Abstract
7-tert-Butylpyrene-1-azine-salicylaldehyde, 1.1 has been synthesized as a dual fluorescent chemosensor based on an excited state intramolecular proton transfer (ESIPT) mechanism. Ligand L1 undergoes AcO-/F- triggered sharp fluorescence enhancement towards Zn2+ in a co-operative fashion to form a complex with 2:1 stoichiometry. In order to investigate the influence of the 7-tert-butyl group, pyrene-1-azine-salicylaldehyde, L2 was also prepared. With ligand L1, fluorescence enhancement in acetonitrile solution is found to be twice as large than with ligand L2. The association constants of L1(O-)(2)superset of Zn2+ in the presence of AcO- and F- were determined to be K-a2 = 9.2 x 10(8) M-1 and 1.5 x 10(6) M-1, respectively using a 2:1 binding model. The results of a DFT interaction study were consistent with the experimental results. (C) 2017 Elsevier Ltd. All rights reserved.