The reaction between Ru3(CO)12 and the surface of fully or partially hydroxylated magnesia leads to the anionic cluster [HRu3(CO)11]-(Mg2+)1/2 ([HRu3(CO)11]- = -). The presence of - at the surface has been deduced from in situ IR and mass balance experiments; finally - has been extracted from the surface by [PPN]Cl. Formation of - from Ru3(CO)12 occurs also on the surface of zinc and lanthanum oxides. During programmed thermal decomposition of - on magnesia under vacuum or controlled atmosphere, various species have been evidenced depending on temperature and hydroxylation degree of the support: mononuclear RuII(CO)n(OMg<)2 and metallic particles of ruthenium (10-15 Å) covered with undissociated carbon monoxide. Simultaneously, three types of reactions involving the cluster carbonyl ligands occur: water gas shift reaction (which transforms those ligands into CO2 and H2), CO dismutation to CO2 and surface carbon, and methanation. The water gas shift reaction is tentatively attributed to the anionic cluster while the latter two are attributed to the metal particles.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry