The Superbulky P<sub>n</sub> Ligand Complexes [Cp<sup>BIG</sup>Fe(η<sup>5</sup>−P<sub>5</sub>)] and [(Cp<sup>BIG</sup>Fe)<sub>2</sub>(μ,η<sup>4:4</sup>-P<sub>4</sub>)]—Synthesis and Characterization

<div><p></p><p>A new synthesis of [Cp<sup>BIG</sup>Fe(CO)<sub>2</sub>]<sub>2</sub><b>3</b> (Cp<sup>BIG</sup> = C<sub>5</sub>(4-<sup>n</sup>BuC<sub>6</sub>H<sub>4</sub>)<sub>5</sub>) was developed starting from Cp<sup>BIG</sup>Na and FeCl<sub>2</sub> in the presence of CO. Reaction of this product with P<sub>4</sub> leads to the two new P<sub>n</sub> ligand complexes [Cp<sup>BIG</sup>Fe(η<sup>5</sup>-P<sub>5</sub>)] <b>1b</b> and [(Cp<sup>BIG</sup>Fe)<sub>2</sub>(μ,η<sup>4:4</sup>-P<sub>4</sub>)] (<b>4</b>) containing the highly sterically demanding Cp<sup>BIG</sup> ligand. Depending on the solvent, different ratios of <b>1b:4</b> are obtained. The products <b>1b</b>, <b>3,</b> and <b>4</b> were characterized by spectroscopic methods as well as by X-ray diffraction.</p></div>