Surface supported metal cluster carbonyls. Chemisorption decomposition and reactivity of Rh4(CO)12 supported on silica and alumina
| Autor: | Albert Theolier, G. M. Zanderighi, Rinaldo Psaro, Michel Leconte, A.K. Smith, Jean-Marie Basset, Renato Ugo |
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| Rok vydání: | 1980 |
| Předmět: |
Organic Chemistry
Inorganic chemistry chemistry.chemical_element Biochemistry Decomposition Oxygen Rhodium Inorganic Chemistry Metal chemistry.chemical_compound Nucleophile chemistry Chemisorption visual_art Materials Chemistry visual_art.visual_art_medium Reactivity (chemistry) Physical and Theoretical Chemistry Carbon monoxide |
| Zdroj: | Journal of Organometallic Chemistry. 191:415-424 |
| ISSN: | 0022-328X |
| Popis: | Chemisorption of Rh 4 (CO) 12 on to a highly divided silica (Aerosil “0” from Degussa), Leads to the transformation: 3 Rh 4 (CO) 12 → 2 Rh 6 (CO) 16 + 4 CO. Such an easy rearrangement of the cluster cage implies mobility of zerovalent rhodium carbonyl fragments on the surface. Carbon monoxide is a very efficient inhibitor of this reaction, and Rh 4 (CO) 12 is stable as such on silica under a CO atmosphere. Both Rh 4 (CO) 12 and Rh 6 (CO) 16 are easily decomposed to small metal particles of higher nuclearity under a water atmosphere and to rhodium(I) dicarbonyl species under oxygen. From the Rh I (CO) 2 species it is possible to regenate first Rh 4 (CO) 12 and then Rh 6 (CO) 16 by treatment with CO ( P co ⩾ 200 mm Hg) and H 2 O ( P H 2 O ⩾ 18 mm Hg). The reduction of Rh I (CO) 2 surface species by water requires a nucleophilic attack to produce an hypothetical [Rh(CO) n ] m species which can polymerize to small Rh 4 or Rh 6 clusters in the presence of CO but which in the absence of CO lead to metal particles of higher nuclearity. Similar results are obtained on alumina. |
| Databáze: | OpenAIRE |
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