Diorganotin(IV) complexes of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone: Synthesis, spectral characterization and crystal structure

Abstract

Three new diorganotin(IV) complexes of the formulae [Me2Sn(cdet)] (2), [Bu2Sn(cdet)] (3) and [Ph2Sn(cdet)] (4) have been synthesized by the reaction of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone [H2cdet, (1)] and appropriate diorganotin(IV) chloride in the presence of KOH in absolute methanol. These compounds have been characterized by CHN analyses, UV–Vis, FT-IR, 1H, 13C and 119Sn NMR spectroscopic techniques. The molecular structures of the ligand (1) and its diphenyltin(IV) complex (4) have been determined by X-ray diffraction analysis. The ligand H2cdet (1) remains as the thione form in the solid state. The crystal structure of [Ph2Sn(cdet)] (4) revealed that the ligand is coordinated to central tin(IV) atom as a dinegatively tridentate chelating agent via the phenoxide oxygen atom, the azomethine nitrogen atom and the thiolate sulfur atom. The 119Sn NMR chemical shift for the complexes (2–4) are found to be −177.08 to −169.22ppm, confirming five coordinated tin(IV) centre. X-ray crystal structure showed that the coordination geometry of central tin(IV) atom is distorted trigonal bipyramid. The oxygen and sulfur atoms are in axial positions while two phenyl groups and the azomethine nitrogen atom of the ligand occupy the equatorial positions.