In the current study,photocatalytic hydrogen production from water under visible light irradiation over Eosin Y-Pt catalyst supported on high specific area SiO2 has been achieved in the presence of electron donor such...In the current study,photocatalytic hydrogen production from water under visible light irradiation over Eosin Y-Pt catalyst supported on high specific area SiO2 has been achieved in the presence of electron donor such as Triethanolamine(TEOA).The optimal pH and concentration of Eosin Y were about 7 and 7.24 × 10-4 mol·L-1,respectively.The highest rate of hydrogen evolution and the highest apparent quantum efficiency under irradiation with a wavelength longer than 420 nm was about 43 μmol·h-1 and 10.4%,respectively.展开更多
Ⅰ. INTRODUCTION Hypocrellin A ( abbreviated as HA ) extracted from Hypocrella bambusae (B et Br.) Sacc. grows abundantly in Yunnan Province, China. HA irradiated with visible light has been used successfully in the t...Ⅰ. INTRODUCTION Hypocrellin A ( abbreviated as HA ) extracted from Hypocrella bambusae (B et Br.) Sacc. grows abundantly in Yunnan Province, China. HA irradiated with visible light has been used successfully in the treatment of some skin diseases. Recently it has been reported that HA could be selectively retained in tumor cells and could展开更多
Photosensitized oxidation of the novel phthalocyanine modified by glycine [ZnPc(NHCH\-2COOH)\-4] in the presence of glucose oxidase or plasmid pBR322 DNA was investigated by using gel electrophoresis, capillary electr...Photosensitized oxidation of the novel phthalocyanine modified by glycine [ZnPc(NHCH\-2COOH)\-4] in the presence of glucose oxidase or plasmid pBR322 DNA was investigated by using gel electrophoresis, capillary electrophoresis and the enzyme activity determination method. As a result, glucose oxidase was cleaved partially by photosensitizer, the cross\|linkage between subunits occurred partially simultaneously and, moreover, enzyme was cleaved continually into pieces. Activity of glucose oxidase was 130 times lower than that of original within 12 h. DNA could be cleaved in the presence of photosensitizer ZnPc(NHCH\-2COOH)\-4. Super helix of DNA was depolymerized into nicked and linear DNA. Then, it was cleaved progressively into pieces. It was suggested that the novel photosensitizer could do apparent damage to biomacromolecules.展开更多
The structures of 26 different congeners of polychlorinated biphenyls（PCBs, including monothrough deca-chlorinated） were optimized using density functional theory（DFT） calculations with the 6-31＋G（d,p） basis se...The structures of 26 different congeners of polychlorinated biphenyls（PCBs, including monothrough deca-chlorinated） were optimized using density functional theory（DFT） calculations with the 6-31＋G（d,p） basis set. The activation energies for the dechlorination of these systems were calculated for direct photodegradation and photosensitized degradation reaction pathways in the presence of natural organic matter（NOM）. The dechlorination mechanism of these PCBs and the ring-opening reaction mechanisms（using QST3 method） of the photosensitive degradation products were analyzed. The results showed that（i） the activation energy for the photosensitized degradation of PCBs was much lower than that of direct photodegradation;（ii） the degradation activities（i.e., C–Cl bond cleavage energies） were the same for both degradation pathways and followed the order ortho 〉 meta 〉 para;（iii） the degradation activities of asymmetric PCBs were higher than those of the corresponding symmetrical PCBs for the direct photodegradation and it was completely opposite in the photosensitive degradation;（iv） there was no correlation between the dissociation energy and the number of C–Cl bonds for the direct photodegradation and dechlorination products were all biphenyl;（v） the degradation activity of PCBs decreased as the number of C–Cl bonds increased in the presence of NOM; and（vi） even when the dechlorination reaction was incomplete, it produced chlorophenol. Furthermore, the free radicals of NOM led to the ring-opening reactions of PCBs via an initial addition step. The main site of these ring-opening reactions was the ortho position. Notably, the likelihood of ring-opening reactions occurring involving the degradation products increased as the degradation degree of PCBs increased.展开更多
