Reaction of [HFeCo3(CO)12] with phosphorus donor ligands

Abstract

The reaction of organophosphine and organophosphite ligands with [HFeCo₃(CO)₁₂] gives a series of substitution complexes of general formula [HFeCo₃(CO)_12–xL_x](L = Ph₃P, Ph₂MeP, Et₃P, (PhO)₃P or (PrO)₃P where depending on the substituent (x= 1–3). Only with the chelating phosphine bisdiphenylphosphinoethane (dppe) could more than three CO groups per molecule be displaced. Some corresponding derivatives of [Co₄(CO)₁₂] have also been synthesised for comparative purposes. The i.r. and ⁵⁷Fe Mössbauer spectra of the substituted iron–cobalt complexes have been recorded and are discussed. The Mössbauer data show that substitution takes place preferentially at cobalt and that the complexes [HFeCo₃(CO)_12–xL_x](x= 1–3) are formed by successive substitution of one CO group at each cobalt atom. The complex [HFeCo₃(CO)₈(dppe)₂] exists as a mixture of two isomers and in one of which a carbonyl group on the iron atom has been substituted.