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排序方式: 共有86条查询结果,搜索用时 15 毫秒
81.
Venkatapuram Padmavathi Pinnu Thriveni Boreddy Chandra Obula Reddy Konda Mahesh 《Journal of heterocyclic chemistry》2007,44(1):93-98
A new class of thiadiazoles, triazoles and oxadiazoles were prepared from phenacylsulfonylacetic ester by protecting the carbonyl group by oximation. Deoximation was affected by using β‐cyclodextrin in the presence of an oxidizing agent. 相似文献
82.
Ganesan P Baggerman J Zhang H Sudhölter EJ Zuilhof H 《The journal of physical chemistry. A》2007,111(28):6151-6156
The photophysical properties of a tetrahedral molecule with naphthalene diimide (NDI) moieties and of two model compounds were investigated. The absorption and fluorescence spectra of dialkyl-substituted NDI are in agreement with literature. While the absorption spectra of phenyl-substituted molecules are similar to all other NDIs, their fluorescence showed a broad band between 500 and 650 nm. This band is sensitive to the polarity of the solvent and is attributed to a CT state. The absorption spectra and lifetime (10+/-2 ps) of the electronically excited singlet state of a dialkyl-substituted NDI was determined by femtosecond transient absorption spectroscopy, and the latter was confirmed by picosecond fluorescence spectroscopy. Nanosecond flash photolysis showed the subsequent formation of the triplet state. The presence of a phenyl substituent on the imide nitrogen of NDI resulted in faster deactivation of the singlet state (lifetime 0.5-1 ps). This is attributed to the formation of a short-lived CT state, which decays to the local triplet state. The faster deactivation was confirmed by fluorescence lifetime measurements in solution and in a low-temperature methyl-tetrahydrofuran glass. 相似文献
83.
Sridharan D Manoharan SP Palaniswamy N 《Bioelectrochemistry (Amsterdam, Netherlands)》2011,82(2):135-139
Marine and freshwater biofilm usually shift the open circuit potential (OCP) of stainless steel towards the electropositive direction by + 450 mV vs SCE. The nature of oxide film and bacterial metabolism were also correlated with ennoblement process by various investigators. Glassy carbon electrode (GCE) was used in the present study and a shifting of potential in the positive side (+ 450 mV) was noticed. It indicates that biofilm contributes to the ennoblement process without any n/p-type semiconducting oxide film. The nature of the cathodic curve for the biofilm covered GCE is compared with the previous literature on the electrochemical behavior of stainless steel. The present study explains the oxidation and reduction peaks of biofilm covered GCE by cyclic voltammetry. Electrochemical impedance result reveals the diffusion process within the manganese biofilm. The present study confirms the previous investigations that the manganese biofilm rules the electrochemical behavior of materials and suggests that oxide film is not necessary to assist the ennoblement process. 相似文献
84.
Padmaja A Muralikrishna A Rajasekhar C Padmavathi V 《Chemical & pharmaceutical bulletin》2011,59(12):1509-1517
A new class of pyrrolyl/pyrazolyl arylaminosulfonylmethyl 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, and 1,2,4-triazoles were prepared and tested for antimicrobial activity. Amongst the tested compounds, 5c displayed high antimicrobial activity. 相似文献
85.
Per-6-amino-beta-cyclodextrin as an efficient supramolecular ligand and host for Cu(I)-catalyzed N-arylation of imidazole with aryl bromides 总被引:2,自引:0,他引:2
Per-6-amino-beta-cyclodextrin (per-6-ABCD), acting simultaneously as a supramolecular ligand for CuI and host for aryl bromides, catalyzes N-arylation of imidazole with aryl bromides under mild conditions. This simple method proceeds with excellent yield for the coupling of imidazole with various substituted aryl bromides demonstrating good tolerance of other functionalities. 相似文献
86.
Padmavathi V Venkatesh BC Muralikrishna A Padmaja A 《Chemical & pharmaceutical bulletin》2012,60(4):449-458
The reactivity of gem cyanoester ketene dithiolates towards the development of a variety of heterocycles was studied and tested for antioxidant property. The compounds bis benzoxazolylmethylthiomethylene pyrazoles and isoxazoles displayed excellent radical scavenging activity when compared with the standard ascorbic acid. 相似文献