A Kinetics Study of the Oxidative Addition of Bromobenzene to Pd(PCy3)(2) (Cy = cyclohexyl) in a Nonpolar Medium: The Influence on Rates of Added PCy3 and Bromide Ion

作者：Mitchell Emily A; Jessop Philip G; Baird Michael C^*

来源：Organometallics, 2009, 28(23): 6732-6738.

DOI：10.1021/om900679w

Bromobenzene oxidatively adds to the palladium(0) compound Pd(PCy3)(2) to give cleanly the palladium(II) product trans-PdBr(Ph)(PCy3)(2). Kinetics studies of this reaction under pseudo-first-order conditions (excess PhBr) as well as in the presence of molar equiv of PCy3 or of added bromide ion (as the toluene-soluble tetraoctylphosphonium salt) have been carried out. We find that oxidative addition is first-order in palladium and that, in the absence of added PCy3, the reaction involves both the 2:1 species Pd(PCy3)(2) and the 1:1 species Pd(PCy3). Interestingly, added PCy3 results in inhibition of oxidative addition both by decreasing the relative amount of the reactive 1: 1 compound and by converting much of the palladium(0) to the kinetically less active 3:1 compound Pd(PCY3)(3). Added bromide ion has essentially no effect on the rate, surprising in view of previous literature reports.

• 出版日期2009-12-14