REACTIVITY OF NITRIC-OXIDE WITH SIMPLE SHORT-LIVED RADICALS IN AQUEOUS-SOLUTIONS

The kinetic parameters and spectral properties of the products of the reaction of nitric oxide (NO) with (SCN)(2)(-), Br-2(-), CO2-, CO3-., and ethyl alcohol radicals were studied by the pulse radiolysis technique. The rate constants for the reaction of NO with these radicals are k[NO + (SCN)(2)(-)] = (4.3 +/- 0.1) x 10(9) M(-1) s(-1), k[NO + CO2-] = (2.9 +/- 0.5) x 10(9) M(-1) s(-1), k[NO + CO3-.] = (3.5 +/- 0.5) x 10(9) M(-1) s(-1), and k[NO + ethanol radicals] = (3.0 +/- 1.0) x 10(9) M(-1) s(-1). (SCN)(2)(-) radical forms an adduct that decomposes by first-order processes to yield ultimately NO2-. The CO3-. radical reacts with NO by O- transfer with the direct formation of NO2-. The CO2- radical reacts with NO forming the NOCO2- transient which reacts with excess NO yielding N2O2-. The ethanol radical-NO adducts rearrange to yield ultimately oximes/hydroxamic acids. Preliminary studies of the reaction of NO with Br-2(-) shaw that, while NOBr2- is formed at a rate similar to that of NO(SCN)(2)(-), k(NO + Br-2(-)) = (4.8 +/- 0.4) x 10(9) M(-1) s(-1)), the corresponding NOBr transient decays by a very complex mechanism that is currently being studied in greater detail. Mechanisms by which the various NO-adducts decay are discussed.