Quenching of triplet states of diazines by H-atom donors. Formation of azyl radicals

✍ Scribed by D.V. Bent; E. Hayon; P.N. Moorthy

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 440 KB
• Volume: 27
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(74)80301-5

✦ Synopsis

The laser flash photolysis ofpyrazine in water and in organic solvents has been examined. The "(II, a*) state in water has absorption bands at 230. = 260, = 295, =. 640,700 and 8 10 nm, and decays with k = 2.2 X 10' set-' . It is quenched by oxygen with k = 3.2 X 10' &I-'set-' and by various H-atom donors, e.g., k = 1.3 X 10' hi-'see-' for isopropyl alcohol. On reac%m with H-atom donors, the chemistry of 3(n, a*) pymzine p?oduces the neutral pyrazyl-radical and the dihydro radical cationz whose characteristic absorption spectra have been identitied. These results are discussed by comparison with 3(n, IT*) diazines and with 3(n, r*) aromatic carbonyl compounds.