4-(二甲基氨基)吡啶与1,2,4,5-四氯-3,6-二碘苯之间形成的一系列2:1共晶的结构,2C7H10N2·C6Cl4I2,1,2,4,5-四溴-3,6-二碘苯,2C7H10N2·C6Br4I2,1-溴-4-碘-2,3,5,6-四氟苯,2C7H10N2·C6BrF4I,和1,2-二溴-4,5-二氟-3,6-二碘苯,报道了2C7H10N2·C6Br2F2I2。在所有五个结构中,核心卤素键合的2:1三分子单元具有几何相似的参数,中心卤素键供体的两侧是两个吡啶卤素键受体,相对于中心卤素键供体以76至86°的角度扭曲。TheI...N卤素键分离都很短,范德华半径总和的73.3%至76.7%,而C-I...N键角基本上是线性的。Br。..与1-溴-4-碘-2,3,5,6-四氟苯形成的共晶中的N卤素键分离是范德华半径总和的80.4%。晶体填料的细微差异归因于次级C-H的作用。..π和弱π型相互作用与氯和溴取代基。共晶2C7H10N2·C6Cl4I2和2C7H10N2·C6Br4I2是同晶的。
The structures of a series of 2:1 cocrystals formed between 4-(dimethylamino)pyridine and each of 1,2,4,5-tetrachloro-3,6-diiodobenzene, 2C7H10N2·C6Cl4I2, 1,2,4,5-tetrabromo-3,6-diiodobenzene, 2C7H10N2·C6Br4I2, 1-bromo-4-iodo-2,3,5,6-tetrafluorobenzene, 2C7H10N2·C6BrF4I, and 1,2-dibromo-4,5-difluoro-3,6-diiodobenzene, 2C7H10N2·C6Br2F2I2, are reported. In all five structures, the core halogen-bonded 2:1 trimolecular units have geometrically similar parameters, with the central halogen-bond donor flanked by two pyridine halogen-bond acceptors twisted with respect to the central halogen-bond donor at angles ranging from 76 to 86°. The I...N halogen-bond separations are all short, ranging from 73.3 to 76.7% of the sum of the van der Waals radii, while the C-I...N bond angles are essentially linear. The Br...N halogen-bond separation in the cocrystal formed with 1-bromo-4-iodo-2,3,5,6-tetrafluorobenzene is 80.4% of the sum of the van der Waals radii. Subtle differences in the crystal packings are attributed to the role of secondary C-H...π and weak π-type interactions with chloro and bromo substituents. The cocrystals 2C7H10N2·C6Cl4I2 and 2C7H10N2·C6Br4I2 are isomorphous.