نتایج جستجو برای: nmr shielding tensor
تعداد نتایج: 110240 فیلتر نتایج به سال:
magnesium oxide nanotubes of finite length are investigated by the density functional theory (dft) at the b3lyp/6-31g (d) level. the (6, 0) zigzag and (4, 4) armchair of mgo nanotubes were considered and nuclear magnetic resonance properties including isotropic and anisotropic chemical shielding parameters (csi and csa) were calculated for 25mg and 17o atoms of the optimized structures for the ...
In this research, the Magnetite nanoparticles (Fe304) were prepared by coprecipitation of Fe- andGinger is a well known spice and flavoring agent which has also been used in traditional medicine inmany countries. Ginger contains essential oils including gingerol and zingiberene. It also containspungent principles such as zingerone, and shogaol. In the paper six theoretical methods were used toc...
bcn compounds have been researched theoretically and experimentally widely. in this paper, weintroduce the theoretical prediction of ternary b-c-n compounds. nmr spectroscopy was employedextensively to study these ternary nanostructures. we discuss the utilization of chemical shiftinformation as well as ab initio calculations of nuclear shielding for h20134c9n4 structuredetermination. we calcul...
in this research, the magnetite nanoparticles (fe304) were prepared by coprecipitation of fe- andginger is a well known spice and flavoring agent which has also been used in traditional medicine inmany countries. ginger contains essential oils including gingerol and zingiberene. it also containspungent principles such as zingerone, and shogaol. in the paper six theoretical methods were used toc...
The local response to an external magnetic field normal to the molecular plane of naphthalene and anthracene was investigated via current density and magnetic shielding density maps. The Biot-Savart law shows that the deshielding caused by pi-ring currents in naphthalene is stronger for alpha- than for beta-protons due to geometrical factors. The shielding tensor of the carbon nuclei in both mo...
We have extended the frozen-density embedding (FDE) scheme within density-functional theory [T. A. Wesolowski and A. Warshel, J. Phys. Chem. 97, 8050 (1993)] to include external magnetic fields and applied this extension to the nonrelativistic calculation of nuclear magnetic resonance (NMR) shieldings. This leads to a formulation in which the electron density and the induced current are calcula...
The effect of subtle changes in the sigma-electron donor ability of 4-substituted pyridine ligands on the lead(II) coordination environment of (2,6-Me(2)C(6)H(3)S)(2)Pb (1) adducts has been examined. The reaction of 1 with a series of 4-substituted pyridines in toluene or dichloromethane results in the formation of 1:1 complexes [(2,6-Me(2)C(6)H(3)S)(2)Pb(pyCOH)](2) (3), [(2,6-Me(2)C(6)H(3)S)(2...
We investigate the nature of higher-order effects arising in solid-state nuclear magnetic resonance ~NMR! when quadrupolar nuclei are subject to significant chemical shift anisotropies. It is shown that the quadrupole interaction can give rise to shielding-derived terms that are not entirely averaged away by conventional magic-angle spinning ~MAS!. These terms are proportional to the square of ...
LiCl and LiNO3 water solutions in the presence of small amounts of 3-helium have been investigated by means of multinuclear resonance spectroscopy. The resulting concentration dependences of the 3He, 6,7Li+, NO3 and 35Cl− resonance radiofrequencies are reported in the infinite limit. This data along with new theoretical corrections of shielding lithium ions was analyzed by a known NMR relations...
in this research, we studied the structure, properties and nmr parameters of interaction f2 gas with pristine and 3c-doped (8, 0) zigzag models of boron phosphide nanotubes (bpnts). in order to reach these aims, we considered four different configurations for adsorption of f2gas on the outer and inner surfaces of bpnts. the structures of all models were optimized by using density functional the...
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