ARENE-METAL COMPLEXES: PREPARATION AND REACTIONS OF h6-ARENE-Cr(CO)2(DIPHOS) AND ANALOGS

Article abstract of DOI:10.1016/S0022-328X(00)87434-3

Reaction of 1,2-bis(triphenylphosphino)ethane (diphos) with h⁶-arenetricarbonylchromium(0) complexes results in replacement of one CO by diphos to give h⁶-arene(diphos)dicarbonylchromium(0) (e.g., complex 4) and μ-diphosbis(h⁶-arene)tetracarbonyldichromium(0).Comparison of rate of arene exchange for h⁶-benzenetricarbonylchromium, h⁶-benzene(triphenylphosphine)dicarbonylchromium, and complex 4 showed that: (1) replacement of CO by a phosphine retards arene exchange and (2) the effect of diphos in stabilizing an h⁴-benzene ligand in complex 4 is not sufficient to allow rapid arene exchange.Nucleophilic substitution for hydrogen was observed for the first time in a phosphine-substituted arene-chromium complex.