Hayward Emily R, Zeller Matthias, Mezei Gellert
Western Michigan University, Department of Chemistry 1903 W Michigan Ave Kalamazoo MI 49008 USA.
Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA.
Acta Crystallogr E Crystallogr Commun. 2024 Jun 28;80(Pt 7):800-805. doi: 10.1107/S2056989024006182. eCollection 2024 Jun 1.
The crystal structures of 4-benzyl-1-pyrazole (CHN, ) and 3,5-di-amino-4-benzyl-1-pyrazole (CHN, ) were measured at 150 K. Although its different conformers and atropenanti-omers easily inter-convert in solution by annular tautomerism and/or rotation of the benzyl substituent around the C(pyrazole)-C(CH) single bond (as revealed by H NMR spectroscopy), crystallizes in the non-centrosymmetric space group 2. Within its crystal structure, the pyrazole and phenyl aromatic moieties are organized into alternating bilayers. Both pyrazole and phenyl layers consist of aromatic rings stacked into columns in two orthogonal directions. Within the pyrazole layer, the pyrazole rings form parallel catemers by N-H⋯N hydrogen bonding. Compound adopts a similar bilayer structure, albeit in the centrosymmetric space group 2/, with pyrazole N-H protons as donors in N-H⋯π hydrogen bonds with neighboring pyrazole rings, and NH protons as donors in N-H⋯N hydrogen bonds with adjacent pyrazoles and other NH moieties. The crystal structures and supra-molecular features of and are contrasted with the two known structures of their analogs, 3,5-dimethyl-4-benzyl-1-pyrazole and 3,5-diphenyl-4-benzyl-1-pyrazole.
在150 K下测定了4-苄基-1-吡唑（CHN, ）和3,5-二氨基-4-苄基-1-吡唑（CHN, ）的晶体结构。尽管其不同的构象异构体和阻转对映体在溶液中通过环互变异构和/或苄基取代基围绕C（吡唑）-C（CH）单键的旋转容易相互转化（如1H NMR光谱所示）， 结晶于非中心对称空间群2。在其晶体结构中，吡唑和苯基芳香部分组织成交替的双层。吡唑层和苯基层均由在两个正交方向上堆叠成柱的芳香环组成。在吡唑层内，吡唑环通过N-H⋯N氢键形成平行的链状二聚体。化合物 采用类似的双层结构，尽管处于中心对称空间群2/，吡唑N-H质子作为供体与相邻吡唑环形成N-H⋯π氢键，NH质子作为供体与相邻吡唑和其他NH部分形成N-H⋯N氢键。 将 和 的晶体结构及超分子特征与其类似物3,5-二甲基-4-苄基-1-吡唑和3,5-二苯基-4-苄基-1-吡唑的两种已知结构进行了对比。
