Complexes containing the unit Rh2P-PM (M=Cr or Mn, P-P=bis(diphenylphosphino)alkane); The independence of the metal centres

Treatment of (eta(5)-C2H5)(2)Rh-2(CO){eta(1)-Ph2P(CH2)(n)PPh2}(mu-eta(1):eta(1)-CF3C2CF3) (I) with (eta(5)-CH3C5H4)Mn(CO)(2)(thf) or Cr(CO)(5)(thf) gives the hetero-trinuclear products (eta-C5H5)(2)Rh-2(CO)(mu-CF3C2CF3){mu:eta(1):eta(1)-Ph2P(CH2)(n)PPh2}(eta-CH3C5H4)Mn(CO)(2)(II, n = 1-4) and (eta(5)-C5H5)(2)Rh-2(CO)(mu-CF3C2CF3){mu:eta(1):eta(1)-Ph2P(CH2)(n)PPh2}Cr(CO)(5) (IV, n = 1-4) in good yields. In these products, the configuration of the CO and bisphosphine units on the Rh-Rh bond is trans. Related reactions between (eta(5):eta(5)-C5H4CH2C5H4)Rh-2(CO){eta(1)-Ph2P(CH2)(n)PPh2}(mu-eta(1):eta(1)-CF3C2CF3) (V) and the same solvated manganese and chromium complexes give (eta(5):eta(5)-C5H4CH2C5H4)Rh-2(CO)(mu-CF3C2CF3){mu:eta(1):eta(1)-Ph2P(CH2)(n)PPh2}(eta-CH3C5H4)Mn(CO)(2) (VI, n = 1, 2 or 4) and (eta(5):eta(5)-C5H4CH2C5H4)Rh-2(CO)(mu-CF3C2CF3){mu:eta(1):eta(1)-Ph2P(CH2)(3)PPh2}CrCO)(5) (VIII). The complexes (VI) and (VIII) have a mutually cis arrangement of CO and the bisphosphine on the Rh-Rh bond. Attempts to induce the complexes (TV), (V), (VI), and (VIII) to form clusters by loss of CO and Rh-M bond formation were not successful. Treatment with trimethylamine oxide or sunlight irradiation generally resulted in loss of the hetero-metal and formation of the dirhodium phosphine oxide complexes (III, n = 2 or 4) and (VII, n = 2, 3).