Abstract
A series of complexes has been prepared of the form [Re(dien)(PPh3)(PF3)(L)]+ (dien = diethylenetriamine), where L is an unsaturated organic molecule. The range of ligands which form η2-coordinate complexes with this metal center includes aldehydes, olefins, and dienes. In addition, thiophene, benzo[b]thiophene, and acetonitrile bind through their heteroatoms. Although {Re(dien)(PPh3)(PF3)}+ (dien = diethylenetriamine) displays chemical and spectroscopic characteristics of a potent π-base, it fails to form stable η2-coordinated complexes with aromatic molecules. However, its carbonyl analogue {Re(dien)(PPh3)(CO)}+, when combined with furan, forms the complex [Re(η2-furan)(dien)(PPh3)(CO)][OTf], a rare example of a thermally stable η2-heterocycle.
