Singlet biradical character of phenalenyl-based Kekule hydrocarbon with naphthoquinoid structure

A new Kekule polycyclic hydrocarbon with a singlet biradical index of 50% was synthesized. The singlet biradical character was assessed with UV and H-1-NMR spectroscopy, cyclic voltammetry, SQUID magnetic susceptibility measurement, and quantum chemical calculations.