Supramolecular association of dopamine with immobilized fluorescent probes

We have designed a two-step procedure to coat silica particles with fluorescent 2,7-diazapyrenium dications. The electron-deficient character of the dications encourages the association of dopamine at the particle/water interface. The supramolecular event produces a significant decrease in the fluorescence intensity. Model binding studies with catechol and propylamine revealed that the interfacial complexation of dopamine is dominated by the interaction of its electron-rich dioxyarene fragment with the electron-deficient fluorophore in neutral aqueous environments.