A gas-phase study of ligand effects on the reactivity of organometallic distonic ion Fe(p-benzyne)(+.)

This paper reports a gas-phase study of ligand effects on the reactivity of the organometallic distonic ion Fe(p-benzyne)(+.). New organometallic dist onic ions are generated by introducing a benzene ligand onto the metal cent er of Fe(p-benzyne)(+.). We were interested in whether the reactivity of th e radical site would be enhanced by 'covering' the metal tenter with extra ligands, i,e, by forming (benzene)Fe(p-benzyne)(+.), since, in general, att achment of ligands reduces the reactivity of the metal center, For comparis on, ions formed by attaching the same ligand to Fe(o-benzyne)(+) and Fe(phe nyl)(+) were also studied. Reacting Fe(p-benzyne)(+.). Fe(o-benzyne)(+) and Fe(phenyl)(+) directly with benzene generates, presumably, (benzene)Fe(p-b enzyne)(+). (benzene)Fe(o-benzyne)(+) and (benzene)Fe(phenyl)(+), respectiv ely. With allyl iodide, isopropyl iodide and dimethyl disulfide, (benzene)F e(p-benzyne)(+.) reacts differently from its even-electron isomer, (benzene )Fe(o-benzyne)(+), and its phenyl analogue, (benzene)Fe(phenyl)(+). Further more, the results from these ion-molecule reactions and collision-induced d issociation of selected product ions indicate that the charge site and the radical site of (benzene)Fe(p-benzyne)(+.) interact with the neutral simult aneously and that the attachment of the benzene ligand does enhance the rea ctivity of the radical site to some extent. Copyright (C) 1999 John Wiley & Sons, Ltd.