Kawata, Tsutomu published the artcileCharacteristics of viologen derivatives for electrochromic display, Application of 1,1-Di-n-octyl-4,4-bipyridinium Dibromide, the main research area is viologen derivative polarog optical absorption; electrochromic display viologen derivative.
The polarog. half-wave potentials (E1/2, in aqueous solutions with pH 3.29 at 25°) and the absorption spectra (at λ = 250-700 nm) in various media (aqueous solution, MeOH, glycerin) were determined to characterize the electrochromic behavior of the viologen derivatives X-RN+C5H4-C5H4N+RX- [= Viol] (R = Pr, C6H13, or C7H15 for X = Br; X = Cl, Br, or I for R = PhCH2). Two polarog. waves were observed for each derivative: the 1st E1/2 [= 0.568-0.710 V vs. SCE] was attributed to the reduction, dication of Viol (I, colorless) + e- ⇄ radical cation (II, colored); and the 2nd E1/2 [= 0.775-0.965 V] was attributed to II + e- ⇄ biradical (III, colored). The E1/2 values were smaller for the PhCH2 derivatives than for the alkyl derivatives For R = PhCH2, the observed absorption maximum were at λ (in nm) ≈ 260 for I, ≈ 260, 400, and 630 for II, and ≈ 380 for III. With a viologen derivative in an electrochromic display device (having a transparent SnO2 cathode and a Pt anode), the writing time decreased with increasing applied voltage, and was ∼0.4-0.8 sec for obtaining a transmittance of 80%. An applied voltage greater than the 2nd E1/2 caused the color to change from purple to yellow; on open circuit, the color changed back to purple.
Japanese Journal of Applied Physics published new progress about Electrochromism. 36437-30-6 belongs to class pyridine-derivatives, name is 1,1-Di-n-octyl-4,4-bipyridinium Dibromide, and the molecular formula is C26H42Br2N2, Application of 1,1-Di-n-octyl-4,4-bipyridinium Dibromide.