The photolysis and subsequent reactions of bis(triaryl phosphite) complexes of iron(0), trans-[Fe(CO)3{P(OAr)3}2]

Abstract

On photolysis in solution,trans-[Fe(CO)₃{P(OAr)₃}₂] complexes (Ar = Ph and o- and p-MeC₆H₄) lose CO to give red products. These cannot be isolated, but react in situ with various ligands, L (e.g. CO, phosphines, phosphites, isocyanides, CS₂, SO₂, tetracyanoethylene, and acetylenes) to give [Fe(CO)₂{P(OAr)₃}₂(L)] derivatives, and with various compounds X–Y (e.g. H–H, D–D, H–Cl, and Cl–SnCl₃) to form [Fe^II(CO)₂{P(OAr)₃}₂(X)(Y)] compounds. These reactions are often not simple and complicated mixtures of products may be obtained. Carbon tetrachloride and N-bromosuccinimide convert the red intermediate to a mixture of [Fe(CO)₂{P(OAr)₃}₂(X)(Y)] and [Fe(CO)₂-{P(OAr)₃}₂X](X = Y = Cl or Br). It is suggested that the latter contain o-metallated phosphite ligands and that the red intermediate compound is related to them and is best formulated as [Fe{P(OC₆H₃Z)(OAr)₂}{P(OAr)₃}-(CO)₂H] rather than [Fe(CO)₂{P(OAr)₃}₂](Z = H or Me).