An ‘open’ transition state in the transfer reaction of a neutral phosphoryl group between phenolate anions

Abstract

A Brønsted exponent (β_nuc) of 0.12 has been obtained for reaction of seventeen substituted phenolate ions with 2,4-dinitrophenyl diphenyl phosphate in methanol/water solution. The Leffler α value for P–O bond formation (0.09) indicates that the transition-state of the symmetrical concerted reaction of 2,4-dinitro phenolate ion with the ester has 91% of the character of the putative phosphorylium ion intermediate state.