Heteroatom-Centered Free Radicals: Some Selected Contributions by Radiation Chemistry.

Publisher Summary The advent of time-resolved techniques such as pulse radiolysis and flash photolysis, allowed direct detection of heteroatom on real time. The reason that hetero-centered radicals have an electronic structure, most often they exhibit intense and easily detectable optical absorptions in the UV, visible, and near-IR. This chapter presents and discusses some specially selected examples of hetero-centered radicals from solution studies as well as highlights some of the general achievements and basic concepts emerging therefrom. The chapter discusses two important groups of radicals belonging to the heteroatom-centered category—namely, those derived from purines and those from pyrimidines. There is also a discussion about the entire family of oxygen-centered radicals. There is a description of the early days of pulse radiolysis and the intermediates generated from organic nitro and nitroso compounds in some elementary redox processes. There is a presentation of some most recent results on aminyl radicals that are derived from amino acids, exemplifying the diversity of possible reactions of a seemingly simple type of radicals. The third example on aniline and aniline radicals aims to demonstrate the potential of time-resolved resonance Raman spectroscopy. All these studies on N-centered radicals focus on the importance of acid/base properties of radicals. The aniline system, in particular, also draws attention to spin and charge distribution and possible implications to the chemistry of radical species.