Gas-phase ion chemistry of organic peroxides

Over the last 30 years, mass spectrometry and allied technologies have provided significant new insights into the intrinsic, gas phase properties of organic peroxides. In this chapter, the formation and interrogation of neutral peroxides, and their ionized analogues in the gas phase are discussed for several key classes of organic peroxides. Methods for the formation of intact, gas phase cations and anions from labile, often nonvolatile, peroxides using conventional and contemporary soft ionization techniques are described. Studies of the unimolecular dissociation of these ionized peroxides are shown to yield new understanding of energetics and bonding as well as providing diagnostic markers for the elucidation of molecular structure. The bimolecular chemistries of peroxides in the gas phase are considered in two categories: (i) reactions of ions with neutral peroxides; and (ii) the reactions of deprotonated organic hydroperoxides with neutral substrates. Advanced topics cover analytical applications of chemical ionization to the detection of peroxides and peroxyl radicals along with the synthesis of distonic peroxyl radical ions. Studies of the gas phase spectroscopy of organic peroxides that exploit the ionized forms of the peroxides are reviewed including negative-ion photoelectron spectroscopy, infrared multiple photon dissociation and action spectroscopy.