Recognition of caffeine in aqueous solutions

R. Fiammengo, Mercedes Crego Calama, P. Timmerman, David Reinhoudt

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    Binding of caffeine in aqueous solutions has been achieved for the first time by using water-soluble, tetracationic peptide-porphyrin conjugates Zn-1 as the receptor molecules. The association constant for caffeine with receptor Zn-1 is in some cases as high as 6000 M-1, only 5-6 times lower than the highest binding constant reported for an artificial caffeine receptor in low polarity aprotic solvents. The binding mechanism has been studied by a combination of experimental techniques such as UV-visible and NMR spectroscopy and microcalorimetry. Recognition of caffeine involves both stacking with the porphyrin ring and metal coordination. Subtle variations of the receptor structure affect the complexation. Receptors Zn-1 have also been investigated for the recognition of molecules structurally related to caffeine, for example, 1-methylimidazole. Selectivity towards oxopurine derivatives (caffeine and theophylline) have been found.
    Original languageUndefined
    Pages (from-to)784-792
    Number of pages9
    JournalChemistry : a European journal
    Issue number3
    Publication statusPublished - 2003


    • water chemistry
    • METIS-215563
    • IR-40871
    • Caffeine
    • Noncovalent interactions
    • Sensors
    • porphyrinoids

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