H/D Exchange in the Reaction of D2 with Bis(triphenylphosphite) (acetylacetonato)rhodium(I), Rh(P(OPh)3)2 (acac)

摘要

The reaction of Rh(P(OPh)3)2(acac) (1) with D2 in benzene has been studied by 1H NMR spectroscopy, and complex 1 has been found to undergo H/D exchange at the ortho positions of the coordinated phosphite ligands and at the central methine position of the acetylacetonate ligand. At 75 C, the exchange reaction proceeds with the extent of deuterium incorporation into P(OPh)3 being the same as that into acac at all stages of the H/D exchange process. At 60 C, deuterium incorporation into P(OPh)3 is initially more rapid than that seen into the acac ligand. The initial rate of deuterium incorporation into P(OPh)3 by 1 in d6-benzene under D2 at 60C proceeds with a first order rate constaNt of 9.6 x 10 to the minus 5th power/sec. A mechanism for this exchange process is proposed.