Molecular Design, Supramolecular Assembly, and Excellent Dye Adsorption Capacity of Natural Rigid Dehydroabietic Acid-Tailored Amide Organogelators

It is very appealing to synthesize functional soft materials from natural and abundant plant diterpenes because they have conformationally rigid and chiral properties. Herein, dehydroabietic-based monoamide (DA-1) and diamide (DA-2) were designed by introducing device interactions, π–π stacking and hydrogen bonding, with an aromatic group, C═O, and N–H. DA-1 and DA-2 can be gelled in a mixed solvent and a single solvent, respectively. Several novel supramolecular organic gels including highly entangled three-dimensional networks composed of rods or fibers were constructed. Interestingly, DA-2 forms a helical structure that is right-handed under the cooperative control of the solvent and the rigid structure of rosin. Gel formation was primarily driven by hydrogen bonding, π–π stacking, and van der Waals force. Combined with Gaussian calculation and X-ray diffraction (XRD), we established pack patterns for each system, revealing the roles played by rosin and amide groups. Moreover, the carbon tetrachloride gel of DA-2 can effectively remove Congo red in an aqueous solution, and the removal rate can reach 98.4%. This research explores an efficient organic gel for adsorbing Congo red dye with the secretions of pine trees.