Supramolecular chirality in organo-, hydro-, and metallogels derived from bis-amides of L-(+)-tartaric acid: Formation of highly aligned 1D silica fibers and evidence of 5-c net SnS topology in a metallogel network

Abstract

A series of bis-amides derived from L-(+)-tartaric acid was synthesized as potential low-molecular-weight gelators. Out of 14 bis-amides synthesized, 13 displayed organo-, hydro-, and ambidextrous gelation behavior. The gels were characterized by methods including circular dichroism, differential scanning calorimetry, optical and electron microscopy, and rheology. One of the gels derived from di-3-pyridyltartaramide (D-3-PyTA) displayed intriguing nanotubular morphology of the gel network, which was exploited as a template to generate highly aligned 1D silica fibers. The gelator D-3-PyTA was also exploited to generate metallogels by treatment with various Cu^II/Zn^II salts under suitable conditions. A structure–property correlation on the basis of single-crystal and powder X-ray diffraction data was attempted to gain insight into the structures of the gel networks in both organo- and metallogels. Such study led to the determination of the gel-network structure of the Cu^II coordination-polymer-based metallogel, which displayed a 2D sheet architecture made of a chloride-bridged double helix that resembled a 5-c net SnS topology.