Change of the tautomeric preference for radical cation of pyruvic acid. DFT studies in the gas phase

Subject Areas : Journal of the Iranian Chemical Research

Ewa Daniela Raczyńska ^{1 *} , Malgorzta Hallmann ² , Kinga Duczmal ³

1 - Department of Chemistry, Warsaw University of Life Sciences, 02-776 Warszawa, Poland
2 - Department of Chemistry, Warsaw University of Life Sciences, 02-776 Warszawa, Poland
3 - Department of Chemistry, Warsaw University of Life Sciences, 02-776 Warszawa, Poland

Received: 2008-07-01 Accepted : 2008-10-06 Published : 2008-11-30

Keywords: DFT, Pyruvic acid, Keto-enol tautomerism, Ionization effect,

Abstract :

Keto-enol tautomerism was investigated for ionized pyruvic acid using the DFT(B3LYP) method and the larger basis sets [6-31++G(d,p), 6-311++G(3df, 3pd) and aug-cc-pVDZ]. Change of the tautomeric preference was observed when going from the neutral to ionized tautomeric mixture. Ionization favors the enolization process (ketoenol) of pyruvic acid, whereas the ketonization (ketoenol) is preferred for the neutral system. Ionization influences also -electron delocalization, which increases exceptionally in the enol form, and slightly decreases in the keto form.