A new class of fluorescent chemosensors based on the β-aminobisphosphonate receptor

The photophysical properties of a range of fluorescent sensors with β-aminobisphosphonate receptors have been studied. The compounds were designed according to the fluorophore–spacer–receptor format of photoinduced electron transfer-based sensors. The sensors displayed unusual fluorescence intensity–pH profiles that were attributed to a receptor–fluorophore H-bonding interaction that resulted in a quenching of fluorescence. The number of receptors and the nature of the fluorophore were both shown to have an effect on the pH profiles of the sensors. In addition, compound 1 was also shown to be selective for Cu2+ ions, in water at pH 7.4 with sensitivity in the micromolar range.