On the mechanisms of fluxionality and isomerisation of [Fe3(CO)12–n{P(OMe)3}n](n= 1–3)

Abstract

Possible alternative mechanisms based on the ligand polyhedral model have been examined to account for the dynamic behaviour and isomerisation of the triiron derivatives [Fe₃(CO)_12–n{P(OMe)₃}_n](n= 1–3). Carbonyl scrambling is considered to occur via two fundamental processes. First, a low-energy libration of the metal cluster unit within the ligand polyhedron and secondly, a higher-energy ligand polyhedral interconversion involving an anticubeoctahedral ligand array as the complementary geometry. Isomerisation is also believed to occur via related ligand polyhedral rearrangements.