Electrochromics by Intramolecular Redox Switching of Single Bonds

Abstract

Compounds of the general structure presented in Scheme 1 are proposed as electrochromic systems (ESs) in which reversible electron transfer is associated with breaking or forming of single bonds. In contrast to classical ESs, both redox states represent closed-shell systems. Whereas type OL/CS (Open form − Long-wavelength absorption/Closed form − Short-wavelength absorption) has already been demonstrated, this paper presents examples of the OS/CL type, in which the long-wavelength absorption is displayed by the ring-closed form. Bis(azines) RED-8, RED-13, RED-16, and RED-17, as well as the bis(amines) RED-22, RED-23, and RED-24 were prepared and characterized by their cyclic vol-

Electrochiroptical Response of 2,2‘-(2,2-Diarylethenyl)binaphthyl-Type Electron Donors That Undergo Reversible C−C Bond Formation/Breaking upon Two-Electron Transfer

“…They are promising candidates for use as chiral redox memories . Compared with extensive studies on electrochromic materials that give UV−vis spectral changes as a sole output, there have been only a few successful examples reported so far of those involving changes in CD spectra. , During the course of our continuing study on new electrochromic materials, we found that β,β-bis(4-dimethylaminophenyl)styrene ( 5 ) undergoes oxidative dimerization to give a stable salt of 1,4-dication 6 2+ in quantitative yield 2c (Scheme ). This result prompted us to design novel bichromophoric redox pairs containing a biaryl skeleton, where the oxidative C−C bonding to the dication is an intramolecular process.…”