Reactions of metal carbonyls. Part III. Steric and stereochemical limitations of higher substitution of manganese carbonyl bromide

Abstract

The reaction of [Mn(CO)₅Br] with the ligands, L [L = P(OMe)₃, P(OEt)₃, P(OMe)₂Ph, PMe₃, PMe₂Ph, and AsMe₂Ph] have given fac- and trans-[Mn(CO)₃L₂Br] and terminated with mer-[Mn(CO)₂L₃Br]. The complex trans-[Mn(CO)₂{P(OMe)₃}₃Br], prepared by hydrazine reduction of trans-[Mn(CO)₂{P(OMe)₃}₃Br]PF₆, further reacts with P(OMe)₃ to give the tetra substituted compound trans-[Mn(CO){P(OMe)₃}₄Br]. Factors influencing the substitution reactions of [Mn(CO)₅Br] with monodentate tertiary phosphorus and arsenic ligands are discussed in terms of incoming ligand size and the stereochemistry of the manganese carbonyl complexes. The i.r. and ¹H n.m.r. spectra of these complexes are discussed.