Journal of Photochemistry最新文献_第3页

Announcement: the Grammaticakis-Neumann award in photochemistry 公告:光化学领域的Grammaticakis-Neumann奖

Journal of Photochemistry Pub Date : 1987-09-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)87057-0

A.M. Braun

引用次数: 0

The influence of substituents on the photodehydrocyclization of 1,2-diphenylcyclopentenes I: Para substituents 取代基对1,2-二苯基环戊烯光脱氢反应的影响ⅰ:对取代基

Journal of Photochemistry Pub Date : 1987-09-01 DOI: 10.1016/0047-2670(87)87051-X

J. Somers, W. H. Laarhoven

引用次数: 2

An examination of diffusion-influenced fluorescence quenching by nearest quenching neighbors in liquids 液体中最近邻猝灭对扩散影响的荧光猝灭的研究

Journal of Photochemistry Pub Date : 1987-09-01 DOI: 10.1016/0047-2670(87)87039-9

B. Stevens, D. N. McKeithan

引用次数: 1

Formation and decay of nitronic acid in the photorearrangement of o-nitrobenzyl esters 邻硝基苯酯光重排中硝酸的形成和衰变

Journal of Photochemistry Pub Date : 1987-08-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)80041-2

Q.Q. Zhu, W. Schnabel, H. Schupp

{"title":"Formation and decay of nitronic acid in the photorearrangement of o-nitrobenzyl esters","authors":"Q.Q. Zhu, W. Schnabel, H. Schupp","doi":"10.1016/0047-2670(87)80041-2","DOIUrl":"10.1016/0047-2670(87)80041-2","url":null,"abstract":"<div>o-Nitrobenzyl benzoate (oNBB), α-methyl-o-nitrobenzyl benzoate (αMoNBB), α-phenyl-o-nitrobenzyl benzoate (αPoNBB) and copolymers of methyl methacrylate and of o-nitrobenzyl, methyl-o-nitrobenzyl and phenyl-o-nitrobenzyl acrylates were flash photolysed or continuously irradiated with UV light in dilute solution. The quantum yield φ(PR) of bond cleavage in the photorearrangement of the o-nitrobenzyl esters does not depend on the chemical nature of the ester group but is significantly influenced by the substituent in the α position φ(PR) = 0.22 ± 0.03 (αMoNBB, αPoNBB) and φ = 0.10 ± 0.02 (oNBB). This was revealed from the yields of carboxylic acid and o-nitrobenzyl groups. The differences in φ(PR) correspond to the differences in the yields of nitronic acid formed as an intermediate. In aqueous systems the kinetics of the decay of the nitronic acid were found to be determined by the formation of rather stable nitronate ions according to the equilibrium <figure><img></figure> The relatively long lifetime of the nitronate ion formed in the case of oNBB (longer than 100 ms) is assumed to be caused by a rather strong intramolecular interaction of the hydrogen at the α-carbon with the nitronate group and the carbonyl group. In acetonitrile solution, where nitronate ions were not formed, the non-substituted compound (oNBB) also behaved differently from the substituted compounds (αMoNBB and αPoNBB): two transients differing in lifetime (6 × 10−4 and 5.8 × 10−3 s) were observed with oNBB which were ascribed to different isomers of the nitronic acid. Addition of H2SO4 to acetonitrile solutions accelerated the rearrangement of the nitronic acid. The acceleration is assumed to be caused by protonation of the oxygen of the carbonyl group. The carbocation formed this way strongly interacts intramolecularly with oxygens of the nitronic acid group, thus inducing the rearrangement.</div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 2","pages":"Pages 317-332"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80041-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83766046","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: 27

A theoretical study of two-color photoionization and autoionization of molecules 分子的双色光离和自离的理论研究

Journal of Photochemistry Pub Date : 1987-08-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)80031-X

