Influence of stereochemistry on the formation and reactivity of phosphorus-bridged dinuclear metal carbonyls. Part III. The crystal structure of µ-tetramethyldiphosphine-bis(tetracarbonyliron)

Abstract

The structure of (OC)₄Fe(PMe₂)₂Fe(CO)₄ has been determined by X-ray diffraction. The molecule has a catenary form and is similar to (OC)₃Ni(PPh₂)₂Ni(CO)₃ in that it is centrosymmetric and has a ‘staggered’ conformation of substituents about the M–P and P–P bonds, but differs from this compound in that the P–P bond has a normal length, and is less readily dissociated. The co-ordination round the iron atoms is trigonal bipyramidal, with the axial Fe–C bond lengths significantly shorter than the equatorial; possible reasons for this are discussed.