Highly sensitive and selective chemosensors for Cu2+ and Al3+ based on photoinduced electron transfer (PET) mechanism

摘要

Two novel acridine based chemosensors 7a and 7b were synthesized and configured as fluorophorespacer-receptor" systems based on photoinduced electron transfer. The probes 7a and 7b exhibited high selectivity and sensitivity for the detection of Cu2+ and Al3+ respectively over commonly coexistent metal ions in CH3CN. The binding association constants (K-a) of 7a-Cu2+ and 7bAl(3+) were found to be 4.0 x 10(4) M-1 and 1.7 x 10(4) M-1 in CH3CN, and the corresponding detection limits were calculated to be 2.8 x 10(-7) M and 5.8 x 10(-7) M, respectively. The fluorescence response of 7a-Cu2+ and 7b-Al3+ with respect to pH change was studied and the resulting demonstrated fluorescence enhancement was observed in the pH range of 7.0-9.0. The chromophores were characterized by FT-IR, H-1-NMR, C-13-NMR and HR Mass spectral analysis.