1H NMR and 35Cl NQR spin—lattice relaxation study of molecular motion in solid trimethylamine—trichloroborane complex

Furukawa, Yoshihiro

doi:10.1016/0022-2860(93)07913-h

Cited by 2 publications

(2 citation statements)

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“…A very recent study of the molecular motion in solid (CH3)3NBC13 using *H NMR and 35C1 NQR demon strated quite clearly that the molecule as a whole ro tates with an activation energy of about 51-52 kJ/mol [24]. This was interpreted as being due to the predom inance of intramolecular over intermolecular forces.…”

Section: Resultsmentioning

confidence: 98%

“…Solid state X H, 19F, and n B NMR spectroscopy have been used to study the various modes of molecular motion for those com pounds with X = H, F, and CI [11,[18][19][20][21][22][23][24]. In particu lar the borane adduct, (CH3)3NBH3 was first studied by Yim and Gilson in 1970 [11], They interpreted second moment results with a model in which rotation of both CH3 and BH3 groups was fast at 120 K; and a torsional oscillation about the B -N bond existed at higher temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Dynamics in the Solid Trimethylamine-Borane Complex: A Deuterium NMR Study

Penner

Zhao

Jeffrey

1995

Zeitschrift Für Naturforschung A

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The molecular dynamics of solid (CH3)3NBH3 is investigated by deuterium NMR spectroscopy. Variable temperature lineshape analyses yield activation energies of 27 + 3, 19 + 2, and 12.5 ± 2 kJ/mol for -CH3, -N(CH3)3 and -BH3 rotation, respectively. Analysis of the temperature depen dence of the spin-lattice relaxation times, Tt , gives activation energies of 33 + 3, 15 + 1.5, and 14 + 1.5 kJ/mol, respectively. Direct comparison of rotational exchange rates (from lineshape simu lations) an of rotational correlation times (from Tx analyses) for -N(CH3)3 and -BH3 rotation indicate that the two motions are correlated in solid (CH3)3NBH3 and together constitute a whole molecule reorientation about the N-B bond. This is supported by an internal rotational barrier of 18.0 kJ/mol for-BH3 rotation, obtained from ab initio molecular orbital calculations at the MP2/6-31G* level.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%