Bactericidal activities of radical species generated by catalytic reactionof iron(III) octacarboxyphthalocyanine

Strong bactericidal activities against various bacteria were observed in th e reaction system of iron(III) octacarboxyphthalocyanine (Fe-III-oapc) and tert-butyl hydroperoxide (tert-BuOOH). The kinetics of the decomposition of tert-BuOOH catalysed by Fe-III-oapc were studied in buffered solutions bet ween pH 5 to 12 using gas chromatography analysis. The rate of catalytic de composition of tert-BuOOH followed second-order kinetics in tert-BuOOH conc entrations. The second-order rate constant (k(2)) had a maximum value at pH 11. Oxygen evolution was observed at high tert-BuOOH concentration, while oxygen consumption was observed at low tert-BuOOH concentration. The former indicates plural radical chain reactions of the tert-butoxyl radical and t he latter suggests decomposition of the tert-butoxyl radical to acetone and methyl radical. By the electron spin resonance spin trapping method using 5,5-dimethyl-1-pyrroline-N-oxide and alpha-phenyl-N-tert-butylnitrone it wa s found that the radical species generated in the reaction system is tert-b utoxyl radical, which plays crucial roles in bactericidal activities. (C) 1 998 John Wiley & Sons, Ltd.