REACTIONS OF THE HEXANUCLEAR MIXED-METAL CLUSTER [RU5RHC(CO)(14)(ETA(5)-C(5)ME(5))] AND THE SYNTHESIS, CHARACTERIZATION AND STRUCTURAL-ANALYSIS OF THE PENTANUCLEAR DERIVATIVE [RU4RHC(CO)(12)(ETA(5)-C(5)ME(5))]

Treatment of the hexanuclear cluster [Ru5RhC(CO)(14)(eta(5)-C(5)Me(5)) ] 1 with 80 atmospheres of CO under 80 degrees C resulted in a series of decapping reactions yielding the complexes. [Ru-3(CO)(12)]. [Ru5C(C O)(15)] and a new green compound [Ru4RhC(CO)(12)(eta(5)-C(5)Me(5))] 2. Cluster 2 crystallises in the monoclinic space group P2(1)/n with a = 19.180(3), b = 13.940(3) and c = 10.728(2) Angstrom. beta = 97.157(2) degrees. The five metal atoms adopt a square-based pyramidal metal fra mework [Ru-Ru 2.776(1)-2.873(1). Ru-Rh 2.798(1)-2.881(1) Angstrom]. Th e octahedral cluster [Ru5RhC(CO)(13)(eta(5)-C(5)Me(5))] 1 reacted at r oom temperature with a methanolic base to yield the methoxide adduct [ Ru5RhC(CO)(13)(CO(2)Me)(eta(5)-C(5)Me(5))](-) 3 which on acidification immediately regenerated the parent compound. On prolonged stirring, c luster 1 reacted irreversibly with the methanolic base to form the sal t N(PPh(3))(2)](2)[Ru5RhC(CO)(13)(eta(5)-C(5)Me(5))] 4.