Diphenylantimony(V) oxo/chloro carboxylates and phosphinates: crystal structures of {SbPh2Cl[O2P(C6H11)2]}2O and [SbPh2(O2CPh)2]2O

Abstract

Reaction of SbPh₂Cl₃(1 mol) with the silver salt of dicyclohexylphosphinic acid (2 mol) afforded {SbPh₂Cl[O₂P(C₆H₁₁)₂]}₂O 1; a similar reaction with AgO₂P(C₈H₁₅)₂ gave a product formulated as {SbPh₂Cl[O₂P(C₈H₁₅)₂]}₂O 2. Similar reactions with silver carboxylates (1 : 3 stoichiometry) led to the crystalline derivatives [SbPh₂(O₂CR)₂]₂O (R = Ph 3, CHPh₂4, 2,4,6-Me₃C₆H₂5, 2-MeC₆H₄6 or 4-MeC₆H₄7), whereas the 1 : 2 reaction afforded crystalline SbPh₂Cl(O₂CR)₂(R = Ph 8, 2-MeC₆H₄9 or 4-MeC₆H₄10). Interconversion of the previously known compounds [SbPh₂(O₂CMe)₂]O and Sb₄Ph₈O₆·3MeCO₂H was achieved and established by ¹H NMR spectroscopy. Compounds 1 and 3 were further characterized by X-ray diffraction; the antimony in 1 is six-co-ordinated with bridging phosphinates whereas in 3 it is seven-co-ordinated with chelating benzoates. Short Sb–O (oxo) distances (1.923 Å) and near linearity at the bridging oxygen (Sb–O–Sb 173.9°) are observed for 3.