Chiral Stable Phenalenyl Radical: Synthesis, Electronic-Spin Structure, and Optical Properties of [4]HeIicene-Structured Diazaphenalenyl

摘要

Helicenes are ortho-annelated polycyclic aromatic molecules with nonplanar helical conjugation of the π -electron system. These aromatic molecules have attracted special attention not only because of the nonplanarity of the it-conjugated skeleton but also because of their inherent helical chirality. Recent developments in helicene chemistry have focused on the synthesis and optical resolution of new helicene derivatives as well as on asymmetric catalysts, molecular recognition, and chiroptical functionalities. However, almost all of the helicene derivatives investigated so far are intrinsically closed-shell electronic systems except for a few examples. Thus, the chemistry of open-shell helicenes has been little explored in the past; to our knowledge there have been no experimental studies on helicene-based nonplanar chiral neutral it-radical systems.