Linking Ion and Neutral Chemistry in CH Bond Electrophilic Activation: Generation and Detection of HO₂^. Reactive Radicals in the Gas Phase

Abstract

The activation of inert CÀH bonds by charged electrophiles is the subject of extensive investigation mainly motivated by one of the most widely debated questions, that is, the conversion of alkanes into more valuable compounds. Studies of ion-molecule reactions in the idealized gaseous state have provided insightful information on this elementary step, thus lending models and concepts which span from the molecular level to the borders of the nanoscale size. [1] These studies have shown the enhanced ability of oxygen-centered radical cations to activate CÀH bonds; [2] the inventory of XOC + reactants now available includes metal oxides and oligomeric cluster ions, mixed metal/nonmetal cluster ions, [2] and also effective metal-free oxide ions. [3] As a result of the H abstraction, the charge and spin of XOC + are separated in the products [Eqs. (1) and (2)], that is, depending on whether one or two electrons are formally transferred in the process, the XOH + /RC or XOHC/R + products are formed, respectively (RH = alkane). [4]