Kinetic isotope effects for oxidation reaction of olefins by p-quinones in water-acetonitrile solutions of cationic and chloride anionic palladium complexes

Abstract

Kinetic isotope effects for oxidation reactions of ethylene and cyclohexene in solutions of cationic palladium(ii) complexes in MeCN-H₂O(D₂O) systems, were measured. It was established that the ratio of the initial reaction rates ${{R_0^{H_2 O} } \mathord{\left/ {\vphantom {{R_0^{H_2 O} } {R_0^{D_2 O} }}} \right. \kern-\nulldelimiterspace} {R_0^{D_2 O} }}$ is equal to 1 for both reactions with the use of cationic complexes of the type Pd(MeCN) _x (H₂O)_4−x ²⁺, which differs from oxidation reactions catalyzed by chloride palladium complexes in the same solutions, where the ratio ${{R_0^{H_2 O} } \mathord{\left/ {\vphantom {{R_0^{H_2 O} } {R_0^{D_2 O} }}} \right. \kern-\nulldelimiterspace} {R_0^{D_2 O} }}$ = 5.0±0.16 and 4.73±0.14 at H⁺ molar fraction of 0.48 and 0.16, respectively (H⁺ molar fraction was calculated based on the sum of [H⁺] and [D⁺]).