Highly stable supramolecular hydrogels formed from 1,3,5-benzenetricarboxylic acid and hydroxyl pyridines

New supramolecular hydrogels with the maximal sol–gel transition temperature (Tgel) of 95 °C were obtained by using gelators formed from 1,3,5-benzenetricarboxylic acid (BTA) and para-hydroxyl pyridine (PHP) or meta-hydroxyl pyridine (MHP). The single crystal structure of the complex formed from BTA and ortho-hydroxyl pyridine (OHP) indicated that the molecules assembled into superstructure via both hydrogen bonds and π–π stacking interaction.