Department of Chemistry, Molecular Design Institute, New York University, 100 Washington Square East, Room 1001, New York City, NY 10003, USA.
Faraday Discuss. 2018 Oct 26;211(0):477-491. doi: 10.1039/c8fd00039e.
X-ray powder diffraction and crystal structure prediction (CSP) algorithms were used in synergy to establish the crystal structure of the eighth polymorph of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY), form R05. R05 crystallizes in the monoclinic space group P21 with lattice parameters a = 11.479(4) Å, b = 11.030(1) Å, c = 10.840(6) Å, β = 118.23(1)°. This is both the first acentric ROY polymorph, and the first with Z' > 1. The torsion angles defined by the S-C-N-C atom sequence of each molecule in the asymmetric unit (R05-1 and R05-2) are 44.9° and -34.0°. These values are between those previously determined for the red and orange forms of ROY. The crystal packing and intermolecular interactions in R05 are explained herein through Hirshfeld surface analysis and an updated energy stability ranking is determined using computational methods. Although the application of CSP was critical to the structure solution of R05, energy stability rankings determined using a series of DFT van der Waals (vdW)-inclusive models substantially differ from experiment, indicating that ROY polymorphism continues to be a challenge for CSP.
X 射线粉末衍射和晶体结构预测（CSP）算法协同使用，确定了 5-甲基-2-[(2-硝基苯基)氨基]-3-噻吩甲腈（ROY）的第八种晶型（ROY）的晶体结构，形式为 R05。R05 结晶于单斜空间群 P21，晶格参数为 a = 11.479(4) Å，b = 11.030(1) Å，c = 10.840(6) Å，β = 118.23(1)°。这既是第一个非中心对称的 ROY 多晶型物，也是第一个 Z' > 1 的多晶型物。在不对称单元（R05-1 和 R05-2）中每个分子的 S-C-N-C 原子序列定义的扭转角为 44.9°和-34.0°。这些值介于 ROY 的红色和橙色形式之前确定的值之间。通过 Hirshfeld 表面分析解释了 R05 中的晶体堆积和分子间相互作用，并通过计算方法确定了更新的能量稳定性排序。尽管 CSP 的应用对于 R05 的结构解决至关重要，但使用一系列包含范德华（vdW）的 DFT 模型确定的能量稳定性排序与实验结果有很大差异，表明 ROY 多晶型性仍然是 CSP 的挑战。
