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

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(CH=NPrⁱ)]. The fluxional properties of these molecules are discussed.