Hydrogen bonding of DPPE with water that surrounded of membrane, plays an important role in permeability ofmembrane that we were presented this matter with analysis of bond angles and torsion angles before and after ofadded water molecules.Interaction with water molecules causes some changes in the geometry of DPPE which were explained bythe contribution of zwitterionic form of DPPE molecule, a...

Recent ab initio calculations of cobalt NMR shielding show that DFT-GIAO calculations using hybrid functionals are found to reproduce experimental values well. This method is used to calculate the variation of the cobalt NMR shielding tensor of sqaure pyramidal nitrosyl complexes with respect to the CoNO geometry and to differing basal ligands. The isotropic shielding is shown to have a large n...

polycyclic aromatic hydrocarbons (pahs) are a class of compounds consisting of more than twobenzene rings fused in a linear, angular, or clustered arrangement and do not contain hetero atomsor carry subsistent. pahs originate from various sources. they are primarily formed byincomplete combustion of carbon-containing fuels such as wood, coal, diesel, fat, or tobacco. thepresent study reports an...

Applications of liquid crystals (LCs), such as smart windows and the ubiquitous display devices, are based on controlling the orientational and translational order in a small volume of LC medium. Hence, understanding the effects of confinement to the liquid crystal phase behaviour is essential. The NMR shielding of (129)Xe atoms dissolved in LCs constitutes a very sensitive probe to the details...

Abstract. DFT quantum-chemical calculations were carried out for the cationic, zwitterionic and anionic form of the L-Alanyl-L-Alanine di-peptide that can be experimentally accessed at different pH. The N NMR chemical shielding tensor of the amide nitrogen was used for theoretical modeling of the cross-correlated relaxations. In particular, effective chemical shielding anisotropies (effective C...

Nuclear magnetic resonance is the most important form of molecular spectroscopy in chemistry and biochemistry but it is normally blind to chirality. It was predicted in 2004 that precessing nuclear spins in chiral molecules in a liquid in a strong magnetic field induce a rotating electric polarization that is of opposite sign for enantiomers. This polarization arises from the distortion of the ...

Complete nuclear magnetic resonance (NMR) chemical-shielding tensors, sigma, have been computed at different levels of density-functional theory (DFT), within the gauge-including atomic orbital (GIAO) formalism, for the atoms of the peptide model For-L-Ala-NH2 as a function of the backbone dihedral angles phi and psi by employing a dense grid of 10 degrees. A complete set of rigorously orthogon...

From the high-resolution L9F NMR spectrum of single crystal S}W-C6C13F3 its chemical shift shielding tensor is determined. The most shielded direction lies perpendicular to the molecular plane and the least shielded one in the molecular plane perpendicular to the C-F bond. The most (CT33) and least (an) shielded components change significantly in going from 5vw-C6H3F3 and JJW-C6C13F3 to C6F6 wh...

The 52.7 MHz deuteron (2H) solid state NMR spectra of benzene-d6 adsorbed on microcrystal­ line boron nitride and on two graphitized carbon blacks (Graphon and Sterling MT) were measured at temperatures between 75 and 120 K. Both on boron nitride and on the graphitized carbons the benzene molecules exhibit hexad axis rotation which is fast on the NM R time scale. From the spectra of benzene on ...

Complete (17)O chemical shielding (CS) and quadrupole coupling (QC) tensors and their molecular orientations were determined for the central residues in two tripeptides Gly-Gly-Val (GGV) and Ala-Gly-Gly (AGG) by single-crystal NMR methods. Tensor orientations in the two peptides are very similar, however, principal components are different. The most shielded CS and smallest magnitude QC compone...