Antioxidant Properties of Kynurenines: Density Functional Theory Calculations
Fig 3
BDE, IP, and k(T) values of kynurenines in the gas phase and water solution.
(a) BDE values. (b) IP values. (c) k(T) values (in logarithmic form). Blue–the gas phase, red–water solution. BDE (IV) rankings for H-atom in the gas phase are nearly the same as for BDE/BDECOR (II, III). BDE is abnormally high for two symmetric compounds, phenol and DTBP. DTBA have much lower BDE, which is in agreement with its high antioxidant power. BDE for DIBP and DIBA are close to those for DTBA and, presumably, the true BDE value for DTBP. For the uncharged kynurenines with the OH group, BDE is maximal for KYNAENOL and minimal for DXAN, both in the gas phase and in water solution. XAA and KYNA have smaller BDE in oxo form than in enol form.