Isothiocarbamido Radicals from Thiourea: Electron Spin Resonance Spectroscopy of N-Benzylidene-t-butylamine-N-oxide and 5,5-Dimethyl-1-pyrroline-N-oxide Spin Adducts

Amidinothio radicals, NH2(=NH)CS·, formed in the reaction of thiourea and hydrogen peroxide and trapped in aqueous solution by N-benzylidene-t-butylamine-N-oxide (PBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin traps are reported for the first time. Stability of the radical is highly dependent on the pH as well as the concentration of thiourea. ESR spectral lines give aN and aβH values as 1.53 mT and 0.24 mT respectively for PBN and 1.46 mT and 2.08 mT respectively for DMPO spin adducts. Preliminary kinetic experiments on the spin trapping reaction are also reported.