On the gas-phase decomposition of acyclic ethers mediated by "rollover" cyclometalated [Pt(bipy-H)]+ (bipy=2,2′-bipyridine): A mechanistic study

The thermal ion/molecule reactions of diethyl, and ethyl methyl ether with cyclometalated [Pt(bipy-H)](+) were probed in gas-phase experiments. For most of the reaction channels the initial step corresponds to a platinum-mediated transfer of an a-hydrogen atom from the ether to the (bipy H)-ligand. This conclusion is based on a combination of extensive deuterium-labeling experiments and analogous reactions with the platinum methyl complexes [Pt(CH3)(bipy)](+), [Pt(CD3)(bipy)](+), [Pt(CH3)(phen)](+), and [Pt(CD3)(phen)](+). Furthermore, the labeling experiments with diethyl ether and ethanol isotopologues permit to derive a mechanistic scheme that is in keeping with the experimental observations. A comparison of these results with those obtained in the ion/molecule reactions of analogous thioethers reveals some distinct differences: while formal dehydrosulfurization dominates the gas-phase chemistry of [Pt(bipy-H)](+) with organic sulfides the analogous process is practically absent for the respective ethers. (C) 2010 Elsevier B.V. All rights reserved.