Sterically induced reductive linkage of iron polypnictides with bulky lanthanide complexes by ring-opening of THF

Abstract

Reduction of [Cp*Fe(η⁵-E₅)] (E = P, As) with divalent lanthanide reagents usually leads to reduction of [Cp*Fe(η⁵-E₅)] followed by a Ln–E bond formation. In contrast, by using the sterically encumbered reagent [(DippForm)₂Sm(thf)₂] (DippForm = {(2,6-ⁱPr₂C₆H₃)NC(H)N(2,6-ⁱPr₂C₆H₃)}⁻), ring-opening of thf and reduction of the polypnictide is observed. This leads to two new 3d/4f polyphosphide or polyarsenide complexes [(DippForm)₂Sm(Cp*Fe)E₅{(CH₂)₄O}{(DippForm)₂Sm(thf)}], in which [(DippForm)₂Sm(thf)₂] and [Cp*Fe(η⁵-E₅)] are linked by a ring-opened thf molecule and no Ln–E bond formation is observed.