Structure of Isolated 1,4-Butanediol: Combination of MP2 Calculations, NBO Analysis, and Matrix-Isolation Infrared Spectroscopy

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• 作者：A. J. Lopes Jesus ; M&#xe1 ; rio T. S. Rosado ; Igor Reva ; Rui Fausto ; M. Ermelinda S. Eus&#xe9 ; bio ; J. S. Redinha
• 刊名：Journal of Physical Chemistry A
• 出版年：2008
• 出版时间：May 22, 2008
• 年：2008
• 卷：112
• 期：20
• 页码：4669 - 4678
• 全文大小：858K
• 年卷期：v.112,no.20(May 22, 2008)
• ISSN：1520-5215

文摘

Theoretical calculations at the MP2 level, NBO and AIM analysis, and matrix-isolation infrared spectroscopy have been used to investigate the structure of the isolated molecule of 1,4-butanediol (1,4-BDO). Sixty-five structures were found to be minima on the potential energy surface, and the three most stable forms are characterized by a folded backbone conformation leading to the formation of an intramolecular H-bond. To better characterize the intramolecular interactions and particularly the hydrogen bonds, natural bond orbital analysis (NBO) was performed for the four most stable conformers, and was further complemented with an atoms-in-molecules (AIM) topological analysis. Infrared spectra of 1,4-BDO isolated in low-temperature argon and xenon matrixes show a good agreement with a population-weighted mean theoretical spectrum, and the spectral features of the conformers expected to be trapped in the matrixes were observed experimentally. Annealing the xenon matrix from 20 to 60 K resulted in significant spectral changes, which were interpreted based on the barriers to intramolecular rotation. An estimation of the intramolecular hydrogen bond energy was carried out following three different methodologies.