Nuclear magnetic resonance studies of pyramidal inversion in complexes of tricarbonylrhenium(I) halides with aliphatic and aromatic mixed thio–seleno ethers

Abstract

Mixed-chalcogen ligand complexes of type fac-[ReX(CO)₃(MeSZSeMe)](X = Cl, Br, or l; Z= CH₂CH₂ or o-C₆H₄) have been prepared and their temperature-dependent ¹H n.m.r. spectra studied. Pyramidal S and/or Se inversions were observed in all cases and quantitatively assessed for the complex fac-[ReBr(CO)₃{o-MeS(C₆H₄)SeMe}] and the dithio-analogues fac-[ReX(CO)₃{o-MeS(C₆H₄)SMe}](X = Cl, Br, or l). The effects of π conjugation and halogen type on the barrier energies are discussed.