نتایج جستجو برای: nmr chemical shielding

تعداد نتایج: 435629  

Adsorption of CO2 on the surface of Single-wall zigzag (5,0) and armchair (4,4) carbon nanotubes (SWCNTs) were studied through using density functional theory (DFT) calculations. Optimizations of geometric were performed at the B3PW91 level of 6-311++G** method standard basis set using GAUSSIAN 03 package of program [1]. Structural models were optimized and adsorption energies, band gap, charge...

Adsorption of CO2 on the surface of Single-wall zigzag (5,0) and armchair (4,4) carbon nanotubes (SWCNTs) were studied through using density functional theory (DFT) calculations. Optimizations of geometric were performed at the B3PW91 level of 6-311++G** method standard basis set using GAUSSIAN 03 package of program [1]. Structural models were optimized and adsorption energies, band gap, charge...

2012
Suvi Ikäläinen Juha Vaara Lauri Halonen Markku Räsänen

Theoretical examination of traditional nuclear magnetic resonance (NMR) parameters as well as novel quantities related to magneto-optic phenomena is carried out in this thesis for a collection of organic molecules. Electronic structure methods are employed, and reliable calculations involving large molecules and computationally demanding properties are made feasible through the use of completen...

F. Naderi H. Masoomi M. Anafcheh M. Ezatvar

DFT calculations were applied to evaluate the electronic and magnetic properties of zigzag BC2Nnanotubes based on the 13C, 15N, and 11B NMR parameters and natural charge analysis. Weconsidered three types of zigzag nanotubes, ZZ-1, ZZ-2, and ZZ-3 (n, 0) with n = 8, 12, and 14. Theobtained results indicated the divisions of the electrostatic environments around C nuclei into a fewlayers, consist...

2001
NICHOLAS F. CAMPAGNA

The unrivaled combination of speed, accuracy, and ease of use make CAE software that employs the BEM ideally suited for analyses involving shielding of MRI and NMR systems.

Journal: :Journal of the American Chemical Society 2004
Cynthia J Jameson

We report, for the first time, a theoretical prediction of the (129)Xe nuclear magnetic resonance chemical shift tensor of xenon atom in a single crystal of silicalite at near-zero occupancy and the temperature dependence of the Xe NMR chemical shift tensor for the polycrystalline silicalite at maximum occupancy. The former is a measure of the sensitivity of the Xe tensor components to the loca...

2006
A. D. Buckingham P. Fischer

Conventional nuclear magnetic resonance spectroscopy is unable to distinguish between the two mirror-image forms (enantiomers) of a chiral molecule. This is because the NMR spectrum is determined by the chemical shifts and spin–spin coupling constants which – in the absence of a chiral solvent – are identical for the two enantiomers. We discuss how chirality may nevertheless be directly detecte...

Journal: :Chemistry 2005
Jose L Sosa-Sánchez Arturo Sosa-Sánchez Norberto Farfán Luis S Zamudio-Rivera Gerson López-Mendoza Javier Pérez Flores Hiram I Beltrán

The reaction between trans-PcSiCl2 (1) and the potassium salts of six fatty acids (2 a-2 f) led to the trans-PcSi[OOC(CH2)nCH3]2 compounds (3 a-3 f), which were characterised by elemental analysis, IR, UV/Vis and 1H, 13C, and 29Si NMR spectroscopy. From a detailed study of the NMR spectra, the strong anisotropic currents of the Pc macrocycle were found to have an effect on up to the sixth methy...

2017
Vangelis Smyrniotopoulos Christian Merten Marcel Kaiser Deniz Tasdemir

Linear diterpenes that are commonly found in brown algae are of high chemotaxonomic and ecological importance. This study reports bifurcatriol (1), a new linear diterpene featuring two stereogenic centers isolated from the Irish brown alga Bifurcariabifurcata. The gross structure of this new natural product was elucidated based on its spectroscopic data (IR, 1D and 2D-NMR, HRMS). Its absolute c...

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