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...

This work investigates the nature of second order effects resulting in solid state nuclear magnetic resonance ~NMR!, from cross-correlations between the quadrupolar and shielding couplings. Using an average Hamiltonian theory, it is shown that these effects can bring the nonsecular terms of the shielding interaction into the realm of conventional detection. Such terms include the antisymmetric ...

Paramagnetic, or open-shell, systems are often encountered in the context of metalloproteins, and they are also an essential part of molecular magnets. Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for chemical structure elucidation, but for paramagnetic molecules it is substantially more complicated than in the diamagnetic case. Before the present work, the theory of NMR of ...

There are several facets to our interest in temperature, solvent, and isotope effects on NMR chemical shifts. Excepting molecular beam studies, the application of NMR to the elucidation of molecular structure and mechanisms of molecular reactions nearly always involves observations of molecules in some environment. Before NMR can be used to obtain structural and mechanistic information unambigu...

The NMR signals of 113Cd have been observed in powder samples of the cadmium halides CdF,, CdCl2, CdBr2 '4H20, Cdl 2 , of the cadmium chalcogenides CdO, CdS, CdSe, CdTe and of CdC03 . For m C d in CdCl2 , CdBr2-4H20, CdS and in CdSe anisotropics of the nuclear magnetic shielding have been detected. The shielding tensor in these powders is axially symmetric. For the other specimens no anisotropi...

We present ProCS15: a program that computes the isotropic chemical shielding values of backbone and Cβ atoms given a protein structure in less than a second. ProCS15 is based on around 2.35 million OPBE/6-31G(d,p)//PM6 calculations on tripeptides and small structural models of hydrogen-bonding. The ProCS15-predicted chemical shielding values are compared to experimentally measured chemical shif...

A counterintuitive gauge-dependence of NMR shieldings for rare-gas dimers is presented and analyzed. It is shown that common belief about the existence of a natural gauge-origin for spherical atoms with respect to NMR shielding calculations is wrong.

Geometrical structure, nuclear magnetic resonance (N1,1It) chemical shielding tensors, and chemical shiftsof silicon and carbon nucler are investigated for twn infinite size zigzag and armchair single-walled siliconcarbide nanotabes (SiCNTs). Geometrical structures of SieNTs, Sit bonds and bond angles of St and Cvertices in both zigzag and armchair nanotubes, Indicate that bond lengths are appr...

The nuclear magnetic resonance (NMR) parameters in porphyrin and porphycene have been calculated to investigate their changes during the process of proton exchange, using density-functional theory (DFT) for both the spin-spin coupling constants and the shielding constants. In addition, in calculations on the smaller 1,3-bis(arylimino)isoindoline molecule, we have tested the performance of our c...