Synthesis and fluxional character of complexes of the type [Fe3H(CO)10(µ-CNR2)] and [Fe3H(CO)9(µ3–CHNR)]

Abstract

Sequential room-temperature carbonyl substitution of [N(PPh₃)₂][Fe₃H(CO)₁₁] with isonitriles CNR (R = Me, Et, or Prⁱ) yields the substituted anions [N(PPh₃)₂][Fe₃H(CO)_11–x(CNR)_x](x= 1 or 2), which on alkylation using R′₃OBF₄(R′= Me or Et) or acidification using CF₃SO₃H yield the complexes [Fe₃H(CO)₁₀(CNRR′)](R = R′= Et; R = Prⁱ, R′= Me or Et; R = Me, R′= Et; R = Me, R′= H) and [Fe₃H(CO)₉,(CNRR′)(CNR)](R = R′= Et). At higher temperatures, an insertion of isonitrile into the M–H–M bond is observed to yield, after acidification, the complex [Fe₃H(CO)₉(CHNPrⁱ)]. The fluxional properties of these molecules are discussed.