The crystal structure of tofacitinib dihydrogen citrate (tofacitinib citrate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Tofacitinib dihydrogen citrate crystallizes in space group P212121 (#19) with a = 5.91113(1), b = 12.93131(3), c = 30.43499(7) Å, V = 2326.411(6) Å3, and Z = 4. The crystal structure consists of corrugated layers perpendicular to the c-axis. Within the layers, cation⋯anion and anion⋯anion hydrogen bonds link the fragments into a two-dimensional network parallel to the ab-plane. Between the layers, there are only van der Waals contacts. A terminal carboxylic acid group in the citrate anion forms a strong charge-assisted hydrogen bond to the ionized central carboxylate group. The other carboxylic acid acts as a donor to the carbonyl group of the cation. The citrate hydroxy group forms an intramolecular charge-assisted hydrogen bond to the ionized central carboxylate. Two protonated nitrogen atoms in the cation act as donors to the ionized central carboxylate of the anion. These hydrogen bonds form a ring with the graph set symbol R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

中文翻译：

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柠檬酸二氢托法替尼 (Xeljanz®)、(C16H21N6O)(H2C6H5O7) 的晶体结构

柠檬酸托法替尼（tofacitinib citrate）的晶体结构已使用同步加速器 X 射线粉末衍射数据进行求解和改进，并使用密度泛函技术进行了优化。托法替尼柠檬酸二氢盐在空间群中结晶磷212121(#19) 与一种= 5.91113(1),b= 12.93131(3),C= 30.43499(7) 埃，五= 2326.411(6) Å3， 和Z= 4. 晶体结构由垂直于C-轴。在层内，阳离子⋯阴离子和阴离子⋯阴离子氢键将碎片连接成一个二维网络，平行于抗体-飞机。层之间只有范德华接触。柠檬酸根阴离子中的末端羧酸基团与离子化的中心羧酸根基团形成强电荷辅助氢键。另一种羧酸充当阳离子羰基的供体。柠檬酸羟基与离子化的中心羧酸盐形成分子内电荷辅助氢键。阳离子中的两个质子化氮原子充当阴离子的电离中心羧酸盐的供体。这些氢键与图集符号形成一个环R2,2(8). 粉末图案已提交给ICDD®包含在 Powder Diffraction File™ 中（PDF®）。