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排序方式: 共有478条查询结果,搜索用时 31 毫秒
71.
Dietmar Leipert Peter Heiduschka Jürgen Mack Hans-Joachim Egelhaaf Dieter Oelkrug Günther Jung 《Angewandte Chemie (International ed. in English)》1998,37(17):2337-2340
Microstructuring of surfaces: Electrochemical polymerization after removal of a photolabile protecting group (nitrobenzyl group) represents a new method for spatially resolved immobilization of ligands or receptors. Thus, the electropolymerization of 3-hydroxyphenylacetyl peptides such as 1 on electrodes can be controlled by light 相似文献
72.
Hans-Joachim Knlker Helmut Goesmann Rüdiger Klauss 《Angewandte Chemie (International ed. in English)》1999,38(5):702-705
The photochemical exchange of all three carbonyl ligands with acetonitrile converts tricarbonyliron–diene complexes into the very labile triacetonitrile-iron–diene complexes. These easily demetalate in high yields to the corresponding free ligands on injection of air at −30°C [Eq. (1)]. The novel demetalation procedure is applied to the tricarbonyliron complexes of cyclopentadienones, cyclohexa-1,3-dienes, and buta-1,3-dienes. 相似文献
73.
Kazuo Watanabe Yoshiyasu Matsumoto Margarethe Kampling Katharina Al-Shamery Hans-Joachim Freund 《Angewandte Chemie (International ed. in English)》1999,38(15):2192-2194
The mean size of the Pd clusters deposited on an Al2O3 thin film influences the efficiency of photodissociation of CD4 into CD3 and D as well as the photodesorpion upon irradiation with 193-nm laser light. The picture shows the degree of desorption on Pd clusters of various sizes (as well as on a Pd(111) single-crystal surface) as a function of temperature; the values given refer to the average thickness of the evaporated metal layer. 相似文献
74.
Tong-Ing Ho Jin-Yi Wu Shun-Li Wang 《Angewandte Chemie (International ed. in English)》1999,38(17):2558-2560
A conrotatory photocyclization , a novel [1,9] hydrogen shift, and a lateral ring opening are involved in the rearrangement of a series of 2-(4-alkylstyryl)furans 1 to 5-(3-alkylbutadienyl)benzo[b]furans 2 in dichloromethane. These novel photochemical rearrangements occur with good yields of isolated products. 相似文献
75.
New β,β′-aryl/heteroaryl 2,3-divinylfuran derivatives (9a-d) in which a hexatriene system is a part of heteroaromatic ring have been synthesized and their photochemical properties were investigated. The primary process observed was the isomerization to trans,trans-isomers 9a-d followed by photochemical rearrangement of the furan ring giving the phototransposition products (I-IV). Stilbenes (20, 21) and phenanthrenes (22, 25, and 26), formed as secondary products from the competitive intermolecular cycloadditions, were also observed. 相似文献
76.
77.
Emad Yousif Emaad Bakir Jumat Salimon Nadia Salih 《Journal of Saudi Chemical Society》2012,16(3):279-285
The photostabilization of poly(methyl methacrylate) (PMMA) films by Schiff bases of 2,5-dimercapto-1,3,4-thiadiazole compounds was investigated. The PMMA films containing concentration of complexes 0.5% by weight were produced by the casting method from chloroform solvent. The photostabilization activities of these compounds were determined by monitoring the hydroxyl index with irradiation time. The changes in viscosity average molecular weight of PMMA with irradiation time were also tracked (using benzene as a solvent). The quantum yield of the chain scission (Φcs) of these complexes in PMMA films was evaluated and found to range between 4.19 × 10?5 and 8.75 × 10?5. Results obtained showed that the rate of photostabilization of PMMA in the presence of the additive followed the trend:[1] > [2] > [3] > [4] > [5].According to the experimental results obtained, several mechanisms were suggested depending on the structure of the additive. Among them, UV absorption, peroxide decomposer, and radical scavenger for photostabilizer mechanisms were suggested. 相似文献
78.
79.
The electrodeless discharge lamp: a prospective tool for photochemistry: Part 3. The microwave photochemistry reactor 总被引:1,自引:0,他引:1
Petr Kln Milan Hjek Vladimír Církva 《Journal of photochemistry and photobiology. A, Chemistry》2001,140(3):1077-189
A simple and original microwave photochemical reactor is described in detail. It consists of an electrodeless discharge lamp placed into the reaction vessel in a modified domestic microwave oven. The microwave field generates ultraviolet radiation by the lamp at the same time when it interacts with the reaction mixture. The construction, experimental set-ups, applications, and safety precautions are discussed. 相似文献
80.