Molecular Binding Behaviors of Pyromellitic and Naphthalene Diimide Derivatives by Tetrasulfonated 1,5-Dinaphtho-(3n+8)-crown‑n (n = 8, 10) in Aqueous Solution

The highly affinitive and selective binding processes of tetrasulfonated 1,5-dinaphtho-38-crown-10 (14–) and tetrasulfonated 1,5-dinaphtho-32-crown-8 (24–) with pyromellitic diimide and naphthalene diimide derivatives bearing cationic terminal groups (PMDI2+ and NDI2+) are comprehensively investigated in aqueous solution by 1H NMR and UV/vis experiments, mass spectrometry, microcalorimetric titration, and crystallographic analysis. The binding process of host–guest complexation is thermodynamically driven by the large enthalpic gain and favorable entropic change with the high association constants in the range of 104–106 M–1 order of magnitude. Combined with our previously reported thermodynamic data of ethyl viologen (EV2+), it is found that the exclusively selective binding behaviors originate from the size/shape matching effect, as well as the electrostatic interaction between negatively charged hosts and positively charged guests and aromatic π-stacking interrelation between electron-rich donors and electron-deficient acceptors.