On February 15, 1987, Kamogawa, Hiroyoshi; Suzuki, Tsuyoshi published an article.Category: pyridine-derivatives The title of the article was Photochromism of viologen crystals. And the article contained the following:
Some viologen crystals bearing a p-toluenesulfonate anion as a counter ion exhibit reversible photoreductions (photochromism) either in air or in vacuum. In a poly(N-vinyl-2-pyrrolidone) matrix all investigated viologens indicated reversible photocolor developments. Amphoteric ions such as 1,1′-bis(3-sulfonatoporpyl)-4,4′-bipyridinium also developed colors with high stabilities. The experimental process involved the reaction of 1,1′-Dipropyl-[4,4′-bipyridine]-1,1′-diium bromide(cas: 52243-87-5).Category: pyridine-derivatives
The Article related to photochromism viologen crystal toluenesulfonate counterion, Radiation Chemistry, Photochemistry, and Photographic and Other Reprographic Processes: Photochromic, Thermochromic, and Electrochromic Imaging Systems and other aspects.Category: pyridine-derivatives