A NIR-II Fluorescent Probe for Hydrogen Sulfide Detection Based on Blocking Intramolecular Charge Transfer

A NIR-II fluorescent probe (Et-1080) for H2S detection was fabricated based on the intramolecular charge transfer blocking mechanism. The enhanced electron density of the indole donor further drove the Et-1080 ' s absorption and emission to the NIR-II region with a high molar absorption coefficient and acceptable fluorescence quantum yield. The C=N double bond of electron-deficient indole can react with H2S rapidly via a nucleophilic addition mechanism, resulting in the destruction of conjugated structure and fluorescence quenching of the Et-1080 molecule. The probe showed high selectivity and sensitivity to H2S, which could realize the rapid detection of H2S in NIR-II band and showed great potential in the further disease diagnosis associated with H2S.