In the structural analysis of lignins by 13C-NMR, signal overlap limits definitive assignment and accurate inten­ sity measurement. Selective labeling by 13C-enrichment of a specific carbon in lignin enhances its signal intensity in the spectrum. Further enhancement of the specifically labeled carbons can be realized via difference spectra created from the enriched and unenriched samples. Diffe...

Some of the Adamantane properties were calculated in this study. Chemical shift, free energy ofsolvation, free energy of cavity formation, Henry's law constant, and other properties ofAdamantane in dry phase, three solvents and three temperatures have been calculated with Abinitio method base on density functional theory (DFT) at B3lyp/6-31g, B31yp/6-31g*, B3lyp/6-31+g* and B3lyp/6-31++g** leve...

13CO NMR chemical shifts and 12CO infrared stretching frequencies have been measured for cytochrome P-450cam-CO in the presence of D-camphor and of various camphor analogues. A linear correlation between both parameters delta (13C) and v(CO) was found indicating that the steric and electrostatic interactions acting on the CO ligand are influenced by the substrate. It has been proved that P-450 ...

The 'H and 13C n.m.r. spectra of N-methylated pyridine, pyridazhe, pyrimidhe and pyrazhe and Nfldimethylated pyrimidine and pyrazine have been recorded and analysed. The change in the "C chemical shifts Mder the influence of N-methylation (As) in the diazabenzenes could be predicted by the AS values of pyridine. A comparison of the A6 values of N-methylation with those of N-protonation showed t...

Given the demonstrated utility of coarse-grained modeling and simulations approaches in studying protein structure and dynamics, developing methods that allow experimental observables to be directly recovered from coarse-grained models is of great importance. In this work, we develop one such method that enables protein backbone chemical shifts (1HN, 1Hα, 13Cα, 13C, 13Cβ, and 15N) to be predict...

The NH2-terminal sialoglycopeptides from human erythrocyte glycophorin A have been obtained by specific proteolytic cleavage and gel filtration chromatography. By cyanogen bromide cleavage, a glycosylated octapeptide was obtained from blood group M donors having an amino acid composition and 13C NMR spectrum consistent with the structure (formula: see text) was demonstrated. By Staphylococcus a...

Geometrical and energetic DFT calculations as well as GIAO and NICS chemical shifts have been calculated for 1H-azepine and 5H-dibenz[b,f]azepine and their cations. The last compound has been studied experimentally by 1H and 13C NMR in neutral and acidic conditions establishing that the cation corresponds to an N-protonated structure. The conclusion is that the neutral molecules are antiaromati...