Kamogawa, Hiroyoshi et al. published their research in Kenkyu Hokoku – Asahi Garasu Kogyo Gijutsu Shoreikai in 1984 |CAS: 52243-87-5

The Article related to viologen electron transfer solvent effect, Physical Organic Chemistry: Oxidation-Reduction, Including Dehydrogenation and Hydrogenolysis and other aspects.Reference of 1,1′-Dipropyl-[4,4′-bipyridine]-1,1′-diium bromide

Kamogawa, Hiroyoshi; Amemiya, Suguru published an article in 1984, the title of the article was Synthesis of novel organic functional substances. II. Spontaneous generation of viologen radical cations in polar aprotic solvents.Reference of 1,1′-Dipropyl-[4,4′-bipyridine]-1,1′-diium bromide And the article contains the following content:

Viologens, when dissolved in polar aprotic solvents (such as N-methyl-2-pyrrolidone or HMPA) under deaerated conditions, gave a blue color (λmax = 608-609nm) indicating the spontaneous generation of the viologen radical cation. Electron transfer from the counter anion of viologen to the viologen cation was proposed. The experimental process involved the reaction of 1,1′-Dipropyl-[4,4′-bipyridine]-1,1′-diium bromide(cas: 52243-87-5).Reference of 1,1′-Dipropyl-[4,4′-bipyridine]-1,1′-diium bromide

The Article related to viologen electron transfer solvent effect, Physical Organic Chemistry: Oxidation-Reduction, Including Dehydrogenation and Hydrogenolysis and other aspects.Reference of 1,1′-Dipropyl-[4,4′-bipyridine]-1,1′-diium bromide

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem