A systematic study of the crystallisation products of a series of dicarboxylic acids with imidazole derivatives

Abstract

Nineteen new crystal structures are reported containing α,ω-alkanedicarboxylic acids (HOOC–(CH₂)_n−2–COOH, n = 0–6), maleic acid and fumaric acid with imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole and 1,2-dimethylimidazole. These were characterised by single crystal X-ray diffraction at 120 K and their crystal structures are discussed together with five published structures. In all of the characterised acid–base combinations at least one of the acidic hydrogens has been transferred to the base and most have a 1 : 1 stoichiometry. Nearly two thirds of the crystal structures adopt a basic sheet topology containing hydrogen bonded anion chains linked by cations. The sheet topologies have been classified based upon the principles of a scheme proposed by MacDonald et al. (J. C. MacDonald, P. C. Dorrestein and M. M. Pilley, Cryst. Growth Des., 2001, 1, 29–38).