The Superbulky Pn Ligand Complexes [CpBIGFe(η5−P5)] and [(CpBIGFe)2(μ,η4:4-P4)]—Synthesis and Characterization

A new synthesis of [CpBIGFe(CO)2]23 (CpBIG = C5(4-nBuC6H4)5) was developed starting from CpBIGNa and FeCl2 in the presence of CO. Reaction of this product with P4 leads to the two new Pn ligand complexes [CpBIGFe(η5-P5)] 1b and [(CpBIGFe)2(μ,η4:4-P4)] (4) containing the highly sterically demanding CpBIG ligand. Depending on the solvent, different ratios of 1b:4 are obtained. The products 1b, 3, and 4 were characterized by spectroscopic methods as well as by X-ray diffraction.