发布求助
文献互助 智能选刊 最新文献

Journal of Photochemistry最新文献

筛选
英文 中文
Photocycloaddition of ketones to olefins as radiationless transitions 作为无辐射跃迁的酮到烯烃的光环加成
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80002-3
Luís G. Arnaut, Sebastião J. Formosinho
{"title":"Photocycloaddition of ketones to olefins as radiationless transitions","authors":"Luís G. Arnaut,&nbsp;Sebastião J. Formosinho","doi":"10.1016/0047-2670(87)80002-3","DOIUrl":"10.1016/0047-2670(87)80002-3","url":null,"abstract":"<div><p>The tunnel effect theory is applied to study the photocycloaddition of ketones to olefins. This theory can quantitatively explain the reactivity, regioselectivity, stereospecificity and efficiency of the photocycloadditions studied. The study covers a large diversity of olefins (electron rich and electron poor) and ketones (alkyl, alkylphenyl and phenyl), in both their <sup>1</sup>(n,π*) and <sup>3</sup>(n,π*) states. The theory does not need to postulate the questionable intermediacy of an exciplex to explain the characteristics of these reactions. Evidence for the dominancy of tunnelling over thermal activation is presented. The results of this study are in line with previous applications of tunnel effect theory and complete the explanation of ketone photoreactivity in solution under the framework of the general intersecting-state model.</p></div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 1","pages":"Pages 13-31"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80002-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81020516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Laser-induced photoionization and single-strand break formation for polynucleotides and single-stranded DNA in aqueous solution: model studies for the direct effect of high energy radiation on DNA 水溶液中多核苷酸和单链DNA的激光诱导光电离和单链断裂形成:高能辐射对DNA直接影响的模型研究
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80013-8
Joachim Opitz, Dietrich Schulte-Frohlinde
{"title":"Laser-induced photoionization and single-strand break formation for polynucleotides and single-stranded DNA in aqueous solution: model studies for the direct effect of high energy radiation on DNA","authors":"Joachim Opitz,&nbsp;Dietrich Schulte-Frohlinde","doi":"10.1016/0047-2670(87)80013-8","DOIUrl":"https://doi.org/10.1016/0047-2670(87)80013-8","url":null,"abstract":"<div><p>Quantum yields for the formation of hydrated electrons (Φ<sub>e</sub>−) and single-strand breaks (Φ<sub>ssb</sub>) were measured for polyadenylic acid (poly A), polycytidylic acid (poly C), polyuridylic acid (poly U) and single-stranded (ss) DNA in deoxygenated aqueous solution at room temperature upon nanosecond laser excitation at 248 nm. The values Φ<sub>e</sub><sup>−</sup> = (1.7 − 3) × 10<sup>−2</sup> and Φ<sub>ssb</sub> = (0.5 − 5) × 10<sup>−4</sup> at intensities of (0.5 − 1.5) × 10<sup>7</sup> W cm<sup>−2</sup> were obtained. The results show that base radical cations of these polynucleotides and of ssDNA lead to ssb formation. The large difference between Φ<sub>e</sub><sup>−</sup> and Φ<sub>ssb</sub> (a factor of 60 – 380) is explained as being the result of back reactions of geminate pairs of radicals and/or radical ions. Conductivity changes after the laser pulse, representing ssb formation, reveal a fast increase and a consecutive show increase for all nucleic acids studied. The activation energies and pre-exponential factors, calculated from the rate constant <em>k</em><sub>obs</sub> of the slow conductivity increase at pH 7.3, are reported. Dithiothreitol (DTT) inhibits ssb formation of poly C (rate constant <em>k</em><sub>DTT</sub> = 1.7 × 10<sup>6</sup> M<sup>−1</sup> s<sup>−1</sup>) and poly U whereas for poly A and ssDNA a smaller effect was found (<em>k</em><sub>DTT</sub> &lt; 0.7 × 10<sup>6</sup> M<sup>−1</sup> s<sup>−1</sup>. The pH dependence of <em>k</em><sub>obs</sub> is very similar for poly A and ssDNA, but different from that of poly C and poly U. This indicates that the slow strand break formation in ssDNA upon laser excitation is related to the purine moiety.</p></div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 1","pages":"Pages 145-163"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80013-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91702484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 48
Separation and identification of the products of the photodegradation of 7-amino-4-methylcoumarin and the mechanism of its photodegradation 7-氨基-4-甲基香豆素光降解产物的分离鉴定及其光降解机理
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80012-6
J. Kunjappu, K. Rao
