Phosphorescent Bismoviologens for Electrophosphorochromism and Visible Light-Induced Cross-Dehydrogenative Coupling

A series
of novel bismuth-bridged viologen analogues, bismoviologens
(BiV2+), synthesized through a combination of a bismuth
atom and viologen skeleton is reported. Their optical and electrochemical
properties were fine-tuned through the N-arylation
or N-alkylation reactions. Bismolviologens not only
showed good redox properties but also exhibited phosphorescence under
ambient conditions (in air at room temperature). This phenomenon makes
BiV2+ the first examples of phosphorescent viologen analogues
reported to date. On the basis of the excellent and unique redox and
optical properties of BiV2+, their electrophosphorochromic
devices were fabricated. Furthermore, BiV2+ was used for
the first time as both a photocatalyst and electron mediator in visible
light-induced cross-dehydrogenative coupling reactions.