A general method is presented for the reconstruction of interatomic vector orientations from nuclear magnetic resonance ~NMR! spectroscopic data of tensor interactions of rank 2, such as dipolar coupling and chemical shielding anisotropy interactions, in solids and partially aligned liquid-state systems. The method, called PRIMA, is based on a principal component analysis of the covariance matr...

A new method for relativistically corrected nuclear magnetic resonance ~NMR! chemical shifts is developed by combining the individual gauge for the localized orbital approach for density functional theory with the normalized elimination of a small component using an effective potential. The new method is used for the calculation of the NMR chemical shifts of Mo and W in various molybdenum and t...

p53 is one of the gene that has important role in human cell cycle and in the human cancers too.models of codon substitution make it possible to separate mutational biases in the dna fromselective constraints on the protein, and offer a great advantage over amino acid models forunderstanding the evolutionary process of proteins and protein-coding dna sequences. in thiswork, we investigated abou...

This work reports an experimental and theoretical study of the conformational preferences of several Prelog-Djerassi lactone derivatives, to elucidate the (1)H NMR chemical shift differences in the lactonic core that are associated with the relative stereochemistry of these derivatives. The boat-like conformation of explains the anomalous (1)H chemical shift between H-5a and H-5b, in which the ...

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...

A complementary approach that combines NMR measurements, analysis of X-ray and neutron powder diffraction data and advanced quantum mechanical calculations was employed to study the α-polymorph of L-polylactide. Such a strategy, which is known as NMR crystallography, to the best of our knowledge, is used here for the first time for the fine refinement of the crystal structure of a synthetic pol...

The magnitude and orientation of the principal components of the carbonyl carbon chemical shift tensor of a typical aryl aldehyde, 3,4-diben~yloxybenzaldehyde-~~C,~H,, 1, have been determined from the analysis of I3C NMR spectra of static powder samples obtained at 4.7 and 9.4 T. The principal components of the carbon shielding tensor of formaldehyde, 2, have been calculated from the experiment...

Self-assembled capsules are hosts that recognize and surround smaller molecule guests of appropriate size, shape, and chemical surfaces. The space available inside is a cage of fixed solvent molecules, many of which are aromatic. These aromatics provide anisotropic shielding to guests, and a map of induced magnetic shielding for the inner space can be obtained through nucleus-independent chemic...

Nuclear spin relaxation provides detailed dynamical information on molecular systems and materials. Here, first-principles modeling of the chemical shift anisotropy (CSA) relaxation time for the prototypic monoatomic (129)Xe gas is carried out, both complementing and predicting the results of NMR measurements. Our approach is based on molecular dynamics simulations combined with pre-parametrize...