2011-02-07, Fischer, Georg, Daltrozzo, Ewald, Zumbusch, Andreas

Very invisible: Bis(pyrrolopyrrole) cyanines are extended chromophores based on diketopyrrolopyrroles (general structure shown). The compounds are characterized by extremely high extinction coefficients, narrowband absorption in the near-IR range, and strong fluorescence around 1 μm. Since absorption in the visible region is negligible, they approach the ideal of selective NIR absorbers.

2011, Fischer, Georg, Klein, Matthias, Daltrozzo, Ewald, Zumbusch, Andreas

To tune their optical properties, a large variety of pyrrolopyrrole cyanines (PPCys) were synthesized with substitutedheteroaromatics such as quinoline, benzothiazole, and oxazole derivatives as terminal groups. Thus, a broad range of stable, highly fluorescing near-infrared (NIR) dyes with high absorptivities between 690 to 845 nm is accessible. The large number of newly synthesized compounds allows a detailed discussion of the correlation between molecular structure and the optical properties of the first electronic transition.

2007, Fischer, Georg, Ehlers, Andreas, Zumbusch, Andreas, Daltrozzo, Ewald