A highly selective fluorescent chemosensor probe for detection of Fe3+ and Ag+ based on supramolecular assembly of cucurbit[10]uril with a pyrene derivative

A new fluorescent probe composed of cucurbit[10]uril (Q[10]) and a water-soluble derivative of pyrene, aminopropyl-1-pyrenebutanamide (PBA), is designated. 1H NMR spectroscopy reveals that PBA is encapsulated into Q[10] in an aqueous solution to form a stable 1:1 host-guest inclusion complex of PBA@Q[10]. This complex behaves as a highly selective fluorescence quenching probe for Fe3+ in aqueous solutions that may be attributed to the efficient absorption of Fe3+, which hindering absorption of PBA@Q[10] probe at the excitation wavelength of 332 nm, and competitive experiments for the coexistence of Fe3+ with one or all of the other metal ions (37 metal ions) reveals that the selectivity of PBA@Q[10] to Fe3+ is not disturbed by the addition of 50.0 equiv. of the other metal ions. The limits of detection of Fe3+ was determined to be 0.55 mM. Furthermore, the fluorescence enhancing effect of PBA@Q[10] for Ag+ is detected at the above wavelength. According to the mechanistic studies, the fluorescence enhancing route involves interaction of Ag+ ions with the probe, mainly under an internal charge transfer between Ag+ and the probe. Outcomes of this study suggest that PBA@Q[10] probably functions as a potential and promising fluorescence sensor for monitoring of different polluting metal ions in waste waters.