5314-03-4Relevant articles and documents
Experimental and computational determination of Bronsted coefficients for equilibrium transfer of the O,O-dimethyl phosphorothioyl group between oxyanion nucleophiles
Edwards, David R.,Maxwell, Christopher I.,Harkness, Robert W.,Neverov, Alexei A.,Mosey, Nicholas J.,Stan Brown
supporting information; scheme or table, p. 258 - 266 (2012/06/30)
An experimental determination of the βEq value for equilibrium transfer of the O,O-dimethyl phosphorothioyl group between oxyanion nucleophiles in water and methanol at 25 °C is presented. The respective βEq values in the two solvents are experimentally the same at -1.45 ± 0.08 and -1.39 ± 0.12. Based on the observation that the Bronsted correlation for the nucleophilic reaction of phenoxides in water with substrate 1d (dimethyl 4-nitrophenyl phosphorothioate, pKa HOAr of 7.14) is linear over the entire range of phenoxides employed (5.53 ≤ pKaNu ≤12.38), the reaction for phenoxide nucleophiles displacing phenoxide leaving groups is probably concerted. The obtained data allow one to calculate, for a symmetrical transition state involving 2,4,5-trichlorophenoxide as a nucleophile and leaving group, an approximately 60% P-OAr cleavage and about 40% P-Nuc bond formation. A computational method is presented for the rapid prediction of the βEq values for such processes in water and methanol, and the results are compared with known values from the literature. Copyright
