SDS对Na2SeO3-GSH-溶解O2体系的作用研究

围绕GSH－Px和Na2SeO3在清除或催化产生ROS过程中可能共同存在的机理，以Na2SeO3-GSH-溶解O2体系为主要研究对象，引入表面活性剂SDS模拟GSH－Px的笼效应，考察其对Na2SeO3体系的影响。结果表明，表面活性剂可抑制该体系中O2^-的产生，并且具有稳定反应中间体GSSeSG的作用，证明了笼效应在GSH－Px及Na2SeO3与GSH反应体系中的重要作用。     

Magnetic Field Effects on Photoreduction Reaction of 2-Methyl-1,4-Naphthoquinone in Brij 35 Micellar Solution with Additional Radical

Introduction In the past three decades, many groups have been concerning and studying magnetic field effects (MFEs) on photoreduction reaction of carbonyl compounds such as benzophenone, benzoquinone and anthraquinone de-rivatives in micellar solutions. The radical pair lifetime and the escaped radical yield increased with the increase of magnetic field strength. The observed MFEs for these systems could be successfully explained by the relaxa-tion mechanism (RM), where the spin relaxation …     

4,4-Dialkyl-substituted N-Methylmorpholinium 3,5-Dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates and Some of Their Properties

4,4-Dialkyl-substituted N-methylmorpholinium 3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates were synthesized by the condensation of 2-alkyl-2-cyanoethyl crotonates with cyanothioacetamide and N-methylmorpholine. They were used for the production of substituted 2-alkylthio-1,4,5,6-tetrahydropyridines, 2-acetylthio-1,4,5,6,-tetrahydropyridine, 6-hydrazino-1,4,5,6-tetrahydropyridine, and 2,3,4,5,6,7-hexahydrothiazolo[3,2-a]pyridine. The structure of 6-bromo-3-bromomethyl-6,8-dicyano-7,7-dimethyl-2,3,4,5,6,7-hexahydrothiazolo[3,2-a]pyridine was proved by X-ray crystallographic analysis.     

Activation Strain Analyses of Counterion and Solvent Effects on the Ion-Pair SN2 Reaction of and CH3Cl

We have computationally studied the bimolecular nucleophilic substitution (S_N2) reactions of M_nNH₂⁽ⁿ⁻¹⁾ + CH₃Cl (M⁺ = Li⁺, Na⁺, K⁺, and MgCl⁺; n = 0, 1) in the gas phase and in tetrahydrofuran solution at OLYP/6-31++G(d,p) using polarizable continuum model implicit solvation. We wish to explore and understand the effect of the metal counterion M⁺ and of solvation on the reaction profile and the stereochemical preference, that is, backside (S_N2-b) versus frontside attack (S_N2-f). The results were compared to the corresponding ion-pair S_N2 reactions involving F⁻ and OH⁻ nucleophiles. Our analyses with an extended activation strain model of chemical reactivity uncover and explain various trends in S_N2 reactivity along the nucleophiles F⁻, OH⁻, and , including solvent and counterion effects. © 2019 Wiley Periodicals, Inc.     

Effects of Solvent, Structure, and Temperature on the Ionization Equilibrium Constants of Phenols and Pyridinium Ions in Mixtures of Water and 1,4-Dioxane

An extensive collection of data has been used to study the effects of solvent, structure, and temperature on the ionization equilibrium constants of some substituted phenols and pyridinium ions in water–1,4-dioxane mixtures (0–70% weight fraction in dioxane) and temperatures ranging from 10 to 50°C. The effects of structure and solvent are explained using Hammett's equation and the Marshall–Quist model at all temperatures. An equation allowing an analysis of the three effects together on the pK values has been developed. The pK data under all experimental conditions fit this equation well, with standard errors of less than 0.3 pH units. Hammett's reaction constant for the ionization of phenols and pyridinium ions has been obtained for all the experimental conditions. The pK and Hammett's reaction constants for the different ionizations in water–1,4-dioxane mixtures correlate well with Kamlet and Taft's solvatochromic parameters ^* and , which measure the dipolarity/polarizability and hydrogen-bonding capacity of the solvent, respectively. These correlations explain more thoroughly the different contributions and origin of the effects of the solvent on the pK.