Spatial Contributions to 1H NMR Chemical Shifts of Free-Base Porphyrinoids

Prediction of 1H NMR chemical shifts using neural networks.

Counterpropagation neural networks were applied to the fast prediction of 1H NMR chemical shifts of CHn groups in organic compounds. The training set consisted of 744 examples of protons that were represented by physicochemical, topological, and geometric descriptors. The selection of descriptors was performed by genetic algorithms, and the models obtained were compared to those containing all ...

The prediction of 1H NMR chemical shifts in organic compounds

www.spectroscopyeurope.com Introduction and historical Proton (H) nuclear magnetic resonance, NMR, spectroscopy began in 1951 with the historic experiment of Arnold, Dharmatti and Packard, when they resolved the three types of hydrogen atoms in ethanol, and this illustrated the immense potential of H NMR in structural organic chemistry. Since this discovery H NMR has become one of the commonest...

1H chemical shifts in NMR: Part 23, the effect of dimethyl sulphoxide versus chloroform solvent on 1H chemical shifts.

The 1H chemical shifts of 124 compounds containing a variety of functional groups have been recorded in CDCl3 and DMSO-d6 (henceforth DMSO) solvents. The 1H solvent shift Delta delta = delta(DMSO) - delta(CDCl3) varies from -0.3 to +4.6 ppm. This solvent shift can be accurately predicted (rms error 0.05 ppm) using the charge model of alpha, beta, gamma and long-range contributions. The labile p...

H Chemical Shifts in NMR

1H chemical shifts in NMR: Part 22-Prediction of the 1H chemical shifts of alcohols, diols and inositols in solution, a conformational and solvation investigation.

The (1)H NMR spectra of a number of alcohols, diols and inositols are reported and assigned in CDCl(3), D(2)O and DMSO-d(6) (henceforth DMSO) solutions. These data were used to investigate the effects of the OH group on the (1)H chemical shifts in these molecules and also the effect of changing the solvent. Inspection of the (1)H chemical shifts of those alcohols which were soluble in both CDCl...