Intermolecular interactions between halo‐substituted p‐benzoquinones (BQ) and halide anions were examined in solution, solid‐state and/or in silico . While X‐ray crystallography revealed only halogen bonding (XB) between tetraiodo‐p‐benzoquinone (I 4 Q) and halides, the results of a UV‐Vis study in solutions were consistent with the formation of 1:1 anion‐π complexes. DFT computations showed that the anion‐π complexes of halides with most halo‐sub­sti­tuted BQ molecules were more stable than their XB analogues (by 2 ‐ 7 kcal/mol), but the stabilities of different complexes of I 4 Q were essentially the same. Thus, the structural features of the co‐crystals with I 4 Q were related to multi­center XB interactions between BQs and halides leading to the formation of 3D‐networks. The observation of anion‐p complexes in solutions was attributed to their higher molar absorptivity (by more than an order of magnitude) than that of their XB analogues. Overall, the stabilities of anion‐π and XB complexes between BQs and halides were well correlated with the values of highest electrostatic potentials on the surfaces of BQ molecules when their polarizations were taken into account.

中文翻译：

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卤素取代的对苯醌与卤化物阴离子之间的分子间相互作用：阴离子π配合物与卤素键的关系

在溶液，固态和/或计算机模拟中检查了卤代对苯醌（BQ）与卤化物阴离子之间的分子间相互作用。X射线晶体学分析仅显示四碘对苯醌（I 4 Q）与卤化物之间的卤素键（XB），而在溶液中进行UV-Vis研究的结果与1：1阴离子-π络合物的形成相一致。DFT计算表明，具有大多数卤素取代的BQ分子的卤化物的阴离子-π配合物比其XB类似物更稳定（2-7 kcal / mol），但不同的I 4 Q配合物的稳定性基本相同。因此，具有I 4 Q的共晶体的结构特征与BQ和卤化物之间的多中心XB相互作用有关，从而导致3D网络的形成。溶液中阴离子对p络合物的观察结果归因于它们的摩尔吸收率比XB类似物更高（大于一个数量级）。总的来说，当考虑到它们的极化时，BQ和卤化物之间的阴离子π和XB络合物的稳定性与BQ分子表面上的最高静电势的值很好地相关。