Hydrogen-bonded structures of the 1:1 and 1:2 compounds of chloranilic acid with pyrrolidin-2-one and piperidin-2-one

Kazuma Gotoh, Hiroyuki Ishida

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11 Citations (Scopus)


In the four compounds of chloranilic acid (2,5-dichloro-3,6-dihy-droxy- cyclo-hexa-2,5-diene-1,4-dione) with pyrrolidin-2-one and piperidin-2-one, namely, chloranilic acid-pyrrolidin-2-one (1/1), C6H 2Cl2O4·C4H7NO, (I), chloranilic acid-pyrrolidin-2-one (1/2), C6H2Cl 2O1·2C4H7NO, (II), chloranilic acid-piperidin-2-one (1/1), C6H2Cl2O4·C 5H9NO, (III), and chloranilic acid-piperidin-2-one (1/2), C6H2Cl2O4·2C 5H9NO, (IV), the shortest inter-actions between the two components are O - H⋯O hydrogen bonds, which act as the primary inter-molecular inter-action in the crystal structures. In (II), (III) and (IV), the chloranilic acid mol-ecules lie about inversion centres. For (III), this necessitates the presence of two independent acid molecules. In (I), there are two formula units in the asymmetric unit. The O⋯O distances are 2.4728 (11) and 2.4978 (11) Å in (I), 2.5845 (11) Å in (II), 2.6223 (11) and 2.5909 (10) Å in (III), and 2.4484 (10) Å in (IV). In the hydrogen bond of (IV), the H atom is disordered over two positions with site occupancies of 0.44 (3) and 0.56 (3). This indicates that proton transfer between the acid and base has partly taken place to form ion pairs. In (I) and (II), N - H⋯O hydrogen bonds, the secondary inter-molecular inter-actions, connect the pyrrolidin-2-one mol-ecules into a dimer, while in (III) and (IV) these hydrogen bonds link the acid and base to afford three- and two-dimensional hydrogen-bonded networks, respectively.

Original languageEnglish
Pages (from-to)o500-o504
JournalActa Crystallographica Section C: Crystal Structure Communications
Issue number12
Publication statusPublished - Dec 2011

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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