Reactions of metal carbonyls. Part 7. Substitution reactions of decacarbonyldimanganese with tertiary phosphorus and arsenic ligands

Abstract

Thermal or photochemical reactions of [Mn₂(CO)₁₀] with L produce [Mn₂(CO)₉L] for L = PMe₂Ph, AsMe₂Ph, and PMePh₂, diaxially substituted [Mn₂(CO)₈L₂] for L = PMe₂Ph,PMePh₂,PPh(OMe)₂, and PPh₂(OMe) and diequatorially substituted [Mn₂(CO)₈L₂] for L = AsMe₂Ph, AsEt₃, and AsMe₃. The diequatorial product [Mn₂(AsMe₂Ph)₂(CO)₈] undergoes ligand exchange with PPh(OMe)₂ and P(OMe)₃ to give diaxial [Mn₂(CO)₈L₂][L = PPh(OMe)₂ and P(OMe)₃]. Thermal reactions of [Mn₂(CO)₁₀] with an excess of L [L = PMePh₂,PEtPh₂,PMe₂Ph, PPh(OMe)₂, and P(OMe)₃] in high boiling solvents give the hydrido-complexes mer-trans-[Mn(CO)₃HL₂] which are more conveniently prepared using Na[BH₄] in refluxing ethanol. Treatment of the hydrides with HPF₆ in acetonitrile gives the salts [Mn(CO)₃(NCMe)L₂][PF₆]. Other cationic complexes of formula [Mn(CO)₅L][PF₆][L = CO, P(OMe)₃, PPh(OMe)₂, or PPh₂(OMe)] are produced from reactions of [Mn₂,(CO)₈L₂] with NOPF₆ in dichloro-methane. Bromination of [Mn₂(CO)₈L₂][L = PPh(OMe)₂ or PPh₂(OMe)] produces trans-[MnBr(CO)₄L] which isomerise to cis-[MnBr(CO)₄L] in refluxing chloroform. Infrared and ¹H n.m.r. data for all the complexes prepared are discussed.