نتایج جستجو برای: nmr shielding

تعداد نتایج: 67435  

2008
MOHAMMED I. M. WAZEER ANVARHUSEIN A. ISAB

Reactions of imidazolidine-2-thione (Imt), 1,3-diazinane-2-thione (Diaz) and 1,3-diazipane-2thione (Diap) with mercury(II) selenocyanate in acetonitrile resulted in formation of 2 : 1 complexes. Both solid state and solution NMR, confirm the exocyclic sulfur atom to be the donor in all cases. Hg shielding tensors and anisotropies were calculated from the solid-state NMR spectra. Based on the so...

F. Mollaamin K. Shahanipour M. Monajjemi T. Nejad Salari

We have evaluated the NMR shielding tensors for active site of oxidized ayurin Azurin is classified to atype I copper protein with ET functionality. We have computed NMR shielding tensor at .133LYP and IDlevels by usum 6-3IG basis set in the gas phase and in different solvents such as water, HMSO,Nitromethane, methanol, ethanol, acetone ,dicholoroethane. These solvents represent a wide range of...

Journal: :journal of physical & theoretical chemistry 2004
m.a seyed sajjadi r. sayadi g. ghasem kh. kalateh

the interaction of magnesium hydrate at the phosphate oxygen atom of the pyrimidine nucleotides (cmp,ump,dtmp) were studied at the hartree-fock level theory. we used lanl2dz basis set for mg and 6-31g* basis set for atoms.the basis set superposition error (bsse) begins to converge for used method/basis set. the gauge-invariant atomic orbital (giao) method and the continuous-set-of-gauge-transfo...

Journal: :international journal of nano dimension 0
m. farahani sama technical and vocational training collage, islamic azad university, malayer branch, malayer, iran. z. ghasemi department of chemistry, boroujerd branch, islamic azad university, boroujerd, iran. a. seif department of chemistry, boroujerd branch, islamic azad university, boroujerd, iran.

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 ...

M. Monajjemi M. Sheikhi

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...

H. Passdar L. Pishkar L. Saedi M. Khaleghian R. Ahmadi S. Reihani Z. Azizi

The interaction of DPPA which is an important component in cellular membrane with molecules of water asmedia, cause some changes in geometry of DPPA .In this study we focused our attention on comparing thismolecule with related hydrated complexes employing different basis sets at hartree-fock levels of theory. Thetheoretical NMR shielding tensor of some imported atoms were also reported.

Journal: :journal of physical & theoretical chemistry 2012
e. pournamdari m. monajjemi

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...

Journal: :journal of physical & theoretical chemistry 2011
m. monajjemi m. sheikhi

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...

Journal: :The Journal of chemical physics 2006
Christoph R Jacob Lucas Visscher

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...

2002
Sungsool Wi Stephen Wimperis Lucio Frydman

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 ...

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