论文信息 - Deuterium Isotope Effect on the Rate of Ligand Exchange between Tetrakis(acetylacetonato)thorium(IV) and Free Acetylacetone in CD3CN

Deuterium Isotope Effect on the Rate of Ligand Exchange between Tetrakis(acetylacetonato)thorium(IV) and Free Acetylacetone in CD3CN

A deuterium isotope effect on the rate of acetylacetonate exchange between tetrakis(acetylacetonato)thorium(IV), Th(acac)4, and free acetylacetone in CD3CN has been examined by means of 1H NMR technique. The second-order rate constant, k, which is expressed as a function of the observed first-order rate constant, kobsd, and the concentration of acetylacetone in the enol form, [acetylacetone]enol, by k=kobsd/[acetylacetone]enol was determined for the reaction of deuterated acetylacetone, Dacac, as well as undeuterated acetylacetone, Hacac. The ratio of second-order rate constants for Hacac and Dacac, kH⁄kD, was approximately 9. This large deuterium isotope effect strongly supports a mechanism proposed in a previous paper that the proton transfer process is the rate determining step of the whole reaction.

H. Tomiyasu | H. Fukutomi | Tomoe Nakagawa | Naoshi Fujiwara

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