Chiral and Achiral Diphosphine Complexes of Ruthenium(II) Incorporating Labile Nitrile Ligands: Synthesis and Solution Chemistry of Mono- and Dinuclear Derivatives of Ru(2)Cl(4)(PP)(2) (PP = Chelating Diphosphine).
A family of nitrile complexes has been prepared by reaction of Ru(2)Cl(4)(PP)(2) or RuCl(2)(PP)(PPh(3)) (PP = Ph(2)P(CH(2))(4)PPh(2) (dppb), Ph(2)PCH(2)CHOCMe(2)OCHCH(2)PPh(2) (diop), 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (binap)) with MeCN or PhCN, the product formed depending strongly on the reaction conditions. At high nitrile concentrations, the principal species present is RuCl(PP)(RCN)(3)(+)X(-) (X = Cl); the cation can generally be isolated (as the PF(6) salt) by abstraction of the chloride counterion with NH(4)PF(6). Use of 2 equiv of NH(4)PF(6) generates Ru(PP)(RCN)(4)(2+)(PF(6)(-))(2) (PP = dppb). In the absence of a halide-abstracting agent, addition of hexanes or diethyl ether precipitates neutral RuCl(2)(PP)(RCN)(2) species, which undergo further loss of nitrile in the solid state (R = Me) or in solution (R = Me, Ph). Redissolution of the neutral species in chlorocarbon solvents gives Ru(2)Cl(3)(PP)(2)(RCN)(2)(+)X(-) (X = Cl) and, in benzene, Ru(2)Cl(4)(PP)(2)(RCN). The dinuclear cation (X = PF(6)) is also accessible by reaction of RuCl(PP)(RCN)(3)(+)PF(6)(-) with CH(2)Cl(2) or CDCl(3), while the mononitrile can be obtained directly by reaction of Ru(2)Cl(4)(PP)(2) or RuCl(2)(PP)(PPh(3)) with small amounts of nitrile in benzene.
Fogg
Deryn E.
DE
Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada.
James
Brian R.
BR