ChemInform Abstract: Vinylogous β‐Carotenes: Generation, Storage, and Delocalization of Charge in Carotenoids.

Abstract

Vinylogous β-Carotenes: Generation, Storage, and Delocalization of Charge in Carotenoids.-The β-carotenes (I)-(IV) of variable chain length containing 5-23 double bonds are synthesized by McMurry and Wittig reactions. The generation of open-shell and closed-shell ions of carotenoids in solution and in the solid state is investigated by cyclic voltammetry and photoelectron spectroscopy. The potential difference between the first oxidation potential and the first reduction potential is a linear function of the reciprocal chain length. An excellent correspondence between the energies of the radical cation states by the 2 methods is observed showing that the formation of radical cations is principally determined by the chain length. -(BROSZEIT, G.; DIEPENBROCK, F.; GRAEF, O.; HECHT, D.; HEINZE, J.; MARTIN, H.-D.; MAYER, B.; SCHAPER, K.; SMIE, A.; STREHBLOW, H.-H.; Liebigs Ann.