engleski

Estimating the SN1 rate constants: Solvolytic Reactivity of Carboxylates

The reactivity of carboxylates in SN1 solvolysis reaction has been examined by quantum chemical calculations. The solvolysis rates of the series of X, Y-substituted benzhydryl carboxylates have been measured conductometrically in aqueous solvents. The nucleofuge specific parameters (Nf and sf) of numerous carboxylate nucleofuges have been determined using the special LFER equation log k = sf(Ef + Nf). DFT-PCM model for calculating the reactivities of carboxylates has been developed. The experimental G (activ.) of eleven dianisylmethyl carboxylates have been correlated with the G (aktiv.) for cyclopropane ring opening (concerted with carboxylate departure) of eleven cis-dihydroxycyclopropyl carboxylates, obtained at PCM-M06-2X/AUG-cc-pVTZ level of theory. The very good correlation between the experimental and calculated barriers has been obtained (r = 0.996), enabling prediction of the reactivities (nucleofugalities) for 37 more different carboxylates.

carboxylates; reactivity; nucleofugality; kinetics; dft; pcm

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