Cucurbituril Host-Guest Based Ratiometric Fluorescent Probe for Recognition of Nilotinib
Host-guest interaction of cucurbituril (Q or CB) with pyrene-derived derivatives was evaluated by fluorescence emission spectra and UV-vis absorption spectra, and the host-guest binding modes were studied by density functional theory (DFT). In the energy minimization structures, the pyrene group of the guest was encapsulated in the larger hydrophobic cavity of Q in parallel from the opposite direction in the form of a head-to-head fashion, forming a 2∶1 inclusion. The thermodynamic data indicated that the two host-guest interactions were enthalpy-driven. Furthermore, the Q host-guest interaction of Q/G2 could be used as ratiometric fluorescent probe based on the unique monomer/excimer emission of pyrene moiety on the guest G2. Experiment results indicated that the host-guest interaction derived probe had good recognition and selectivity for nilotinib in aqueous solution, and the detection limit was 7.05 μmol/L.