Stilinović Vladimir, Horvat Gordan, Hrenar Tomica, Nemec Vinko, Cinčić Dominik
Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, Zagreb, Croatia.
Chemistry. 2017 Apr 19;23(22):5244-5257. doi: 10.1002/chem.201605686. Epub 2017 Feb 15.
A study of strong halogen bonding within three series of halogen-bonded complexes, derived from seven para-substituted pyridine derivatives and three N-halosuccinimides (iodo, bromo and chloro), has been undertaken with the aid of single-crystal diffraction, solution complexation and computational methods. The halogen bond was compared with the hydrogen bond in an equivalent series based on succinimide. The halogen-bond energies are in the range -60 to -20 kJ mol and change regularly with pyridine basicity and the Lewis acidity of the halogen. The halogen-bond energies correlate linearly with the product of charges on the contact atoms, which indicates a predominantly electrostatic interaction. The binding enthalpies in solution are around 19 kJ mol less negative due to solvation effects. The optimised geometries of the complexes in the gas phase are comparable to those of the solid-state structures, and the effects of the supramolecular surroundings in the latter are discussed. The bond energies for the hydrogen-bonded series are intermediate between the halogen-bond energies of iodine and bromine, although there are specific differences in the geometries of the halogen- and hydrogen-bonded complexes.
借助单晶衍射、溶液络合和计算方法，对由七种对位取代吡啶衍生物和三种N - 卤代琥珀酰亚胺（碘代、溴代和氯代）衍生的三个系列卤键配合物中的强卤键进行了研究。将卤键与基于琥珀酰亚胺的等效系列中的氢键进行了比较。卤键能在 - 60至 - 20 kJ mol范围内，并随吡啶碱性和卤素的路易斯酸度有规律地变化。卤键能与接触原子上电荷的乘积呈线性相关，这表明主要是静电相互作用。由于溶剂化作用，溶液中的结合焓约少19 kJ mol的负值。气相中配合物的优化几何结构与固态结构的相当，并讨论了后者中超分子环境的影响。氢键系列的键能介于碘和溴的卤键能之间，尽管卤键和氢键配合物的几何结构存在特定差异。
