Electrochemical synthesis, structural, spectral studies and DFT calculations of heteroleptic metal-chelates bearing N, N, S tridentate tosylamino functionalized pyrazole containing Schiff base and 1,10-phenathroline

The electrochemical oxidation of a zero-valent metals (copper, cobalt, nickel, zinc, and cadmium) (1–5) in an acetonitrile-methanol solution containing the equimolar amounts of 1,10-phenanthroline (phen) and the N, N, S-tridentate basic form of the Schiff base N-[2-[[3-methyl-1-phenyl-5-thioxo-pyrazole-4-ylidenemethyl]amino]phenyl]-4-methylbenzenesulfonamide (H2L) resulted in the formation of the mixed ligand complexes with a common formula [M(L)phen]. All compounds were characterized with C, H, N elemental analysis, FT-IR, 1H NMR, X-ray absorption spectroscopy and magnetic measurements. The structures of the complexes [Cu(L)phen] (1) and [Zn(L)phen] (4) were determined by X-ray single-crystal diffraction. In both complexes the metal centers are surrounded with imine and amide nitrogens, sulfur of thiol group of H2L and two nitrogens of phen used as co-ligand. The assignment and the nature of the bands in experimental UV–Vis spectra of adducts were analyzed using time-dependent (TD) DFT calculations.