The excited triplet of C60 or C70 is generated via either direct excitation by laser light or energy transfer from excited states of solvent to C60 and C70. The cation radical of C60 is produced either via hole transf...The excited triplet of C60 or C70 is generated via either direct excitation by laser light or energy transfer from excited states of solvent to C60 and C70. The cation radical of C60 is produced either via hole transfer from cation radical of CCl4 to C60 or via electron transfer from excited triplet of C60 to CCl4. C60 and C70 could be added to trichloromethyl radical to produce adduct radicals with different mechanisms.展开更多
Due to the nontoxicity and efficient anti-cancer activity, more and more attention has been paid to N-glycoside compounds. Laser photolysis of N-(α-D-glucopyranoside) salicyloyl hydrazine (NGSH) has been performed fo...Due to the nontoxicity and efficient anti-cancer activity, more and more attention has been paid to N-glycoside compounds. Laser photolysis of N-(α-D-glucopyranoside) salicyloyl hydrazine (NGSH) has been performed for the first time. The research results show that NGSH has high photosensitivity and is vulnerable to be photo-ionized via a monophotonic process with a quantum yield of 0.02, generating NGSH+· and hydrated electrons. Under the aerobic condition of cells, the hydrated electrons are very easy to combine with oxygen to generate 1O2 and O2-, both of which are powerful oxidants that can kill the cancer cells. In addition, NGSH+· can be changed into neutral radicals by deprotonation with a pKa value of 4.02 and its decay constant was determined to be 2.55×109dm3·mol-1·s-1. NGSH also can be oxidized by SO4-. with a rate constant of 1.76×109 dm3·mol-1.s-1, which further confirms the results of photoionization. All of these results suggest that this new N-glycoside compound might be useful for cancer treatment.展开更多
Ⅰ. INTRODUCTIONPhotolysis and radiolysis of Ⅰ<sup>-</sup>and other halide ion Ⅹ<sup>-</sup>have been Studied extensively. However, only two transient absorption maxima at 390 nm and 290 nm w...Ⅰ. INTRODUCTIONPhotolysis and radiolysis of Ⅰ<sup>-</sup>and other halide ion Ⅹ<sup>-</sup>have been Studied extensively. However, only two transient absorption maxima at 390 nm and 290 nm were observed and attributed to Ⅰ<sub>2</sub> and Ⅰ<sub>3</sub><sup>-</sup> respectively, the mechanism of which was suggested展开更多
The transient absorption spectra of triphenylamine (TPA) in various solvents have beeninvestigated by the methods of nanosecond laser photolysis. The lifetimes of TPA were meas-ured. In hexane and ethanol, the transie...The transient absorption spectra of triphenylamine (TPA) in various solvents have beeninvestigated by the methods of nanosecond laser photolysis. The lifetimes of TPA were meas-ured. In hexane and ethanol, the transient absorptions of triplet state and triplet excimer ofTPA were observed. However, the transient absorptions of the TPA cation radical was alsoobserved in acetonitrile besides that of the triplet TPA monomer and excimer. According tothe experimental facts, the transient photophysical mechanism of TPA in various solvents hasbeen proposed.展开更多
The electron transfer reaction between triplet anthraquinone-2-sulfonate and poly-guanylic acid (5’) in CH3CN-H2O (97 : 3) has been investigated by 248 nm (KrF) laser flash photolysis. The transient absorption spectr...The electron transfer reaction between triplet anthraquinone-2-sulfonate and poly-guanylic acid (5’) in CH3CN-H2O (97 : 3) has been investigated by 248 nm (KrF) laser flash photolysis. The transient absorption spectra and kinetics obtained from the interaction of triplet anthraquinone-2-sulfonate and poly[G] demonstrate that the primary ionic radical pair, radical cation of poly[G] and radical anion of anthraquinone-2-sulfonate have been detected simultaneously. The free energy changes in the process of the electron transfer were also calculated.展开更多
A novel fat-soluble porphyrin derivative—isopropyl-ether porphyrindiol (IPEP) has been investigated using the nanosecond laser photolysis and pulse radiolysis. In acetonitrile, IPEP-excited triplet state shows two re...A novel fat-soluble porphyrin derivative—isopropyl-ether porphyrindiol (IPEP) has been investigated using the nanosecond laser photolysis and pulse radiolysis. In acetonitrile, IPEP-excited triplet state shows two relative absorption areas peaking at 320 and 430 nm, molar extinction coefficients by energy transfer method (in benzene solution) are proved to be ε (315) = 1.07}105, ε (450)=3.3}104 L3 · mo-1 · cm-1 and the excited triplet state quantum yield by comparative method is 0.18. Laser photolysis of IPEP in dGMP-containing solution shows that the triplet state cannot excite/oxidize dGMP via the energy/electron transfer process.展开更多
Introduction Electron transfer oxidation of DNA by triplet artificial photonuclease reveals a bright prospect of its application in biology and medicine. Both molecular orbital calculation and laser experiments have ...Introduction Electron transfer oxidation of DNA by triplet artificial photonuclease reveals a bright prospect of its application in biology and medicine. Both molecular orbital calculation and laser experiments have indicated that the homo guanine sequence should be the final localization site of photoexcited hole via long range migration within DNA. However, the direct observation of the produced ion pairs of biomolecules especially the stabilized radical cation DNA or its components is hampered by the overwhelming transient absorption of protonated radical anion of photosensitizers, such as 2-methyl-1,4-naphthaguinonel （MQ）.展开更多
文摘The excited triplet of C60 or C70 is generated via either direct excitation by laser light or energy transfer from excited states of solvent to C60 and C70. The cation radical of C60 is produced either via hole transfer from cation radical of CCl4 to C60 or via electron transfer from excited triplet of C60 to CCl4. C60 and C70 could be added to trichloromethyl radical to produce adduct radicals with different mechanisms.
