A glyceride containing three ferulic groups was first synthesized in order to investigate intermolecular synergistic antioxidant activity. The antioxidant activity was evaluated via a radical-scavenging reaction of D...A glyceride containing three ferulic groups was first synthesized in order to investigate intermolecular synergistic antioxidant activity. The antioxidant activity was evaluated via a radical-scavenging reaction of DPPH˙ radical. Although the scavenging capacities of both antioxidants, ferulic acid and glyceride tri-ferulate, were roughly equal, the apparent activation energy(Ea) of 19.50 kJ/mol for glyceride tri-ferulate is obviously lower than that of 28.80 kJ/mol for ferulic acid. The synergistic effect on Ea was further explained by a parallel π-π-stacking interaction.展开更多
L-Tyr-EMPO,a new EMPO analogue bearing an L-tyrosine methyl ether group,was first synthesized by acylation.Various radicals,including O-·2,·OH,·OR,and ·R,have been efficiently detected and characte...L-Tyr-EMPO,a new EMPO analogue bearing an L-tyrosine methyl ether group,was first synthesized by acylation.Various radicals,including O-·2,·OH,·OR,and ·R,have been efficiently detected and characterized via L-Tyr-EMPO.The half-life of the L-Tyr-EMPO superoxide adduct was estimated to be ca.6.5 min.More importantly,the present study demonstrated a new synthetic strategy for covalent conjugation between cyclic-nitrone and amino group in peptides or proteins,by which the site-specifically spin trapping can be performed via antibody linked nitrone in the near future.Furthermore,with the help of the covalent link,the targeting for the areas of interest in which the monitored radical species was sitespecially generated.展开更多
Six linear nitrones,three DBN derivatives and their phosphoryl analogues,were first synthesized in this article,and the structures of their O-·2-spin trapping products,the nitroxides,were theoretically and experi...Six linear nitrones,three DBN derivatives and their phosphoryl analogues,were first synthesized in this article,and the structures of their O-·2-spin trapping products,the nitroxides,were theoretically and experimentally analyzed.The theoretical calculations on the optimized geometries of the spin adducts,using DFT method at B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level,demonstrated that both the intromolecular H-bonds and their internal rotations around C—N bond are the key factors for stabilizing the spin adducts.展开更多
由于拥有―C(O)S―和―NCO基团,FC(O)SNCO的分子和电子结构是非常有趣的.利用FC(O)SCl和Ag NCO制备了FC(O)SNCO,并利用He I光电子能谱(PES)、光电离质谱(PIMS)以及理论计算研究了其分子和电子结构.通过将实验、理论计算以及自然键轨道(N...由于拥有―C(O)S―和―NCO基团,FC(O)SNCO的分子和电子结构是非常有趣的.利用FC(O)SCl和Ag NCO制备了FC(O)SNCO,并利用He I光电子能谱(PES)、光电离质谱(PIMS)以及理论计算研究了其分子和电子结构.通过将实验、理论计算以及自然键轨道(NBO)分析结合起来,获得了FC(O)SNCO的最稳定分子构型.利用外壳层格林函数(OVGF)方法以及与相似化合物的比较,对其光电子能谱进行了指认.理论计算表明,对于中性分子最稳定的构型为syn-syn非平面构型,而电离后的离子最稳定构型为syn-syn平面构型.实验结果表明,第一电离能来自于S的孤对电子轨道,为10.33 e V.第二至第六电离能分别为12.03、13.23、13.77、14.78、15.99 e V,并对这些电离能进行了指认.在光电离质谱中产生了六个质谱峰,分别为SN+、FC(O)+、SNCO+、FC(O)SN+、C(O)SNCO+、FC(O)SNCO+,其中FC(O)SNCO+的峰是最强峰.结合HeI光电子能谱和理论计算,对PIMS进行了分析,并研究了可能的电离和解离过程并对其进行了讨论.展开更多
基金supported by the Hundred Talents Fund of Chinese Academy of SciencesNational Natural Science Foundation of China(20703048,20803083,20933008)Center for Molecular Sciences Foundation of Institute of Chemistry,Chinese Academy of Sciences(CMS-LX200902)~~
文摘A glyceride containing three ferulic groups was first synthesized in order to investigate intermolecular synergistic antioxidant activity. The antioxidant activity was evaluated via a radical-scavenging reaction of DPPH˙ radical. Although the scavenging capacities of both antioxidants, ferulic acid and glyceride tri-ferulate, were roughly equal, the apparent activation energy(Ea) of 19.50 kJ/mol for glyceride tri-ferulate is obviously lower than that of 28.80 kJ/mol for ferulic acid. The synergistic effect on Ea was further explained by a parallel π-π-stacking interaction.
