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.