Improved synthesis of di- and trinuclear iron carbonyl complexes containing bridging diphenylethenyl ligand. X-ray structure of [PPh₄][Fe₂(CO)₆(μ-CO) (μ-PhC=CHPh)]

The cluster anion [PPh4][HFe3(CO)11] (1) reacts with one equivalent of methyl iodide and diphenylacetylene in acetone at room temperature to give the dinuclear complex [PPh4][Fe2(CO)6(μ-CO) (μ-PhC=CHPh)] (2) in high yield. The same reaction performed in boiling acetone yields only the trinuclear cluster [PPh4] [HFe3(CO)9(μ-PhC=CPh)] (3). When the reaction of [PPh4][HFe3(CO)11] (1) is carried out with an excess of methyl iodide at room temperature, the dinuclear neutral complex [Fe2(CO)6 {μ-CPhCPhCH(OCH3)}] (4) is obtained as a sole product of the reaction. Complex 2 was characterized by X-ray analyses. © 2003 Elsevier B.V. All rights reserved.