acetonitrile. Additional quantitative studies of the anion‐binding properties of receptors 1–5 were performed by isothermal titration calorimetry (ITC). The experimental results indicated that 1 and 2 formed 1:1 hydrogen‐bonded complexes with most of the anions investigated. In the case of receptors 3–5, the formation of the 1:1 adduct was observed only with anions of low basicity (i.e., chloride, bromide
在这项工作中,我们比较受体的阴离子结合能力1 - 5,其特征在于相似的结构,但具有不同的氢键供体基团(
尿素,squaramide,和磺酰胺)。受体骨架上发色性取代基的存在允许通过对受体在纯
乙腈溶液中的阴离子进行UV / Vis滴定来测定缔合常数。受体的阴离子结合特性的额外定量研究1 - 5通过等温滴定量热法(ITC)进行。实验结果表明1和2与所研究的大多数阴离子形成了1:1的氢键配合物。在受体的情况下,3 - 5,1的形成:观察到仅与低碱度(即,
氯化物,
溴化物,
碘化物和
硫酸氢)的阴离子1加合物。对于更多的碱性阴离子(例如
乙酸根和
磷酸二氢根),分光光度法和ITC滴定法都可导致磺酰胺基团的去质子化,包括受体共轭碱基的形成。