Ouvrard Carole, Le Questel Jean-Yves, Berthelot Michel, Laurence Christian
Laboratoire de Spectrochimie et Modélisation (EA 1149, FR CNRS 2465), Université de Nantes, 2, rue de la Houssinière, BP 92208, 44322 Nantes CEDEX 3, France.
Acta Crystallogr B. 2003 Aug;59(Pt 4):512-26. doi: 10.1107/s0108768103011510. Epub 2003 Jul 25.
X-ray crystal structures of 141 halogen-bonded complexes Y-X.B formed between homo- and heteronuclear dihalogens Cl(2), Br(2), I(2), IBr and ICl with O, S, Se, N, P and As Lewis bases show remarkable and constant geometrical features. The metrics of the halogen bond found in the gas phase for simple complexes [Legon (1999a). Angew Chem. Int. Ed. Eng. 38, 2686-2714] is supported (i). in the solid state, (ii). for new Lewis acids (I(2) and IBr), (iii). for new basic centers (Se, As and =N-) and (iv). for more complicated bases. The Y-X...B arrangement is more linear than the corresponding Y-H...B hydrogen bond and the axis of the Y-X molecule lies in the plane of the B lone pair(s), with a preference for the putative lone-pair direction within that plane. However, exceptions to this lone-pair rule are found for sterically hindered thiocarbonyl and selenocarbonyl bases. A bond-order model of the halogen bond correctly predicts the observed correlation between the shortening of the X...B distance and the lengthening, deltad(Y-X), of the Y-X bond. The expectation that the solid-state geometric parameters d(X...B) and deltad(Y-X) reflect the strength of the interaction is supported by their significant relationships with the solution thermodynamic parameters of Lewis acidity and basicity strength, such as the Gibbs energy of 1:1 complexation of Lewis bases with diiodine. This analysis of halogen-bonded complexes in the solid state reinforces the similarities already known to exist between hydrogen and halogen bonding.
同核和异核双卤分子Cl₂、Br₂、I₂、IBr和ICl与O、S、Se、N、P和As等路易斯碱形成的141个卤键复合物Y-X·B的X射线晶体结构显示出显著且恒定的几何特征。简单复合物在气相中发现的卤键参数[莱贡（1999a）。《德国应用化学》国际版 38，2686 - 2714]得到了如下支持：（i）在固态中；（ii）对于新的路易斯酸（I₂和IBr）；（iii）对于新的碱性中心（Se、As和=N-）；（iv）对于更复杂的碱。Y-X…B的排列比相应的Y-H…B氢键更线性，且Y-X分子的轴位于B孤对电子所在平面内，更倾向于该平面内假定的孤对电子方向。然而，对于空间位阻较大的硫代羰基和硒代羰基碱，发现了该孤对电子规则的例外情况。卤键的键级模型正确地预测了观察到的X…B距离缩短与Y-X键伸长量deltad(Y-X)之间的相关性。固态几何参数d(X…B)和deltad(Y-X)反映相互作用强度的预期得到了它们与路易斯酸度和碱度强度的溶液热力学参数（如路易斯碱与二碘1:1络合的吉布斯自由能）之间显著关系的支持。对固态卤键复合物的这种分析强化了氢和卤键之间已知的相似性。