{"title":"Separation and identification of the products of the photodegradation of 7-amino-4-methylcoumarin and the mechanism of its photodegradation","authors":"J. Kunjappu, K. Rao","doi":"10.1016/0047-2670(87)80012-6","DOIUrl":"https://doi.org/10.1016/0047-2670(87)80012-6","url":null,"abstract":"","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"89 1","pages":"135-143"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88441721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Flash photolysis study of diaminopyridines 二氨基吡啶的闪光光解研究
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80004-7
J. Wolleben, A.C. Testa
{"title":"Flash photolysis study of diaminopyridines","authors":"J. Wolleben,&nbsp;A.C. Testa","doi":"10.1016/0047-2670(87)80004-7","DOIUrl":"https://doi.org/10.1016/0047-2670(87)80004-7","url":null,"abstract":"<div><p>The triplet—triplet absorption spectra of three diaminopyridines have been assigned from variable-temperature flash photolysis studies. In all cases the lowest triplet state is ππ* with a phosphorescence lifetime of about 2 s at 77 K in ethyl ether—pentane—ethyl alcohol. Complete neglect of differential overlap—configuration interaction calculations were performed to supplement the interpretation of the fluorescence and phosphorescence data and to provide a satisfactory correlation of the observed and predicted behavior of these molecules.</p></div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 1","pages":"Pages 41-47"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80004-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137200271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Photoconductivity measurement using a simulated electrostatic recording device 利用模拟静电记录装置测量光电导率
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80014-X
N.S. Allen , E.T. Robinson , C.M. Stott , F.F. Thompson , D.C. Dobson, A.J. Nelson
{"title":"Photoconductivity measurement using a simulated electrostatic recording device","authors":"N.S. Allen ,&nbsp;E.T. Robinson ,&nbsp;C.M. Stott ,&nbsp;F.F. Thompson ,&nbsp;D.C. Dobson,&nbsp;A.J. Nelson","doi":"10.1016/0047-2670(87)80014-X","DOIUrl":"https://doi.org/10.1016/0047-2670(87)80014-X","url":null,"abstract":"<div><p>Measurementds of photoconductivity on thin polymer films are described using an electrostatic recordimg device built in our laboratory from components actually utilized in a commercial photocopier. The voltage applied to the surface of thin films may be measured using an electrostatic voltmeter and photodecays may be easily monitored by a digital-type storage oscilloscope which when coupled to a BBC microcomputer, via the RS423 input, gives an accurately stored decay profile of the charge with time on the millisecond scale. In this paper, the construction of the equipment and its operation are described and some measurements are presented which support its practical viability under various conditions</p></div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 1","pages":"Pages 165-172"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80014-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91702483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Homogeneous and heterogeneous photoreactions of decomposition and oxidation of carboxylic acids 羧酸分解和氧化的均相和非均相光反应
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80010-2
M. Bideau, B. Claudel, L. Faure, M. Rachimoellah
{"title":"Homogeneous and heterogeneous photoreactions of decomposition and oxidation of carboxylic acids","authors":"M. Bideau,&nbsp;B. Claudel,&nbsp;L. Faure,&nbsp;M. Rachimoellah","doi":"10.1016/0047-2670(87)80010-2","DOIUrl":"10.1016/0047-2670(87)80010-2","url":null,"abstract":"<div><p>Decarboxylation and oxidation reactions of carboxylic acids in the presence of various light receivers are reviewed from the experimental and mechanistic standpoints. The homogeneous photoreceivers studied are the ions UO<sub>2</sub><sup>2+</sup>, Fe<sup>2+</sup> and Cu<sup>2+</sup>. They differ in activity and in selectivity as far as the nature of the hydrocarbons formed by decarboxylation is concerned. The activity of the heterogeneous photocatalyst TiO<sub>2</sub> (anatase) in oxidation is shown to be greatly increased in the presence of dissolved substances, <em>e.g.</em> Fe<sup>3+</sup> and Cu<sup>2+</sup>.</p></div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 1","pages":"Pages 107-128"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80010-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77174176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 26
Formation of methylanisole in the photolysis of chlorotoluene in methanol 氯甲苯在甲醇中光解过程中甲基甲苯的形成
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80011-4
Teijiro Ichimura, Masayoshi Iwai, Yuji Mori
