The nature of the lowest triplet state of cinnoline

✍ Scribed by Jim A. Stikeleather

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 441 KB
• Volume: 24
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(74)85444-8

✦ Synopsis

Cinnoline (1,2_diazanaphtha:ene) and its 4-methyl derivative are shown to be non-phosphorescent in hydrocarbon rigid glass solvents, but to undergo dramatic phosphorescence activation in hydroxylic rigid glass sovents. These yellow phosphorescences (0, O-bands at 51.5 nm) are assigned as being of ( n, I;*) character owing to their relatively long lifetimes of 0.17 set for cinnoline and 0.23 XC for 4-methylcinnoline. The lack of phosphorescence for the cinnolines in hydrocarbon solvents is attributed to a fast triplet radiationless decay resulting from the pseudo-Jahn-Teller effect.