Abstract
Polyhydrido transition metal complexes are a constant source of interest due to their variety in bonding and reactivity. Yet, well-defined paramagnetic polyhydrido systems are relatively rare given their instability. Herein, we extend the protonolysis reactivity of the Brønsted acidic Cp*IrH(4) polyhydride toward transition metal silylamides. Specifically, we report the synthesis and characterization of a polyhydrido diiron tetrairidium paramagnetic cluster, [Fe-(Cp*IrH(3))(2)](2), 1, from the reaction between Fe-(HMDS)(2)(THF) and Cp*IrH(4). Attempted reduction of this complex with potassium graphite yields instead an anionic species, K-[Fe-(Cp*IrH(3))(3)], 2, in a proposed disproportionation mechanism. Complex 2 can be independently synthesized in good yields upon treating 1 with K-[Cp*IrH(3)]. Attempts to synthesize Fe-(III) analogues from the oxidation of 1 or 2 failed, with oxidation occurring at the Ir centers. Likewise, reactions between Fe-(III) precursors and iridium polyhydride species consistently yield complex 1. This highlights the unexpected driving force toward this very stable tetrairidium diiron paramagnetic polyhydride complex reported in this work.