Sugar-Based Phase-Selective Supramolecular Self-Assembly System for Dye Removal and Selective Detection of Cu2+ Ions.

Simple, effective, and eco-friendly sugar-based phase-selective gelators were synthesized at a low cost. They showed high gelling ability toward a wide range of solvents at lower concentrations (minimum gelation concentration ∼0.3%). Preliminary tests reveal that these low molecular weight organogelators can immediately and phase-selectively gel benzene, toluene, petrol, and kerosene in water at room temperature. We also identified G13 in toluene as the good gelator, and the corresponding organogel proficiently removes water-soluble dyes from their concentrated aqueous solutions. This efficient removal of toxic organic solvents and dyes from water suggests promising applications in removing organic substances from contaminated water resources. The thermoreversible gel exhibits effective rechargeability up to five cycles of burning and gelation, which imply the flame stability of the gel. Interestingly, these compounds had a high detection ability toward Cu2+ ions with a state change from gel to the solution. The physical justification for gelation mechanisms and the molecular interaction with metal ions were further confirmed by computational studies.

Sugar-benzohydrazide based phase selective gelators for marine oil spill recovery and removal of dye from polluted water.

The synthesis of 3,4,5-tri-O-benzohydrazide based N-glycosylamines were characterized using NMR (1H and 13C) and mass spectral analysis. Gelation properties of the synthesized molecules in different solvents and oils were studied and gelation was observed with minimum Critical Gelator Concentration (CGC) of 0.8% (w/v) in benzene. The free hydroxyl group of the sugar moiety, benzohydrazide and three alkyl chains present in all these compounds afford the collective driving forces for gelation. Phase-Selective Organo-Gelators (PSOGs) are molecules that can gel the oil selectively from the biphasic combination of oil and water and it is one of the good candidates for recovering oil in case of oil spill. It is observed that these gelators can be used as solid particles on a biphasic system consist of oil and water. It solidifies the oil selectively which can be taken out by means of the physical process. FT-IR and UV-Vis spectroscopy suggest that the driving forces for the gelation are hydrogen-bonding, π-π stacking and van der Waals interaction. The gels were studied using FE-SEM, DSC and rheological techniques. FE-SEM analysis shows that the formation of thin fibers and large wrinkle like aggregate structure in the gel state is due to the presence of different weak molecular interactions. The phase selection and gel-sol transition properties of these molecules confer their ability to absorb and release dyes with high efficiency.

Self-assembly of sugar based glyco-lipids: Gelation studies of partially protected d-glucose derivatives.

A series of sugar-based glycolipid derivatives were prepared by N-glycosylamines, and their organogelation property has been analyzed. We have observed the efficient gelation for some of the anilines substituted glycolipids derivatives in different aromatic and aliphatic solvents. It was found that the gelation occurred predominantly in aliphatic solvents with CGC of 0.8% (w/v) attributed to the presence of long alkyl chain in the glycolipids. The structural and morphological properties of the xerogels were investigated by NMR, powder XRD, and FE-SEM respectively. Furthermore, the thermal stability was analyzed by DSC.