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. 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, which form gel at pH 11. However, the storage modulus exhibits 8-fold increase upon adding Ca2+.image

Automated summary

Organic-inorganic hybrid materials are crucial for designing bioinspired structures and functions. In this study, the synthesis and metallogelation of triazole-appended phenylalanine were demonstrated, resulting in stiffness enhancement. The addition of Ca2+ to the gel prepared from basic solutions led to a significant 8-fold increase in storage modulus, indicating the manipulation of mechanical properties by calcium-induced gelation.