Electron transfer and multi-atom abstraction reactions between atomic metal anions and NO, NO2 and SO2

Anionic Reactions Degrading SF6 Using Metals: Insights From the Gas Phase

Alkali metals have been used to degrade SF6 in liquid ammonia. The products include metal fluorides. In this study, we reacted K- and Ag- with SF6 in a triple quadrupole mass spectrometer. The atomic metal anions were formed by in-source collision-induced dissociation (CID) of their respective oxalate salts as previously described by our group. The only two reaction products observed were SF6 - and SF5 -. At low collision energy, the latter was deduced to be formed via an abstraction by the metal of F from SF6 - formed by electron transfer in the encounter complex between the metal anion and neutral SF6. As the collision energy was increased, there was evidence of a CID contribution to SF5 - directly from SF6 -.

ORGANOMETALLIC GAS-PHASE ION CHEMISTRY AND CATALYSIS: INSIGHTS INTO THE USE OF METAL CATALYSTS TO PROMOTE SELECTIVITY IN THE REACTIONS OF CARBOXYLIC ACIDS AND THEIR DERIVATIVES

Carboxylic acids are valuable organic substrates as they are widely available, easy to handle, and exhibit structural and functional variety. While they are used in many standard synthetic protocols, over the past two decades numerous studies have explored new modes of metal-mediated reactivity of carboxylic acids and their derivatives. Mass spectrometry-based studies can provide fundamental mechanistic insights into these new modes of reactivity. Here gas-phase models for the following catalytic transformations of carboxylic acids and their derivatives are reviewed: protodecarboxylation; dehydration; decarbonylation; reaction as coordinated bases in C-H bond activation; remote functionalization and decarboxylative C-C bond coupling. In each case the catalytic problem is defined, insights from gas-phase studies are highlighted, comparisons with condensed-phase systems are made and perspectives are reached. Finally, the potential role for mechanistic studies that integrate both gas- and condensed-phase studies is highlighted by recent studies on the discovery of new catalysts for the selective decomposition of formic acid and the invention of the new extrusion-insertion class of reactions for the synthesis of amides, thioamides, and amidines. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.