Copper(II) and molybdenum(VI) complexes of a tridentate ONN donor isothiosemicarbazone: Synthesis, characterization, X-ray, TGA and DFT

Stable Cu(II) and Mo(VI) complexes with the Schiff base ligand 3-methoxy-2-hydroxobenzaldehyde S-ethyl-isothiosemicarbazone (H2L) were prepared in good yields. The complexes were fully characterized by analytical and spectroscopic techniques. Single-crystal X-ray crystallography reveals the copper and molybdenum complexes have distorted square planar and octahedral geometries respectively. H2L acts as a tridentate ONN donor ligand. The ligand is presented in mono-negative (amido) and di-negative (imino) forms in the Cu(II) and Mo(VI) complexes respectively. The thermogravimetric analysis of the complexes shows CuO and MoO3 as residues. The computed parameters from DFT calculations for structure optimizations and vibrational frequencies are in good agreement with the experimental data. The NBO calculations show the majority of the electron density of the donor atoms tends to be on the central atoms since the calculated formal charges for the central Cu(II) and Mo(VI) ions are much smaller than +2 and +6.

Graphical abstractTwo new isothisemicarbazone complexes of Cu(II) and Mo(VI) are synthesized. The structure, spectral, TG and DFT studies are performed. Copper and molybdenum adopt square planar and octahedral geometries respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide