Author:
Chihara Yukiko N.,Nakamura Nobuo,Chihara Hideaki
Abstract
The proton and fluorine second moments and the spin-lattice relaxation times T1 (at 25.75 MHz) were measured in the solid complex trimethylamine–trifluoroborane from 53 to 300 K. There is a cross-relaxation effect between 1H and 19F below 120 K. Their T1 minima near 140 K led to activation energies of 10.6 and 11.1 kJ mol−1 for the reorientation of the methyl and the trifluoride groups, respectively. An additional minimum observed in the T1 of protons at about 240 K was attributed to the reorientation of the trimethylamine group about the N—B bond with an activation energy of 25.0 kJ mol−1. A comparison of these potential parameters with those in other trimethylamine complexes led to a notion that the activation energies for the reorientation of the (CH3)3N group in the trimethylamine–trifluoroborane complex are mainly governed by the intramolecular steric effect.
Publisher
Canadian Science Publishing
Subject
Organic Chemistry,General Chemistry,Catalysis
Cited by
4 articles.
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