In this tutorial review, we discuss the utilization of chemical shift information as well as ab initio calculations of nuclear shieldings for protein structure determination. Both the empirical and computational aspects of the chemical shift are reviewed and the role of molecular dynamics and the accuracy of different computational methods are discussed. It is anticipated that incorporating the...

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 fullerene structures of c20cage and bowl,c20h10 and their n-doped structures as c20cage nh,c20bowl nh, c20h10nh, c20h10n and their isomers are optimized using the mpw1pw91/6-31g level of the theory. magnetic shielding tensors of 14n and 13c atoms are calculated by the same level of the theory. results show that doping an n atom on fullerenes affects differently on the chemical shielding of ...

The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of (1)H(35)Cl are CCl = ...

(‒)-Encecanescin (1) has been isolated from the leaves of Eupatorium aschembornianum. Two conformers are present in the crystal structure as a result of molecular disorder. The structure of 1 was established by 1H- and 13C-NMR spectroscopy in CDCl3 solution using 2D NMR techniques (gHSQC, gHMBC and NOESY). A Monte Carlo random search using molecular mechanics followed by the geometry optimizati...

Despite the importance of (11)B nuclear magnetic resonance (NMR) in structural studies of borate glasses, no clear means of correlating NMR parameters with the number of nonbridging oxygens on three-coordinate boron has been demonstrated. In this work, a series of anhydrous, polycrystalline, binary borates has been examined by (11)B magic-angle spinning (MAS) NMR to obtain precise measurements ...

Through-space isotropic NMR shielding values of a perpendicular diatomic hydrogen probe moved in a 0.5 Å grid 2.5 Å above several polycyclic aromatic/antiaromatic ring and aromatic/aromatic hydrocarbons were computed with Gaussian 03 at the GIAO HF/6-31G(d,p) level. Combinations of benzene fused with cyclobutadiene, with the tropylium ion, and with the cyclopentadienyl anion were investigated. ...

in this work, we have studied binding of clonidine drug (c9h9cl2n3) with zigzag single walled carbonnanotubes (swcnt) (5, 0) by theoretical methods of theory using gaussian 09 software package.binding energies, nmr parameters and homo- lumo gap energy were calculated. results frombinding energies indicate that it is possible thermodynamically to bind clonidine drug to swcnt.the calculated nmr p...

The synthesis of the new vicinal frustrated Lewis pair 5 containing (C6F5)2P-Lewis base and (C6F5)BH-Lewis acid functionality is described. It forms a unique cyclotrimer (5)3 which was structurally characterized by X-ray crystallography and high-resolution solid-state NMR spectroscopy. The relevant NMR Hamiltonian parameters ((11)B and (31)P chemical shielding tensors, (11)B quadrupolar couplin...