ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The oxidation of trans-stilbene, phenylacetylene, and diphenylacetylene by Tl(OAc)3 in aqueous acetic acid medium in the presence of HClO4 follows the rate law \documentclass{article}\pagestyle{empty}\begin{document}$$ -\frac{{d[{\rm TI(OAc})_3]}}{{dt}} = k_2 [{\rm substrate}][{\rm TI(OAc}_3)]H_0 $$\end{document} in [H+] of 0.1-1.0M, the [H+] dependence below 0.1M being marginal. The reactions are strongly dielectric dependent. The order of reactivity among the substrates is styrene 〉 phenylacetylene and trans-stilbene 〉 diphenylacetylene. A mechanism involving the oxythallation adduct by the Tl+(OAc)2 species has been discussed. The use of Ru(III) as a homogeneous catalyst brings a change in the kinetic orders for trans-stilbene, the rate law being \documentclass{article}\pagestyle{empty}\begin{document}$$ -\frac{{d[{\rm TI(OAc})_3]}}{{dt}} = \frac{{kK[{\rm substrate}][{\rm Ru(III})][{\rm TI(OAc})_3]^\circ }}{{1 + K[{\rm substrate}]}} $$\end{document} The formation constants K for the Ru(III)-alkene π complex at 40, 50, and 60°C are 90.14M-1, 105.2M-1, and 127.7M-1, respectively. Interestingly the oxidation of phenylacetylene and diphenylacetylene does not undergo catalysis by Ru(III). The mechanism involving the metal-arene π complex is discussed.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550150609
