A Library of Multipurpose Supramolecular Supergelators: Fabrication of Structured Silica, Porous Plastics, and Fluorescent Gels

Abstract

Supramolecular gels find applications in various fields. Usually, a specific gelator is useful only for a specific application. This one-gelator-one-application format is one factor that limits the usefulness of supramolecular gels. We report the synthesis of a library of gelators from a common core by using a click-chemistry approach. Thus, the click reaction of β-azido-4,6-O-benzylidene-galactopyranoside (1) with various alkynes gave 11 different gelators having varying gelation abilities. Whereas gelators having alkyl-chain substituents congealed alkanes and tetraethylorthosilicate (TEOS), the gelators having aromatic substituents congealed aromatic solvents. We exploited this difference in gelling behavior in the templated synthesis of silica rods and porous plastics. The styrene gel of gelator 2 j was polymerized, and the gelator was removed by washing to obtain porous polystyrene. The TEOS gel of gelator 2 b was polymerized to silica, and the gelator template was removed by calcination to give microstructured silica rods. We also developed fluorescent gelator 2 f by this method, which might find applications by virtue of its fluorescence in the assembled state.

Recently Developed Carbohydrate Based Gelators and Their Applications

“…Krishnan et al reported the synthesis and gelation properties of a series of 11 4,6benzylidene acetal protected β-triazole derivatives from D-galactose ( Figure 33) [80]. These compounds were tested in hydrocarbon solvents and oils with CGCs in the range of 0.10 to 3.58 wt %.…”

“…The aromatic derivatives formed gels in organic solvents, but not in oil. An anthracene-containing gelator 48f showed interesting fluorescent properties and could have applications in various fields [80]. Figure 33) [80].…”

“…An anthracene-containing gelator 48f showed interesting fluorescent properties and could have applications in various fields [80]. Figure 33) [80]. These compounds were tested in hydrocarbon solvents and oils with CGCs in the range of 0.10 to 3.58 wt %.…”

“…The aromatic derivatives formed gels in organic solvents, but not in oil. An anthracene-containing gelator 48f showed interesting fluorescent properties and could have applications in various fields [80]. A series of triazolylarabinoside derivatives were also reported and two of these derivatives shown in Figure 34 were effective organogelators [81].…”

Carbohydrate Derived Organogelators and the Corresponding Functional Gels Developed in Recent Time

“…Among these, the formation of a well-defined architecture of nano or meso structured silica by sol-gel transcription of a supramolecular gel has been extensively studied [5,27,124]. A library of eleven organogelators ( 40 , Figure 29) has been designed and synthesized utilizing azido 4,6- O -benzylidene-β- d -galactopyranose as a common building block utilizing click chemistry [125]. Gelators with an alkyl chain on the triazole moiety, gelated alkanes, and tetraethyl orthosilicate (TEOS), those having an aromatic substituent on the triazole moiety, caused congelation of aromatic solvents.…”