Vaduganathan Manickkam, Doraisamyraja Kalaivani
PG and Research Department of Chemistry, Seethalakshmi Ramaswami College, Tiruchirappalli 620 002, Tamil Nadu, India.
Acta Crystallogr Sect E Struct Rep Online. 2014 Sep 27;70(Pt 10):256-8. doi: 10.1107/S1600536814021084. eCollection 2014 Oct 1.
The title mol-ecular salt, C5H7N2 (+)·C12H8ClN4O7 (-)·0.5H2O, crystallizes as a hemihydrate. The two rings in the barbiturate anion are not coplanar but make a dihedral angle of 43.17 (16)°. The two nitro groups deviate from the ring to which they are attached; the nitro group ortho with respect to the ring junction is more deviated [39.3 (4)°] than that in the para position [4.2 (5)°], probably to overcome steric hindrance. As a result of this, the latter nitro group is more involved in delocalizing the negative charge of the anion than the former nitro group. In the crystal, the cations and anions are linked via N-H⋯O hydrogen bonds forming zigzag chains along [10-1]. The chains are linked by O-H⋯O and C-H⋯O hydrogen bonds, forming slabs lying parallel to (10-1). Further C-H⋯O hydrogen bonds link the slabs, forming a three-dimensional structure.
标题分子盐C5H7N2(+)·C12H8ClN4O7(-)·0.5H2O以半水合物形式结晶。巴比妥酸盐阴离子中的两个环不共面，二面角为43.17 (16)°。两个硝基偏离它们所连接的环；相对于环连接点邻位的硝基比对位的硝基偏离程度更大[39.3 (4)°对4.2 (5)°]，这可能是为了克服空间位阻。因此，后一个硝基比前一个硝基更有助于使阴离子的负电荷离域。在晶体中，阳离子和阴离子通过N-H⋯O氢键相连，沿[10-1]形成锯齿链。这些链通过O-H⋯O和C-H⋯O氢键相连，形成平行于(10-1)的层板。进一步的C-H⋯O氢键连接这些层板，形成三维结构。
