Site-selective ligand substitution in CoRu(CO)7(μ-PPh2) using (Z)-Ph2PCH=CHPPh2 and reactivity of DMAD with CoRu(CO)5[(Z)-Ph2PCH=CHPPh2](μ-PPh2).: X-ray structures of CoRu(CO)5[(Z)-Ph2PCH=CHPPh2](μ-PPh2) and CoRu(CO)3(μ-CO)[(Z)-Ph2PCH=CHPPh2] [μ, η3-Ph2PC(CO2Me)C(CO2Me)]

The heterometallic complex CoRu(CO)(7)(mu-PPh2) (1) reacts with the diphosphine ligand (Z)-Ph2PCH=CHPPh2 under both thermolysis and Me3NO activation to furnish CoRu(CO)(5)[(Z)-Ph2PCH=CHPPh2](mu-PPh2) (2) in good yield. Treatment of 2 with dimethyl acetylenedicarboxylate (DMAD) at elevated temperature leads to the formal insertion of the DMAD ligand into the Co-phosphido bond and formation of the metallocyclic compound CoRu(CO)(3)(mu-CO)[(Z)-Ph2PCH=CHPPh2][mu,eta(3)-Ph2PC(CO2Me)C(CO2Me)] (3) that contains a 5e(-) alkenylphosphine moiety. These new CoRu compounds have been isolated by chromatography and fully characterized in solution by IR and NMR (H-1 and P-31) spectroscopies, and the solid-state structures of both 2 and 3 have been determined by X-ray diffraction analysis. CoRu(CO)(5)[(Z)-Ph2PCH=CHPPh2](mu-PPh2) crystallizes in the monoclinic space group P2(1)/n, a = 11.493(8), b = 20.24(1), c = 17.04(1) Angstrom, beta = 91.03(1)degrees, V = 3964(5) Angstrom(3), Z = 4, D-calc = 1.477 Mg/m(3); R = 0.0475, R-w = 0.1054 for 5120 observed reflections with I > 2sigma(I). CoRu(CO)(3)(mu-CO)(Z)-Ph2PCH=CHPPh2][mu,eta(3)-Ph2PC(CO2Me)C(CO2Me)], as the CH2Cl2 solvate, crystallizes in monoclinic space group P2(1)/c, a = 17.0307(9) Angstrom, b = 11.2124(6) Angstrom, c = 24.083(1) Angstrom, beta = 97.755(1)degrees, V = 4556.8(4) Angstrom(3), Z = 4, D-calc = 1.579 Mg/m(3); R = 0.0379, R-w = 0.0609 for 10774 observed reflections with I > 2sigma(I). The regioselective coordination of the (Z)-Ph2PCH=CHPPh2 ligand to the two equatorial sites of the ruthenium center in 2 and the presence of the metallocyclic alkenylphosphine ligand in 3 are confirmed by the structural studies. The regiochemistry found in the coordination of (Z)-Ph2PCH=CHPPh2 to 1 is contrasted with the related diphosphine ligands bma and bpcd, while the DMAD insertion reactivity with 2 is discussed relative to alkyne reactions reported for the parent compound CoRu(CO)(7)(mu-PPh2).