Solvent Effects on Cyanine Derivatives: A PCM Investigation

International audienceThe authors present time-​dependent d. functional theory calcns. of the excited-​state geometries and electronic properties of both model cyanines and BODIPY derivs., which are particularly challenging dyes for theor. chem. In particular, the authors focus on environmental effects, using a panel of approaches derived from the polarizable continuum model, including full cor. linear response (cLR) values detd. through a very recently developed approach. In idealized quasi-​linear cyanines, all approaches provide very similar excited-​state geometries though linear response (LR)​, and cLR models yield very different transition energies. For the fluoroborate derivs., LR apparently overestimates the planarity of the excited-​state geometries, and cLR optimizations yield slightly smaller fluorescence energies than LR, making these values closer to exptl. refs. The computed corrections are however too small to explain (taken alone) the significant theory​/expt. discrepancies