Crystal and molecular structures of some six-coordinate tin(IV) halogeno complexes with phosphorus-containing ligands

Six new complexes of tin(IV) halides with phosphorus-containing ligands have been fully characterized by single-crystal X-ray diffraction at low temperature. Three of the compounds, derived from the diphosphanes bis-(diphenylphosphino)methane or bis-(dicyclohexylphosphino)methane, have a novel zwitterionic structure, with five Cl ligands and one unidentate phosphorus-containing ligand on tin, together with a proton on the second phosphorus atom of the potentially bidentate ligand; these are Cl 5Sn-p(Ph2)CH2PPh2H+ (1), Cl5Sn- OP(Ph2)CH2- PPh2H+ (2), and Cl5Sn- OP(cy2)CH2Pcy 2H+ (3). The other three complexes have a bidentate donor attached to the SnX4 moiety; they comprise Cl4SnOP(Ph 2)- (CH2)2PPh20 (4), a derivative of bis-(diphenylphosphino) ethane dioxide, I4SnOP(Ph 2)CH2PPh20 (5), a similar derivative of bis-(diphenylphosphino)- methane dioxide, and the very unusual Br 4SnAs- (Ph2)(CH2)2PPh20 (6), with coordination to tin by As and O. Since the starting material for the last compound was Ph2As(CH2)2PPh2, this result illustrates well the more facile oxidation of P(III) than As(III). © 2009 Wiley Periodicals, Inc.