Axially and Helically Chiral Cationic Radical Bicarbazoles: SOMO–HOMO Level Inversion and Chirality Impact on the Stability of Mono- and Diradical Cations

• DOI: 10.1021/jacs.0c08948
• Publication Date: 2020-11-17T21:52:07Z
• Authors: Sitthichok Kasemt...; Laura Abella; Marion Jean; Marie Cordier; Thierry Roisnel; Nicolas Vanthuyne; Thierry Guizouarn; Olivier Cador; Jochen Autschbach; Jeanne Crassous; Ludovic Favereau
• Keywords: Diradical; Chirality; Axial symmetry; Cationic polymerization

We report persistent chiral organic mono- and diradical cations based on bicarbazole molecular design with an unprecedented stability dependence the type of chirality, namely, axial versus helical. An unusual chemical was observed for sterically unprotected radical in comparison monocarbazole helical ones. Such results were experimentally theoretically investigated, revealing inversion energy singly occupied orbital (SOMO) highest (doubly) (HOMO) both monoradicals along a subtle difference electronic coupling between two carbazole units, which is modulated by their relative dihedral angle related to chirality. findings allowed us explore depth SOMO-HOMO (SHI) systems provide new insights regarding its impact radicals. Finally, these specific properties prepare persistent, intrinsically chiral, notably displayed near-infrared circular dichroism responses up 1100 nm almost degenerate singlet-triplet ground states weak antiferromagnetic interactions evaluated magnetometry experiments.