ChemInform Abstract: Synthesis and Chemistry of (η3-Pentadienyl)iron Tricarbonyl Halides.
Abstract
Halide ions induce an isomerization of the η5-pentadienyl ligand in the Fe complexes (I) and (III) in preference to displacement of CO to give the neutral, preferred syn (W-shaped) η3-pentadienyl complexes (II) and (IV) respectively.
ChemInform Abstract
Halide ions induce an isomerization of the η5-pentadienyl ligand in the Fe complexes (I) and (III) in preference to displacement of CO to give the neutral, preferred syn (W-shaped) η3-pentadienyl complexes (II) and (IV) respectively. The minor pentadienyl products (V) are unstable oils. The structure for the η3-pentadienyl complexes are confirmed by X-ray structure analysis on (IVb) (space group P21/n, Z=4). Although (IVb) crystallizes as the endo conformer, a mixture of endo and exo isomers is established in solution for (IV) with dominating endo conformer in each case. Limited reactivity studies on these pentadienyl-Fe compounds reveal a propensity for coupling of the dienyl ligand, presumably via radical processes. For example, treatment of (IVc) with MeMgCl (VI) under an atmosphere of CO (VII) leads to the acetyl-substituted η4-diene complex (VIII).
