Complexes of potentially chelating vinylsilanes and their carbon analogues with palladium(II) halides

Abstract

Eight members of the series of 1 : 1 complexes of palladium(II) halides (chloride, bromide, and iodide) with the ligands 2,2,NN-tetramethylbut-3-enylamine (1a), 2,2-dimethylbut-3-enyl methyl sulphide (1b), and 2,2-dimethyl-2-silabut-3-enyl methyl sulphide (2b) have been isolated. The remaining complex, Pdl₂·(2b), is unstable, disproportionating to give Pdl₂·2(2b). Infrared and ¹H n.m.r. data are reported. In solution all the 1 : 1 complexes, even the iodides, are chelated and the ring apparently adopts similar conformations. Variable-temperature ¹H n.m.r. studies of two exchange processes, labilisation of the metal–olefin bond and, for the sulphur chelates, inversion at sulphur, are discussed.