The photosensitized oxidation mechanism of peptide in the presence of the CIAIPcS is studied by UV-Vis spectroscopic method. It is found that the oxidation of peptide is totally quenched in 1.1 ×10<sup>-2&l...The photosensitized oxidation mechanism of peptide in the presence of the CIAIPcS is studied by UV-Vis spectroscopic method. It is found that the oxidation of peptide is totally quenched in 1.1 ×10<sup>-2</sup> mol/L NaN<sub>3</sub> solution, and the same reaction cannot proceed in the dark. K<sub>3</sub>Fe（CN）<sub>6</sub> and L-Cys cannot quench the reaction. Therefore, the reaction mechanism is mainly Foote’s type Ⅱ. This reaction process can be inferred as follows: （ ⅰ ） active oxygen can attack acylamida bond near by carbon atom; （ ⅱ ） carboxyl group departs from peptide; （ ⅲ ） l-benzazole cycle is destroyed when reaction is continued; （ Ⅳ ） the peptide is completely damaged.展开更多
IN photodynamic therapy, the damage of protein results from the photooxidation of one ormore of only five amino acid residues (tryptophanyl, tyrosyl, histidyl, methionyl and cys-teinyl). These five amino acids are als...IN photodynamic therapy, the damage of protein results from the photooxidation of one ormore of only five amino acid residues (tryptophanyl, tyrosyl, histidyl, methionyl and cys-teinyl). These five amino acids are also readily photooxidized in their monomeric states. How-ever, the reaction kinetics and mechanisms of free amino acids and bound amino acid residuesin proteins are somewhat different. For example, Tassin found that the incorporation of tryp-tophan into a peptide linkage dramatically altered its susceptibility to photooxidation as well展开更多
The chain reaction of 1,2-dichloroethane was initiated by photosensitization of SF_6 under the selective excitation using a cw CO_2 laser.Vinyl chloride with high purity was produced in the reaction process.The initia...The chain reaction of 1,2-dichloroethane was initiated by photosensitization of SF_6 under the selective excitation using a cw CO_2 laser.Vinyl chloride with high purity was produced in the reaction process.The initiation of the photosensitized chain reaction depends on the irradiated laser frequency.The mechanism of intermolecular resonant transfer of vibrational energy has been discussed.展开更多
Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of...Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of quadri- cyclane(Ⅱ_a,Ⅱ_b,Ⅱ_c)operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.展开更多
A method for quantitative evaluating the enhancement of the rate of Type Ⅱ photosensitized oxidation by D_2O was suggested. The effect of substrate concentration on this process was also discussed.
文摘In the current study,photocatalytic hydrogen production from water under visible light irradiation over Eosin Y-Pt catalyst supported on high specific area SiO2 has been achieved in the presence of electron donor such as Triethanolamine(TEOA).The optimal pH and concentration of Eosin Y were about 7 and 7.24 × 10-4 mol·L-1,respectively.The highest rate of hydrogen evolution and the highest apparent quantum efficiency under irradiation with a wavelength longer than 420 nm was about 43 μmol·h-1 and 10.4%,respectively.
基金Project supported by the National Natural Science Foundation of China
文摘Ⅰ. INTRODUCTION Hypocrellin A ( abbreviated as HA ) extracted from Hypocrella bambusae (B et Br.) Sacc. grows abundantly in Yunnan Province, China. HA irradiated with visible light has been used successfully in the treatment of some skin diseases. Recently it has been reported that HA could be selectively retained in tumor cells and could
文摘Photosensitized oxidation of the novel phthalocyanine modified by glycine [ZnPc(NHCH\-2COOH)\-4] in the presence of glucose oxidase or plasmid pBR322 DNA was investigated by using gel electrophoresis, capillary electrophoresis and the enzyme activity determination method. As a result, glucose oxidase was cleaved partially by photosensitizer, the cross\|linkage between subunits occurred partially simultaneously and, moreover, enzyme was cleaved continually into pieces. Activity of glucose oxidase was 130 times lower than that of original within 12 h. DNA could be cleaved in the presence of photosensitizer ZnPc(NHCH\-2COOH)\-4. Super helix of DNA was depolymerized into nicked and linear DNA. Then, it was cleaved progressively into pieces. It was suggested that the novel photosensitizer could do apparent damage to biomacromolecules.
