Hydride Transfer Reactivity of an Open-Shell [Fe₃H]^- Cluster

We report herein the synthesis and reactivity of the high-spin iron-hydride cluster [K(C₂₂₂)][(^tbsL)Fe₃(μ³-H)]. Direct hydride transfer reaction attempts led to cluster reduction to afford the anionic cluster [(^tbsL)Fe₃]^-, whereas metathesis using phenylsilane and an alkoxide-bound cluster (e.g., [(^tbsL)Fe₃(μ³-OMe)]^-) afforded the targeted hydride-bearing cluster [K(C₂₂₂)][(^tbsL)Fe₃(μ³-H)]. The hydride cluster was verified using both solution (e.g., NMR, cyclic voltammetry) and solid-state techniques (e.g., ⁵⁷Fe Mössbauer, X-ray crystallography). The anionic hydride was shown to be reactive with unsaturated small molecule substrates (e.g., aldehydes, isonitriles, alkynes) to afford their cooperatively bound reduction products. Furthermore, the anionic hydride cluster was shown to be a viable catalyst for hydrosilylation of aldehyde substrates, converting benzyl and alkyl aldehydes to their corresponding silylethers.