CO substitution and cluster-ligand reductive coupling in the reaction of 2,3-bis(diphenylphosphino)maleic anhydride (bma) with the mixed-metal clusters PhCCo2MCp(CO)(8) (where m = cr, w): Synthesis and x-ray diffraction structures of the phosphido-br

摘要

The ligand substitution behavior of the mixed-metal tetrahedrane clusters PhCCo2MCp(CO)(8) [where M = Cr (1), W (3)] with the diphosphine ligand 2,3-bis(diphenylphosphino) maleic anhydride (bma) has been examined, and the phosphido-bridged clusters Co2MCp(CO) 5[mu(2),eta(2),eta(1)-C(Ph)C=C(PPh2)C(O)OC(O)](mu-P Ph-2) [where M = Cr (2), W (4)] have been confirmed as the principal reaction products. Both 2 and 4 have been isolated and characterized in solution by IR and 31 P NMR spectroscopies, and the molecular structures established by X-ray diffraction analyses. Clusters 2 and 4 each contain 48e- and exhibit triangular Co2M cores that are bridged by a phosphido moiety across the M-Co bond and face-capped by a six-electron mu(2),eta(2),eta(1)-C( Ph)C= C(PPh2)C(O)OC(O) ligand. The reactivity of clusters 1 and 3 with bma is contrasted to the corresponding molybdenum clusters PhCCo2MoCp(CO)(8) and PhCCo2Mo(indenyl)(CO)(8) previously investigated by our groups.