New Organotin Derivatives of Trilacunary Keggin Polyanions

Abstract

Three new organotin derivatives of polyoxometalates have been obtained by reaction between the trilacunary precursors [PW₉O₃₄]⁹⁻ and [AsW₉O₃₄]⁹⁻ and organotin trichlorides RSnCl₃ (R=Me, Bu) in aqueous solution. The compounds were characterized using elemental and thermogravimetrical analysis, UV, IR, Raman and multinuclear (¹H, ¹³C, ³¹P) NMR spectroscopy, ESI‐MS and cyclic voltammetry. Ion‐exchange, and ESI‐MS experiments provided evidence for covalent, inner‐sphere bonding of organotin groups to the trilacunary [XW₉O₃₄]⁹⁻ heteropolyanions. Cyclic voltammograms of all three organotin complexes exhibited two pairs of reduction/oxidation waves with negative half‐wave potential (E_1/2) values. These waves were attributed to redox processes corresponding to the polyoxotungstate framework.

Keywords:

• heteropolyanion
• Keggin structure
• organotin
• polyoxometalate

Acknowledgments

This work was supported by the NURC Grant Nr. 32575/COD 295, Theme 36, and was also partially funded by a Greek‐Romanian bilateral cooperation project. A.R.T. is grateful to the GSRT (Greece) and MER (Romania) for financial support.