基金supported by the National Natural Science Foundation of China(21465021,21463023)Key Project of Ministry of Education,China(211189)+1 种基金Natural Science Foundation of Gansu Province,China(1208RJZE139)Program of Gansu Provincial University for Leaders of Disciplines in Science,China(11zx-04)~~
文摘L-Tyr-EMPO,a new EMPO analogue bearing an L-tyrosine methyl ether group,was first synthesized by acylation.Various radicals,including O-·2,·OH,·OR,and ·R,have been efficiently detected and characterized via L-Tyr-EMPO.The half-life of the L-Tyr-EMPO superoxide adduct was estimated to be ca.6.5 min.More importantly,the present study demonstrated a new synthetic strategy for covalent conjugation between cyclic-nitrone and amino group in peptides or proteins,by which the site-specifically spin trapping can be performed via antibody linked nitrone in the near future.Furthermore,with the help of the covalent link,the targeting for the areas of interest in which the monitored radical species was sitespecially generated.
文摘Six linear nitrones,three DBN derivatives and their phosphoryl analogues,were first synthesized in this article,and the structures of their O-·2-spin trapping products,the nitroxides,were theoretically and experimentally analyzed.The theoretical calculations on the optimized geometries of the spin adducts,using DFT method at B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level,demonstrated that both the intromolecular H-bonds and their internal rotations around C—N bond are the key factors for stabilizing the spin adducts.
基金supported by the National Natural Science Foundation of China(91645203,21773253)China Postdoctoral Science Foundation(2017M611002)+1 种基金Beijing Natural Science Foundation,China(2182092)Youth Innovation Promotion Association,Chinese Academy of Sciences(2018041)~~
基金supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB05010400)National NaturalScience Foundation of China(41105085,21073051)Natural Science Foundation of Hebei Province,China(B2010000368)~~
文摘由于拥有―C(O)S―和―NCO基团,FC(O)SNCO的分子和电子结构是非常有趣的.利用FC(O)SCl和Ag NCO制备了FC(O)SNCO,并利用He I光电子能谱(PES)、光电离质谱(PIMS)以及理论计算研究了其分子和电子结构.通过将实验、理论计算以及自然键轨道(NBO)分析结合起来,获得了FC(O)SNCO的最稳定分子构型.利用外壳层格林函数(OVGF)方法以及与相似化合物的比较,对其光电子能谱进行了指认.理论计算表明,对于中性分子最稳定的构型为syn-syn非平面构型,而电离后的离子最稳定构型为syn-syn平面构型.实验结果表明,第一电离能来自于S的孤对电子轨道,为10.33 e V.第二至第六电离能分别为12.03、13.23、13.77、14.78、15.99 e V,并对这些电离能进行了指认.在光电离质谱中产生了六个质谱峰,分别为SN+、FC(O)+、SNCO+、FC(O)SN+、C(O)SNCO+、FC(O)SNCO+,其中FC(O)SNCO+的峰是最强峰.结合HeI光电子能谱和理论计算,对PIMS进行了分析,并研究了可能的电离和解离过程并对其进行了讨论.
