A Chiral Hemiporphyrazine Derivative: Synthesis and Chiroptical Properties

The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325-450nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220-325nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at -0.85V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.