Bats Jan W, Schell Peter, Engels Joachim W
Institut für Organische Chemie und Chemische Biologie, Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main, Germany.
Acta Crystallogr C. 2013 May;69(Pt 5):529-33. doi: 10.1107/S0108270113009293. Epub 2013 Apr 11.
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···N(imidazole) [for (I)] or N-H····N(cyano) [for (II) and (III)] hydrogen bonds.
报道了三种用作核苷甲基亚磷酰胺偶联反应催化剂的取代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)；以及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。在所有三种化合物中，咪唑基团与末端苯基之间存在空间排斥，导致分子呈非平面性。(III)的萘基团显示出明显的非平面偏差。咪唑环中的C-N键长范围为1.325 (2)至1.377 (2) Å。分子通过分子间N-H···N(咪唑)[对于(I)]或N-H····N(氰基)[对于(II)和(III)]氢键连接成锯齿链。
