Hydrogen Activation by Biomimetic Diiron Dithiolates

Using the thermally stable salts of [Fe(2)(SR)(2)(CO)(3)(PMe(3))(dppv)]BAr(F)(4), we found that the azadithiolates [Fe(2)(adtR)(CO)(3)(PMe(3))(dppv)](+) react with high pressures of H(2) to give the hydride [Fe(2)(mu-H)(adtR)(CO)(3)(dppv)(PMe(3))]BAr(F)(4). The related oxadithiolate and propanedithiolate complexes are unreactive toward H(2). Molecular hydrogen is proposed to undergo heterolysis assisted by the amine followed by isomerization of an initially formed terminal hydride. Use of H(2) and D(2)O gave the deuteride as well as the hydride, implicating protic intermediates.