Design of Benzocoumarin-Based Small Molecular Gelators in CN ^– Recognition, Oil Spill Recovery, and Dye Adsorption through Phase-Selective Gelation

Lauryl and cholesterol carbonate-linked benzocoumarin conjugates <b>1</b> and <b>2</b> have been designed, synthesized, and successfully established as supramolecular gelators. Both show gelation in DMF-H₂O (2:1, v/v), DMSO-H₂O (2:1, v/v), hexane, and fuel oil such as petrol, kerosene, and diesel. The aggregation behavior is explained spectroscopically. The gels are stable and exhibit good viscoelastic properties. The storage modulus (<i>G</i>') in each gel is considerably higher than the loss modulus (<i>G</i>″). The higher value of crossover point for the gel of <b>1</b> compared to the gel of <b>2</b> demonstrates the better gelation behavior of <b>1</b> over <b>2</b> in DMF-H₂O (2:1, v/v) and DMSO-H₂O (2:1, v/v). FESEM images reveal a fibrous morphology with different packings. Gels are anion-responsive. DMF-H₂O (2:1, v/v) gels of <b>1</b> and <b>2</b> recognize selectively CN^- ion over a series of other anions involving a gel-to-gel color change. Owing to the phase-selective gelation (PSG) abilities, both <b>1</b> and <b>2</b> respond to oil spill recovery. Additionally, gelator <b>1</b> removes the cationic dye from water via phase-selective gelation.