S.H. Lin, A. Boeglin, S.M. Lin

引用次数: 5

The effect of added salts on electron transfer reactions involving exciplexes: the N,N-dimethylaniline-photosensitized dechlorination of 4-chlorobiphenyl 添加盐对杂络合物电子转移反应的影响:N,N-二甲基苯胺光敏脱氯

Journal of Photochemistry Pub Date : 1987-08-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)80036-9

C.A. Chesta, J.J. Cosa, C.M. Previtali

引用次数: 17

Photoresponsive peptide and polypeptide systems IV: Light-induced conformational changes in ϵ-poly(l-lysine) wit photochromic side chains 光响应肽和多肽系统IV:具有光致变色侧链的ϵ-poly(l-赖氨酸)的光诱导构象变化

Journal of Photochemistry Pub Date : 1987-08-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)80043-6

Hiroyuki Yamamoto, Yasuko Miyagi, Ayako Nishida, Toru Takagishi, Shoji Shima

{"title":"Photoresponsive peptide and polypeptide systems IV: Light-induced conformational changes in ϵ-poly(l-lysine) wit photochromic side chains","authors":"Hiroyuki Yamamoto, Yasuko Miyagi, Ayako Nishida, Toru Takagishi, Shoji Shima","doi":"10.1016/0047-2670(87)80043-6","DOIUrl":"10.1016/0047-2670(87)80043-6","url":null,"abstract":"<div>ϵ(Poly(l-lysine) containing a high mole percentage of azo aromatic side chains was synthesized by the active ester method. The photochemical properties of the azo polypeptide, ϵ-poly(Nα-phenylazobenzoyl-l-lysine) (ϵ-PPABLL), were investigated by absorption and circular dichroism (CD) spectroscopy in hexafluoro-2-propanol (HFIP). The photochromism of the absorption band in the near UV and visible wavelength region was found to be mostly reversible as a function of irradiation time at different wavelengths (360 nm and 460 nm) owing to the trans—cis photoisomerization of the azo aromatic moieties. The CD spectrum exhibited multistage photochromism on irradiation by light. The whole CD spectrum, especially at the dichroic bands at 300 nm (positive), 340 nm (negative) and 365 nm (trans, positive), showed a peculiar reversible photochromism on irradiation by 360 nm and 460 nm light, except the first irradiation time course. The position and magnitude of the negative dichroic band at 225 nm suggested that the backbone conformational change of ϵ-PPABLL was a light-induced partial reversible transition from a β-form-rich structure to a random-coil-rich structure.</div>","PeriodicalId":16771,"journal":{"name":"Journal of Photochemistry","volume":"39 2","pages":"Pages 343-350"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0047-2670(87)80043-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79293188","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: 9

Fluorescence and phosphorescence of harmol and harmalol at 77 K 哈莫酚和哈莫酚在77k下的荧光和磷光

Journal of Photochemistry Pub Date : 1987-08-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)80038-2

A. Olba, P. Medina, A. Codonñer, S. Monsó

引用次数: 6

Methylene-blue-sensitized photochemical hydroxylation of 2-hydroxybenzoic acid by hydrogen peroxide: photocatalytic effect of ferric chloride 过氧化氢对2-羟基苯甲酸的亚甲基蓝敏化光化学羟基化反应:三氯化铁的光催化作用

Journal of Photochemistry Pub Date : 1987-08-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)80035-7

Stanislav Luňák, Petr Sedlák, Pavel Lederer

引用次数: 10

Study of the photoreduction of uranyl ions by triphenylphosphine, triphenylarsine, tri-p-tolylphosphine and tri-p-tolylarsine in acetone 三苯基膦、三苯基larsin、三对甲基膦和三对甲基larsin在丙酮中光还原铀酰离子的研究

Journal of Photochemistry Pub Date : 1987-08-01 Epub Date: 2002-01-30 DOI: 10.1016/0047-2670(87)80034-5

S.S. Sandhu, M.S. Sidhu, R.J. Singh

引用次数: 12