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Molecular dynamics in solid l-adrenaline by proton NMR

โœ Scribed by E.R. Andrew; B. Peplinska; M. Kempka

Publisher
Elsevier Science
Year
1998
Tongue
English
Weight
114 KB
Volume
10
Category
Article
ISSN
0926-2040

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โœฆ Synopsis

Proton NMR measurements of the spectrum, second moment, spin-lattice relaxation time T and dipolar relaxation time 1 T were carried out on polycrystalline L-adrenaline at 14 and 25 MHz between 55 and 400 K. Between 70 K and 250 K 1D relaxation is dominated by C reorientation of the single methyl group in each molecule, characterized by an activation 3 energy 8.3 " 0.3 kJrmole. Below 70 K tunnelling assisted relaxation is significant, characterized by an excitation energy of 1.9 " 0.2 kJrmole. Above 250 K an additional molecular motion becomes significant, with activation energy above 28 kJrmole, attributed to conformational motion of the methylene group in the ethylamine side chain. q 1998 Elsevier Science B.V.

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