Synthesis and structural characterisation of some cyclopentadienyliron–bismuth complexes

Abstract

Treatment of BiCl₃ with 2 equivalents of Na[Fe(CO)₂(η-C₅H₄Me)] in tetrahydrofuran affords the green iron–bismuth complex [{[Fe(CO)₂(η-C₅H₄Me)]₂BiCl}₃], identified by X-ray crystallography and containing a planar Bi₃Cl₃ six-membered ring derived from the cyclotrimerisation of Fe(BiCl)(CO)₂(η-C₅H₄Me) units. Similar compounds are formed with C₅H₅ and C₅Me₅ ligands although in the latter case significant amounts of the iron chloro species [FeCl(CO)₂(η-C₅Me₅)] are also formed, an X-ray structure of which is reported. Treatment of BiCl₃ with 3 equivalents of Na[Fe(CO)₂(η-C₅H₄Me)] affords the tri-iron–bismuth complex [Bi{Fe(CO)₂(η-C₅H₄Me)}₃], containing a trigonal-pyramidal bismuth bonded to three Fe(CO)₂(η-C₅H₄Me) fragments. Photolysis of this compound leads to loss of three carbonyl groups and formation of the closo Fe₃Bi complex [Fe₃(η-C₅H₄Me)₃(µ-CO)₃(µ₃-Bi)]. Both of the tri-iron–bismuth complexes were characterised by X-ray crystallography.