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Abstract Metalation of the polynucleating ligandF,tbsLH6(1,3,5‐C6H9(NC6H3−4‐F−2‐NSiMe2tBu)3) with two equivalents of Zn(N(SiMe3)2)2affords the dinuclear product (F,tbsLH2)Zn2(1), which can be further deprotonated to yield (F,tbsL)Zn2Li2(OEt2)4(2). Transmetalation of2with NiCl2(py)2yields the heterometallic, trinuclear cluster (F,tbsL)Zn2Ni(py) (3). Reduction of3with KC8affords [KC222][(F,tbsL)Zn2Ni] (4) which features a monovalent Ni centre. Addition of 1‐adamantyl azide to4generates 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 of5reveals 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 for5.
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Multi-active Site Dynamics on a Molecular Cr/Co/Se Cluster Catalyst
This study provides detailed insights into the interconnected reactivity of the three catalytically active sites of an atomically precise nanocluster Cr3(py)3Co6Se8L6 (Cr3(py)3, L = Ph2PNTol–, Ph = phenyl, Tol = 4-tolyl). Catalytic and stoichiometric studies into tosyl azide activation and carbodiimide formation enabled the isolation and crystallographic characterization of key metal-nitrenoid catalytic intermediates, including the tris(nitrenoid) cluster Cr3(NTs)3, the catalytic resting state Cr3(NTs)3(CNtBu)3, and the mono(nitrenoid) cluster Cr3(NTs)(CNtBu)2. Nitrene transfer proceeds via a stepwise mechanism, with the three active sites engaging sequentially to produce carbodiimide. Comparative structural analysis and CNtBu bind-ing studies reveal that the chemical state of neighboring active sites regulates the affinity for substrates of an individual Cr-nitrenoid edge site, intertwining their reactivity through the inorganic support.
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- Award ID(s):
- 1944843
- PAR ID:
- 10313477
- Date Published:
- Journal Name:
- ChemRxiv
- ISSN:
- 2573-2293
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.26434/chemrxiv-2022-zkfsp
