Calculations of BODIPY dyes in the ground and excited states using the M06-2X and PBE0 functionals

A number of fluorescent dyes based on BODIPY (4,4'-difluoro-4-bora-3a,4a-diaza-s-indacene) have been studied theoretically. This paper presents the results of calculations of these BODIPY dyes in their ground and excited states, performed using DFT and TD-DFT methods, respectively. The influences of N,N-dimethylaminobenzyl, ortho-fluorophenol, and methyl substituents as well as the solvent polarity on the positions of the absorption and emission bands of the dyes were analyzed. The computational data obtained in this work were compared to the corresponding experimental data. The trends in the experimental data were found to agree with those shown by the computational data. Differences between the potential curves obtained when using linear-response (LR) and state-specific (SS) approaches for the ground and excited states are also reported. Graphical Abstract The article shows that the trends of the experimental dependencies λ_abs = f(Δf) and λ_em = f(Δf) well described by PBE0 (LR approach) and M06-2X (SS approach) calculations, respectively. The influence of substituents on the spectral characteristics of the BODIPY chromophore are analysed.