{"title":"Formation of methylanisole in the photolysis of chlorotoluene in methanol","authors":"Teijiro Ichimura,&nbsp;Masayoshi Iwai,&nbsp;Yuji Mori","doi":"10.1016/0047-2670(87)80011-4","DOIUrl":"https://doi.org/10.1016/0047-2670(87)80011-4","url":null,"abstract":"<div><p>Photolyses of <em>p</em>-, <em>m</em>- and <em>o</em>-chlorotoluene in methanol gave formation quantum yields of methylanisoles of the order of 10<sup>−2</sup>, which are substantially smaller than that for chlorobenzene. The values for the para and ortho isomers are smaller than that for the metal isomer. This result can be explained in terms of the effect of the methyl substituent, which induces negative charges at the ortho and para positions. The effect of biacetyl addition was also examined and the results indicated that the triplet route is significant, as in the case of chlorobenzene. However, about half the methylanisole was formed without any dependence on the biacetyl concentration, indicating the presence of an intermediate state with a very short lifetime.</p></div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 1","pages":"Pages 129-134"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80011-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90021694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Benzylidene fluorene ozonolysis under chemiluminescence mimetic conditions in homogeneous and micellar media III: Substituent effect in the micellar pseudophase 均相和胶束介质中模拟化学发光条件下的苯并芴臭氧分解III:胶束假相中的取代基效应
Journal of Photochemistry Pub Date : 1987-07-01 DOI: 10.1016/0047-2670(87)80009-6
L. Papalambros, J. Nikokavouras
{"title":"Benzylidene fluorene ozonolysis under chemiluminescence mimetic conditions in homogeneous and micellar media III: Substituent effect in the micellar pseudophase","authors":"L. Papalambros, J. Nikokavouras","doi":"10.1016/0047-2670(87)80009-6","DOIUrl":"https://doi.org/10.1016/0047-2670(87)80009-6","url":null,"abstract":"","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"269 1","pages":"97-105"},"PeriodicalIF":0.0,"publicationDate":"1987-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75164514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Photodimerization of dibenz[b,f] azepine derivatives and their reaction intermediates 二苯并[b，f]氮杂平衍生物及其反应中间体的光二聚反应
Journal of Photochemistry Pub Date : 1987-06-01 DOI: 10.1016/0047-2670(87)87027-2
Kazuo Ashikaga, Shinzaburo Ito, Masahide Yamamoto, Yasunori Nishijima
{"title":"Photodimerization of dibenz[b,f] azepine derivatives and their reaction intermediates","authors":"Kazuo Ashikaga,&nbsp;Shinzaburo Ito,&nbsp;Masahide Yamamoto,&nbsp;Yasunori Nishijima","doi":"10.1016/0047-2670(87)87027-2","DOIUrl":"https://doi.org/10.1016/0047-2670(87)87027-2","url":null,"abstract":"<div><p>It is clearly demonstrated that the photodimerization of 5-acyl dibenz[<em>b,f</em>]azepine (DBA) derivatives occurs via excited triplet intermediates. The excited triplet state of 5-acyl DBA derivatives is barely formed on direct excitation, but is formed efficiently by triplet—triplet (T—T) energy transfer from a triplet sensitizer. Benzophenone-sensitized photoexcitation gave a unique reaction product, the <em>anti</em>-cyclobutane dimer of DBA. Under the sensitized conditions, the quantum yield for the photodimerization was estimated to be 0.15 at 25°C ([DBA]=2.0×10<sup>−3</sup> mol l<sup>−1</sup>). The triplet intermediate of this reaction was detected by nanosecond laser photolysis and the kinetic parameters of the triplet species were determined.</p></div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"38 ","pages":"Pages 321-329"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)87027-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72261005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Photosensitized conjugation of methyl 9,12-octadecadienoate 9,12-十八烯二酸甲酯的光敏偶联
Journal of Photochemistry Pub Date : 1987-06-01 DOI: 10.1016/0047-2670(87)87029-6
M. Julliard, A. Luciani, J. Chevalier, G. Cecchi, E. Ucciani
{"title":"Photosensitized conjugation of methyl 9,12-octadecadienoate","authors":"M. Julliard, A. Luciani, J. Chevalier, G. Cecchi, E. Ucciani","doi":"10.1016/0047-2670(87)87029-6","DOIUrl":"https://doi.org/10.1016/0047-2670(87)87029-6","url":null,"abstract":"","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"1 1","pages":"345-355"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84347614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
首页 上一页 下一页 尾页
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整，为了账户安全，请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们：info@booksci.cn Book学术提供免费学术资源搜索服务，方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号：481959085
Book学术官方微信