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Electron Diffraction Analysis for the Molecules with Multiple Large Amplitude Motions. 3-Nitrostyrene – A Molecule with Two Internal Rotorsстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 5 апреля 2017 г.
- Авторы: Kovtun Dmitry M., Kochikov Igor V., Tarasov Yury I.
- Журнал: The Journal of Physical Chemistry A: Molecules, Clusters, and Aerosols
- Том: 119
- Номер: 9
- Год издания: 2015
- Издательство: American Chemical Society
- Местоположение издательства: United States
- Первая страница: 1657
- Последняя страница: 1665
- DOI: 10.1021/jp5082774
- Аннотация: ABSTRACT. Dynamic structural analysis of the molecules possessing large-amplitude degrees of freedom has been attempted by many researchers; however, so far electron diffraction investigations involved only one large-amplitude coordinate (internal rotation or bending). Current state of computational facilities allows extending general dynamic approach to the systems possessing two or more large-amplitude motions. This paper presents the first practical implementation of the theoretical method developed previously by the authors for solving dynamic-structural problem with two or more large-amplitude coordinates; the procedure is applied to a molecule of 3-nitrostyrene. The molecule is represented as a set of pseudoconformers built on a two-dimensional grid corresponding to both internal rotation coordinates present in the molecule (with 10 to 30 degrees step by each angle); altogether up to 342 pseudoconformers were used. Structural analysis was based on the experimental electron diffraction data supported by quantum chemical calculations (at the MP2 and B3LYP levels of theory) and molecular spectroscopy data. Quantum chemistry predicts the planar structure of both syn- and anti- stable conformations with close energies and weak interaction between internal rotations of nitro and vinyl groups. The gas phase electron diffraction experimental data are compatible with the quantum chemical predictions. The principal equilibrium geometry parameters of the molecule (syn-conformation) have been determined as follows; re(C-C)ring, avg. = 1.391(1) Å, re(C-C) = 1.477(5) Å, re(C=C) = 1.333(7) Å, re(C-N) = 1.463(5) Å, re(N=O) = 1.227(3) Å, ∠e(O=N=O) = 124.3 (4)°. Experimental data for this molecule is insufficient to make estimates of the barrier heights of internal rotation; population ratio of syn- and anti- conformations is evaluated as 50±20 per cent. Results of our investigation confirm the presence of significant internal rotations in 3-nitrostyrene molecule.
- Добавил в систему: Ковтун Дмитрий Михайлович