Synthesis, spectroscopic characterization and thermal behavior of metal complexes formed with (Z)-2-oxo-2-(2-(2-oxoindolin-3-ylidene)hydrazinyl)-N-phenylacetamide (H2OI)

Complexes of Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and U(IV)O2 with (Z)-2-oxo-2-(2-(2-oxoindolin-3-ylidene)hydrazinyl)-N-phenylacetamide (H2OI) are reported and have been characterized by various spectroscopic techniques like (IR, UV–Vis, ESR 1H and 13C NMR) as well as magnetic and thermal (TG and DTA) measurements. It is found that the ligand behaves as a neutral tridentate, neutral tetradentate, monoanionic tridentate, monoanionic tridentate and dianionic tridentate. An octahedral geometry for all complexes except [Cu2(H2OI)(OAc)4](H2O)2 and [Cu(HOI)Cl](H2O)2 which have a square planar geometry. Furthermore, kinetic parameters were determined for each thermal degradation stage of some studied complexes using Coats–Redfern and Horowitz–Metzger methods. The bond lengths, bond angles, HOMO, LUMO and dipole moments have been calculated to confirm the geometry of the ligand and the investigated complexes.