Theoretical and Experimental Insights into the Self-Assembly and Ion Response Mechanisms of Tripodal Quinolinamido-Based Supramolecular Organogels.

The exploration and understanding of self-assembly and stimuli-responsive mechanisms of supramolecular systems are of fundamental importance for researchers to plan syntheses reasonably. Herein, the self-assembly and ions responsive mechanisms of a tripodal quinolinamido-based supramolecular organogel (TBT-gel) were investigated through experiments and theoretical calculations including independent gradient model (IGM), localized orbitals locator (LOL) and hole-electron theory. According to these studies, the self-assembly mechanism of TBT-gel was based on strong threefold H-bonding and π-π interactions, which induced the TBT forming helical, one-dimensional supramolecular polymer. After addition of Fe3+ into the TBT-gel, the one-dimensional supramolecular polymer had been crosslinked by the Fe3+ through coordination interaction and formed a metallogel (TBT-Fe-gel). Interestingly, the TBT-gel showed selective fluorescent response for Fe3+ and F- based on a competitive coordination mechanism. Moreover, the study on fluorescence responsive mechanism of TBT-gel for Fe3+ and F- implied the ICT mode governs both the electron excitation and de-excitation processes. The calculated results were in agreement with the corresponding experimental results. Notably, the quantum chemical calculations provided a deep understanding and visualized presentation of the assembly and stimuli-responsive mechanisms.