2,4,5-Trimethylimidazolium Scaffold for Anion Recognition Receptors Acting Through Charge-Assisted Aliphatic and Aromatic C–H Interactions

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• 作者：Paula Sabater ; Fabiola Zapata ; Antonio Caballero ; Israel Fernández ; Carmen Ramirez de Arellano ; Pedro Molina
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：May 6, 2016
• 年：2016
• 卷：81
• 期：9
• 页码：3790-3798
• 全文大小：589K
• 年卷期：0
• ISSN：1520-6904

文摘

A series of two-armed 2,4,5-trimethylimidazolium-based oxoanion receptors, which incorporate two end-capped photoactive anthracene rings, being the central core an aromatic or heteroaromatic ring, has been designed. In the presence of HP₂O₇^3–, H₂PO₄^–, and SO₄^2– anions, ¹H- and ³¹P NMR spectroscopical data clearly indicate the simultaneous occurrence of several charge-assisted aliphatic and aromatic C–H noncovalent interactions, i.e., significant downfield shifts were observed for the imidazolium C(2)–CH₃ protons, the methylene N–CH₂ protons, and the inner aromatic proton or the outer heteroaromatic protons. Density functional theory calculations confirm the occurrence of these noncovalent interaction and suggest that the interaction between the anions and the receptors is mainly electrostatic in nature.