Crystal structures are reported for three substituted 1H-imidazole-4,5-dicarbonitrile compounds used as catalysts for the coupling reaction of nucleoside methyl phosphonamidites, namely 2-(3′,5′-dimethylbiphenyl-2-yl)-1H-imidazole-4,5-dicarbonitrile, C19H14N4, (I), 2-(2′,4′,6′-trimethylbiphenyl-2-yl)-1H-imidazole-4,5-dicarbonitrile, C20H16N4, (II), and 2-[8-(3,5-dimethylphenyl)naphthalen-1-yl]-1H-imidazole-4,5-dicarbonitrile, C23H16N4, (III). The asymmetric unit of (I) contains two independent molecules with similar conformations. There is steric repulsion between the imidazole group and the terminal phenyl group in all three compounds, resulting in the nonplanarity of the molecules. The naphthalene group of (III) shows significant deviation from planarity. The C—N bond lengths in the imidazole rings range from 1.325 (2) to 1.377 (2) Å. The molecules are connected into zigzag chains by intermolecular N—H...Nimidazole[for (I)] or N—H...·Ncyano[for (II) and (III)] hydrogen bonds.
报告了用作核苷甲基膦酰氨基化合物偶联反应催化剂的三种取代的 1H-咪唑-4,5-二甲腈化合物的晶体结构,即 2-(3′,5′-二甲基联苯-2-基)-1H-咪唑-4、5-二甲腈,C19H14N4,(I),2-(2′,4′,6′-三甲基联苯-2-基)-1H-咪唑-4,5-二甲腈、C20H16N4,(II)和 2-[8-(3,5-二甲基苯基)萘-1-基]-1H-咪唑-4,5-二甲腈,C23H16N4,(III)。(I)的不对称单元包含两个构象相似的独立分子。在这三种化合物中,咪唑基团和末端苯基之间存在立体排斥,导致分子的非平面性。(III)的萘基明显偏离平面性。咪唑环中的 C-N 键长度为 1.325 (2) 至 1.377 (2) Å。分子间通过 N-H......咪唑[对于 (I)]或 N-H......-Ncyano[对于 (II) 和 (III)]氢键连接成人字形链。