Theoretical Study of the Substituent Effects on the S−H Bond Dissociation Energy and Ionization Energy of 3-Pyridinethiol: Prediction of Novel Antioxidant
journal contributionposted on 21.09.2006, 00:00 by Pham Cam Nam, Minh Tho Nguyen, Asit K. Chandra
The S−H bond dissociation enthalpies [BDE(S−H)] of a set of 5-X- and 6-X-3-pyridinethiols (X = F, Cl, CH3, OCH3, NH2, N(CH3)2, CF3, CN, and NO2) have been computed using the density functional theory based (RO)B3LYP procedure with 6-311++G(2df,2p) basis set. The effects of substituents on the BDE(S−H), proton affinity of the pyridinethiol anion [PA(S-)] and ionization energy (IE) are analyzed and their correlations with Hammett's substituent constants are examined. Subsequently, a series of 6-substituted 3-pyridinethiols have been explored to find out their antioxidant potentials. Finally, a number of 3-pyridinethiol based compounds are theoretically proposed as novel antioxidants.