Tripeptide based super-organogelators: structure and functionElectronic supplementary information (ESI) available: Peptide synthesis, NMR spectra, rheology curves, Fig. ESI S1-S35, peptide single crystals. CCDC 1855060. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8nj05578e

A novel series of tripeptide-based low molecular weight super-organogelators were synthesized and characterized. Four tripeptides with diverse steric crowding at the central amino acid residue were studied. From this series, only sterically less hindered peptide 1 and peptide 3 formed organogels in different saturated hydrocarbons, crude oil, and aromatic solvents. In diesel, the peptides formed gels at 1 wt%, i.e. they act as super-organogelators. Interestingly both the peptide gels show high stability and remarkable self-healing properties. As the peptides have an electron rich phenyl system, the corresponding gels also interact with cationic dyes and can selectively remove cationic dyes from waste water. The super-gelators have very high efficiency to solidify only the oil from a biphasic mixture of oil-water. Due to the high solubility of the super-gelators in non-toxic organic solvent ethanol, the solution is easy to handle and just by spraying the ethanol solution over an oil-water mixture it is able to perform a gelling function at room temperature. The trapped water under the organogel can be pumped out and the oil can be recovered from the organogel by vacuum distillation. So, the super-gelators can be used as a low cost, non-toxic, and easy to use at room temperature material for oil-spill recovery. The peptide based super-gelators are highly soluble in non-toxic organic solvent ethanol, the solution is easy to handle and just by spraying the ethanol solution over an oil-water mixture it is able to form an organogel at room temperature.