[FeFe]-Hydrogenase Models and Hydrogen: Oxidative Addition of Dihydrogen and Silanes

摘要

Intense interest has recently been focused on the biophysics and synthetic models of [FeFe]-hydrogenases. Such studies promise to contribute to the development of nonprecious metal catalysts for the production and utilization of hydro-gen. A challenge in current research is the resistance of [FeFe]-hydrogenase models, diiron dithiolato carbonyl complexes, to form complexes directly from H2, as well as related hydrogenic substrates. It is possible that the direct reaction of diiron dithiolates with hydrogen-rich substrates has been overlooked because it is considered too difficult or too obvious, or both. Although some diiron complexes promote isotopic H/D exchange under photochemical conditions, such reactions yield no isolable hydrides. A mixture of the electron-rich diiron ethanedithiolate [Fe2(S2C2H4)(CO)4-(PMe3)2] reacted with H2 in the presence of B(C6F5)3. In this case the borane activated H2, and the diiron center serves as a base[Eq. (1)].