Protonation of cyclopropene complexes of platinum(0) and the reduction of cyclopropene by nitrogenases

Article abstract of DOI:10.1016/s0020-1693(98)00203-5

The reactions of a series of platinum(0) cyclopropene complexes with HCl have been studied, and it is shown that the products include both ring-intact (cyclopropane-type) and ring-opened (propene-type) materials. All products are believed to be formed by hydrocarbon insertions into transient platinum-hydrogen bonds formed by addition of HCl to platinum. Mechanistic interpretation is complicated by group migrations, and double-bond shifts. Oxidative additon of a σ-cyclopropyl to platinum plays a part in ring-opening reactions, whereas the cyclopropanes are believed to be produced by further hydrocarbon insertions into transient platinum-hydrogen bonds. The relevance of these models to the mechanism of reduction of cyclopropene by nitrogenases is discussed.