Synthesis, Characterization, Fluoride Ion Sensing and DFT Studies of Carbamate-Based Bistriazole.

A carbamate-linked-bistriazole (5) was prepared by click reaction of diethynyl 1,3-phenylenedicarbamate (2) and phenyl azide derivative (4) in DMF/H2O using copper sulfate and sodium ascorbate as a catalyst at room temperature for fluoride ion sensing. The structural analysis of synthesized compound was done by using 1HNMR, 13C NMR, FTIR and HRMS. The sensing behavior of carbamate-linked-bistriazole (5) was examined by 1HNMR, UV–vis and fluorescence study. NMR titration study suggested the participation of triazole, amide and aromatic protons in binding of fluoride ion. UV–visible study established the 1:1 complexation ratio between sensor 5 and F– ion with stability constant K of 2.64 × 104 M−1 and detection limit in µM range (9.372 µM). Further, fluorescence titration for 5 (9.2 × 10−6 M) with fluoride ions exhibited an emission quenching at 424 nm along with small bathochromic shift. Density functional theory (DFT) calculations also confirmed interaction mechanism in 5a-F– complex established by, UV–visible, 1H NMR and fluorescence studies. [ABSTRACT FROM AUTHOR]