Reactions of Cu+(1S,3D) and Au+(1S,3D) with CH3Br

Abstract

The reactions of Cu+(1S,3D) and Au+(1S,3D) with CH3Br have been carried out in the gas phase at 150 K using a drift cell. State specific product channels were identified by observing the occurrence of product ions when ionization conditions were manipulated to either produce or eliminate excited states of the two metal ions. Reactant ion state distributions were determined by electronic state chromatography. State-specificity was confirmed by correlating reactant and product arrival time distributions. Association products correlate to singlet metal ion states for both Cu+ and Au+. Additionally, Cu+(3D) participates in association under these conditions. The 3D state of both metals exhibits Br abstraction, and CH3 is abstracted by Au+(3D). Formation of AuCH2+ exclusively via Au+(1S) is also indicated. State-specificity with respect to bimolecular channels for both metals is consistent with thermochemical requirements and formal conservation of electron spin. Parallel formation of AuCH2+ and Au+·CH3Br suggests a mechanism leading to HBr elimination that involves a long-lived insertion intermediate.