Synthesis, characterization and X-ray crystal structures of the bis?ligand zinc(II) and cadmium(II) complexes of the methylpyruvate Schiff base of S-methyldithiocarbazate

Abstract

New bis-chelated Zn II and Cd II complexes of empirical formula, [M(mpsme) 2 ] (mpsme ¼ the anionic form of the tridentate ONS donor ligand formed from methylpyruvate and S-methyldithiocarbazate) have been prepared and characterized by conductance, i.r., electronic and n.m.r. spectroscopic techniques. Spectral evidence supports a sixcoordinate distorted octahedral structure for these complexes. X-ray crystallographic structural analysis also confirms that, in both the [Zn(mpsme) 2 ] and [Cd(mpsme) 2 ] complexes, the methylpyruvate Schiff base of S-methyldithiocarbazate is coordinated to the metal ions as a uninegatively charged tridentate ONS chelating agent via the carbonyl oxygen atom, the azomethine nitrogen atom and the thiolate sulfur atom. Both complexes are assigned a distorted octahedral geometry in which the ligands are arranged meridionally around the metal ions. The distortion from regular octahedral geometry is attributable to the restricted bite angles of the ligand.