Preparation of Tris-Tetrazole-Based Metallogels and Stabilization of Silver Nanoparticles: Studies on Reduction Catalysis and Self-Healing Property

An ionic multifunctional gelator molecule triethylammonium 5-(3,5-bis((1H-tetrazol-5-yl)carbamoyl)benzamido)tetrazol-1-ide G7 is synthesized and characterized by spectroscopic tools and mass spectrometry. G7 tends to form a stable organogel in a mixture of N,N-dimethylformamide/dimethylsulfoxide (DMF/DMSO) and water. Introduction of different metal perchlorate salts in a DMSO solution of G7 furnished a series of metallogels M(1)G7, M(2)G7, M(3)G7, M(4)G7, M(5)G7, M(6)G7, and M(7)G7 [M-1 = Fe(III), M-2 = Co(II), M-3 = Cu(II), M-4 = Zn(II), M-5 = Ag(I), M-6 = Ni, and M-7 = Fe(II)]. Among them, M(1)G7, M(3)G7, M(4)G7, M(6)G7, and M(7)G7 help individually in the synthesis and stabilization of bimetallic nanocomposites containing silver nanoparticles (AgNPs). Iron(III)-containing nanocomposites M(1)G7AgNPs have been utilized in the form of catalysts in the reduction reaction of nitroaromatic compounds to corresponding amines with a quantitative yield. The organogel G7 has also shown the abilities to absorb different metal ions from aqueous solutions and allow selective transition of M(1)G7 from the gel state to the crystalline state. Fe(III) formed dual metallogels with Zn(II), which can be used for further applications. Furthermore, the nanocomposite M(1)G7AgNP powder, in the presence of the organogel G7, gets converted into a nanostructured metallogel, which shows exclusive self-healing properties. This is the first example where a nanocomposite powder contains the dual-metal system (Fe(III) and Ag(0)) and shows a reduction catalytic property, and its nanostructured dual-metallogel form manifests the self-healing property in a fabricated metallogel.

Automated summary

A multifunctional gelator molecule G7 has been synthesized and characterized, with the ability to form metallogels and stabilize bimetallic nanocomposites containing silver nanoparticles. These metallogels show catalytic properties in the reduction reaction of nitroaromatic compounds and also have abilities to absorb metal ions and exhibit self-healing properties.