Stimuli-responsive bile acid-based metallogels forming in aqueous media

• A bile acid–picolinic acid conjugate forms gels with Cu2+ ions in aqueous solvents.
• These gels are responsive to mechanical and chemical stimuli.
• The systems undergo reversible redox-responsiveness combined with phase transitions.
• NMR proves pyridine moiety’s essential role in chelating the Cu2+ ions in the gels.
• MS and SEM are used in further characterization the systems.

The synthesis and gelation properties of a picolinic acid conjugated bile acid derivative in the presence of metal salts along with the stimuli-responsiveness of the systems are reported. The gels are formed in the presence of Cu2+ ions in the solvent systems composed of 30–50% of organic solvent (MeOH, acetonitrile, or acetone) in water. The gels respond to various stimuli: they can be formed upon sonication or shaking, and their gel–sol transformation can be triggered by a variety of chemical species. NMR, MS, and SEM techniques are exploited in order to gain a deeper insight on the self-assembled systems.

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