6533b861fe1ef96bd12c455f

RESEARCH PRODUCT

Azolium and acetate ions in DMF: Formation of free N-heterocyclic carbene. A voltammetric analysis

Francesca D'annaCarla RizzoAchille InesiLuigi OrnanoIsabella ChiarottoMarta Feroci

subject

Cyclic voltammetryNHCInorganic chemistryTetrabutylammonium acetate010402 general chemistryAcetic acid01 natural sciencesMedicinal chemistryIonlcsh:ChemistryBenzaldehydeAcetic acidchemistry.chemical_compoundDeprotonationBenzoinElectrochemistryBenzoin condensationBenzoin condensation010405 organic chemistryChemistry0104 chemical sciencesAzolium saltslcsh:Industrial electrochemistrylcsh:QD1-999Acetic acid; Azolium salts; Benzoin condensation; Cyclic voltammetry; NHC; Tetrabutylammonium acetate; ElectrochemistryAzolium saltCyclic voltammetryCarbenelcsh:TP250-261

description

In order to reveal the possible formation of free N-heterocyclic carbene (NHC) in DMF-azolium and acetate solutions, the proton exchange equilibrium between azolium cations and CH3COO− was investigated (by cyclic voltammetry) by adding CH3COOH or tetrabutylammonium acetate to DMF solutions of imidazolium or thiazolium salts of different acidity.The voltammetric analysis confirms that the deprotonation of the azolium cation by CH3COO− (with the formation of free NHC) is significant in the case of the more acidic thiazolium cations, while it is not effective with the less acidic imidazolium ones.Accordingly, the NHC-catalyzed benzoin condensation was carried out in DMF solutions of azolium salts, tetrabutylammonium acetate, and benzaldehyde. Benzoin was isolated only starting from the more acidic thiazolium salts. Keywords: Cyclic voltammetry, NHC, Azolium salts, Tetrabutylammonium acetate, Acetic acid, Benzoin condensation

yearjournalcountryeditionlanguage
2016-06-01
10.1016/j.elecom.2016.03.012http://hdl.handle.net/11573/867532