Synthesis and characterization of pentagonal bipyramidal organotin(IV) complexes of 2,6-diacetylpyridine Schiff bases of S-alkyl- and aryldithiocarbazates

Abstract

New organotin(IV) complexes with empirical formula Sn(SNNNS)R₂, where SNNNS is the dianionic form of 2,6-diacetylpyridine Schiff bases of S-methyldithiocarbazate (H₂dapsme) or S-benzyldithiocarbazate (H₂dapsbz) and R = Ph or Me, have been prepared and characterized by IR, UV-Vis, NMR and Mössbauer spectroscopic techniques and conductance measurements. The molecular structures of the Sn(dapsme)R₂ (R = Ph and Me) have been determined by single crystal X-ray diffraction techniques. Both complexes have a distorted pentagonal-bipyramidal geometry in which the tin is coordinated by a dinegatively charged pentadentate chelating agent via pyridine nitrogen, two azomethine nitrogens, and two thiolate sulfurs. The five donors (N₃S₂) provided by the Schiff base occupy the equatorial plane close to a pentagonal planar array while the carbanion ligands occupy axial sites.

Keywords:

• Organotin(IV) complexes
• Dithiocarbazates
• 2,6-Diacetylpyridine Schiff bases of S-alkyldithiocarbazates
• Seven-coordinate organotin(IV) complexes

Acknowledgments

M. Akbar Ali and A.H. Mirza gratefully acknowledge the Department of Chemistry, Universiti Brunei Darussalam for supporting this work. The financial support for the ¹¹⁹Sn Mössbauer work from the National Institute of Health, Biomedical Research Support Program (MBRS/SCORE, GM08005) is gratefully acknowledged. P.V. Bernhardt acknowledges support from the Australian Research Council and the University of Queensland.