Hydrogen-bonded structures of the 1:1 and 1:2 compounds of chloranilic acid with pyrrolidin-2-one and piperidin-2-one
作者:Kazuma Gotoh、Hiroyuki Ishida
DOI:10.1107/s0108270111048165
日期:2011.12.15
In the four compounds of chloranilic acid (2,5-dichloro-3,6-dihydroxycyclohexa-2,5-diene-1,4-dione) with pyrrolidin-2-one and piperidin-2-one, namely, chloranilic acid-pyrrolidin-2-one (1/1), C6H2Cl2O4 center dot C4H7NO, (I), chloranilic acid-pyrrolidin-2-one (1/2), C6H2Cl2O4 center dot 2C(4)H(7)NO, (II), chloranilic acid-piperidin-2-one (1/1), C6H2Cl2O4 center dot C5H9NO, (III), and chloranilic acid-piperidin-2-one (1/2), C6H2Cl2O4 center dot 2C(5)H(9)NO, (IV), the shortest interactions between the two components are O-H center dot center dot center dot O hydrogen bonds, which act as the primary intermolecular interaction in the crystal structures. In (II), (III) and (IV), the chloranilic acid molecules 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 center dot center dot center dot O distances are 2.4728 (11) and 2.4978 (11) angstrom in (I), 2.5845 (11) angstrom in (II), 2.6223 (11) and 2.5909 (10) angstrom in (III), and 2.4484 (10) angstrom 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 center dot center dot center dot O hydrogen bonds, the secondary intermolecular interactions, connect the pyrrolidin-2-one molecules 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.