Pyramidal inversion and novel 1,2-metal shifts in pentacarbonyl-chromium, -molybdenum, and -tungsten derivatives of dialkyl disulphides and dialkyl diselenides

Abstract

Variable temperature ¹H n.m.r. spectroscopy of the mononuclear complexes [M(CO)₅(Me₃SiCH₂EECH₂SiMe₃)], M = Cr, Mo, and W, E = S and Se, establishes the occurrence of two distinct fluxional phenomena; the first is not-unexpected pyramidal inversion about the co-ordinated sulphur or selenium atoms, but at higher temperatures a novel 1,2-metal shift between the two ligand atoms of the disulphide or diselenide occurs.