芳酰胺-吖啶分子钳对中性分子的识别性能II.新型吖啶类分子钳的研究

Recognition of Neutral Molecules by Aromatic Amide-Acridine Molecular Tweezers II. Studies on Novel Type of Acridine Molecular Tweezers

采用差紫外谱法研究了新型芳酰胺-吖啶分子钳(1～7)对苯胺、苯二胺(邻,间,对)等中性分子的识别性能.测定了结合常数(K_a)和自由能变化(△G°),结果表明,所有的分子钳受体与所考察的客体分子均形成1∶1型超分子配合物.识别作用的主要推动力为多重氢键、van der Waals等的协同作用.主客体间尺寸/形状匹配、几何互补等因素对识别性能均有重要的影响.利用核磁氢谱与计算机模拟作为辅助手段对主要的实验结果与现象进行了解释.

Molecular recognition properties of the novel type of aromatic amide-acridine molecular tweezers for phenylamine, phenyldiamine （o-, m-, p-） have been investigated by UV-vis spectroscopic titration in CHCl3 at 25℃. The association constant （Ka） and Gibbs free energy changes （△G°） have been calculated. The results show that all the molecular tweezers （1-7） can form 1 ： 1 inclusion complexes with guest molecules. The main driving forces are multiple hydrogen bonding and van der waals interaction between host and guest molecules. The recognition ability is discussed from the viewpoint of the size/shape-fit and geometrical complementary relationship. Computer-aided study and ^1H NMR spectroscopy have been employed to elucidate the binding behavior of these molecular tweezers.