title: Kinetic and computational studies on Pd(I) dimer-mediated halogen exchange of aryl iodides.
abstract: Building on our previous discovery and reactivity explorations of the Pd(I) dimer [(PtBu3)PdBr]2-mediated halogen exchange of aryl iodides [Chem. Sci. 2013, 4, 4434], this report presents kinetic studies of this process, giving first-order kinetic dependence in the Pd(I) dimer and aryl iodide. An activation free energy barrier of ΔG(‡) = 24.9 ± 3.3 kcal/mol was experimentally determined. Extensive computational studies on the likely reaction pathway were subsequently carried out. A variety of DFT methods were assessed, ranging from dispersion-free methods to those that better account for dispersion (M06L, ωB97XD, D3-DFT). While significant discrepancies in the quantitative prediction of activation barriers were observed, all computational methods consistently predicted the analogous qualitative reactivity that is in agreement with all spectroscopic and reactivity data collected. Overall, these data provide compelling additional support of the direct reactivity of Pd(I)-Pd(I) with aryl iodides.
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University , Landoltweg 1, 52074 Aachen, Germany.
authors.forename: Indrek
authors.initials: I
authors.lastname: Kalvet
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Bonney
authors.forename: Franziska
authors.initials: F
authors.lastname: Schoenebeck