COMPLEXES CONTAINING THE UNIT RH2P-PM (M=CR OR MN, P-P=BIS(DIPHENYLPHOSPHINO)ALKANE) - THE INDEPENDENCE OF THE METAL CENTERS

Treatment of ta(1)-Ph2P(CH2)(n)PPh2}(mu-eta(1):eta(1)-CF3C2CF3) (I) wi th (eta(5)-CH3C5H4)Mn(CO)(2)(thf) or Cr(CO)(5)(thf) gives the hetero-t rinuclear products eta(1)-Ph2P(CH2)(n)PPh2}(eta-CH3C5H4)Mn(CO)(2)(II, n = 1-4) and C2CF3){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 ta(1)-Ph2P(CH2)(n)PPh2}(mu-eta(1):eta(1)-CF3C2CF3) (V) and the same solvated manganese and chromium complexes give (1):eta(1)-Ph2P(C H2)(n)PPh2}(eta-CH3C5H4)Mn(CO)(2) (VI, n = 1, 2 or 4) and 3C2CF3){mu:e ta(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 t he 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 irradiatio n 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).