Building a supramolecular gel with an ultra-low-molecular-weight Schiff base gelator and its multiple-stimulus responsive properties

An unprecedented Schiff base gelator with ultra-low molecular weight (Mw=188) was facilely prepared from readily available starting materials in a single step. The gelator was found to possess a strong gelation ability with the critical gelation concentration down to 0.45 wt% in dichloromethane (DCM). FT-IR NMR, XRD, SEM, theoretical calculation, and control experiment were combined to elucidate the assembly mechanism of gelator leading to gel. It was revealed that the hydrogen bonding associated with the triazole NH moiety plays a crucial role in the formation of the fibrillar gel network. This supramolecular gel demonstrated multiple-stimulus responsive (temperature, pH, metal ion) gel-sol phase transition behavior, particularly interesting aspect is that only 0.13 eq. F- is required to collapse the gel, representing the most sensitive supramolecular gel to F- anion up to now and endowing it with great potential as F- detector. The newly found Schiff base gelator reported here would offer prospects for the future design of more intelligent materials based on simple but versatile molecular scaffolds.