Formation of the Palladium(IV) Complex [(Me₃tacn)Pd^IVMe₃]⁺ through Aerobic Oxidation of (Me₃tacn)Pd^IIMe₂ (Me₃tacn = <i>N</i>,<i>N</i>′,<i>N</i>″-Trimethyl-1,4,7-triazacyclononane)

Abstract

The dimethyl PdII complex (Me3tacn)PdIIMe2 (Me3tacn = N,N′,N″-trimethyl-1,4,7-triazacyclononane) undergoes facile aerobic oxidation to yield the stable species [(Me3tacn)PdIVMe3]+. EPR, UV–vis, and ESI-MS studies suggest an inner-sphere mechanism for the oxidation of (Me3tacn)PdMe2 by O2 and formation of PdIV species. In addition, the structurally characterized complex [(Me3tacn)PdIVMe3]I undergoes selective elimination of ethane at elevated temperatures. Overall, this system represents one of the first examples of aerobic oxidation of a PdII organometallic precursor to yield a well-defined PdIV product, supporting the role of PdIV species as viable intermediates in Pd-mediated catalytic or stoichiometric aerobic oxidative transformations.