84027-59-8Relevant academic research and scientific papers
Hydrogenation of trimetallic clusters of the iron triad containing bridging carbyne ligands. Reductive cleavage of a triply bridging carbyne
Keister, Jerome B.,Payne, Martin W.,Muscatella, Michael J.
, p. 219 - 225 (1983)
The clusters HM3(μ-COMe)(CO)10 (1) (a, M = Fe; b, M = Ru; c, M = Os), prepared by methylation of the corresponding HM3(μ-CO)(CO)10 monoanion, react with hydrogen to give H3M3(μ3-COMe)(CO)9 (2). This process may be reversed under carbon monoxide. For these and other related carbyne-containing clusters the relative stabilities of HM3(μ-CX)(CO)10-nLn and H3M3(μ3-CX)(CO9-nLn are found to depend upon (i) the metal, (ii) the carbyne substituent X, and (iii) the ligands L. Thus, although 2a is unstable under ambient conditions, reverting nearly quantitatively to 1a, the substituted derivative H3Fe3(μ3-COMe)(CO)7(SbPh 3)2 (5a) can be isolated in fair yield by hydrogenation of 1a in the presence of triphenylantimony. Similarly, although HRu3(μ-CN(Me)CH2Ph)(CO)10 (4) does not react with hydrogen to give a stable product, in the presence of 4 equiv of triphenylantimony H3Ru3(μ3-CN(Me)CH2Ph)(CO) 6-(SbPh3)3 (6) can be prepared in good yield. These observations are rationalized in terms of the relative importance of M3-CX and C-X π-bonding interactions and the relative metal-carbonyl and metal-hydrogen bond strengths. Under more severe conditions reductive cleavage of the carbyne ligand as CH3X can be achieved. At 130°C and 3.5 MPa of 1:1 carbon monoxide-hydrogen, 2b decomposes to dimethyl ether and Ru3(CO)12. This process represents overall reduction of a carbonyl ligand by molecular hydrogen and is made possible by the activation of this carbonyl by methylation. The trends observed for cluster hydrogenation may have implications for potential Lewis acid activation of cluster-bound carbonyl ligands.
