Tripeptide based super-organogelators: structure and function†
Abstract
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.