Abstract
The rate of reaction of hydrogen with the 17 e- metal centered radical ·Cr(CO)3C5Me5 obeys the third-order rate law d[P]/dt=kobs[·Cr]2[H2] in toluene solution. In the temperature range 20-60°C, kobs=330±30 M-2 s-1, ΔH≠=0±1 kcal mol-1, ΔS≠=-47±3 cal mol-1 deg-1. The rate of oxidative addition is not inhibited by added pressure of CO. The rate of binding of D2 is slower than that of H2: k(H2)/k(D2)=1.18. These results are combined with earlier work to generate a complete reaction profile for hydrogenation of the metal-metal bonded dimer [Cr(CO)3C5Me5]2+H 2→2H-Cr(CO)3C5Me5. A similar reaction profile for Co2(CO)8+H2→2H-Co(CO)4 under high pressures of CO is constructed based on literature data and estimated activation parameters for reaction of the ·Co(CO)4 radical with hydrogen.
Original language | English (US) |
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Pages (from-to) | 23-30 |
Number of pages | 8 |
Journal | Journal of Organometallic Chemistry |
Volume | 586 |
Issue number | 1 |
DOIs | |
State | Published - Jul 31 1999 |
Keywords
- Chromium
- Cobalt
- Free radicals
- Hydrogen
- Oxidative addition
ASJC Scopus subject areas
- Biochemistry
- Inorganic Chemistry
- Organic Chemistry
- Physical and Theoretical Chemistry
- Materials Chemistry