In contrast to the well-known methods for the generation of radical cations, such as radiolysis, electrolysis and single electron transfer reactions, the formation of radical cations by ultrasound is little known. It ...In contrast to the well-known methods for the generation of radical cations, such as radiolysis, electrolysis and single electron transfer reactions, the formation of radical cations by ultrasound is little known. It has been demonstrated that free radicals produced by sonolysis of carbon tetrachloride can be trapped by 2-methyl-2-nitrosopropane and identified by ESR. Recently, unambiguous evidence for the formation of hydroxyl radicals and hydrogen atoms during sonolysis of water by using DMPO(5,5-dimethyl-1-pyrroline-1-oxide)展开更多
he stable radical cation salts of phenothiazine and N-alkyl-phenothiazine(alkyl =methyl , ethyl , isohutyl , isopentyl and benzyl) hexachloroantimonate ,per-chlorate , and iodide were prepared by means of one-electron...he stable radical cation salts of phenothiazine and N-alkyl-phenothiazine(alkyl =methyl , ethyl , isohutyl , isopentyl and benzyl) hexachloroantimonate ,per-chlorate , and iodide were prepared by means of one-electron oxidation with 2 ,2 , 6 ,6-tetramethyl- 4-acetoxypiperidine oxoammonium hexachloroantimonate , perchloricacid, hydrogen peroxide, and molecular iodine, respectively. The radical cationswere characterized using ESR spectroscopy. Conformational analysis based on theESR parameters suggests that the radical cations adopt a planar configuration withthe nitrogen radical as the center.展开更多
The present study deals with the study of some Friedel-Crafts alkylating system and the accurate measurement of hyperfine coupling constants by ESR and ENDOR techniques. The results indicate that the observed ESR spec...The present study deals with the study of some Friedel-Crafts alkylating system and the accurate measurement of hyperfine coupling constants by ESR and ENDOR techniques. The results indicate that the observed ESR spectra are due to polycyclic aromatic radical cations formed from their parent hydrocarbons.It is suggested that benzyl halides produced in the Friedel-Crafts alkylating reaction undergo Scholl condensation reaction to give polycyclic aromatic hydrocarbons, which were converted into the corresponding polycyclic aromatic radical cations in the presence of aluminum chloride.展开更多
Electron transfer reaction between vitamin A (1) and tris(p-bromophenyl)aminium hexachloroautimonate (2) in dichloromethane (DCM) has been investigated by means of UV-VIS absorption and ESR spectroscopy. The title rad...Electron transfer reaction between vitamin A (1) and tris(p-bromophenyl)aminium hexachloroautimonate (2) in dichloromethane (DCM) has been investigated by means of UV-VIS absorption and ESR spectroscopy. The title radical cation formed in the reaction was characterized by a new absorption band around 600 nm and a singlet unresolved ESR spectrum with g factor of 2.0038-2.0039 and line width of 20 G. Further studies indicated that ESR pattern and parameters of the radical cation generated by 7-irradiation of 1 in CFCl3 matrix at 77 K are consistent with that resulted in the chemical oxidation in DCM at ambient temperature.展开更多
IN the last few years phenothiazine(PTH)and its derivatives have captured much attention inthe fields of medicines,biology,and microelectronic materials due to their ability to ef-ficiently photosensitize acid product...IN the last few years phenothiazine(PTH)and its derivatives have captured much attention inthe fields of medicines,biology,and microelectronic materials due to their ability to ef-ficiently photosensitize acid production in the presence of vicinal dibromides and hence tochange the solubilization of polymer films.The photophysical and photochemical properties re-lated to the processes have been studied.Monica Barra et al.found that the triplet展开更多
文摘In contrast to the well-known methods for the generation of radical cations, such as radiolysis, electrolysis and single electron transfer reactions, the formation of radical cations by ultrasound is little known. It has been demonstrated that free radicals produced by sonolysis of carbon tetrachloride can be trapped by 2-methyl-2-nitrosopropane and identified by ESR. Recently, unambiguous evidence for the formation of hydroxyl radicals and hydrogen atoms during sonolysis of water by using DMPO(5,5-dimethyl-1-pyrroline-1-oxide)
文摘he stable radical cation salts of phenothiazine and N-alkyl-phenothiazine(alkyl =methyl , ethyl , isohutyl , isopentyl and benzyl) hexachloroantimonate ,per-chlorate , and iodide were prepared by means of one-electron oxidation with 2 ,2 , 6 ,6-tetramethyl- 4-acetoxypiperidine oxoammonium hexachloroantimonate , perchloricacid, hydrogen peroxide, and molecular iodine, respectively. The radical cationswere characterized using ESR spectroscopy. Conformational analysis based on theESR parameters suggests that the radical cations adopt a planar configuration withthe nitrogen radical as the center.
基金Study supported by the Science and Technique Foundation of Lanzhou Branch, Academia Sinica.
文摘The present study deals with the study of some Friedel-Crafts alkylating system and the accurate measurement of hyperfine coupling constants by ESR and ENDOR techniques. The results indicate that the observed ESR spectra are due to polycyclic aromatic radical cations formed from their parent hydrocarbons.It is suggested that benzyl halides produced in the Friedel-Crafts alkylating reaction undergo Scholl condensation reaction to give polycyclic aromatic hydrocarbons, which were converted into the corresponding polycyclic aromatic radical cations in the presence of aluminum chloride.
基金Project supported by the National Natural Science Foundation and the State Education Commission of China.
文摘Electron transfer reaction between vitamin A (1) and tris(p-bromophenyl)aminium hexachloroautimonate (2) in dichloromethane (DCM) has been investigated by means of UV-VIS absorption and ESR spectroscopy. The title radical cation formed in the reaction was characterized by a new absorption band around 600 nm and a singlet unresolved ESR spectrum with g factor of 2.0038-2.0039 and line width of 20 G. Further studies indicated that ESR pattern and parameters of the radical cation generated by 7-irradiation of 1 in CFCl3 matrix at 77 K are consistent with that resulted in the chemical oxidation in DCM at ambient temperature.
文摘IN the last few years phenothiazine(PTH)and its derivatives have captured much attention inthe fields of medicines,biology,and microelectronic materials due to their ability to ef-ficiently photosensitize acid production in the presence of vicinal dibromides and hence tochange the solubilization of polymer films.The photophysical and photochemical properties re-lated to the processes have been studied.Monica Barra et al.found that the triplet
