## Abstract Carbon‐13 spin–lattice relaxation times were measured for some penta‐ and tricarbonylchromium complexes of organic ligands. The chemical shift anisotropy of the carbonyl carbons was estimated to be __ca.__ 500 ppm. The contributions of dipole–dipole and chemical shift anisotropy mechani
Molecular modelling, NOED and spin—lattice relaxation study of the stereochemistry of some terpenoids
✍ Scribed by Ning Qing; Lawrence D. Colebrook; Fernando Commodari
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 539 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
NOED, COSY and HETCOR experiments in conjunction with molecular mechanics calculations, were used to assign the ^1^H and ^13^C NMR spectra of the terpenoids α‐ionone and methyl O‐methylpodocarpate and to investigate their stereochemistry. These compounds were used as models to investigate the ability of molecular mechanics and associated calculations to predict ^1^H spin—lattice relaxation rates in molecules of this type.
📜 SIMILAR VOLUMES
A numerical estimate of the spin-lattice relaxation in molecular crystals and mixed molecular crystals is presented on the assumption that a direct mixing of the spin-levels arises because of the modulatIcn of the spin-orbit Interaction by the orbit-lattice interaction. The cases of neat and mixed c
Proton spin-lattice relaxation rates (Rl values) have been measured, at 400 MHz, for a number of 2-methyland 2,2-dimethyl-substituted 4,6-diamino-l-aryl-l,2-dihydro-s-~es. These compounds have high barriers to internal rotation about the aryl C-N bond, and exist in solution as mixtures of enantiomer
## Abstract The motional behaviour of 5‐nitro‐2‐(2‐pyridinylthio)pyridine (NPTP) was ananlysed by ^13^C NMR spin‐lattice relaxation times (__T__~1~). The analysis of the experimental __T__~1~ data was performed by using an analytical model to describe the overall and internal motions fo the molecul
It is shown that the spm-spin and spin-lattice relaxation rates in the lowest triplet state of aniline in a p-xylene host crystal are determmed by the presence of a close-lying local phonon state. It is concluded that the motion of the aniline molecule has a highly localised character.