Substituent effects on the photoreactivity of Ru-containing ionic liquids exhibiting reversible ionic conductivity changes

Controlling the ionic conductivity of liquids using external fields is crucial for electronic device applications. We have recently developed metal-containing ionic liquids (ILs) exhibiting reversible ionic conductivity changes upon UV photoirradiation and heating based on the photochemical oligomerization reaction of sandwich Ru complexes. In this study, to explore the controllability of the reaction, we synthesized several Ru-containing ILs with different substituents containing a cyano or dimethylamino group at the terminal position. The photochemical reaction was significantly affected by the coordination ability and flexibility of the substituents, and mixing ILs having different reactivity allowed controlling the conversions. Upon successive photoirradiation-heating cycles, the ionic conductivity of these ILs underwent reversible changes, whose extent reflected the photoreactiv-ity of the ILs. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

Controlling the ionic conductivity of liquids is essential for electronic device applications, and we have developed metal-containing ionic liquids that exhibit reversible changes in ionic conductivity through UV photoirradiation and heating. The substituents in these liquids significantly affect the photochemical reaction, and by combining liquids with different reactivity, the conversions can be controlled. The ionic conductivity of these liquids undergoes reversible changes through successive photoirradiation-heating cycles, reflecting their photoreactivity.