Carbonfluorine bond activation by iron(I). CF bond cleavage induced by addition of phosphines or thiols to a perfluorovinyldiiron complex

Abstract

The reaction of phosphines PXYH (X  Y  Ph, i-Pr; X  Ph, Y  H) or ethanethiol with the perfluorovinyl compound [{Fe(CO) 3} 2{μ-C(SMe)(CF 3)CCF 2}] ( 1) proceeds with cleavage of one CF bond and gives rise to unusual ligand transformations. The multicenter processes involved lead to new diiron complexes [{Fe(CO) 3} 2{μ-C(SMe)(CF 3)C(PXY)CF}] (X  Y  Ph, 2a; X  Y- i-Pr, 2b; X  Ph, Y  H, 2c) and [{Fe(CO) 3} 2{μ-C(SMe)(CF 3)C(SEt)CF}] ( 3). Mechanisms for these reactions are proposed. The fluxional behavior of 2a and 3 has been investigated by variable-temperature 13C NMR spectroscopy. The molecular structure of 2a has been established by a single-crystal X-ray diffraction study. The Fe 2(CO) 6 core contains an FeFe bond of 2.633(1)Å bridged by the six-electron donor C(SMe)(CF 3)C(PPh 2)CF ligand. 2a crystallizes in the triclinic space group P 1 with a = 9.019(2), b = 9.550(2), c = 18.583(3) A ̊ , α = 101.06(2), β = 92.53(2), γ = 116.48(2)°, R = 0.0419 for 3984 reflections.