Molecular binding behaviors of pyromellitic and naphthalene diimide derivatives by tetrasulfonated 1,5-dinaphtho-(3 n +8)-crown- n (n = 8, 10) in aqueous solution

摘要

The highly affinitive and selective binding processes of tetrasulfonated 1,5-dinaphtho-38-crown-10 (1~(4-)) and tetrasulfonated 1,5-dinaphtho-32-crown-8 (2~(4-)) with pyromellitic diimide and naphthalene diimide derivatives bearing cationic terminal groups (PMDI ~(2+) and NDI~(2+)) 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 10~4-10~6 M~(-1) order of magnitude. Combined with our previously reported thermodynamic data of ethyl viologen (EV~(2+)), 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.