Pulse radiolysis investigations on the nature of (OH)-O-center dot radicalreactions with 1-fluoro-2-iodobenzene in aqueous solutions

The transient optical absorption bands (lambda(max) = 310 nm, 330-350 nm, k = 3.2x10(9) dm(3) mol(-1) s(-1)) formed on reaction of (OH)-O-. radicals w ith 1-fluoro-2-iodobenzene in neutral aqueous solutions are assigned to OH- adduct, which decayed by second order kinetics with 2k; = 2.9x10(9) dm(3) m ol(-1) s(-1). The absorption band (lambda(max) = 630 nm) observed in acidic solutions (pH = 3) is assigned to solute radical cation formed on removal of an electron from iodine, which decayed by first order kinetics with k = 5.6x10(5) s(-1). At pH = 1, the OH-adduct was found to react with H+ (k = 4 .7x10(5) s(-1)) and formed a broad absorption band in 350 - 400 nm region. It is assigned to solute radical cation formed on removal of an electron fr om fluorine. Acid-catalyzed dehydration of OH-adduct is observed with simil ar to 85% at iodine and similar to 15% at fluorine. The iodine centered rad ical cation is a strong one-electron oxidant and is able to oxidize I- and Br- with late constant in the diffusion controlled range. SO4.- radical ani on is able to undergo electron transfer with the solute and absorption band s due to iodine centered radical cation (lambda = 630 nm), and OH-adduct (l ambda = 310, 330-370 nm) are observed.