Synthesis, Reactivity, and Structural Characterization of Octahedral Ruthenium(II) Complexes with Small Molecules Containing Hemilabile Ether-Phosphine Ligands

Article abstract of DOI:10.1021/ic00128a023

The octahedrally coordinated bis(ether-phosphine)ruthenium(II) complexes Cl2Ru(PO)2 (1a-c) (PO, η2(O,P)-chelated ether-phosphine; a, Ph2PCH2CH2OCH3; b, Ph2PCH2C4H7O2; c, Cy2PCH2CH2OCH3) represent potentially unsaturated 14-electron metal species which are weakly protected by intramolecular chelation of the ether moiety. The ease of Ru-O bond cleavage isshown by the reaction with a variety of small molecules. Sulfur dioxide, acetonitrile, and tert-butyl isocyanide are readily added to 1a-c to generate the corresponding complexes Cl2Ru(P.apprx.O)(PO)(η1-SO2) (2a-c) (P.apprx.O, η1(P)-coordinated ether-phosphine), Cl2Ru(CH3CN)(P.apprx.O)(PO) (4a-c), and Cl2Ru(CNCMe3)2(P.apprx.O)2 (8a-c), respectively.The action of carbon disulfide on 1c affords an insertion into the Ru-Pbond to give the phosphoniodithiocarboxylato complex Cl2Ru(S2CP.apprx.O)(PO) (5c). Phenylacetylene is activated by the starting complexes 1a-c to yield the vinylidene compounds Cl2Ru(=C=CHPh)(P.apprx.O)(PO) (3a-c). All complexes are accessible under moderate reaction conditions in almost quantitative yields. The fluxional behavior of a variety of substrate complexes in solution was investigated by temperature-dependent (31)P{(1)H} NMR spectroscopy. Remarkably, the vinylidene complexes 3a,b show complex exchange phenomena which account for two dynamic processes. The structures of 2a, 3a, 3c, trans-Cl2Ru(CNCMe3)(P.apprx.O)(PO) (9a), and cis-Cl2Ru(CNCMe3)(P.apprx.O)(PO) (1Ob) were determined by single-crystal X-ray diffraction. Aside from the coordinated small molecules, the structures of 3c and 9a are similar with trans-arranged phosphines, whereas 2a, 3a, and 1Ob are set up with cis-positioned phosphines. 2a and 1Ob crystallize in the monoclinic space group P21/c with Z = 4, and 3a, 3c, and 9ahave the triclinic space group P1- with Z = 2. The cell dimensions are as follows: for 2a, a = 18.991(7) ?, b = 9.717(3) ?, c = 19.930(6) ?, β = 110.94(3)°; for 3a, a = 9.687(1) ?, b = 11.768(2) ?, c = 16.386(2) ?, α = 103.08(1)°, β = 103.84(1)°, γ = 91.37(1)°; for 3c, a = 12.420(2) ?, b = 12.621(2) ?, c = 13.556(2) ?, α = 91.66(3)°, β = 101.34(3)°, γ = 110.11(3)°; for 9a, a =9.416(2) ?, b = 12.791(2) ?, c = 15.665(4) ?, α = 79.39(2)°, β = 76.59(2)°, γ = 78.43(1)°; for 1Ob, a = 9.870(3) ?, b = 11.171(4) ?, c = 34.778(14) ?, β = 93.27(4)°.