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 [Ru-3(CO)(6)(mu-H)(2)(mu-PCy(2))(2)(mu-Ph(2)PCH(2)PPh(2))] and the electron-deficient carbonyl cluster [Ru-3(mu-CO)(CO)(4)(mu(3)-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 [Ru-3(mu-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 yield 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 85% 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 electronically 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. The molecular structures of 4 and 7 were determined by single-crystal X-ray studies (dppm = Ph(2)PCH(2)PPh(2); Ad = Adamantyl).