Optical signatures of borico dyes: a TD-DFT analysis

Using time-dependent density functional theory, we investigate the excited-state properties of a series of emissive dyes combining the properties of coumarins and fluoroborate compounds. These boron-iminocoumarins (borico) compounds have been synthesized very recently by Frath et al. (Chem Commun 49:4908, 2013) . We determine both their vertical and 0-0 energies, reproduce and analyze their characteristic experimental band shape, investigate the nature of the excited-states in large dyads containing two different fluoroborate complexes and design red-shifted compounds. We also consider an additional panel of fused coumarin-BODIPY emitters.