The Structures of Mono and Bis β-Diketonate Tin(IV) Alkoxide Complexes

Abstract

Tin(IV) alkoxides react with pentane-2,4-dione (acetylacetone) and other β-diketones to yield Sn(OR)3(chel) or Sn(OR)2(chel)2 derivatives. Sn(Opri)3(acac) has been shown to be dimeric in the solid state by a single-crystal X-ray diffraction study, the tin atoms being linked by two alkoxide bridges. In solution l19sn n.m.r. spectral data show that this single complex rapidly converts into a mixture of tin-containing species followed by slow disproportionation to the bis derivative Sn(OPri)2(acac)2 and Sn(Opri)4. The bis complexes Sn(OR)2(acac)2 appear to exist predominantly in solution with cis arrangements of alkoxide groups even when OBut or 2,2,6,6-tetramethylheptane-3,5-dione (dipivaloylmethane) are present.