Near-infrared dyes and fluorophores based on diketopyrrolopyrroles

NIRly there: The chromophore of compounds with intramolecular H bonds have been rigidified by substitution of the protons of the N-H⋯N bridges by BR2 groups (R = F, Ph). This stiffening and the polymethine character of the chromophores affords dyes with intense fluorescence at room temperature and high NIR absorption, but virtually no absorption in the visible range (see the picture for an example, -: absorption, •••••: fluorescence). (Figure Presented). © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.