Laboratory of Theoretical and Computational Chemistry, Chemistry and Chemical Engineering College, Yantai University, Yantai 264005, People's Republic of China.
J Chem Phys. 2012 Aug 28;137(8):084314. doi: 10.1063/1.4748264.
In this paper, the cooperative effect of halogen bond with hydrogen bond has been used to make a halogen bond in FCl-CNH dimer vary from a chlorine-shared one to an ion-pair one. The halogen bond is strengthened in FCl-CNH-CNH trimer and its maximal interaction energy equals to -76 kJ/mol when the number of CNH in FCl-CNH-(CNH)(n) polymer approaches infinity. Once the free H atom in FCl-CNH-CNH trimer is replaced with alkali metals, the halogen bond becomes strong enough to be an ion-pair one in FCl-CNH-CNLi and FCl-CNH-CNNa trimers. An introduction of a Lewis acid in FCl-CNH dimer has a more prominent effect on the type of halogen bond. A prominent cooperative effect is found for the halogen bond and hydrogen bond in the trimers. FH-FCl-CNH-CNH and FH-FCl-CNH-CNLi tetramers have also been studied and the interaction energy of halogen bonding in FH-FCl-CNH-CNLi tetramer is about 12 times as much as that in the FCl-CNH dimer. The atoms in molecules and natural bond orbital analyses have been carried out for these complexes to understand the nature of halogen bond and the origin of the cooperativity.
在本文中，我们利用卤键与氢键的协同作用，使得 FCl-CNH 二聚体中的卤键由氯共享型转变为离子对型。在 FCl-CNH-CNH 三聚体中，卤键得到增强，当 FCl-CNH-(CNH)(n) 聚合物中的 CNH 数量趋近于无穷大时，其最大相互作用能可达-76 kJ/mol。一旦 FCl-CNH-CNH 三聚体中自由 H 原子被碱金属取代，卤键就会变得足够强，成为 FCl-CNH-CNLi 和 FCl-CNH-CNNa 三聚体中的离子对型卤键。在 FCl-CNH 二聚体中引入路易斯酸对卤键的类型有更显著的影响。在三聚体中，卤键和氢键存在显著的协同作用。我们还研究了 FH-FCl-CNH-CNH 和 FH-FCl-CNH-CNLi 四聚体，发现 FH-FCl-CNH-CNLi 四聚体中卤键的相互作用能约为 FCl-CNH 二聚体的 12 倍。我们对这些配合物进行了分子中的原子和自然键轨道分析，以了解卤键的性质和协同作用的起源。
