Obendorf S K, Pickworth Glusker J, Hansen P R, Berman H M, Carrell H L
Bioinorg Chem. 1976;6(1):29-44. doi: 10.1016/s0006-3061(00)80048-4.
The crystal structure of the biological stain, "acridine orange," has been determined. This compound, when crystallized from ethanol, is shown to be a zinc chloride double salt of acridine orange, containing, in addition, acetic acid of crystallization. These additional components are residuals from the method of preparation of acridine orange. This complex, 2 acridine orange-2HCl-ZnCl2-CH3COOH, (2C17H19N3-2HCl-ZnCl2-CH3COOH) crystallizes in the monoclinic space group P21, a = 9.965 (2), b = 21.507 (6), c = 9.645 (2) A, beta = 113.98 degrees (2), V = 1888.7 (8) A3, FW = 800.0, Z = 2, DX = 1.41 g-cm-3, Dobs = 1.43 (9) g-cm-3. Three-dimensional diffraction data were collected with CuKalpha radiation, and the structure refined to R = 0.065 for 1885 observed reflections. In the crystal structure hydrogen bonds are formed, via the protonated nitrogen atom of the central rings of two acridine orange cations, to two chloride ions in a ZnCl42- tetrahedral grouping. These two acridine orange molecules are stacked in parallel planes, approximately 3.4 A apart, with the long axes of the ring systems inclined at 26.5 to each other. Thus an apparent dimerization of the acridine, orange is facilitated by the anions present, resulting in the complex studied. The two -N(CH3)2 groups of each acridine orange molecule are not protonated in this crystalline form. The mode of molecular packing found here may be relevant to models for the external stacking of acridine orange around a DNA molecule. The importance of removing any zinc salt from acridine orange preparations prior to aggregation studies is stressed.
生物染色剂“吖啶橙”的晶体结构已被确定。该化合物从乙醇中结晶时，显示为吖啶橙的氯化锌复盐，此外还含有结晶乙酸。这些额外的成分是吖啶橙制备方法中的残留物。这种配合物，2吖啶橙 - 2HCl - ZnCl₂ - CH₃COOH，(2C₁₇H₁₉N₃ - 2HCl - ZnCl₂ - CH₃COOH) 结晶于单斜空间群P2₁，a = 9.965(2)，b = 21.507(6)，c = 9.645(2) Å，β = 113.98°(2)，V = 1888.7(8) ų，FW = 800.0，Z = 2，DX = 1.41 g - cm⁻³，Dobs = 1.43(9) g - cm⁻³。用CuKα辐射收集了三维衍射数据，结构针对1885个观测反射精修至R = 0.065。在晶体结构中，通过两个吖啶橙阳离子中心环的质子化氮原子与ZnCl₄²⁻四面体基团中的两个氯离子形成氢键。这两个吖啶橙分子平行排列在相距约3.4 Å的平面上，环系统的长轴相互倾斜26.5°。因此，存在的阴离子促进了吖啶橙明显的二聚化，形成了所研究的配合物。每个吖啶橙分子的两个 -N(CH₃)₂基团在这种晶体形式中未被质子化。这里发现的分子堆积模式可能与吖啶橙围绕DNA分子的外部堆积模型有关。强调了在聚集研究之前从吖啶橙制剂中去除任何锌盐的重要性。
