M. Atar, Ö. Taspinar, Sebastian Hanft
Nov 26, 2019
Citations
0
Influential Citations
17
Citations
Journal
The Journal of organic chemistry
Abstract
The fluorescence emission of the parent 2-aminobenzimidazole (ABZ, 1), the mono- and disubstituted derivatives (2, 3), the 2-amino naphthoimidazole (4) and the 4-amino dinaphthodiazepine 5 (em = 315 - 400 nm) are strongly quenched in the presence of aqueous hydrogen peroxide. The quenching process is dual: for the diazepine 5 quenching is dynamic at lower H2O2 concentrations with linear reduction of the fluorescence lifetime from 4.3 to 2.6 ns. At higher H2O2 concentrations, a second species appears in the absorption and emission spectra with fluorescence lifetimes of 1.3 ns indicating the formation of a new (ground-state) hydrogen-bonded ABZ-H2O2 complex (static quenching). Sensors 1 and 2 show also dual quenching that fits with a static 1:1 and 1:2 model with K1:1 = 8 (11) M-1 and K1:2 = 21 (147) M-1 for 1 (2). The formation of a 1:2 complex (1:(H2O2)2) is also supported by DFT-calculations and spectra simulations.