ESR Study of Hydroxyl Radicals, Superoxide Anion Radicals and Molecular Singlet Oxygen Generated by Mercaptoundecahydro-closo-Dodecaborate(2-) Solution Irradiated by Neutrons under Conditions of Boron Neutron Capture Reaction

Recently, we have reported the generation of superoxide anion-radicals by neutron irradiation and UV light irradiation of mercaptoborates in water solutions at room temperature1. Now, we have irradiated 2.10-3 molar aqueous solutions of two types of mercaptoborates: Na2B12H11SH, [N(CH3)4]2B12H11SH and, for comparison Na2B4O7by thermal neutron flux on LVR-15 reactor in Řež/Czech Rep./ with total doses 5 Gy and 18 Gy, respectively. The generation of hydroxyl radicals ·OH, superoxide anion-radicals O2·−, and singlet molecular oxygen 1O2 were identified and determined by electron spin resonance spectroscopy. The quantity of generated radicals depend on initial oxygen concentration in irradiated solutions and on the energy of used neutron beam. The generation of radicals on the BNCT conditions could play an important role in therapeutical mechanism.