Multiple iron atoms bridged by hydrides is a common structural feature of the active species that have been postulated in the biological and industrial reduction of N. In this study, the reactions of an Fe(II) amide complex with pinacolborane in the presence/absence of phosphines afforded a series of hydride-supported [Fe] and [Fe] clusters Fe(μ-H)(μ-H){N(SiMe)}(PR) (PR = PMe (2a), PMePh (2b), PEt (2c)), Fe(μ-H)(μ-H)(PMe) (3), and (η-CH)Fe(μ-H){μ-N(SiMe)}{N(SiMe)} (4), which were characterized crystallographically and spectroscopically. Under ambient conditions, these clusters catalyzed the silylation of N to furnish up to 160 ± 13 equiv of N(SiMe) per 2c (40 equiv per Fe atom) and 183 ± 18 equiv per 3 (31 equiv per Fe atom). With regard to the generation of the reactive species, dissociation of phosphine and hydride ligands from the [Fe] and [Fe] clusters was indicated, based on the results of the mass spectrometric analysis on the [Fe] cluster, as well as the formation of a diphenylsilane adduct of the [Fe] cluster.

A square-planar Co amide cluster, Co {N(SiMe ) } (2), and an octahedral Co hydride cluster, Co H (P Pr ) (4), were obtained from metathesis-type amide to hydride exchange reactions of a Co amide complex with pinacolborane (HBpin) in the absence/presence of P Pr . The crystal structure of 4 revealed face-capping hydrides on each triangular [Co ] face, while the formal Co Co oxidation state of 4 indicated a reduction of the cobalt centers during the assembly process. Cluster 4 catalyzes the hydrosilylation of 2-cyclohexen-1-one favoring the conjugate reduction. Generation of the catalytically reactive Co cluster species was indicated by a trapping experiment with a chiral chelating agent.

A square‐planar Co4 amide cluster, Co4{N(SiMe3)2}4 (2), and an octahedral Co6 hydride cluster, Co6H8(PiPr3)6 (4), were obtained from metathesis‐type amide to hydride exchange reactions of a CoII amide complex with pinacolborane (HBpin) in the absence/presence of PiPr3. The crystal structure of 4 revealed face‐capping hydrides on each triangular [Co3] face, while the formal CoII2CoI4 oxidation state of 4 indicated a reduction of the cobalt centers during the assembly process. Cluster 4 catalyzes the hydrosilylation of 2‐cyclohexen‐1‐one favoring the conjugate reduction. Generation of the catalytically reactive Co cluster species was indicated by a trapping experiment with a chiral chelating agent.