The crystal and molecular structure of disperse dye 3-(4-diethylamino-phenyl-azo)phthalimide C18H17N402 has been determined by single crystal X-ray diffraction technique at low temperature. It crystallizes in the orthorhombic system with cell parameters: a= 17.784(1) A, b = 8.048 Â, c = 21.72 Â; the space group is Pbcn with 8 molecules per unit cell. Experimental data were collected on Picker FACS-1 diffractometer at -~162°C. 3028 intensities were measured. The structure was solved using SHELX-76 and refined of R of 0.06. The hydrogen atoms were located in a difference fourier map and their positions refined. The molecules exist as the azo conformers and are in contrary to previously reported 4-(4-diethylamino-phenyl-azo)phthalimide not planar, but twisted. Each molecule is paired with a second one by hydrogen bonding of the phthalimide group about a center of symmetry.

中文翻译：

---

偶氮分散染料3-(4-二乙氨基-苯基-偶氮)邻苯二甲酰亚胺的晶体和分子结构

分散染料3-(4-二乙氨基-苯基-偶氮)邻苯二甲酰亚胺C18H17N402的晶体和分子结构已通过低温单晶X射线衍射技术确定。它在具有单元参数的正交系统中结晶：a= 17.784(1) A, b = 8.048 Â, c = 21.72 Â; 空间群是 Pbcn，每个晶胞有 8 个分子。在 -~162°C 下在 Picker FACS-1 衍射仪上收集实验数据。测量了 3028 个强度。使用 SHELX-76 解析结构并精修 R 为 0.06。氢原子位于差分傅立叶图中并且它们的位置被精化。这些分子以偶氮构象异构体的形式存在，与之前报道的 4-（4-二乙氨基-苯基-偶氮）邻苯二甲酰亚胺相反，不是平面而是扭曲的。