基金supported by the Fundamental Research Funds for the Central Universities in 2013(JB2013146)the Key Projects in the National Science&Technology Pillar Program in the Eleventh Five-Year Plan Period(2008BAC43B01)
文摘The structures of 26 different congeners of polychlorinated biphenyls（PCBs, including monothrough deca-chlorinated） were optimized using density functional theory（DFT） calculations with the 6-31＋G（d,p） basis set. The activation energies for the dechlorination of these systems were calculated for direct photodegradation and photosensitized degradation reaction pathways in the presence of natural organic matter（NOM）. The dechlorination mechanism of these PCBs and the ring-opening reaction mechanisms（using QST3 method） of the photosensitive degradation products were analyzed. The results showed that（i） the activation energy for the photosensitized degradation of PCBs was much lower than that of direct photodegradation;（ii） the degradation activities（i.e., C–Cl bond cleavage energies） were the same for both degradation pathways and followed the order ortho 〉 meta 〉 para;（iii） the degradation activities of asymmetric PCBs were higher than those of the corresponding symmetrical PCBs for the direct photodegradation and it was completely opposite in the photosensitive degradation;（iv） there was no correlation between the dissociation energy and the number of C–Cl bonds for the direct photodegradation and dechlorination products were all biphenyl;（v） the degradation activity of PCBs decreased as the number of C–Cl bonds increased in the presence of NOM; and（vi） even when the dechlorination reaction was incomplete, it produced chlorophenol. Furthermore, the free radicals of NOM led to the ring-opening reactions of PCBs via an initial addition step. The main site of these ring-opening reactions was the ortho position. Notably, the likelihood of ring-opening reactions occurring involving the degradation products increased as the degradation degree of PCBs increased.
文摘The photosensitized oxidation mechanism of peptide in the presence of the CIAIPcS is studied by UV-Vis spectroscopic method. It is found that the oxidation of peptide is totally quenched in 1.1 ×10<sup>-2</sup> mol/L NaN<sub>3</sub> solution, and the same reaction cannot proceed in the dark. K<sub>3</sub>Fe（CN）<sub>6</sub> and L-Cys cannot quench the reaction. Therefore, the reaction mechanism is mainly Foote’s type Ⅱ. This reaction process can be inferred as follows: （ ⅰ ） active oxygen can attack acylamida bond near by carbon atom; （ ⅱ ） carboxyl group departs from peptide; （ ⅲ ） l-benzazole cycle is destroyed when reaction is continued; （ Ⅳ ） the peptide is completely damaged.
文摘IN photodynamic therapy, the damage of protein results from the photooxidation of one ormore of only five amino acid residues (tryptophanyl, tyrosyl, histidyl, methionyl and cys-teinyl). These five amino acids are also readily photooxidized in their monomeric states. How-ever, the reaction kinetics and mechanisms of free amino acids and bound amino acid residuesin proteins are somewhat different. For example, Tassin found that the incorporation of tryp-tophan into a peptide linkage dramatically altered its susceptibility to photooxidation as well
文摘The chain reaction of 1,2-dichloroethane was initiated by photosensitization of SF_6 under the selective excitation using a cw CO_2 laser.Vinyl chloride with high purity was produced in the reaction process.The initiation of the photosensitized chain reaction depends on the irradiated laser frequency.The mechanism of intermolecular resonant transfer of vibrational energy has been discussed.
基金the authors thank the help of professor Liang Xiao-guangZhang Bao-wen and Tung Chen-ho of our Institute
文摘Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of quadri- cyclane(Ⅱ_a,Ⅱ_b,Ⅱ_c)operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.
文摘A method for quantitative evaluating the enhancement of the rate of Type Ⅱ photosensitized oxidation by D_2O was suggested. The effect of substrate concentration on this process was also discussed.
