排序方式: 共有97条查询结果,搜索用时 15 毫秒
81.
Rupam Dinda Paresh Kumar Majhi Parbati Sengupta Sagarika Pasayat Saktiprosad Ghosh Larry R. Falvello Thomas C.W. Mak 《Polyhedron》2010
The syntheses and characterization of alkali metal complexes [{VO2L}M(H2O}n] (1 and 2) [M = Na+ (1), K+ (2)] of anionic cis-dioxovanadium(V) species (LVO2−) of the Schiff base 2-hydroxybenzoylhydrazone of 2-hydroxybenzaldehyde have been reported. The number of coordinated water molecules in [{VO2L}M(H2O}n] decreases as the charge density of the alkali metal ion decreases (n = 5 for Na+ and 1 for K+). These compounds represented M+-mediated supramolecular assembly [{VO2L}M(H2O}n]∝ with an infinite polymeric structure containing an alternating array of cis-dioxo vanadium(V), [VO2L]−, units and aquated metal ion centres, as confirmed by X-ray crystallographic investigation of both. All the compounds are characterized by elemental analysis, IR, UV–Vis and NMR spectroscopy. 相似文献
82.
Shishir Gupta Sumit Kumar Vishwakarma Dinesh Kumar Majhi Santimoy Kundu 《Applied Mathematical Modelling》2013,37(10-11):6652-6660
The present paper investigates the Love wave propagation in an anisotropic porous layer under the effect of rigid boundary. Effect of initial stresses on the propagation of Love waves in a fluid saturated, anisotropic, porous layer having linear variation in directional rigidities lying in contact over a pre-stressed, inhomogeneous elastic half-space has also been considered. The dispersion equation of phase velocity has been derived and the influence of medium characteristic such as porosity, rigid boundary, initial stress, anisotropy and inhomogeneity over it has been discussed. The velocities of Love waves have been calculated numerically as a function of KH (where K is the wave number and H is the thickness of the layer) and are presented in a number of graphs. 相似文献
83.
Rahul Basu V. Ravindran D. Choudhury R. Gavai S. Gupta J. P. Singh Swapan K. Majhi B. P. Mahapatra Prakash Mathews Rajarshi Ray D. Chakrabarti Pijush Bhattacharjee 《Pramana》2003,60(2):401-404
We discuss potential problems in hadronic physics. Recent developments are reviewed and possible future studies in some interesting
areas which are underway are highlighted. 相似文献
84.
Xing Yang Pankaj Kumar Majhi Huifang Chai Bin Liu Jun Sun Ting Liu Yonggui Liu Liejin Zhou Jun Xu Jiawei Liu Dongdong Wang Yanli Zhao Zhichao Jin Yonggui Robin Chi 《Angewandte Chemie (International ed. in English)》2021,60(1):159-165
The dominated approaches for asymmetric aldol reactions have primarily focused on the aldol carbon–carbon bond‐forming events. Here we postulate and develop a new catalytic strategy that seeks to modulate the reaction thermodynamics and control the product enantioselectivities via post‐aldol processes. Specifically, an NHC catalyst is used to activate a masked enolate substrate (vinyl carbonate) to promote the aldol reaction in a non‐enantioselective manner. This reversible aldol event is subsequently followed by an enantioselective acylative kinetic resolution that is mediated by the same (chiral) NHC catalyst without introducing any additional substance. This post‐aldol process takes care of the enantioselectivity issues and drives the otherwise reversible aldol reaction toward a complete conversion. The acylated aldol products bearing quaternary/tetrasubstituted carbon stereogenic centers are formed in good yields and high optical purities. 相似文献
85.
Biswanath Das Katta Venkateswarlu Kanaparthy Suneel Anjoy Majhi 《Tetrahedron letters》2007,48(31):5371-5374
A convenient and straightforward method has been developed for the synthesis of quinoxalines and dihydropyrazines (DHPs) using α-bromo ketones and 1,2-diamines in the presence of silica supported perchloric acid (HClO4·SiO2) at room temperature. The quinoxalines and DHPs were presumably formed via cyclization-oxidation. The catalyst works under heterogeneous conditions and can be recycled. 相似文献
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Das R Geethangili M Majhi A Das B Rao YK Tzeng YM 《Chemical & pharmaceutical bulletin》2005,53(7):861-862
A new highly oxygenated pseudoguaianolide, 8-beta-acetoxyhysterone C, along with the known compounds, parthenin, coronopilin and hysterone C, has been isolated from a collection of the flowers of Parthenium hysterophorus. The structure of the new compound was derived from the extensive studies of its spectral (mainly 1D and 2D NMR) data. 相似文献
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