Synthesis, Physical Properties, and Reactivity of Persistent π-Conjugated Carbon-Centered Radicals

Recently, long-lived organic radical species have attracted much attention of chemists and material scientists because of their unique electronic properties derived from magnetic spin and singly occupied molecular orbitals. Most stable and persistent organic radicals are hetero-atom centered radicals, whereas carbon-centered radicals are generally very reactive, and therefore, have been far from application. Because physical properties of carbon-centered radicals depend predominantly on the topology of the pi-electron array, the development of new carbon-centered radicals is key to new basic molecular skeletons that promise novel and diverse applications of spin materials. This article describes our recent studies on the development of novel carbon-centered radicals, including phenalenyl, fluorenyl, and triarylmethyl radicals.