Highly selective recognition of Al 3+ and I - ions using a bi-functional fluorescent probe.

A tripodal fluorescent probe L1 armed with Rhodamine B and 1-naphthaleneisothiocyanates was prepared in high yield. A study of the recognition properties revealed that probe L1 exhibited high sensitivity and selectivity towards Al ³⁺ through a "FRET" fluorescence response and colorimetric response with low detection limits of the order of 10 ^-8 M. Meanwhile, probe L1 also possessed high recognition ability for I ^- through fluorescence decay, which given there are comparatively few selective fluorescent probes for I ^- , is significant. Furthermore, the complexation mechanisms were fully investigated by spectral titrations, ¹ H NMR spectroscopic titrations and mass spectrometry. The utility of probe L1 as a biosensor in living cells (PC3 cells) towards Al ³⁺ ions has also been demonstrated.