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Completing a series of nickel-group 13 complexes, a coordinatively unsaturated nickel-boron complex and its derivatives with a H 2 , N 2 , or hydride ligand were synthesized and characterized. The toggling “on” of a Ni(0)–B( iii ) inverse-dative bond enabled the stabilization of a nickel-bound anionic hydride with a remarkably low thermodynamic hydricity of kcal mol −1 in THF. The flexible topology of the boron metalloligand confers both favorable hydrogen binding affinity and strong hydride donicity, albeit at the cost of high H 2 basicity during deprotonation to form the hydride. 

A tin-supported iron catalyst produces 5.9 turnovers of NH 3 from N 2 , using [Ph 2 NH 2 ]OTf as the acid and CoCp 2 * as the reductant. Two redox states of the Fe(N 2 ) adduct and an Fe silyldiazenido complex were characterized using X-ray crystallography along with NMR and Mössbauer spectroscopies. Density functional theory calculations reveal that the charge on the Sn center correlates strongly with both the polarization of the N 2 moiety and the charge on the distal N atom. 

Abstract An anionic Rh−Ga complex catalyzed the hydrodefluorination of challenging C−F bonds in electron‐rich aryl fluorides and trifluoromethylarenes when irradiated with violet light in the presence of H₂, a stoichiometric alkoxide base, and a crown‐ether additive. Based on theoretical calculations, the lowest unoccupied molecular orbital (LUMO), which is delocalized across both the Rh and Ga atoms, becomes singly occupied upon excitation, thereby poising the Rh−Ga complex for photoinduced single‐electron transfer (SET). Stoichiometric and control reactions support that the C−F activation is mediated by the excited anionic Rh−Ga complex. After SET, the proposed neutral Rh⁰intermediate was detected by EPR spectroscopy, which matched the spectrum of an independently synthesized sample. Deuterium‐labeling studies corroborate the generation of aryl radicals during catalysis and their subsequent hydrogen‐atom abstraction from the THF solvent to generate the hydrodefluorinated arene products. Altogether, the combined experimental and theoretical data support an unconventional bimetallic excitation that achieves the activation of strong C−F bonds and uses H₂and base as the terminal reductant.