Ruthenium Carbonyl Clusters in Faujasite Cages:  Synthesis and Characterization

• Published in: Inorganic chemistry Vol. 37; no. 21; pp. 5497 - 5506
• Main Authors: Shen, Guo-Cheng, Liu, An Ming, Ichikawa, Masaru
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 19.10.1998
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic9709990

The synthesis of the intrafaujasite anchoring of ruthenium carbonyl clusters involves the adsorption of metal carbonyl species or metal ion exchange into faujasite cages followed by reductive carbonylation under an atmosphere of CO and H2. The characterization of the structure and properties of these samples was based on a multianalytical approach, including FT-IR, UV−vis, PXRD, and EXAFS spectroscopies, CO/H2 gas chemisorption, and 13CO isotopic exchange. From this study, several key points emerge. (a) [Ru3(CO)12] clusters thermally diffused into dehydrated faujasite cages. (b) [Ru3(CO)12] guests in Na56Y were thermally activated, in a hydrogen atmosphere, generating intrafaujasite [H4Ru4(CO)12]. (c) Hexammineruthenium(III) complexes in Na56X and Na56Y underwent progressive thermal activation, in a CO and H2 atmosphere. The generation process was considered to occur through conversion of the intermediates [Ru(NH3)5(CO)]2+ and RuI(CO)3 to [Ru6(CO)18]2-. (d) A rapid 13CO/12CO isotopic exchange was found to reversibly occur for [Ru6(CO)18]2-/Na56X under H2 coexistence. (e) Internal and external confinement of ruthenium carbonyl clusters were compared. (f) Oxidation fragmentation under an O2 atmosphere and reductive regeneration under a CO and H2 atmosphere were found to reversibly occur for [Ru6(CO)18]2- guests. (g) Intrafaujasite anchoring of ruthenium carbonyl clusters showed a strong interaction with the extraframework Na+ α-cage cations, through involvement of the oxygen end of the bridging or equatorial terminal carbonyl ligands.