Copper(II) and molybdenum(VI) complexes with 5-bromosalicylaldehyde S-allylisothiosemicarbazone: Syntheses, characterizations and crystal structures

Abstract

A new tridentate Schiff base, 5-bromosalicylaldehyde S-allylisothiosemicarbazone hydrobromide (H₂L), and several new mononuclear complexes of copper(II) and molybdenum(VI) of this ligand with general formulas ([Cu(L)Im] (1)), ([Cu(L)NH₃]·4H₂O (2)), and ([MoO₂(L)1-MeIm] (3), Imidazole: Im, 1-methylimidazole: 1-MeIm) were prepared and characterized by elemental analyses, IR, proton magnetic resonance Spectroscopy, and ultraviolet–visible techniques. The physico-chemical results suggested that the H₂L coordinates in the dianionic tridentate form. Crystal structures of the Cu(II) complexes reveal a square planar configuration surrounded by the dianionic tridentate isothiosemicarbazone (ONN) and Im and NH₃ for 1 and 2, respectively. The L^2-, two oxo, and 1-methylimidazole are coordinated to molybdenum(VI) in a distorted octahedral geometry in 3. Formation of pure metal oxide residues was confirmed by thermal degradation of the complexes.

Keywords:

• Schiff base
• Isothiosemicarbazone
• Copper and molybdenum complexes
• TGA
• Crystal structure

Acknowledgements

Reza Takjoo would like to thank the Ferdowsi University of Mashhad for supporting this work. We thank the Università di Messina (Italy) for the provision of a diffractometer.