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https://doi.org/10.5562/cca3040

Nucleofugality of Pentafluorophenolate in Various Solvents: Solvolytic Behavior of Phenolates

Mirela Matić ; University of Zagreb, Faculty of Pharmacy and Biochemistry, Ante Kovačića 1, HR-10000 Zagreb, Croatia
Nives Bebek ; University of Zagreb, Faculty of Pharmacy and Biochemistry, Ante Kovačića 1, HR-10000 Zagreb, Croatia
Bernard Denegri orcid id orcid.org/0000-0001-6335-6723 ; University of Zagreb, Faculty of Pharmacy and Biochemistry, Ante Kovačića 1, HR-10000 Zagreb, Croatia
Olga Kronja ; University of Zagreb, Faculty of Pharmacy and Biochemistry, Ante Kovačića 1, HR-10000 Zagreb, Croatia


Puni tekst: engleski pdf 1.853 Kb

str. 355-362

preuzimanja: 1.047

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Sažetak

The leaving group ability (nucleofugality) of the pentafluorophenolate anion has been determined from first order solvolytic rate constants (k) of X,Y-substituted benzhydryl pentafluorophenolates measured in a series of solvents, by using the three parameter LFER equation: log k = sf (Ef + Nf). Comparison with other leaving groups reveals that pentafluorophenolate is a moderate leaving group, whose nucleofugality (Nf value) is between the nucleofugalities of phenyl carbonate and 3,5-dinitrobenzoate leaving groups. However, due to its high reaction constant (sf = 1.29 in 80 % aq. ethanol), relative reactivities of benzhydryl pentafluorophenolates and corresponding benzhydryl carboxylates vary with the electrofugality of a carbocation formed in the heterolytic step, i.e., inversion of the reactivity of benzhydryl series with different leaving groups occurs. The plots of Δ‡G° vs. ΔrG° for solvolysis of benzhydryl phenolates and carboxylates reveal that phenolates solvolyze over the lower Marcus intrinsic barrier than corresponding carboxylates.

This work is licensed under a Creative Commons Attribution 4.0 International License.

Ključne riječi

nucleofugality; leaving group; LFER; phenolate; intrinsic barrier; solvolysis

Hrčak ID:

172243

URI

https://hrcak.srce.hr/172243

Datum izdavanja:

28.9.2016.

Posjeta: 1.664 *