Departamento de Química Física y Analítica, Universidad de Jaén, Campus Las Lagunillas, E-23071, Jaén, Spain.
Phys Chem Chem Phys. 2019 Sep 18;21(36):19879-19889. doi: 10.1039/c9cp03209f.
1H-Benzotriazole crystallizes as two different polymorphs, namely 4aα and 4aβ. One polymorph is chiral and it resolves spontaneously as conglomerates. The other polymorph crystallizes in a centrosymmetric space group and it is therefore achiral. In both polymorphs supramolecular structures are formed starting from achiral monomers. An analysis of these two polymorphs of 1H-benzotriazole has been carried out by a complete strategy involving different solid-state experimental techniques and quantum chemical calculations (DFT, Density Functional Theory). In particular, X-ray crystallography, NMR spectroscopy and vibrational spectroscopy techniques (FarIR, IR and Raman) that are not sensitive to chirality have been used to characterize the two polymorphs structurally. Vibrational spectroscopy (VCD, Vibrational Circular Dichroism) that is sensitive to chirality was employed to determine the absolute configuration (M or P helices) of the chiral supramolecular structure of 4aα.
1H-苯并三唑结晶为两种不同的多晶型物，分别为 4aα 和 4aβ。其中一种多晶型物具有手性，会自发地以聚集体的形式拆分。另一种多晶型物则在中心对称的空间群中结晶，因此没有手性。在这两种多晶型物中，超分子结构均由非手性单体起始形成。我们采用涉及不同固态实验技术和量子化学计算（DFT，密度泛函理论）的完整策略，对 1H-苯并三唑的这两种多晶型物进行了分析。特别是，我们使用对手性不敏感的 X 射线晶体学、NMR 光谱和振动光谱技术（远红外、IR 和拉曼）对手性结构进行了表征。我们还采用对手性敏感的振动光谱（VCD，振动圆二色性）来确定 4aα 手性超分子结构的绝对构型（M 或 P 螺旋）。
