Ethene complexes of chromium; the generation and characterisation of [Cr(CO)5(C2H4)] and cis- and trans-[Cr(CO)4(C2H4)2] and their relative stabilities in liquid xenon solution

Abstract

The unstable complexes [Cr(CO)₅(C₂H₄)] and cis- and trans-[Cr(CO)₄(C₂H₄)₂] are generated by photolysis of [Cr(CO)₆] in C₂H₄-doped liquid xenon and are characterised by i.r. spectroscopy; these complexes are all unstable, even at -78 °C with the cis-[Cr(CO)₄(C₂H₄)₂] complex being the least stable, decomposing with an enthalpy of activation, ΔH^‡, of ∼60 kJ mol^–1.