Synthesis of a novel α phosphorus containing spin trap, DEPPEPO[5 (diethoxyphosphoryl) 5 phenylethyl 1 pyrroline] N oxide and evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were...Synthesis of a novel α phosphorus containing spin trap, DEPPEPO[5 (diethoxyphosphoryl) 5 phenylethyl 1 pyrroline] N oxide and evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were described in the present article. The ability for trapping an active superoxide anion radicals generated in the HX/XO system and the stability of their spin adduct of DEPPEPO were analyzed. In addition, the effects of 5 phenylethyl and 5 phenyl substituted analogues of DMPO on the stereochemistry of the corresponding spin adducts were systematically illustrated.展开更多
The synthesis of a novel α phosphorus containing spin trap, DEPDMPO(5 diethoxy Phosphoryl 2, 5 dimethyl 1 pyrroline \%N\% oxide) and the evaluation of its ability to spin trap the hydroxyl and the superoxide anion ra...The synthesis of a novel α phosphorus containing spin trap, DEPDMPO(5 diethoxy Phosphoryl 2, 5 dimethyl 1 pyrroline \%N\% oxide) and the evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were described in the present article. The ability to trap an active superoxide anion radical generated in the photo system Ⅱ(PSII) and the stability of their spin adduct of DEPDMPO as well as three previously reported traps DMPO, DEPMPO and M 3PO were comparatively analyzed according to their chemical structures. In addition, the effects of 2 methyl and \%α\% phosphoryl substituted analogues of DMPO on the stabilities of the corresponding spin adduts were systematically展开更多
Two kinds of the phosphorus-centered radicals produced from hydrogen atomion by 2, 2-diphenyl-1-picrylhydrazyl(DPPH were trapped by N-tert-butyl-α-phenylnitrone(PBN) and 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), and ...Two kinds of the phosphorus-centered radicals produced from hydrogen atomion by 2, 2-diphenyl-1-picrylhydrazyl(DPPH were trapped by N-tert-butyl-α-phenylnitrone(PBN) and 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), and investigated by means of EPR spectroscopy. The spin adducts with a characteristic hyperfine coupling constant(hfcc) caused by a phosphorus atom were observed. Based on the hfcc values caused by the phosphorus and hydrogen atoms, the con formational positions of the adducts trapped by PBN and DMPO are discussed.展开更多
It has earlier been noticed that under low pressure, high frequency or microwave discharge can make the organic compound vapors cause chemical reactions, but it is not clear whether these reactions proceed through the...It has earlier been noticed that under low pressure, high frequency or microwave discharge can make the organic compound vapors cause chemical reactions, but it is not clear whether these reactions proceed through the radical mechanism or not. In the past, inferences were usually drawn from the analysis of the final reaction products and not directly proved. Even though they can be measured by ESR now, their ESR spectra are extremely complicated and the sensitivity as well as resolution of the ESR spectrometer used is re-展开更多
In order to f urther improve the photosensitizing activity of hypocrellin B(HB), the complex o f 5,8 di Br HB with Al 3+ was designed and synthesized in high yield. Th e complex of aluminium ion with 5,8 di Br HB is a...In order to f urther improve the photosensitizing activity of hypocrellin B(HB), the complex o f 5,8 di Br HB with Al 3+ was designed and synthesized in high yield. Th e complex of aluminium ion with 5,8 di Br HB is a new water soluble perylene quinonoid derivative with enhanced absorption over HB in the phototherapeutic wi ndow (600-900 nm). Electron paramagnetic resonance (EPR) measurement and 9,10 diphenyl anthracene bleaching methods were used to investigate the photosensiti zing activity of [Al 2(5,8 di Br HB)Cl 4] n in the prese nce of oxygen. Singlet oxygen, superoxide anion radical, hydroxyl radical can be generated by [Al 2(5,8 di Br HB)Cl 4] n photosensit ization. The results showed that the production of hydroxyl radical ( · OH) by [Al 2(5,8 di Br HB)Cl 4] n photosensitization comes from the Fenton Haber Weiss reaction and the decom position of DMPO 1O 2 adduct. Formation of H 2O 2 as one of main intermedi ates in the photogeneration of hydroxyl radical was detected by using the cataly zed oxidation of the DPD reagent by the POD enzyme method. Moreover, the experim ents of EPR spin trap and catalase enzyme excluded the effect of organoperoxide on DPD oxidization. These results further support the proposed mechanism of · OH formation.展开更多
The attitude motion of a dual-spin spacecraft composed of two asymmetric bodies isdiscussed by using the method in Refs. [1-3] in combination with asymptotic expansionequations and averaging algorithm. The nutational ...The attitude motion of a dual-spin spacecraft composed of two asymmetric bodies isdiscussed by using the method in Refs. [1-3] in combination with asymptotic expansionequations and averaging algorithm. The nutational stability is calculated. The dynamic trapstate, i. e. a nonlinear resonance in the attitude motion, is investigated when the spin rateof the rotor comes near that of the relative rotation during the despun process. The presenceof trap state is shown to depend on double transverse inertia asymmetry between the rotorand platform.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
文摘Synthesis of a novel α phosphorus containing spin trap, DEPPEPO[5 (diethoxyphosphoryl) 5 phenylethyl 1 pyrroline] N oxide and evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were described in the present article. The ability for trapping an active superoxide anion radicals generated in the HX/XO system and the stability of their spin adduct of DEPPEPO were analyzed. In addition, the effects of 5 phenylethyl and 5 phenyl substituted analogues of DMPO on the stereochemistry of the corresponding spin adducts were systematically illustrated.
