Reaction of 1,1,3,3-Tetraoxa-2,2-dibromo- 4,4,5,5,6,6-hexafluoro-1,3-dithiacyclohexane with Pyrazine and Hexamethylphosphoramide: Unexpected Cocrystals through Halogen Bonding

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• 作者：Shizheng Zhu ; Huiling Jiang ; Jingwei Zhao ; and Zhanting Li
• 刊名：Crystal Growth & Design
• 出版年：2005
• 出版时间：September 2005
• 年：2005
• 卷：5
• 期：5
• 页码：1675 - 1677
• 全文大小：248K
• 年卷期：v.5,no.5(September 2005)
• ISSN：1528-7505

文摘

At room temperature, a mixture of 1,1,3,3-tetraoxa-2,2-dibromo-4,4,5,5,6,6-hexafluoro-1,3-dithiacyclohexane(O₂S(CF₂)₃SO₂CBr₂, 2) and excess pyrazine and hexamethylphosphoramide (HMPA) in dichloromethane gave two unexpectedproducts. The first product was the cocrystal 2O₂S(CF₂)₃SO₂CBr₂···2Br (6), in which two bromide ions bridged two moleculesof 2 via four C-Br···Br halogen bonds. The second product was the zwitterion O₂S(CF₂)₃SO₂C^--CH₂N⁺HMe₂, which formeda 1:1 cocrystal with HMPA, O₂S(CF₂)₃SO₂C^--CH₂N⁺HMe₂···O=P(NMe₂)₃ (5), via a strong N-H···O hydrogen bond. Bothproducts have been fully characterized by spectroscopic methods and single-crystal X-ray diffraction analysis. The reactionmechanism is discussed.