Syntheses and X-ray crystal structures of the tricobalt mono(ethylidyne) clusters Cp*{sub 3}Co{sub 3}({mu}{sub 3}-CCH{sub 3}) ({mu}{sub 3}-CO)({mu}{sub 2}-H), Cp*{sub 3}Co{sub 3}({mu}{sub 3}-CCH{sub 3})({mu}{sub 3}-CNCMe{sub 3})({mu}{sub 2}-H), and Cp*{sub 3}Co{sub 3}({mu}{sub 3}-CCH{sub 3})({mu}{sub 3}-NO)
- Univ. of Wisconsin, Madison, WI (United States)
Cp*{sub 3}Co{sub 3}({mu}{sub 3}-CCH{sub 3})({mu}{sub 3}-H) (3) reacted with CO to form the 1:1 carbonyl ethylidyne adduct Cp*{sub 3}Co{sub 3}({mu}{sub 3}-CCH{sub 3})- ({mu}{sub 3}-CO)({mu}{sub 2}-H) (5) in 82% yield. Similarly, tert-butyl isocyanide reacted with 3 to form the 1:1 isocyanide ethylidyne adduct Cp*{sub 3}Co{sub 3}({mu}{sub 3}-CCH{sub 3})({mu}{sub 3}-CNCMe{sub 3})({mu}{sub 2}-H) (6) in 87% yield. The reaction of 3 with NO formed the nitrosyl ethylidyne cluster Cp*{sub 3}Co{sub 3}({mu}{sub 3}-CCH{sub 3})({mu}{sub 3}-NO) (7) in 84% yield. The structures of clusters 5-7 were determined by X-ray crystallography. Each cluster consists of an equilateral triangle of cobalt atoms symmetrically capped on one face by a {mu}{sub 3}-CCH{sub 3} ligand and capped on the opposite face by a {mu}{sub 3}-CO (5), {mu}{sub 3}-CNCMe{sub 3} (6), or {mu}{sub 3}-NO (7) ligand. Line shape analysis of the Cp* peaks in the variable-temperature {sup 1}H NMR spectra of 5 and 6 allowed measurement of the barrier for migration of the hydride ligand between adjacent pairs of cobalt atoms in 5 [{Delta}G{double_dagger} = 10.3(1) kcal mol{sup -1}] and 6 [{Delta}G{double_dagger} = 12.2(2) kcal mol{sup -1}].
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 457122
- Journal Information:
- Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 12 Vol. 33; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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