Indaphyrins and Indachlorins: Optical and Chiroptical Properties of a Family of Helimeric Porphyrinoids

Another paper resulting from the collaboration with the Bringmann Group at the University of Würzburg was published! Indaphyrins and indachlorins possess large chiral porphyrinoid π-systems with particularly long-wavelength absorption properties. All indaphyrin derivatives, including the indaphyrin M(II) complexes (M = Ni(II), Cu(II), Zn(II), and Pt(II)), adopt strongly ruffled and metal-dependent conformations incorporating a helimeric twist, thus forming two stereochemically stable helimeric enantiomers. Resolution of the racemic mixtures of the helimers of all derivatives Introduction was achieved by HPLC on a chiral phase and their absolute stereostructures were assigned. The much altered UV/Vis spectra of the indaphyrin derivatives, when compared to those of porphyrins, were rationalized using excited state calculations. The report forms the basis for future applications that exploit the chiral properties of the chromophores: Götz, D. C. G.; Gehrold, A.; Dorazio, S.; Samankumara, L.; Daddario, P.; Bringmann, G.; Brückner, C.; Bruhn, T. Eur. J. Org. Chem. 2015, 3913–3922.