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排序方式: 共有72条查询结果,搜索用时 8 毫秒
31.
Paul D. Woodgate Yogendra Singh Clifton E. F. Rickard 《Journal of organometallic chemistry》1998,560(1-2)
Two novel tricarbonyl[(3a,7a)-octahydro-3-substituted-2-(η6-phenyl)benzoxazole]chromium(0) complexes have been synthesised in excellent yield and characterised by X-ray crystallography. Treatment of complex 1 with butyllithium followed by electrophile quench (MeI, MeSSMe, Me3SiCl, Me3SnCl, Ph2PCl, PhCH2Br, PhCHO) gave 1,2-disubstituted (η6-arene)Cr(CO)3 complexes in excellent yield, by completely diastereoselective ortho-deprotonation. The structures of the products 5 and 10 have been established by X-ray crystallographic analyses. 相似文献
32.
Summary Dichlorobis(methylcyclopentadienyl)titanium(IV) reacts with 1,5-diarylthiocarbazones (aryl=phenyl,p-tolyl,o-chlorophenyl orp-chlorophenyl) in 11 and 12 molar ratios in tetrahydrofuran in the presence of triethylamine, to yield [(MeCp)2Ti(HDz)Cl], [(MeCp)2Ti(Dz)] and [(MeCp)2-Ti(HDz)2] (MeCp=methylcyclopentadienyl; HDz– and Dz2– are the mono- and di-anions of a 1,5-diarylthiocarbazone, H2Dz).S-Methyl-1,5-diphenylthiocarbazone and [(MeCp)2TiCl2] react to give [(MeCp)2Ti(MeDz)Cl] and [(MeCp)2Ti(MeDz)2] (MeDz– represents the mono-anion ofS-methyl-1,5-diphenylthiocarbazone, HMeDz) in an excess of triethylamine. These new derivatives have been characterised on the basis of elemental analyses, magnetic moment, electrical conductance, i.r.,1H n.m.r. and electronic spectral studies. 相似文献
33.
In the present investigation an analytical technique using Chebyshev series expansion has been presented and used to study the non-linear transient behavior of shallow spherical shells with and without damping. The two coupled non-linear differential equation governing the shallow shell behavior are initially linearised using Taylor's series expansion. Results have been presented for three types of transient loadings, namely, step function, N-shaped pulse and sine wave pulse. It is shown that accurate results can be obtained using a five terms Chebyshev series expansion which is unlikely in the conventional methods. 相似文献
34.
Singh Y Stoermer MJ Lucke AJ Guthrie T Fairlie DP 《Journal of the American Chemical Society》2005,127(18):6563-6572
A major chemical challenge is the structural mimicry of discontinuous protein surfaces brought into close proximity through polypeptide folding. We report the design, synthesis, and solution structure of a highly functionalized saddle-shaped macrocyclic scaffold, constrained by oxazoles and thiazoles, supporting two short peptide loops projecting orthogonally from the same face of the scaffold. This structural mimetic of two interhelical loops of cytochrome b(562) illustrates a promising approach to structurally mimicking discontinuous loops of proteins. 相似文献
35.
Ram N. Patel Yogendra Singh Yogendra Pratap Singh Raymond J. Butcher 《Journal of Coordination Chemistry》2016,69(15):2377-2390
The two new nickel(II) complexes, [Ni(HL)(L)](NO3)?H2O (1) and [Ni(L)2] (2) (where HL/L = N′-[(E)-phenyl(pyridin-2-yl)methylidene]benzohydrazide), have been synthesized and characterized by elemental analysis, spectroscopic, magnetic susceptibility, and cyclic voltammetric measurements. Single-crystal X-ray analysis of [Ni(HL)(L)](NO3)?H2O (1) and [Ni(L)2] (2) has revealed the presence of a distorted octahedral geometry around nickel(II). The X-ray and spectral characterizations have confirmed the existence of the keto-enol form of the ligands in the complexes. The electronic structures and spectral properties of the ligands and the complexes have been explained by DFT and TDDFT calculations. Superoxide dismutase activity of these complexes has also been measured. 相似文献
36.
37.
Ramesh C. Ghildiyal Shrikant M. Nanoti Narendra N. Kulsrestha Bachan S. Rawat Yogendra Kumar Rajamani Krishna 《Fluid Phase Equilibria》1989,50(3):339-346
For the toluene-methyl ethyl ketone-water system the liquid-liquid equilibrium tie-line data have been determined at 40 and 0°C and the binodal curve for this system has been determined at 40, 0 and −10°C. The tie-line data at 40 and 0°C could be correlated with good accuracy using NRTL and UNIQUAC model equations. 相似文献
38.
Yogendra Kumar Sanjay Kumar Saxena Meera Venkatesh Ashutosh Dash 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):109-114
This article presents the development, the testing and the efficiency estimation of a system for the monitoring of the atmospheric
concentration of radon using a detector ionization chamber type in pulse mode for environmental measurements in which the
measurement of the average value of the ionization current is completed with the recording of the impulses of the ionization
current caused by the alpha disintegrations from the sensible volume of the detector. 相似文献
39.
Narayanan S Fedorov AG Joshi YK 《Langmuir : the ACS journal of surfaces and colloids》2011,27(17):10666-10676
A semianalytical, continuum analysis of evaporation of water confined in a cylindrical nanopore is presented, wherein the combined effect of electrostatic interaction and van der Waals forces is taken into account. The equations governing fluid flow and heat transfer between liquid and vapor phases are partially integrated analytically, to yield a set of ordinary differential equations, which are solved numerically to determine the flow characteristics and effect on the resulting shape and rate of evaporation from the liquid-vapor interface. The analysis identifies three important parameters that significantly affect the overall performance of the system, namely, the capillary radius, pore-wall temperature, and the degree of saturation of vapor phase. The extension of meniscus is found to be prominent for smaller nanoscale capillaries, in turn yielding a greater net rate of evaporation per unit pore area. The effects of temperature and ambient vapor pressure on net rate of evaporation are shown to be analogous. An increase in pore-wall temperature, which enhances saturation pressure, or a decrease in the ambient vapor pressure result in enhancing the net potential for evaporation and increasing the curvature of the interface. 相似文献
40.
Manish Pratap Singh Yogendra Lal Verma Abhishek Kumar Gupta Rajendra Kumar Singh Suresh Chandra 《Ionics》2014,20(4):507-516
Dielectric relaxation measurement has been carried out on an ionic liquid (1-butyl-3-methyl imidazolium hexafluorophosphate, [BMIM][PF6]) confined in nano-porous silica matrix. Two dielectric relaxation peaks have been observed in the confined ionic liquid (IL) while there is only one relaxation peak for bulk IL. Confinement results in layering of some IL molecules near the pore wall while other molecules, less affected by pore wall interaction, remain in the central core. The two relaxation peaks are assigned to the different dynamical behaviors of the central core and layered IL molecules. 相似文献