base ligand, 5-chloro-2-[4-phenylthiazol-2-yl-iminomethyl]phenol (HL) have been synthesized. The molar ratio for all synthesized complexes is M: L = 1:2 which was established from the results of chemical analysis. The complexes have been characterized by elemental analysis, spectral (IR, UV–Vis, (1H and 13C) NMR, mass, ESR, XRD, CV, fluorescence, and magnetic as well as thermal analysis measurements. The IR spectra of the prepared complexes were suggested that the Schiff base ligand behaves as a bi-dentate ligand through the azomethine nitrogen atom and phenolic oxygen atom. The crystal field splitting, Racah repulsion and nepheloauxetic parameters and determined from the electronic spectra of the complexes. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. From the modeling studies, the bond length, bond angle, core–core interaction, heat of formation, electronic energy, binding energy, HOMO, LUMO and dipole moment had been calculated to confirm the geometry of the ligand and their investigated complexes. Also, the thermal behavior and the kinetic parameters of degradation were determined using Coats–Redfern, Horowitz–Metzger and Piloyan–Novikova methods. Moreover, the in vitro antibacterial studies of all compounds screened against pathogenic bacteria (two Gram +ve and three Gram −ve) and three antifungal to assess their inhibiting potential. The assay indicated that the inhibition potential is metal ion dependent. The interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by UV absorption method, and the mode of CT-DNA binding to the complexes has been explored. Furthermore, the DNA cleavage activity by the complexes was performed.