Anion–π interaction at the solid/water interfaces†
Anion–π interaction has been found to play a key role in interfacial phenomena. In this study, we evaluated the anion–π interactions at the solid/water interface. Anion adsorption originating from anion–π interaction at the interfaces followed the hydration energy and the presence of conjugated systems of the anions by the QCM measurements. Force curve measurements revealed that the single-molecule force of anion–π interaction between an NDI unit and the negatively charged surface of the cantilever was ∼40 pN. To the best of our knowledge, this is the first example of obtaining a single-molecule force for anion–π interactions.