E. Mitchell, P. Jessop, M. C. Baird
Nov 10, 2009
Citations
0
Influential Citations
31
Citations
Journal
Organometallics
Abstract
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 1 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.