Complexes of tin(IV) halides and organotin(IV) halides with organic sulphides and selenides: the low temperature cessation of sulphur and selenium inversion and its structural consequences

Abstract

We report the preparation and characteristisation of the 1:2 complexes [SnX 4(R 2E) 2] (R = C 6H 5CH 2, Me 3SiCH 2; E = S, Se; X = Cl, Br) and the 1:1 complexes [SnCl 4(bmt)] (bmt = 3,4-bis(methylthio)-toluene and [SnCl 3(C 6H 5)(dth)] (dth = 2,5-dithiahexane). Variable temperature 1H NMR studies have confirmed the previously observed cis/trans isomerism about tin in the [SnX 4L 2] complexes, and we have additionally discovered at low temperature the cessation of the pyramidal atomic inversion about sulphur and selenium. This latter phenomenon is characterised by the observation of prochiral centres in the [SnX 4L 2] complexes and mixtures of dl and meso isomers in the chelate complexes.