Thioformaldehyde S-Sulfide, Sulfur Analogue of the Criegee Intermediate: Structures, Energetics, and Rovibrational Analysis

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• 作者：Kevin V. Murphy ; Whitney J. Morgan ; Zhi Sun ; Henry F. Schaefer IIIJay Agarwal
• 刊名：Journal of Physical Chemistry A
• 出版年：2017
• 出版时间：February 9, 2017
• 年：2017
• 卷：121
• 期：5
• 页码：998-1006
• 全文大小：430K
• ISSN：1520-5215

文摘

The ephemeral Criegee intermediate, first postulated over 70 years ago, has only recently been isolated in the gas phase. The sulfur analogue of this canonical zwitterion, thioformaldehyde S-sulfide, has eluded similar analysis; however, argon matrix isolation has been achieved ( te>Angew. Chem., Int. Ed.te>ttp://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve"> 2001ttp://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve">, 40ttp://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve">, 393−396). Here thioformaldehyde S-sulfide and its valence isomer dithiirane are examined with high-level coupled-cluster methods, including the minimum-energy pathway for interconversion. Relative enthalpies calculated from extrapolated energies at the complete basis set limit of the full CCSDTQ method are reported. Isomerization from thioformaldehyde S-sulfide to the lower-lying dithiirane (−7.2 kcal mol^–1) is predicted to include a 27.0 kcal mol^–1 barrier. Harmonic and anharmonic vibrational frequencies are also predicted using second-order vibrational perturbation theory. These results should aid in future gas-phase identification.