Estimating flavonoid oxidation potentials: mechanisms and charge-related regression models.

Abstract In this paper, I tested our quadratic regression models for the estimation of flavonoid oxidation potentials based on spin populations, the differences in the net atomic charges between a cation and a neutral flavonoid, between a radical and an anion of a flavonoid, and between a radical and a neutral flavonoid on a larger set of flavonoids (N = 35). By including six new flavonoids (5,6,7-trihydroxyflavone, 3,3’,4’,7-tetrahydroxyflavone, 3,7-dihydroxyflavone, 4’,7-dihydroxyflavone, 4’,5,7-trihydroxyisoflavone, and 6-hydroxyflavone), we created a respectable calibration set of 35 flavonoids with their oxidation potentials all measured at the same conditions by the same experimentalist. The best model was based on the mean values of the three variables using differences in the net atomic charges (R2 = 0.970, S.E. = 0.043), which are connected with the three different mechanisms of electrochemical oxidation, SET-PT, SPLET, and HAT.