Effects of methoxy substituents on self-assembly and gelation performance of benzamide-based organogelators

Low molecular weight organogelators (LMOGs) have garnered widespread attention due to their unique properties and potential applications in various fields. However, the discovery of most LMOGs has largely been serendipitous. The molecular structural diversity and self-assembly mechanism complexity of LMOGs pose significant challenges in elucidating the structure-property relationship. Herein, a series of LWMOs derived from methoxy-substituted benzamide-based compounds were designed and synthesized via a one-step condensation reaction that entailed fine-tuning of substitution position of methoxy. Gelation study revealed that para-substituted and 3,4-substituted derivatives were efficient LMOGs that could self-assembly and gel various organic solvents with the minimum gelation concentration lower than 2.60% w/v. Furthermore, the relationships between molecule structures and gelation properties were studied and their self-assembly mechanisms were explored. In addition, optimized structures of molecular monomers and dimers as well as electrostatic potential diagrams were obtained using theoretical calculation. Both the experimental and theoretical results confirmed that a symmetrical methoxy substituent in benzamide structure was more favorable for the self-assembly of LMOGs.