PDF(Pubmed)
Abstract：
The crystal structures of 4-benzyl-1H-pyrazole (C10H10N2, 1) and 3,5-di-amino-4-benzyl-1H-pyrazole (C10H12N4, 2) 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(CH2) single bond (as revealed by 1H NMR spectroscopy), 1 crystallizes in the non-centrosymmetric space group P21. 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 2 adopts a similar bilayer structure, albeit in the centrosymmetric space group P21/c, with pyrazole N-H protons as donors in N-H⋯π hydrogen bonds with neighboring pyrazole rings, and NH2 protons as donors in N-H⋯N hydrogen bonds with adjacent pyrazoles and other NH2 moieties. The crystal structures and supra-molecular features of 1 and 2 are contrasted with the two known structures of their analogs, 3,5-dimethyl-4-benzyl-1H-pyrazole and 3,5-diphenyl-4-benzyl-1H-pyrazole.
摘要：
在150K下测量4-苄基-1H-吡唑（C10H10N2，1）和3,5-二氨基-4-苄基-1H-吡唑（C10H12N4，2）的晶体结构。尽管其不同的构象异构体和atropenanti-异构体很容易在溶液中通过环形互变异构和/或围绕C（吡唑）-C（CH2）NMR1H单键的取代基旋转而相互转化1在非中心对称空间群P21中结晶。在它的晶体结构中，吡唑和苯基芳族部分被组织成交替的双层。吡唑和苯基层都由沿两个正交方向堆叠成柱的芳环组成。在吡唑层中，吡唑环通过N-H-N氢键形成平行的基团。化合物2采用类似的双层结构，尽管在中心对称空间群P21/c中，以吡唑N-H质子为供体，与相邻的吡唑环形成N-H-π氢键，和NH2质子作为N-H-N氢键与相邻的吡唑和其他NH2部分的供体。1和2的晶体结构和超分子特征与它们的类似物的两个已知结构形成对比。3,5-二甲基-4-苄基-1H-吡唑和3,5-二苯基-4-苄基-1H-吡唑。
