Solid State Annular Tautomerism in a Molecule Containing Two Imidazole Moieties

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• 作者：Michael G. B. Drew ; Debashree Das ; Senjuti De ; Jnan Prakash Naskar and Dipankar Datta
• 关键词：Imidazole ; Tautomerisation ; Hydrogen bonding ; DFT
• 刊名：Journal of Chemical Crystallography
• 出版年：2008
• 出版时间：July, 2008
• 年：2008
• 卷：38
• 期：7
• 页码：507-512
• 全文大小：270.5 KB

文摘

Abstract The X-ray crystal structure of the 1:2 condensate (1) of hydrazine hydrate and 4-methyl-imidazole-5-carboxaldehyde has been determined. The molecule is centrosymmetric crystallising in the space group Fddd with cell dimensions: a = 10.557(14), b = 17.062(22), c = 24.759(27) ?. Fourier map shows that the NH hydrogen atom of each imidazole moiety has equal possibility of occupying any of its two ring N atoms. This poses the possibility of finding three tautomers in 1 in the solid state. Consideration of the H-bonding pattern observed in 1 and related B3LYP/6-311+G(2d,p) calculations show that only two tautomers are present in the solid state. The situation is compared with that in the structure of 4(5)-nitro-5(4)-methoxy-imidazole reported previously by Kubicki.