Sathya D, Jagan R, Padmavathy R, Kumar R Mohan, Sivakumar K
Department of Physics, Anna University, Chennai 600 025, India.
Acta Crystallogr C. 2013 Aug;69(Pt 8):904-9. doi: 10.1107/S0108270113017629. Epub 2013 Jul 13.
In bis(2-aminoanilinum) fumarate, 2C₆H₉N₂⁺·C₄H₂O₄²⁻, (I), the asymmetric unit consists of two aminoanilinium cations and one fumarate dianion, whereas in 3-methylanilinium hydrogen fumarate, C₇H₁₀N⁺·C₄H3O₄⁻, (II), and 4-chloroanilinium hydrogen fumarate, C₆H₇ClN⁺·C₄H3O₄⁻, (III), the asymmetric unit contains two symmetry-independent hydrogen fumate anions and anilinium cations with a slight difference in their geometric parameters; the two salts are isostructural. In (II) and (III), the carboxylic acid H atoms of the anions are disordered across both ends of the anion, with equal site occupancies of 0.50. Both the 4-chloroanilinium cations of (III) are disordered over two orientations with major occupancies fixed at 0.60 in each case. The hydrogen fumarate anions of (II) and (III) form one-dimensional anionic chains linked through O-H∙∙∙O hydrogen bonds. Salts (II) and (III) form two-dimensional supramolecular sheets built from R₄⁴16), R₄⁴(18), R₅⁵(25) and C₂²(14) motifs extending parallel to the (010) plane, whereas in (I), an (010) sheet is formed built from two R₄³(13) motifs, two R₂²(9) motifs and an R₄⁴(18) motif.
在富马酸双（2-氨基苯胺）盐（2C₆H₉N₂⁺·C₄H₂O₄²⁻，（I））中，不对称单元由两个氨基苯胺阳离子和一个富马酸二阴离子组成，而在富马酸氢3-甲基苯胺盐（C₇H₁₀N⁺·C₄H3O₄⁻，（II））和富马酸氢4-氯苯胺盐（C₆H₇ClN⁺·C₄H3O₄⁻，（III））中，不对称单元包含两个对称独立的富马酸氢阴离子和苯胺阳离子，其几何参数略有差异；这两种盐是同构的。在（II）和（III）中，阴离子的羧酸H原子在阴离子的两端无序分布，位点占有率均为0.50。（III）中的两个4-氯苯胺阳离子在两个取向上无序分布，每种情况下主要占有率固定为0.60。（II）和（III）中的富马酸氢阴离子通过O-H∙∙∙O氢键形成一维阴离子链。盐（II）和（III）形成二维超分子片层，由平行于（010）平面延伸的R₄⁴（16）、R₄⁴（18）、R₅⁵（25）和C₂²（14） motif组成，而在（I）中，一个（010）片层由两个R₄³（13） motif、两个R₂²（9） motif和一个R₄⁴（18） motif组成。
