Multi-input-multi-output molecular response system based on dynamic redox behavior of hexaphenylethane-type electron donors with the tetrahydrophenanthrazepine skeleton: strong chiroptical signals through the transmission of point chirality to helicity.
The title heterocyclic donors undergo reversible C-C bond formation/cleavage upon electron transfer (dynamic redox behavior). The helical sense in both neutral and cationic states is interconvertible by facile ring flipping. The pi-type asymmetric center on the azepine nitrogen atom induces a significant degree of diasteromeric preference, thus endowing strong CD activity based on exciton coupling. Chiroptical properties could be modified not only by redox reactions but also by heat and protonation. The present redox pairs can serve as unprecedented three-way-input (e, H+, delta) and two-way-output (UV/Vis, CD) response systems.
Suzuki
Takanori
T
Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. tak@sci.hokudai.ac.jp
Tanaka
Shoko
S
Kawai
Hidetoshi
H
Fujiwara
Kenshu
K