Palladium(II) and Palladium(0) Complexes of BINAP(O) (2-(Diphenylphosphino)-2‘-(diphenylphosphinyl)-1,1‘-binaphthyl)

The coordination organopalladium chemistry of 2-(diphenylphosphino)-2‘-(diphenylphosphinyl)-1,1‘-binaphthyl (BINAP(O)) was found to be totally different from that of other phosphine−phosphine oxide ligands, as well as of BINAP. The reaction of [(MeCN) 2 PdCl 2 ] with BINAP(O) (1 equiv) afforded [(BINAP(O))PdCl 2 ] ( 1 ), in which BINAP(O) is P,O-chelated to Pd in the solid state (X-ray) and in solution (NMR). Treatment of 1 with free BINAP(O) led to the reversible formation of a P,P-bonded nonchelate, [(BINAP(O)) 2 PdCl 2 ] ( 2 ), which could not be isolated due to the equilibrium being strongly shifted toward 1 . Reduction of 1 with LiBH 4 in the presence of BINAP(O) afforded a new zerovalent Pd complex [(BINAP(O)) 2 Pd] ( 3 ), in which both BINAP(O) ligands are P-bonded to Pd and one provides η 2 -arene coordination via the C C bond adjacent to the phosphinyl group (X-ray). Oxidative addition of PhI to 3 led cleanly to [(BINAP(O))Pd(Ph)I] ( 4; Ph trans to O; X-ray) which was also prepared by the reaction of [Pd 2 (dba) 3 ] with BINAPO and PhI. The ultrasound-promoted I/F exchange reaction of [(BINAPO)Pd(Ph)I] with AgF afforded [(BINAP(O))Pd(Ph)F] ( 5 ), which was decomposed thermally to produce a mixture of P−F and C−P reductive elimination products.