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Published on: July 19, 2019
Double Dynamic Structural Change Enabling Tricolor Chromism by the Realization of Apparent Two-Electron Transfer to
Takashi Harimoto1, Yuka Sugai1, Kazuma Sugawara1
1Department of Chemistry, Faculty of Science, Hokkaido University, N10 W8, North-ward, Sapporo, 060-0810, Japan.
Abstract:
Most redox systems generally cannot avoid the involvement of open-shell species upon generating multiply charged species, which often reduces reversibility in multi-color electrochromic systems. In this study, we newly synthesized octakis(aminophenyl)-substituted pentacenebisquinodimethane (BQD) derivatives and their hybrids with alkoxyphenyl analogues. Thanks to apparent two-electron transfer accompanied by double dramatic changes in the structure of the arylated quinodimethane skeleton, the dicationic and tetracationic states were generated and isolated quantitatively because of the negligible steady-state concentration of intermediary open-shell species such as monocation or trication radicals. When two electrophores with different donating abilities are attached to the BQD skeleton, a dicationic state with a different color can be isolated in addition to the neutral and tetracationic states. For these tetracations, an interchromophore interaction induces a red-shift of the NIR absorptions, thus realizing tricolor UV/Vis/NIR electrochromic behavior involving only closed-shell states.
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