Structural Tunability on Naphthalimide-Based Dendrimer Gelators via Glaser Coupling Interaction with Tailored Gelation Solvent Polarity and Stimuli-Responsive Properties

Abstract

To date, most of the low-molecular-weight gels are found serendipitously, and modification on known gelator structures via organic synthesis is an efficient methodology to prepare gel series. However, a simple, direct, and rational modification method for a known gelator is still a challenge. Herein, we employ Glaser coupling reaction to synthesize a novel dendrimer gelator BisDEC with the (ALS2)2 structure, starting from terminal alkyne-based gelator DEC with the ALS2 structure. This structural change results in gels with distinct gelation solvents, mechanical properties, and stimuli-responsive abilities. The gelation abilities of DEC and BisDEC in nonpolar and polar solvents, respectively, have been examined and discussed by several experiments and Hansen constants. It is also shown that the BisDEC gel system shows intriguing self-healing, self-supporting, and grinding chromism properties.

Making and Breaking of Gels: Stimuli-Responsive Properties of Bis(Pyridyl-N-oxide Urea) Gelators

“…The modification of these functional groups will lead to the alteration of specific interactions arising from the particular functional group, which can be considered as an excellent strategy to evaluate the role of specific interactions in gel formation [30,31]. For example, Zinchuan et al have synthesized a cholesterol-based dendrimer gelator from the parent terminal alkyne-based gelator and have shown that the modified compounds formed gel in polar solvents compared to the parent compound, which only formed gel in nonpolar solvents [32]. McNeil's group has developed nitrite sensor-based LMWGs from a known azosulfonate gelator scaffold [33].…”