Redox Properties of <i>N,N′</i>-Disubstituted Dihydrophenazine and Dihydrodibenzo[<i>a,c</i>]phenazine: The First Isolation of Their Crystalline Radical Cations and Dications
Bin Huang, Hao Kang, Xiao‐Li Zhao, Hai‐Bo Yang, Xueliang Shi
Abstract
In this study, the redox behaviors of N,N′-disubstituted dihydrophenazine and dihydrodibenzo[a,c]phenazine and the distinct properties of their corresponding radical cation and dication species were systematically investigated and compared. A structure–activity relationship investigation revealed that the dication of dihydrophenazine was very reactive and unstable. Nevertheless, the unprecedented crystallization and single-crystal structures of their radical cation and dication species, especially the dication of dihydrophenazine DPPZ-B2+, were successfully achieved. X-ray crystallographic analysis unveiled the unique changes in the molecular geometry and electronic structure of dihydrophenazine and dihydrodibenzo[a,c]phenazine before and after oxidation. Moreover, the geometry planarization in the dihydrodibenzo[a,c]phenazine radical cation (DPAC•+) and dication (DPAC2+) was demonstrated for the first time, which could contribute to the understanding of its intriguing conformation-adaptive behavior. We expect that this study will provide new insight into the understanding of the structure–activity and structure–conformation relationship of dihydrophenazines, which can be helpful to the design and application of dihydrophenazine-based materials in the future.