Mobility of Solid tert-Butyl Alcohol Studied by Deuterium NMR | Sciact - CRIS-system of Boreskov Institute of Catalysis

Mobility of Solid tert-Butyl Alcohol Studied by Deuterium NMR Full article

Journal

The Journal of Physical Chemistry A
ISSN: 1089-5639 , E-ISSN: 1520-5215

Output data

Year: 2011, Volume: 115, Number: 26, Pages: 7428-7436 Pages count : 9 DOI: 10.1021/jp203353x

Tags

Activation energy; Anisotropy; Deuterium; Functional groups; Nuclear magnetic resonance spectroscopy; Rotation; Spin-lattice relaxation; Tools

Authors

Nishhenko Alena M. ¹ , Kolokolov Daniil I. ² , Stepanov Alexander G. ²

Affiliations

1	Faculty of Physics, Department of Chemical and Biological Physics, Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
2	Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia

The molecular mobility of solid deuterated tert-butyl alcohol (TBA) has been studied over a broad temperature range (103–283 K) by means of solid-state 2H NMR spectroscopy, including both line shape and anisotropy of spin–lattice relaxation analyses. It has been found that, while the hydroxyl group of the TBA molecule is immobile on the 2H NMR time scale (τC > 10(–5) s), its butyl group is highly mobile. The mobility is represented by the rotation of the methyl [CD3] groups about their 3-fold axes (C3 rotational axis) and the rotation of the entire butyl [(CD3)3-C] fragment about its 3-fold axis (C3′ rotational axis). Numerical simulations of spectra line shapes reveal that the methyl groups and the butyl fragment exhibit three-site jump rotations about their symmetry axes C3 and C3′ in the temperature range of 103–133 K, with the activation energies and preexponential factors E1 = 21 ± 2 kJ/mol, k(01) = (2.6 ± 0.5) × 10(12) s(–1) and E2 = 16 ± 2 kJ/mol, k(02) = (1 ± 0.2) × 10(12) s(–1), respectively. Analysis of the anisotropy of spin–lattice relaxation has demonstrated that the reorientation mechanism of the butyl fragment changes to a free diffusion rotational mechanism above 173 K, while the rotational mechanism of the methyl groups remains the same. The values of the activation barriers for both rotations at T > 173 K have the values, which are similar to those at 103–133 K. This indicates that the interaction potential defining these motions remains unchanged. The obtained data demonstrate that the detailed analysis of both line shape and anisotropy of spin–lattice relaxation represents a powerful tool to follow the evolution of the molecular reorientation mechanisms in organic solids.

Nishhenko A.M. , Kolokolov D.I. , Stepanov A.G.
Mobility of Solid tert-Butyl Alcohol Studied by Deuterium NMR
The Journal of Physical Chemistry A. 2011. V.115. N26. P.7428-7436. DOI: 10.1021/jp203353x WOS Scopus РИНЦ ANCAN OpenAlex

Submitted:	Apr 11, 2011
Accepted:	May 27, 2011
Published online:	Jun 10, 2011
Published print:	Jul 7, 2011

Web of science:	WOS:000292281300005
Scopus:	2-s2.0-79959781367
Elibrary:	17000095
Chemical Abstracts:	2011:734972
Chemical Abstracts (print):	155:93510
OpenAlex:	W2074835605

DB	Citing
Web of science	18
Scopus	18
Elibrary	17
OpenAlex	18