Synthesis and crystal structures of 2-bromo-1,3-di-methyl-imidazolium iodides

Martin Lampl; Gerhard Laus; Volker Kahlenberg; Klaus Wurst; Hubert Huppertz; Herwig Schottenberger

doi:10.1107/S2056989018003390

Synthesis and crystal structures of 2-bromo-1,3-di-methyl-imidazolium iodides

Acta Crystallogr E Crystallogr Commun. 2018 Mar 9;74(Pt 4):497-501. doi: 10.1107/S2056989018003390. eCollection 2018 Apr 1.

Authors

Martin Lampl¹, Gerhard Laus¹, Volker Kahlenberg², Klaus Wurst¹, Hubert Huppertz¹, Herwig Schottenberger¹

Affiliations

¹ University of Innsbruck, Faculty of Chemistry and Pharmacy, Innrain 80-82, 6020 Innsbruck, Austria.
² University of Innsbruck, Institute of Mineralogy and Petrography, Innrain 52, 6020 Innsbruck, Austria.

Abstract

Attempts at direct bromination of 1,3-di-methyl-imidazolium salts were futile. The title compounds, 2-bromo-1,3-di-methyl-imidazolium iodide chloro-form 0.33-solvate, C₅H₈BrN₂⁺·I^-·0.33CHCl₃, 2-bromo-1,3-di-methyl-imidazolium iodide di-chloro-methane hemisolvate, C₅H₈BrN₂⁺·I^-·0.5CH₂Cl₂, and 2-bromo-1,3-di-methyl-imidazolium iodide hemi(diiodide), C₅H₈BrN₂⁺·I^-·0.5I₂, were obtained by methyl-ation of 2-bromo-1-methyl-imidazole. They crystallized as CHCl₃, CH₂Cl₂ or I₂ solvates/adducts. The Br atom acts as a σ-hole to accept short C-Br⋯I inter-actions. C-H⋯I hydrogen bonds are observed in each structure.

Keywords: bromo; chloroform; crystal structure; dichloromethane; imidazole; iodide.