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991.
Edward S. Galbavy Keren Ram Cort Anastasio 《Journal of photochemistry and photobiology. A, Chemistry》2010,209(2-3):186-192
2-Nitrobenzaldehyde (2NB) is a convenient, photochemically sensitive, and thermally robust actinometer. Although 2NB has been used in a number of solution and ice experiments in the laboratory, the quantum efficiencies and molar absorptivities of 2NB have not been critically evaluated, especially on ice. Using a series of laboratory and field measurements we have measured the light absorbance and photochemical properties of 2-nitrobenzaldehyde in solution (water and/or acetonitrile) and in/on water ice. Our results show that the molar absorptivities of 2NB are only weakly dependent upon temperature and that the quantum yield is independent of temperature in water; the quantum yield is also independent of wavelength, as shown by past reports. Furthermore, we find that the photochemistry of 2NB in/on water ice is the same as in liquid water. While most studies employing 2NB cite and use a quantum yield of 0.50, based on a review of the literature, and on our new experimental data, we recommend a quantum yield of 0.41 for 2NB photolysis for both solution and water ice. 相似文献
992.
B. Madhu Babu G. Santosh KumarPramod B. Thakur Vikas M. BangadeH.M. Meshram 《Tetrahedron letters》2014
A mild and novel approach is described for the synthesis of functionalized fused imidazole analogues in solvent-free and catalyst-free condition in ionic liquid. The short reaction time, good isolated yields, generality and environmentally benign reaction media are the significant features of this protocol. 相似文献
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Anatoliy A. Pogoruy Ramón M. Rodríguez-Dagnino 《Advances in Applied Clifford Algebras》2010,20(1):79-84
The aim of this work is to prove some basic properties of coquaternions and to find the zeros of polynomials involving coquaternionic
elements. We also provide some expansions of hyperholomorphic function on coquaternion algebra by using Fueter polynomials. 相似文献
996.
Amalia M. Estévez Raquel G. Soengas José M. Otero Juan C. Estévez Robert J. Nash Ramón J. Estévez 《Tetrahedron: Asymmetry》2010,21(1):21-26
A divergent synthesis of the two novel polyhydroxylated azepanes (2R,3R,4R,5R,6R)-2-(hydroxymethyl)azepane-3,4,5,6-tetraol and (2R,3R,4R,5R,6S)-2-(hydroxymethyl)azepane-3,4,5,6-tetraol from d-mannose is described. The method involves a Henry reaction between dimethyl-tert-butylsilyl 2,3-O-isopropylidene-α-d-lyxo-pentodialdo-1,4-furanoside and 2-nitroethanol followed by a reductive ring closure of the resulting epimeric nitro aldols. Glycosidase inhibition tests showed that (2R,3R,4R,5R,6S)-2-(hydroxymethyl)azepane-3,4,5,6-tetraol exhibits a weak but selective inhibition against α-l-fucosides. 相似文献
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The reaction of hydroxylamine hydrochloride with ethyl 3‐aroyl‐1‐cyano‐4‐hydroxy‐2,4,6‐triarylcyclohexanecarboxylate has led to the formation of ethyl 2‐[amino(hydroxyimino)methyl]‐3‐aryl‐5‐(hydroxyimino)‐5‐arylpentanoate via a tandem ring opening and oximation process. The structures of the products are confirmed by NMR and X‐ray techniques, and the conformational features of the product arrived at are compared with a molecular dynamics simulation study. 相似文献
1000.
Atma Ram Sahu 《International Journal of Mathematical Education in Science & Technology》2013,44(6):727-735
An attempt has been made to present an overview of the current research work done in the area of ‘Microteaching’. It also incorporates a list of current research resources for the use of research workers in this area. The study has led to some pertinent research questions which need further experimentation and investigation in the field of microteaching for their resolution. 相似文献