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

Reduction of [Cp*Fe(eta(5)-E-5)] (E = P, As) with divalent lanthanide reagents usually leads to reduction of [Cp*Fe(eta(5)-E-5)] followed by a Ln-E bond formation. In contrast, by using the sterically encumbered reagent [(DippForm)(2)Sm(thf)(2)] (DippForm = {(2,6-(Pr2C6H3)-Pr-i)NC(H)= N(2,6-(Pr2C6H3)-Pr-i)}(-)), ring-opening of thf and reduction of the poly-pnictide is observed. This leads to two new 3d/4f polyphosphide or polyarsenide complexes [(DippForm)(2)Sm(Cp*Fe)E-5{(CH2)(4)O}-{(DippForm)(2)Sm(thf)}], in which [(DippForm)(2)Sm(thf)(2)] and [Cp*Fe(eta(5)-E-5)] are linked by a ring-opened thf molecule and no Ln-E bond formation is observed.