Use of a bis-1,2,3-triazole gelator for the preparation of supramolecular metallogels and stabilization of gold nanoparticles

In this work we have applied a double isosteric substitution of the amide groups presented in the gelator N,N '-((1S,2S)-cyclohexane-1,2-diyl)didodecanamide (C-12-Cyc) by 1,2,3-triazole rings affording the corresponding isosteric gelator (click-C-12-Cyc). This approach enabled the preparation of different metallogels and fine-tuning their properties. In particular, C-12-Cyc was found to form stable and reversible metallogels with Pd-II and Au-III in DMSO and DMF, whereas click-C-12-Cyc formed metallogels in these solvents only in the presence of Au-III. Comparing the gels made of C-12-Cycvs.click-C-12-Cyc in the presence of HAuCl4 center dot 3H(2)O, the former showed higher T-gel values and 5-8 times slower gelation kinetics. Furthermore, the incorporation of Et3N as reducing agent in the formulations facilitated the in situ formation of non-aggregated gold nanoparticles embedded in the viscoelastic networks made of either pure isosteres or with an equimolar mixture of click-C-12-Cyc and C-12-Cyc. So-formed NPs showed similar size distribution regardless the gold concentration and the nature of the gelator system.