A tetranuclear nickel hydride cluster capable of reversible activation of aromatic and aliphatic C-H bonds.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 42527391.
- Also identified by DOI 10.1038/s41467-026-76006-4 and PMC identifier 13421524.
- Licence recorded as CC BY-NC-ND.
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Abstract
Metal cluster complexes supported by multiple hydrides are useful for activating inert bonds and molecules, while nickel-based variants capable of activating external substrates remain scarce. Here, we report a tetranuclear Ni-hydride-phosphine cluster, [Ni<sub>4</sub>H<sub>4</sub>(P<sup>t</sup>Bu<sub>3</sub>)<sub>4</sub>] (1), which we synthesize by reacting [Li(THF)<sub>x</sub>][Ni{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>] (x ≈ 4.5 - 5) with pinacolborane (HBpin) in the presence of tri-tert-butylphosphine (P<sup>t</sup>Bu<sub>3</sub>). Its molecular structure features a tetrahedral Ni<sub>4</sub> core, with four face-capping μ<sub>3</sub>-hydrides and four terminally bound P<sup>t</sup>Bu<sub>3</sub> ligands. Cluster 1 is capable of reversible C-H and C-D bond cleavage of benzene-d<sub>6</sub>, toluene-d<sub>8</sub>, n-octane-d<sub>18</sub>, and its own P<sup>t</sup>Bu<sub>3</sub> ligands at 50 °C, leading to H/D exchange between the deuterated solvents and the ligands in 1. This reactivity is further utilized in the catalytic hydrogen isotope exchange reaction between benzene-d<sub>6</sub> and toluene. The reversible dissociation of one P<sup>t</sup>Bu<sub>3</sub> ligand in 1 is proposed as the key step to trigger the C-H and C-D bond activation. Quantum chemical computations propose the reversible displacement of one of the P<sup>t</sup>Bu<sub>3</sub> ligands in 1 as the key step in triggering C-H and C-D bond activation.