The mechanism of isomerisation of the CC bond in ethenethiolato ligands co-ordinated to molybdenum and tungsten. The molecular structures of (E)-exo-[W{η3-SC(CF3)C(CF3)H}(CF3CCCF3)(η5-C5H5)] and (Z)-endo-[W{η3-SC(CF3)C(CF3)H}(CF3CCCF3)(η5-C5H5)]

Abstract

Thermolysis of the η²-vinyl complex [W{η³-C(CF₃)C(CF₃)SBu^t}(CF₃CCCF₃)(η⁵-C₅H₅)] gives the η³-ethenethiolato derivative (E)-exo-[W{η³-SC(CF₃)C(CF₃)H}(CF₃CCCF₃)(η⁵-C₅H₅)], which undergoes concomitant exo→endo and E→Z isomerisation to give (Z)-endo-[W{η³-SC(CF₃)C(CF₃)H}(CF₃CCCF₃)(η⁵-C₅H₅)], thus providing evidence for a ring-flip mechanism in metal-promoted alkene isomerisations.