文摘The synthesis of a novel α phosphorus containing spin trap, DEPDMPO(5 diethoxy Phosphoryl 2, 5 dimethyl 1 pyrroline \%N\% oxide) and the evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were described in the present article. The ability to trap an active superoxide anion radical generated in the photo system Ⅱ(PSII) and the stability of their spin adduct of DEPDMPO as well as three previously reported traps DMPO, DEPMPO and M 3PO were comparatively analyzed according to their chemical structures. In addition, the effects of 2 methyl and \%α\% phosphoryl substituted analogues of DMPO on the stabilities of the corresponding spin adduts were systematically
文摘Two kinds of the phosphorus-centered radicals produced from hydrogen atomion by 2, 2-diphenyl-1-picrylhydrazyl(DPPH were trapped by N-tert-butyl-α-phenylnitrone(PBN) and 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), and investigated by means of EPR spectroscopy. The spin adducts with a characteristic hyperfine coupling constant(hfcc) caused by a phosphorus atom were observed. Based on the hfcc values caused by the phosphorus and hydrogen atoms, the con formational positions of the adducts trapped by PBN and DMPO are discussed.
基金Project supported by the National Natural Science Foundation of China.
文摘It has earlier been noticed that under low pressure, high frequency or microwave discharge can make the organic compound vapors cause chemical reactions, but it is not clear whether these reactions proceed through the radical mechanism or not. In the past, inferences were usually drawn from the analysis of the final reaction products and not directly proved. Even though they can be measured by ESR now, their ESR spectra are extremely complicated and the sensitivity as well as resolution of the ESR spectrometer used is re-
文摘In order to f urther improve the photosensitizing activity of hypocrellin B(HB), the complex o f 5,8 di Br HB with Al 3+ was designed and synthesized in high yield. Th e complex of aluminium ion with 5,8 di Br HB is a new water soluble perylene quinonoid derivative with enhanced absorption over HB in the phototherapeutic wi ndow (600-900 nm). Electron paramagnetic resonance (EPR) measurement and 9,10 diphenyl anthracene bleaching methods were used to investigate the photosensiti zing activity of [Al 2(5,8 di Br HB)Cl 4] n in the prese nce of oxygen. Singlet oxygen, superoxide anion radical, hydroxyl radical can be generated by [Al 2(5,8 di Br HB)Cl 4] n photosensit ization. The results showed that the production of hydroxyl radical ( · OH) by [Al 2(5,8 di Br HB)Cl 4] n photosensitization comes from the Fenton Haber Weiss reaction and the decom position of DMPO 1O 2 adduct. Formation of H 2O 2 as one of main intermedi ates in the photogeneration of hydroxyl radical was detected by using the cataly zed oxidation of the DPD reagent by the POD enzyme method. Moreover, the experim ents of EPR spin trap and catalase enzyme excluded the effect of organoperoxide on DPD oxidization. These results further support the proposed mechanism of · OH formation.
基金Project supported by National Natural Science Foundation of China.
文摘The attitude motion of a dual-spin spacecraft composed of two asymmetric bodies isdiscussed by using the method in Refs. [1-3] in combination with asymptotic expansionequations and averaging algorithm. The nutational stability is calculated. The dynamic trapstate, i. e. a nonlinear resonance in the attitude motion, is investigated when the spin rateof the rotor comes near that of the relative rotation during the despun process. The presenceof trap state is shown to depend on double transverse inertia asymmetry between the rotorand platform.
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.
