Hydrogen Peroxide Sensors Based on Fluorescence Quenching of the 2-AminobenzimidazoleFluorophore

Abstract

The fluorescence emission of the parent 2-aminobenzimidazole (ABZ, 1), the mono- and disubstituted derivatives (2, 3), 2-aminonaphthoimidazole (4), and 4-amino dinaphthodiazepine 5 (λem = 315–400 nm) is strongly quenched in the presence of aqueous hydrogen peroxide. The quenching process is dual: for 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 K 1:1 = 8(11) M–1 and K 1:2 = 21(147) M–1 for 1(2). The formation of a 1:2 complex (1:(H2O2)2) is also supported by density functional theory (DFT) calculations and spectra simulations.

Transition‐Metal‐Free Base‐Controlled C−N Coupling Reactions: Selective Mono Versus Diarylation of Primary Amines with 2‐Chlorobenzimidazoles

“…[6] 2-Aminobenzimida-zole was also utilized as a ligand to modify the structures of zeolitic imidazolate frameworks (ZIFs), thereby adjusting the properties of the corresponding materials. [7] Besides, the 2-aminobenzimidazole skeleton is prevailing in chemical sensors for the detection of anions [8] as well as in corrosion inhibitors. [9] In view of the widespread applications, expedient synthetic approaches were described for accessing 2aminobenzimidazoles.…”

Synthesis, density functional theory (DFT) studies and urease inhibition activity of chiral benzimidazoles

“…Recent studies in medicinal chemistry have demonstrated them as potential drug motifs for the pharmaceutical industry [ 7 ]. They have also well-known applications in chemo-sensing [ 8 ], fluorescence [ 9 ], crystal engineering [ 10 ], corrosion science [ 11a,b ] and asymmetric catalysis [ 12 ]. The bioactivity of drug molecule depends predominantly on their interaction with drug targets, such as proteins, enzymes, nucleic acids and the biological membranes [ 13a,b ].…”

Highly Selective and Rapid Naked-Eye Colorimetric Sensing and Fluorescent Studies of Cu2+ Ions Derived from Spherical Nanocellulose

“…It is evident that totally switched-off fluorescence emission was observed with the higher Cu 2+ ions concentrations of 100 ppm of Cu 2+ ions solution. To explain the fluorescence (static or dynamic) turn off/quenching in the case of SNC-DETA-EA, we employed the Stern–Volmer equation as presentedhere. , with I 0 and I being the intensities observed, respectively, in the absence and presence of quencher, and Q is quencher concentration, K sv is the Stern–Volmer constant, and n is the binding constant.…”