Speciation of Iron (III) Oxide Nanoparticles and Other Paramagnetic Intermediates during High-Temperature Oxidative Pyrolysis of 1-Methylnaphthalene.

Low Temperature Matrix Isolation - Electron Paramagnetic Resonance (LTMI-EPR) Spectroscopy was utilized to identify the species of iron oxide nanoparticles generated during the oxidative pyrolysis of 1-methylnaphthalene (1-MN). The otherwise gas-phase reactions of 1--MN were impacted by a polypropylenimine tetra-hexacontaamine dendrimer complexed with iron (III) nitrate nonahydrate diluted in air under atmospheric conditions. The EPR fine structure of Fe (III)₂O₃ nanoparticles clusters, characterized by g-factors of 2.00, 2.28, 3.76 and 4.37 were detected on a cold finger maintained at 77 K after accumulation over a multitude of experiments. Additionally, a high valence Fe (IV) paramagnetic intermediate and superoxide anion-radicals, O₂^•- adsorbed on nanoparticle surfaces in the form of Fe (IV) --- O₂^•- were detected from the quenching area of Zone 1 in the gas-phase.