Silver-promoted gelation studies of an unorthodox chelating tripodal pyridine–pyrazole-based ligand: templated growth of catalytic silver nanoparticles, gas and dye adsorption

Abstract

A novel tripodal pyridine–pyrazole based tris amide ligand, namely, N1,N3,N5-tris(3-(pyridin-2-yl)-1H-pyrazol-5-yl)benzene-1,3,5-tricarboxamide was synthesized. The ligand acts as a promising low molecular weight gelator that gels silver salts in presence of water. The gels formed were found to be highly stable to heat and stress. Moreover, silver ions not only act as a gelling agent but also participate in nanoparticulate formation. The three-dimensional ligand–silver gel matrix serves as an excellent platform for the growth of these silver nanoparticles. The gels were characterized thoroughly using IR spectroscopy, UV-visible spectroscopy, SEM, TEM and rheological studies. TEM pictures revealed the nanoparticles to be attached exclusively onto the gel fibres confirming template formation. The silver nanoparticles not only provide high strength and stability to the gel network but also show excellent catalytic properties in reducing 4-nitrophenol and Methylene Blue dye in presence of sodium borohydride. In addition to the catalytic properties, xerogels displayed gas and dye adsorption properties.