SYNTHESIS AND SPECTROSCOPIC CHARACTERIZATION OF CLOSO-RU-4(CO)(12)(MU(4),ETA(2)-HC2PH) AND U-4(CO)(9)(MU-CO)(2)(MU(4),ETA(2)-HC2PH)(MU(4)-SE) - CRYSTAL-STRUCTURE OF CLOSO-RU-4(CO)(12)(MU(4),ETA(2)-HC2PH)

Reaction of the chalcogen stabilised butterfly cluster Fe-2(CO)(6){mu- SeC(H)=C(Ph)Se} with Ru-3(CO)(12) occurs under thermal conditions affo rding the clusters FeRu2(CO)(9)(mu-Se)(2) (2), closo-Ru-4(CO)(12)(mu(4 ) eta(2)-HC2Ph) (3) and u-4(CO)(9)(mu-CO)(2)(mu(4),eta(2)-HC2Ph)(mu(4) -Se) (4) in 30%, 22% and 18% yield respectively. They were characteris ed by IR and H-1, C-13 and Se-77 NMR spectroscopy. Compound 3 was furt her characterised by X-ray methods: space group P2(1)/n, a = 20.138(4) , b = 9.333(2), c = 26.219(6) Angstrom, beta = 97.43(2)degrees, Z = 8, rho(calc) = 2.291 gcm(-3). The structure was solved using direct meth ods and was refined to the final values of the residuals R = 0.0377 an d R-w = 0.0455. The molecule consists of a butterfly arrangement of fo ur ruthenium atoms with a quadruply bridged alkyne ligand. Compound 4 was characterised by comparison of its spectroscopic data with that of the analogous S-compound.