ALKYNE, TRIORGANOSILYL, AND TRIORGANOSTANNYL DERIVATIVES OF ANIONIC TRIRUTHENIUM CARBONYL CLUSTER COMPLEXES CONTAINING BRIDGING PYRAZOLYL LIGANDS

The anionic cluster complex [Ru-3(mu-H)(mu-CO)(CO)(10)](-) reacts with 3,5-dimethylpyrazole (Hdmpz) to give [Ru-3(mu-dmpz)(mu-CO)(3)(CO)(7)](-) (1) in high yield. The reactivity of complex 1 with protic acids, alkynes, tertiary silanes, and tertiary stannanes is described. Complex 1 reacts with trifluoroacetic acid to give the known neutral hydride derivative [Ru-3(mu-H)(mu-dmpz)(CO)(10)] (2). With diphenylacetylene, complex 1 gives [Ru-3(mu-dmpz)(mu(3)-Ph(2)C(2))(mu-CO)(2)-(CO)(6)](-) (3), in which the alkyne ligand interacts with the three ruthenium atoms. An X-ray structure analysis of [PPN]3 is reported. Complex 2 reacts with 2 equiv of tertiary silanes or stannanes to give [Ru-3(mu-dmpz)(mu-H)(2)(ER(3))(2)(CO)(8)](-) (ER(3) = Sift(3) (4), Si(OMe)(3) (5), SiPh(3) (6), SnBu(3) (7), SnPh(3) (8)). Their spectroscopic data (IR, H-1 and C-13 NMR) indicate that the structure of the dihydrido disilyl complexes 4-6 (C-1 symmetry) is different from that of the dihydrido distannyl derivatives 7 and 8 (C-s symmetry). Compound 1 does not promote the hydrosilylation of alkynes; in fact, the reaction of complex 3 with tertiary silanes affords cis- and trans-stilbene as the only alkyne-derived products, and complexes 4-8 do not react with phenyl- or diphenylacetylene. All anionic cluster complexes have been prepared as[Et(4)T](+) and [PPN](+) salts.