Related Experiment Videos
Synthesis and tunability of highly electron-accepting, N-benzylated "phosphaviologens"
Monika Stolar1, Javier Borau-Garcia, Mark Toonen
1Department of Chemistry and Centre for Advanced Solar Materials, University of Calgary , 2500 University Drive Northwest, Calgary, Alberta T2N 1N4, Canada.
Abstract:
We report a structure-property study on phosphoryl-bridged viologen analogues with a remarkably low reduction threshold. Utilizing different benzyl groups for N-quaternization, we were able to confirm the p-benzyl substituent effect on the electronic tunability of the system while maintaining the characteristic chromic response of viologens with two fully reversible one-electron reductions. Due to the considerably increased electron-acceptor properties of the phosphoryl-bridged bipyridine precursor, N-benzylation was found to be very challenging and required the development of new synthetic strategies toward the target viologen species. This study also introduces a new and convenient way for the anion exchange of viologen systems by utilizing methyl triflate. Finally, the practical utility of the new species was verified in simplified proof-of-concept electrochromic devices.
Related Concept Videos
Electrophilic Aromatic Substitution: Nitration of Benzene
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Electrophilic Aromatic Substitution: Sulfonation of Benzene
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Nucleophilic Aromatic Substitution: Elimination–Addition
Directing Effect of Substituents: meta-Directing Groups