Electron-Transfer Processes in Highly-Correlated Electron Systems of Thiazyl Radicals

Heterocyclic thiazyl radicals possess unique chemical and physical properties as building blocks for molecule-based conductors and magnetic materials. They do not need protecting groups on their molecular skeletons, and the lack of such substituents permits close packing in the solid state. Moreover, thiazyl radical solids often involve a multidimensional network consisting of pi-pi overlaps and S center dot center dot center dot N contacts. The electronic structures of the thiazyl radicals can be compared to highly-correlated electron systems. In this account, we describe various electron-transfer processes in the solids of the thiazyl radicals, which manifest themselves by external stimuli such as temperature change, electric field, and photoillumination.