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ESR Spectra of radicals produced by reduction of pyridine and pyrazine

✍ Scribed by Richard W. Fessenden; P. Neta

Publisher
Elsevier Science
Year
1973
Tongue
English
Weight
366 KB
Volume
18
Category
Article
ISSN
0009-2614

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✦ Synopsis

Radicals produced by reaction of e;ls with pyridine, pyrazine, and pyrazincdicarboxylic acid have been studied by elcctrwr spin resonance using the in situ radiolysis steady-state ESR technique. The radical anions initially produced have been found to undergo rapid protonation on nitrogen to form pyridinyl and pyrazinyl radicals. The NPi proton of pyridinyl radical does not dissociate even at pH 13.7. 'The radical from pyrazine has been observed only in the doubly protonnted positively charged form in acid and neutral solutions, but no spectrum was observed in akalinc media. With 2,3_pyrazinedicarbosylic acid the doubly protonated radical has been observed at pH 4-8 and the singly protonated one at PH 1 l.-12. The p# for this dixociation is 9.2. l?e hyperfine constants of the pyridinyl radical are compared with those obtained from lND0 molecular orbital calculations.

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