Photochemical reactivity of the triosmium cluster 1,1-Os-3(CO)(10)(bpcd) in the presence of P(OEt)(3) and X-ray crystal structure of HOs3(CO)(7)[P(OEt)(3)][mu-{PPh(C6H4)}C=C(PPh2)C(O)CH2C(O)]: Unexpected ortho metalation and cluster face capping by a

摘要

Photochemical activation of the bpcd-chelated cluster 1,1-Os-3(CO)(10)(bpcd) (1) in the presence of P(OEt)(3) furnishes the simple substitution product 1,1,2- Os-3(CO)(9)[P(OEt)(3)](bpcd) (2) initially, followed by the formation of the hydride cluster HOs3(CO)(7)[P(OEt)(3)][mu- {PPh(C6H4)} C=C(PPh2) C(O) CH2C(O)] ( 3). Both new clusters were isolated and characterized in solution by IR and NMR (H-1 and P-31) spectroscopies, with the solid-state structure of cluster 3 determined by X-ray diffraction analysis. Cluster 3 crystallizes in the triclinic space group P-1, a = 9.366( 2) angstrom, b = 14.182(4) angstrom, c= 17.672(4) angstrom, alpha = 87.787(4)degrees, beta = 78.488(4)degrees, gamma = 71.785(4)degrees, V = 2184.1( 9) angstrom(3), Z = 2, D-cacl = 2.123 Mg/m(3); R = 0.0488, R-w = 0.1059 for 8527 observed reflections with I > 2 sigma( I). The presence of the seven-electron ligand mu-P{Ph(C6H4)} C=C(PPh2) C(O) CH2C(O) that caps one of the triangular faces in 3 through both phosphine moieties, the pi bond of the dione ring, and an ortho-metalated aryl ligand is established.