η-Benzenebis(trimethylphosphine)iron as a precursor to [Fe(η-C5R5)(PMe3)2](R = H or Me) derivatives: the equilibrium [Fe](PMe3)Et ⇌[Fe](η-C2H4)H + PMe3, where [Fe]= Fe(η-C5Me5)(PMe3)

Abstract

New or improved syntheses of the compounds [Fe(η-C₆H₆)(PMe₃)₂], [Fe(η-C₅R₅)(PMe₃)₂X](R = H or Me; X = H, Me, Et, or Cl), [[graphic omitted]CH₂)(PMe₃)₂], [Fe(η-C₅H₄CH₂CH₂I)(PMe₃)₂I], [Hg{Fe(η-C₅R₅)(PMe₃)₂}₂](R = H or Me), and [Fe(η-C₅R₅)(PMe₃)₃]BF₄(R = H or Me) are described. The thermal equilibrium [Fe(η-C₅Me₅)(PMe₃)(η-C₂H₄)H]+ PMe₃⇌[Fe(η-C₅Me₅)(PMe₃)₂Et] has been demonstrated and studied by variable-temperature n.m.r. spectroscopy.