STUDY OF ELECTROCHEMICAL BETANIDIN OXIDATION PATH USING COMPUTATIONAL METHODS

GAVILAN ARRIAZU, E M; RODRIGUEZ, S A

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Año: 2022

1463-9076

Betalains can be used in food, drugs, and cosmetic industries and have shown their bioactive potential. For these reasons, unraveling their oxidation mechanism is of high importance and demands a systematic and multidisciplinary study. Moreover, the properties commented above are drastically influenced by pH and other physicochemical conditions. Betanidin (1) is a relevant molecule of this family and is crucial to elucidating the oxidation mechanism in which its pigment is involved. In the present study, the pKas and oxidation potential (E°ox) values for all protic groups of 1 were analyzed using the B3LYP/6-31+G(d,p)/SMD as computational methodology. Moreover, six explicit water molecules were added to improve the solvation-free energy values. The oxidation mechanism at each pH was constructed and analyzed in deep. On the other hand, cyclic voltammetry simulations allowed to obtain electrochemical data from experiments and englobe the proposed mechanism. In the present work, the main oxidation path of 1 is described and consists of a concerted electron-proton transference followed by a sequential electron and proton transfer to obtain the o-quinone product or a quinone methide molecule.