Nickel(II), copper(II), cobalt(II), and palladium(II) complexes with a Schiff base: crystal structure, DFT study and copper complex catalyzed aerobic oxidation of alcohol to aldehyde

Abstract

Ni(II), Cu(II), Co(II), and Pd(II) complexes were synthesized with a Schiff base containing thioether with ONS donors chelating to the metal center. The ligand and complexes were characterized by elemental analysis, FT-IR, ¹H-NMR, UV–visible spectroscopy and magnetic studies. The crystal structures of the ligand and its Ni(II) and Pd(II) complexes were determined by single-crystal X-ray diffraction analysis. Structures revealed that the ligand chelated with Ni(II) and Pd(II) center in slightly distorted octahedral and slightly distorted square planar fashion, respectively. DFT studies of the Pd(II) complex revealed that the calculated structural parameters are very close with the experimentally observed data. The Cu(II) complex shows very good catalytic activity toward the conversion of alcohol to aldehyde under aerobic oxidation with ammonium persulfate.

Keywords:

• Schiff base
• Crystal structure
• Catalytic activities
• DFT study

Acknowledgments

The authors gratefully acknowledge Indian Association for the Cultivation of Science, Kolkata, for the Gaussian 09 program package, Tezpur University, Tezpur and IIT Bombay, Mumbai, for spectral and analytical data. Also thanks to Director of NIT, Silchar, for financial assistance (K.S, N.D, and M.K).