基金the National Natural Science Foundation of China (Grant Nos. 30570376 and 50673078)Shanghai Project (Grant Nos. 06JC14068 and 08ZZ21)
文摘Due to the nontoxicity and efficient anti-cancer activity, more and more attention has been paid to N-glycoside compounds. Laser photolysis of N-(α-D-glucopyranoside) salicyloyl hydrazine (NGSH) has been performed for the first time. The research results show that NGSH has high photosensitivity and is vulnerable to be photo-ionized via a monophotonic process with a quantum yield of 0.02, generating NGSH+· and hydrated electrons. Under the aerobic condition of cells, the hydrated electrons are very easy to combine with oxygen to generate 1O2 and O2-, both of which are powerful oxidants that can kill the cancer cells. In addition, NGSH+· can be changed into neutral radicals by deprotonation with a pKa value of 4.02 and its decay constant was determined to be 2.55×109dm3·mol-1·s-1. NGSH also can be oxidized by SO4-. with a rate constant of 1.76×109 dm3·mol-1.s-1, which further confirms the results of photoionization. All of these results suggest that this new N-glycoside compound might be useful for cancer treatment.
文摘Ⅰ. INTRODUCTIONPhotolysis and radiolysis of Ⅰ<sup>-</sup>and other halide ion Ⅹ<sup>-</sup>have been Studied extensively. However, only two transient absorption maxima at 390 nm and 290 nm were observed and attributed to Ⅰ<sub>2</sub> and Ⅰ<sub>3</sub><sup>-</sup> respectively, the mechanism of which was suggested
基金Project supported by the National Natural Science Foundation of China and the Applied Organic Chemistry Laboratory, Lanzhou University.
文摘The transient absorption spectra of triphenylamine (TPA) in various solvents have beeninvestigated by the methods of nanosecond laser photolysis. The lifetimes of TPA were meas-ured. In hexane and ethanol, the transient absorptions of triplet state and triplet excimer ofTPA were observed. However, the transient absorptions of the TPA cation radical was alsoobserved in acetonitrile besides that of the triplet TPA monomer and excimer. According tothe experimental facts, the transient photophysical mechanism of TPA in various solvents hasbeen proposed.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39830090).
文摘The electron transfer reaction between triplet anthraquinone-2-sulfonate and poly-guanylic acid (5’) in CH3CN-H2O (97 : 3) has been investigated by 248 nm (KrF) laser flash photolysis. The transient absorption spectra and kinetics obtained from the interaction of triplet anthraquinone-2-sulfonate and poly[G] demonstrate that the primary ionic radical pair, radical cation of poly[G] and radical anion of anthraquinone-2-sulfonate have been detected simultaneously. The free energy changes in the process of the electron transfer were also calculated.
基金The author Zhang Lianwen thanks Prof. Zheng Zhide and Zhang Wenlong for their technical support in the experiment. This work was supported by the National Natural Science Foundation of China (Grant No. 39830090) and the Ninth-Five Year Key Project of Chi
文摘A novel fat-soluble porphyrin derivative—isopropyl-ether porphyrindiol (IPEP) has been investigated using the nanosecond laser photolysis and pulse radiolysis. In acetonitrile, IPEP-excited triplet state shows two relative absorption areas peaking at 320 and 430 nm, molar extinction coefficients by energy transfer method (in benzene solution) are proved to be ε (315) = 1.07}105, ε (450)=3.3}104 L3 · mo-1 · cm-1 and the excited triplet state quantum yield by comparative method is 0.18. Laser photolysis of IPEP in dGMP-containing solution shows that the triplet state cannot excite/oxidize dGMP via the energy/electron transfer process.
文摘Introduction Electron transfer oxidation of DNA by triplet artificial photonuclease reveals a bright prospect of its application in biology and medicine. Both molecular orbital calculation and laser experiments have indicated that the homo guanine sequence should be the final localization site of photoexcited hole via long range migration within DNA. However, the direct observation of the produced ion pairs of biomolecules especially the stabilized radical cation DNA or its components is hampered by the overwhelming transient absorption of protonated radical anion of photosensitizers, such as 2-methyl-1,4-naphthaguinonel （MQ）.
