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High-field orientation effects in the high-resolution proton NMR spectra of diverse porphyrins

✍ Scribed by A. A. Bothner-By; C. Gayathri; P. C. M. van Zijl; C. MacLean; Jan-Ji Lai; Kevin M. Smith

Publisher
John Wiley and Sons
Year
1985
Tongue
English
Weight
369 KB
Volume
23
Category
Article
ISSN
0749-1581

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✦ Synopsis

Dipolar splittings with a quadratic dependence on static magnetic field strength are reported for selected pairs of nuclei in several porphyrins. These splittings are detectable as a result of a slight molecular alignment caused by the interaction of the static magnetic field with the anisotropic magnetic susceptibilities of the porphyrin rings. The magnitude of the splitting yields an effective value for Ax, the anisotropy of the susceptibility. This value includes association effects which may be estimated therefrom. Dipolar splittings between protons of attached vinyl groups can also be measured, and provide information about the average dihedral angle between the planes of the vinyl group and porphyrin ring.

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