Evaluation of BODIPY-based dye sensors functionalized with different electrophilic groups for H₂S detection

Hydrogen sulfide (H₂S) is an important endogenous signaling molecule, making the development of selective detection methods highly relevant. This work computationally evaluated BODIPY-based fluorescent chemosensors functionalized with different electrophilic groups to investigate their optical response toward H₂S. Ground- and excited-state properties of reactants and products were studied using DFT (CAM-B3LYP/def2-TZVP) and TD-DFT, considering different substitution patterns and anchoring positions of the electrophilic group. The reaction with H₂S promoted significant changes in the electronic absorption spectra, with variations in absorption maxima and transition intensities depending on the molecular structure. Among the systems analyzed, the 2,4-NO₂-substituted derivative anchored at position b exhibited the largest spectral shift (≈1600 cm⁻¹), indicating enhanced sensitivity. These results demonstrate the potential of these BODIPY derivatives as fluorescent chemosensors and provide guidelines for the rational design of new molecular technologies for H₂S sensing.