crystal structures of 1-hydroxyimidazole and its salts1-hydroxyimidazole及其盐的晶体结构.pdf

Crystals 2012, 2, 1492-1501; doi:10.3390/cryst2041492 OPEN ACCESS crystals ISSN 2073-4352 /journal/crystals Article Crystal Structures of 1-Hydroxyimidazole and Its Salts Gerhard Laus 1,* and Volker Kahlenberg 2 1 Faculty of Chemistry and Pharmacy, University of Innsbruck, 6020 Innsbruck, Austria 2 Institute of Mineralogy and Petrography, University of Innsbruck, 6020 Innsbruck, Austria; E-Mail: volker.kahlenberg@uibk.ac.at * Author to whom correspondence should be addressed; E-Mail: gerhard.laus@uibk.ac.at; Tel.: +43-512-507-57080; Fax: +43-512-507-57099. Received: 19 September 2012; in revised form: 28 September 2012 / Accepted: 9 October 2012 / Published: 31 October 2012 Abstract: The crystal structures of 1-hydroxyimidazole and four protic salts (chloride, bromide, sulfate, nitrate) thereof were determined. The molecular geometries (bond lengths and angles) of the free base and the salts were compared. Hydrogen bonding patterns were studied, and OH …N, OH …Cl, OH…Br, OH …O, NH…Cl, NH…Br, and NH …O interactions were identified. Hirshfeld surface analysis gave quantitative insight into these interactions. Keywords: hydrogen bond; hydroxyimidazole; imidazole; Hirshfeld surface analysis 1. Introduction Synthetic routes to 1-hydroxyimidazoles include cyclization of linear precursor molecules, condensation of small fragments, oxidation of imidazole, and partial reduction