Pyramidal inversion in configurational isomers of tetracarbonyl[1,1,2,2-tetrakis(methylthio)ethane]chromium(0): a two-dimensional nuclear magnetic resonance exchange study

Abstract

Pyramidal inversion of the co-ordinated sulphur atoms in the cis and trans configurational isomers of [Cr(CO)₄{(MeS)₂CHCH(SMe)₂}] has been examined by n.m.r. spectroscopy. The two dimensional NOESY method was used to identify individual invertomers of each isomer at low temperature. One-dimensional band-shape analyses performed at higher temperatures yielded ΔG^‡ values in the ranges 45–50 and 50–54 kJ mol^–1 for the trans and cis isomers respectively. No evidence for cis–trans interconversion was obtained, probably because of the limited thermal stability of the complex.