نتایج جستجو برای: chemical shift

تعداد نتایج: 506697  

In the present work, the quantum theoretical calculations of the molecular structure of the (N-(2-benzoylphenyl) oxalamate has been investigated and are evaluated using Density Functional Theory (DFT). The geometry of the title compound was optimized by B3LYP method with 6-311+G(d) basis set. The theoretical 1H and 13C NMR chemical shift (GIAO method) values of the title compound are calculated...

Journal: :Chemical science 2017
Lars A Bratholm Jan H Jensen

The accurate prediction of protein chemical shifts using a quantum mechanics (QM)-based method has been the subject of intense research for more than 20 years but so far empirical methods for chemical shift prediction have proven more accurate. In this paper we show that a QM-based predictor of a protein backbone and CB chemical shifts (ProCS15, PeerJ, 2016, 3, e1344) is of comparable accuracy ...

Journal: :Journal of the American Chemical Society 2002
Xiaolan Yao Mei Hong

We present a new method for determining the orientation of chemical shift tensors in polycrystalline solids with site resolution and demonstrate its application to the determination of the Calpha chemical shift tensor orientation in a model peptide with beta-sheet torsion angles. The tensor orientation is obtained under magic angle spinning by modulating a recoupled chemical shift anisotropy (C...

ژورنال: :international journal of new chemistry 0

using the computational methods, the interaction effect  of glutamine amino acid on graphene was investigated. for this purpose, the density functional theory) dft (in the ground state of 6-31g was used, and the interaction effects of glutamine on graphene was investigated through attachment to two different base positions. different parameters such as energy levels, the amount of chemical shif...

Journal: :journal of physical & theoretical chemistry 2014
maryam mehdizadeh barforushi karim zare

the dopamine has been studied theoretically at the b3lyp/6-31g* level were performed in gasphase. we calculated physical parameters like atomic charges, energy (=>), asymmetry parameter(?), chemical shift @iso, dipole moment and isotropic nmr determinant and in this work we usedgaussian 03 at nmr and calculation by using b3lyp methods with 6-31g* basis set.

2007
Sik Lok Lam

DSHIFT is a web server for predicting chemical shifts of DNA sequences in random coil form or double helical B-form. The prediction methods are based on sets of published reference chemical shift values and correction factors which account for shielding or deshielding effects from neighboring nucleotides. Proton, carbon and phosphorus chemical shift predictions are available for random coil DNA...

1998
Todd M. Alam

The influence of changes in the contracted Gaussian basis set used for ab initio calculations of nuclear magnetic resonance (NMR) phosphorous chemical shift anisotropy (CSA) tensors was investigated. The isotropic chemical shift and chemical shift anisotropy were found to converge with increasing complexity of the basis set at the Hartree-Fock (HF) level. The addition of d polarization function...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2007
Yoko Kawata Yuko Adachi Saori Haga Junko Fukutomi Hirohiko Imai Atsuomi Kimura Hideaki Fujiwara

Temperature and pressure dependences of the 129Xe NMR chemical shift and the signal intensity have been investigated using ZSM-5 as an adsorbent under routine conditions without using any high-pressure or especially high-temperature facilities. The use of a rigorously shielded system and a calibration sample for the signal intensity was found to be valuable to obtain reliable data about the che...

Fatematozzahra Mosavi Salma Ehsani Tilami Seyed Naser Azizi

Nowadays NMR spectroscopy becomes a powerful tool in chemistry because of the NMR chemical shifts. Hartree–Fock theory and the Gauge-including atomic orbital (GIAO) methods are used in the calculation of 29Si NMR chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. Calculations have been performed at geo...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید