Altered mechanisms of reactions ofphosphate esters bridging a dinuclear metal center
Document Type
Article
Journal/Book Title
Journal of the American Chemical Society
Publication Date
2004
Volume
126
First Page
11864
Last Page
11869
Abstract
Kinetic isotope effects in the nucleophile and leaving group were obtained for the reaction of p-nitrophenyl phosphate monoester coordinated to a dinuclear Co(III) complex. The metal complex of the p-nitrophenyl phosphate monoester was found to hydrolyze by a single-step concerted mechanism, with significant nucleophilic participation in the transition state. By contrast, the hydrolysis of uncomplexed p-nitrophenyl phosphate occurs by a very loose transition state with little bond formation to the nucleophile. Previously, the metal complex of the diester methyl-p-nitrophenyl phosphate was found to hydrolyze via a two-step addition−elimination mechanism, in contrast to the concerted hydrolysis mechanism followed by uncomplexed diesters with the p-nitrophenolate leaving group. These results show that coordination to a metal complex can significantly alter the mechanism of phosphoryl transfer.
Recommended Citation
T. Humphry, M. Forconi, N. H. Williams and A. C. Hengge. “Altered mechanisms of reactions of phosphate esters bridging a dinuclear metal center” J. Am. Chem. Soc., 2004, 126, 11864-11869.
