Synthesis of carbido and related derivatives from calcium carbide and ruthenium carbonyl clusters

Reactions between a carbide anion (C-2(2-)) source and ruthenium cluster carbonyls are reported for the first time. The reaction between CaC2 and Ru-3(CO)(12), carried out in thf, affords putative Ca[Ru-10(C)(2)(CO)(24)], which can be converted into [ppn](2)[Ru-10(C)(2)(CO)(24)] (1) in overall 60% yield. The X-ray structure of 1 as its 2CH(2)Cl(2) solvate is described, together with those of the minor products Ru-4(mu(4)-HC2H)(2)(mu-CO)(2)(CO)(9) (3), Ru6C(mu(3)-HC2Me)(CO)(15) (4) and Ru-4(mu(4)-CHCHCO)(mu-CO)(CO)(10)(tmeda) (5). The latter contains an Ru-3 spiked Ru-3 core carrying a CHCHCO ligand; the tmeda chelates the spike Ru atom. The only product from Ru-3(mu-dppm)(CO)(10) and CaC2 is the known compound Ru-6(mu(4)-CCH2)(2)(mu-dppm)(2)(CO)(12) (6), formed in 24% yield.