Synthesis of 2,5‐Diphenyl‐2H‐[1,2,3]triazole‐4‐carboxylic Acid Appended Phenylalanine for Thixotropic Metallogelation and Stiffness Manipulation

Organic‐inorganic hybrid materials are highly important for designing and engineering bioinspired structures and functions. Herein, we have demonstrated the synthesis and metallogelation of triazole‐appended phenylalanine and resulting stiffness enhancement. The 2,5‐diphenyl‐2H‐[1,2,3]triazole‐4‐carboxylic acid was synthesized by sequential C−N bond formation and electro‐oxidative N−N coupling under metal‐free conditions and coupled with L‐Phe to develop the gelator. Starting with basic (pH 11) solutions (5 mg/mL) of gelator, we show that significant stiffness enhancement is achieved upon adding Ca²⁺. From rheology, the storage modulus exhibits 8‐fold increase by the calcium‐induced gelation. The calcium‐induced gels are thixotropic in nature. The calcium ion bivalency leads to “cross‐links” and promote assembly of gelators, which not only influences the gel microstructure but also manipulates subsequent mechanical properties of the metallogels.