REACTIONS OF [RU-3(CO)(10)(MU-PH(2)PCH(2)PPH(2))] WITH SECONDARY PHOSPHINES R(2)PH INVOLVING BULKY SUBSTITUENTS (R =(T)BU, 1-AD, CY) - X-RAY CRYSTAL-STRUCTURES OF )(6)(MU-H)(2)(MU-PCY(2))(2)(MU-PH(2)PCH(2)PPH(2))] AND THE ELECTRON-DEFICIENT CARBONYL CLUSTER )-H)(MU-H)(MU-P(T)BU(2))(2)(MU-PH(2)PCH(2)PPH(2))]

The reaction of [Ru-3(CO)(10)(mu-dppm)] (1) with secondary phosphines R(2)PH (R = (t)Bu, 1-Ad) in heptane under reflux leads to the electron -deficient metal cluster complexes CO)(CO)(4)(mu(3)-H)(mu-H)(mu-PR(2)) (2)(mu-dppm)](R = (t)Bu 4; R = 1-Ad 5) in good yields. The reactions y ield first the monosubstituted compounds [Ru-3(CO)(9)(R(2)PH)(mu-dppm) ](R = (t)Bu, 2; R = 1-Ad 3), which could be isolated in yields up to 8 5% after 1 h in refluxing THF. The related reaction of 1 with the less bulky phosphine Cy(2)PH in heptane under reflux gave the new electron ically saturated complex [Ru-3(CO)(6)(mu-H)(2)(mu-PCy(2))(2)(mu-dppm)] (7). In this case the intermediate [Ru-3(CO)(9)(Cy(2)PH)(mu-dppm)] (6 ) could also be isolated. Compounds 4 and 5 seem to be coordinatively saturated, in that no reaction with carbon monoxide or dihydrogen was observed, either under normal conditions or under elevated pressure. T he molecular structures of 4 and 7 were determined by single-crystal X -ray studies (dppm = Ph(2)PCH(2)PPh(2); Ad = Adamantyl).