Vinyliden-Uebergangsmetallkomplexe XV. Mesitylen-Osmiumkomplexe mit Hydrido-, Carboxylato-, Carbonyl- und Vinyliden-Liganden

Article abstract of DOI:10.1016/0022-328X(91)86154-I

The complexes (Mes)Os(L)Cl2 (L = MeCN, PPh3, PⁱPr3, PMe^tBu2) have been prepared in excellent yield from <(Mes)OsCl2>_n (1) and ligand L.Reaction of 1 with excess CH3CO2Ag or CF3CO2Ag leads to the formation of the bis(carboxylato)osmium compounds (Mes)Os(η²-O2CCH3)(η¹-O2CCH3) and (Mes)Os(η²-O2CCF3)(η¹-O2CCF3).Treatment of 1 with an equimolar amount of silver acetate gives the complex (Mes)Os(η²-O2CCH3)Cl.The monohydrido compounds (Mes)OsH(L)Cl (L = PMe3, PⁱPr3, PPh3, DMSO) are obtained from (Mes)Os(L)Cl2 by three different routes.Reaction of(Mes)OsH2(PMe3) with HBF4 at -78 deg C in ether gives the BF4 salt of the cation <(Mes)OsH3(PMe3)>⁺, which according to the T₁ value of > 2 s has a classical hydride structure.On protonation of (Mes)OsH(PⁱPr3)Cl with HBF4, the coordinatively unsaturated cation <(Mes)Os(PⁱPr3)Cl>⁺ is formed which spontaneously reacts with CO and CH3C<*>CH to give the complexes <(Mes)Os(CO)(PⁱPr3)Cl>⁺ and <(Mes)Os(=C=CHMe)(PⁱPr3)Cl>⁺, respectively.The synthesis of the compounds <(Mes)Os(CO)(PR3)Cl>PF6 (R = Me, ⁱPr, Ph) and <(Mes)Os(=C=CHMe)(PMe^tBu2)Cl>PF6, using (Mes)Os(PR3)Cl2 as starting material, is also described.On deprotonation of <(Mes)Os(=C=CHMe)(Pr3)Cl>⁺, the alkynyl osmium complexes (Mes)Os(C<*>CMe)(PR3)Cl (PR3 = PⁱPr3, PMe^tBu2) are obtained.