Lewis Acid Supported Nickel Nitrenoids

Metalation of the polynucleating ligand ^F,tbsLH₆ (1,3,5-C₆H₉(NC₆H₃−4-F−2-NSiMe₂^tBu)₃) with two equivalents of Zn(N(SiMe₃)₂)₂ affords the dinuclear product (^F,tbsLH₂)Zn₂ ( 1 ), which can be further deprotonated to yield (^F,tbsL)Zn₂Li₂(OEt₂)₄ ( 2 ). Transmetalation of 2 with NiCl₂(py)₂ yields the heterometallic, trinuclear cluster (^F,tbsL)Zn₂Ni(py) ( 3 ). Reduction of 3 with KC₈ affords [KC₂₂₂][(^F,tbsL)Zn₂Ni] ( 4 ) which features a monovalent Ni centre. Addition of 1-adamantyl azide to 4 generates the bridging μ³-nitrenoid adduct [K(THF)₃][(^F,tbsL)Zn₂Ni(μ³-NAd)] ( 5 ). EPR spectroscopy reveals that the anionic cluster possesses a doublet ground state (S = ). Cyclic voltammetry of 5 reveals two fully reversible redox events. The dianionic nitrenoid [K₂(THF)₉][(^F,tbsL)Zn₂Ni(μ³-NAd)] ( 6 ) was isolated and characterized while the neutral redox isomer was observed to undergo both intra- and intermolecular H-atom abstraction processes. Ni K-edge XAS studies suggest a divalent oxidation state for the Ni centres in both the monoanionic and dianionic [Zn₂Ni] nitrenoid complexes. However, DFT analysis suggests Ni-borne oxidation for 5 .