Novel 1D and multidimensional solid-state NMR (SSNMR) methods using very fast magic-angle spinning (VFMAS) (spinning speed > 20 kHz) for performing 13C high-resolution SSNMR of paramagnetic organometallic complexes are discussed. VFMAS removes a majority of 13C-1H and 1H-1H dipolar couplings, which are often difficult to remove by RF pulse techniques in paramagnetic complexes because of large p...

Isotope shifts are a well-established tool for structural analysis by NMR. The substitution of a protium with a deuterium is the most widely studied of these effects. However, such studies call for specific deuteration that requires complex synthetic techniques owing to the low natural abundance of deuterium. 13C occurs at a higher natural abundance and couples strongly with its attached proton...

We report a strategy for structure determination of organic materials in which complete solid-state nuclear magnetic resonance (NMR) spectral data is utilized within the context of structure determination from powder X-ray diffraction (XRD) data. Following determination of the crystal structure from powder XRD data, first-principles density functional theory-based techniques within the GIPAW ap...

A remarkable temperature dependence on the 13C NMR and 15N NMR chemical shifts of pyridoxine in water (pH = 7.0) has been observed. C-3, C-6, and N-1 were the most sensitive nuclei to the temperature effect. This dependence has been explained on the basis of an equilibrium shift thermally induced between the neutral and the dipolar form of this molecule. The thermodynamic characterization of ta...

Nearly complete 1H, 13C and 15N NMR assignments have been obtained for a doubly labeled 14-base pair DNA duplex in solution both in the free state and complexed with the uniformly 15N-labeled Antennapedia homeodomain. The DNA was either fully 13C, 15N-labeled or contained uniformly 13C, 15N-labeled nucleotides only at those positions which form the protein-DNA interface in the previously determ...

N,N-dioctyl-azepanium, -piperidinium and -pyrrolidinium bromides 1-3, have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by B3LYP/6-31G(d,p) approach have been presented. Both FTIR and Raman spectra of 1-3 are consistent with the calculated structures in the gas pha...

13C NMR spectra of molecules containing one or two benzene rings linked with CH=CH2, CH=CH (transor cis-), C C and CH=N groups revealed the existence of long range deuterium isotope effects on 13C chemical shifts. It was found that deuterium isotope effects over six bonds (6D) are related to the conformation of investigated molecules. Molecular torsional angles were calculated by ab initio HF/6...

Halogen bonding is a noncovalent interaction between the electrophilic region of a halogen (σ-hole) and an electron donor. We report a crystallographic and structural analysis of halogen-bonded compounds by applying a combined X-ray diffraction (XRD) and solid-state nuclear magnetic resonance (SSNMR) approach. Single-crystal XRD was first used to characterize the halogen-bonded cocrystals forme...

[reaction: see text] Low-temperature 13C NMR spectra of cis-1,4-di-tert-butylcyclohexane (1) showed signals for the twist-boat (1a) and chair (1b) conformations. 13C NMR signals were assigned to specific carbons based on the different populations, different symmetries (time-averaged C(2v) for 1a and time-averaged C(s) for 1b), and calculated chemical shifts (GIAO, HF/6-311+G*). In addition to s...