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Piyush Deokar Dr. Monica Vasiliu Prof. Dr. David A. Dixon Prof. Dr. Karl O. Christe Prof. Dr. Ralf Haiges 《Angewandte Chemie (International ed. in English)》2016,55(46):14350-14354
The binary zirconium and hafnium polyazides [PPh4]2[M(N3)6] (M=Zr, Hf) were obtained in near quantitative yields from the corresponding metal fluorides MF4 by fluoride–azide exchange reactions with Me3SiN3 in the presence of two equivalents of [PPh4][N3]. The novel polyazido compounds were characterized by their vibrational spectra and their X‐ray crystal structures. Both anion structures provide experimental evidence for near‐linear M‐N‐N coordination of metal azides. The species [M(N3)4], [M(N3)5]? and [M(N3)6]2? (M=Ti, Zr, Hf) were studied by quantum chemical calculations at the electronic structure density functional theory and MP2 levels. 相似文献
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Ujashkumar A. Shah Hemantkumar S. Deokar Shivajirao S. Kadam Vithal M. Kulkarni 《Molecular diversity》2010,14(3):559-568
Cyclooxygenase-2 (COX-2) inhibitors are widely used for the treatment of pain and inflammatory disorders such as rheumatoid
arthritis and osteoarthritis. A series of novel 2-(4-methylsulfonylphenyl)pyrimidine derivatives has been reported as COX-2
inhibitors. In order to understand the structural requirement of these COX-2 inhibitors, a ligand-based pharmacophore and
atom-based 3D-QSAR model have been developed. A five-point pharmacophore with four hydrogen bond acceptors (A) and one hydrogen
bond donor (D) was obtained. The pharmacophore hypothesis yielded a 3D-QSAR model with good partial least-square (PLS) statistics
results. The training set correlation is characterized by PLS factors (r
2 = 0.642, SD = 0.65, F = 82.7, P = 7.617 e − 12). The test set correlation is characterized by PLS factors (Q
2
ext = 0.841, RMSE = 0.24,Pearson−R = 0.91). A docking study revealed the binding orientations of these inhibitors at active site amino acid residues (Arg513,
Val523, Phe518, Ser530, Tyr355, His90) of COX-2 enzyme. The results of ligand-based pharmacophore hypothesis and atom-based
3D-QSAR give detailed structural insights as well as highlights important binding features of novel 2-(4-methylsulfonylphenyl)pyrimidine
derivatives as COX-2 inhibitors which can provide guidance for the rational design of novel potent COX-2 inhibitors. 相似文献
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Ralf Haiges Piyush Deokar Karl O. Christe 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(21):5535-5538
Several new donor–acceptor adducts of niobium and tantalum pentaazide with N‐donor ligands have been prepared from the pentafluorides by fluoride–azide exchange with Me3SiN3 in the presence of the corresponding donor ligand. With 2,2′‐bipyridine and 1,10‐phenanthroline, the self‐ionization products [MF4(2,2′‐bipy)2]+[M(N3)6]−, [M(N3)4(2,2′‐bipy)2]+[M(N3)6]− and [M(N3)4(1,10‐phen)2]+[M(N3)6]− were obtained. With the donor ligands 3,3′‐bipyridine and 4,4′‐bipyridine the neutral pentaazide adducts (M(N3)5)2⋅L (M=Nb, Ta; L=3,3′‐bipy, 4,4′‐bipy) were formed. 相似文献
15.
Solid H3Mo12O40P is used for an efficient one-pot synthesis of amidoalkyl naphthols using aromatic aldehydes, β-naphthol, and urea or amides in carbon tetrachloride. The catalyst was efficiently recovered from the reaction mixture and reused with negligible loss of catalyst activity. Ambient conditions, simple workup, and good yield are some of the striking features of the present protocol. 相似文献
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H Machner M Betigeri J Bojowald A Budzanowski A Chatterjee J Ernst L Freindl D Frekers W Garske K Grewer A Hamacher J Ilieva L Jarczyk K Kilian S Kliczewski W Klimala D Kolev T Kutsarova J Lieb H Machner A Magiera H Nann L Pentchev HS Plendl D Protić B Razen P Von Rossen BJ Roy R Siudak J Smyrski RV Srikantiah A Strzałkowski R Tsenov K Zwoll 《Pramana》2001,57(2-3):399-416
Total and differential cross sections for the reactions p + d → 3He + m
0 with m=π, η and p + d → 3H+π+ were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon
resonance. For both reactions a strong forward-backward asymmetry was found. The data were compared with model calculations.
The aspect of isospin symmetry breaking is studied.
Representing the GEM Collaboration 相似文献
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DJ Smith KW Ledingham RP Singhal T McCanny P Graham HS Kilic P Tzallas C Kosmidis AJ Langley PF Taday 《Rapid communications in mass spectrometry : RCM》1999,13(14):1366-1373
With the development of high intensity femtosecond lasers, the ionisation and dissociation dynamics of molecules has become an area of considerable interest. Using the technique of femtosecond laser mass spectrometry (FLMS), the molecules carbon disulphide, pyrimidine, toluene, cyclohexanone and benzaldehyde are studied with pulse widths of 50 fs in the near infrared (IR) wavelength region (790 nm). Results are presented and contrasted for laser beam intensities around 10(15) and 10(16) W cm(-2). For the lower intensities, the mass spectra yield dominant singly charged parent ions. Additionally, the appearance of doubly charged parent ions is evident for carbon disulphide, toluene and benzaldehyde with envelopes of doubly charged satellite species existing in these local regions. Carbon disulphide also reveals a small triply charged component. Such atomic-like features are thought to be a strong fingerprint of FLMS at these intensities. However, upon increasing the laser intensity to approximately 10(16) W cm(-2), parent ion dominance decreases and the appearance of multiply charged atomic species occurs, particularly carbon. This phenomenon has been attributed to Coulomb explosions in which the fast absorption of many photons may produce transient highly ionised parent species which can subsequently blow apart. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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M. D'angelo G. Deokar S. Steydli A. Pongrácz B. Pécz M.G. Silly F. Sirotti C. Deville Cavellin 《Surface science》2012,606(7-8):697-701
We have studied CO interaction with SiO2/Si system at high temperature (~ 1100 °C) and 350 mbar by core-level photoemission. Even for short annealing time (5 min) the signal from Si2p and C1s core levels shows a clear change upon CO treatment. Shifted components are attributed to formation of SiC. This is confirmed by TEM imaging which further shows that the silicon carbide is in the form of nano-crystals of the 3C polytype. Photoemission spectroscopy moreover reveals the formation of silicon oxicarbide which could not be evidenced by other methods. Combining these results with previous Nuclear Resonance Profiling study gives a deeper insight into the mechanisms involved in the nanocrystals growth and especially for the reaction equation leading to SiC formation. We show that CO diffuses as a molecule through the silica layer and reacts with the silicon substrate according the following reaction: 4 CO + 4 Si → SiO2 + 2SiC + SiO2C2. 相似文献
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Hydrogenic (two-body) systems are the only atomic systems for which uncertainties in calculations of the energy levels approach the current state of the art in frequency measurement. This article discusses progress in the theory and measurement of transition frequencies in hydrogenic systems. These studies have relevance to the determination of fundamental constants and the testing of physical theories, especially quantum electrodynamics. A set of high accuracy calculable frequency standards could also be realized by using hydrogenic systems. 相似文献
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