Kinetics of reactions of hydrogen with [Os3(CO)11(NCMe)] and [Os3(CO)10(NCMe)2]
- 1 January 1989
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 11,p. 2235-2240
- https://doi.org/10.1039/dt9890002235
Abstract
The kinetics of reactions of [Os3(CO)11(NCMe)] with H2 and CO, and of [Os3(CO)10(NCMe)2] with H2, have been studied in the presence of free MeCN. The reactions involve slow dissociation of MeCN from the clusters and subsequent competition between MeCN and H2 or CO for the vacant co-ordination site on the intermediate cluster. Rate constants for nucleophilic attack on [Os3(CO)11] are in the order MeCN > PPh3≈ CO > H2 and temperature-dependence studies provide activation enthalpy and entropy differences. These, together with a value of 1.34 ± 0.03 for the deuterium kinetic isotope effect, are consistent with a simple three-centre transition state for reaction of [Os3(CO)11] with H2. The cluster [Os3H2(CO)10] reacts with MeCN to form [Os3H2(CO)10(NCMe)] and equilibrium data for this reaction have been obtained.Keywords
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