Synthesis of monoorganotin(IV) chloride complexes of cis-1,2-bis(diphenylphosphino)ethylene: Solution and solid state structures

Organotin(IV) complexes of the type [RSnCl3(cis-Ph2PCHdouble bond; length as m-dashCHPPh2)] [R = Me (1), nBu (2), Ph (3)] were prepared by the reaction of RSnCl3 with the rigid bisphosphine ligand, cis-1,2-bis(diphenylphosphino)ethylene in dichloromethane. The complexes have been characterized both in solution and the solid state. Low temperature 31P and 119Sn NMR studies indicate two different phosphorus environments. The crystal structures indicate a weak but chelating mode of coordination of the two phosphorus atoms to tin, leading to a distorted octahedral geometry. In solution the complexes 1–3 undergo a redistribution reaction to form [SnCl4(cis-Ph2PCHdouble bond; length as m-dashCHPPh2)] (4) as one of the products. In order to confirm the redistribution, complex 4 has been prepared separately and characterized both structurally and spectrally.