Molecular engineering of 1,3,5-triaryl-2-pyrazoline fluorescent logic systems responsive to acidity and oxidisability and attachment to polymer beads

摘要

1,3,5-Triaryl-2-pyrazolines were designed, synthesised and covalently immobilised onto submillimetre TentaGel~R polystyrene beads (functionalised with amino-terminated polyethyleneglycol ligands) by peptide bond formation. The molecules are modularly designed based on photoinduced electron transfer (PET) according to electron-donor-spacer-fluorophore-receptor and receptor1-spacer-fluorophore-receptor formats with ferrocene and N,N-dimethylaniline as the electron donor and receptor1. A reference fluorophore-receptor compound, associated with an internal charge transfer (ICT) mechanism, is included for comparison. A carboxylate moiety at the para-position of the 1-phenyl ring assists the molecules with aqueous solubility and serves as the site for covalent attachment to the polystyrene beads. The H~+, Fe~(3+)-driven INHIBIT, H~+-driven off-on-off and H~+-driven NOT logic systems are demonstrated in aqueous methanol and attached onto heterogeneous polymer submillimeter beads. The INHIBIT gate was tested with the stronger oxidant, ammonium persulfate, which resulted in a greater fluorescence quantum yield (Φf = 0.192). A double-tagged polymer bead integrating INHIBIT and off-on-off multi-valued logic was also prepared.