Reaction of tin metal powder with triorganophosphorus dihalides: isolation and spectroscopic characterisation of [PR3X][SnX3] and cis- and trans-Sn(PR3)2X4(X = Br or I; R3= Ph3, Ph2Me or PhMe2)

Abstract

The novel reaction of some R₃PX₂ compounds (X = Br or I; R₃= Ph₃, Ph₂Me or PhMe₂) with unactivated coarse-grain tin metal powder has been investigated. Initially a tin(II) species results which is then further oxidised leading to the formation of both cis- and trans-Sn(PR₃)₂X₄. The products formed have been characterised by elemental analysis, NMR, Raman and Mössbauer spectroscopy and compared to analogous complexes. The synthesis and isolation of the iodo complexes Sn(PR₃)₂I₄ by this new synthetic route is straightforward and contrasts with difficulties using conventional techniques, viz. the reaction of Snl₄ with PR₃. The relative proportions of cis- and trans-SnX₄(PR₃)₂ isomers formed from the reaction have been determined from Mössbauer spectroscopic studies and the reason for their formation is discussed.