Restricted intramolecular vibrations assisted enhanced fluorescence emission response of probe: A new experimental and theoretical approach for the detection of hydrogen peroxide

Hydrogen peroxide (H2O2) is a harmful chemical used as a signature compound in forming easily synthesizable peroxide-based explosives. Therefore, detecting H2O2 vapors and solutions is imperative to avoid terroristic activities. Aggregation induced emission enhancement (AIEE) active probe PAT detected H2O2 based on geometry-dependent hydrogen bonding. Unlike frequently reported fluorescent probes, probe PAT exhibited a strong fluorescence emission enhancement response for H2O2 due to restrictions in intramolecular vibrations of probe. This unique sensing phenomenon enhances our probe's versatility and potential applications in the selective and sensitive detection of H2O2. 1H NMR titration experiments and extensive density functional theory (DFT) calculations explained the distinct sensing mechanism. As a result of efficient interaction, probe could detect H2O2 with critical features of excellent selectivity, nanoscale level detection (LOD; 10 nM), fast response (20 sec.), and distinguished photostability. Conveniently, probe PAT-embedded fluorescent strips were successfully employed as a portable sensing tool for rapidly recognizing H2O2 vapors. Moreover, probe PAT was also capable of H2O2 determination in industrial water, orange juice, milk samples and commercially available products. Therefore, our probe holds promising features for trace detection of H2O2 in vapor and solution phase that make it highly useful.