Coordination-Induced Condensation of [Ta6O19]8-: Synthesis and Structure of [{(C6H6)Ru}2Ta6O19]4- and [{(C6H6)RuTa6O18}2(μ-O)]10-

Reaction of [(C6H6)RuCl2](2) and Na-8[Ta6O19] gives two new hybrid organometallic POM complexes, Na-10[{(C6H6)RuTa6O18}(2)(mu-O)]center dot 39.4H(2)O (Na-10-1) and Na-4(trans-[{(C6H6)Ru}(2)Ta6O19]center dot 20H(2)O (Na-4-2). In both cases the half-sandwich fragments {(C6H6)Ru}(2+) are coordinated as additional vertices to the {Ta-3(mu(2)-O)(3)} triangles of the hexatantalate. According to NMR and ESI-MS data, the dimeric complex [{(C6H6)RuTa6O18}(2)(mu-O)](10-) dissociates in water with the formation of monomeric [(C6H6)RuTa6O19](6-) species (1a). X-ray structural characterization and aqueous speciation of the complexes by C-13, H-1, and DOSY NMR; ESI-MS; and capillary electrophoresis (CE) have been carried out.