| |
[摘要]：The synthesis and photophys. characterization of a fluorophore-spacer-receptor1-spacer-receptor2 system, which combines the 1,8-naphthalimide fluorophore with amine and urea receptor units, is reported. Photoinduced electron transfer (PET) from the amino group was blocked by protonation, leading to a drastic fluorescence enhancement (ca. 20 times). Interaction of the urea receptor with anions (F-, AcO-, H2PO4-) via hydrogen bonding or urea NH deprotonation resulted in significant fluorescence quenching of the 1,8-naphthalimide chromophore in an appropriately chosen model compd. (ca. 30-45%). In the presence of both chem. input species, protons and anions, the fluorescence was also quenched. The binding of the anions by NH+ ammonium receptor has been assumed. The apparent anion binding consts. of the protonated conjugate follow the basicity trend of the anions: AcO- ~ F- > H2PO4-. The investigated system constitutes an example for the flexible and modular realization of functionally integrated INH logic at the mol. level, using protons and anions as chem. input species and the fluorescence of a PET-active signaling unit as output. |
|
