Harnessing Multi‐Center‐2‐Electron Bonds for Carbene Metal‐Hydride Nanocluster Catalysis

N-Heterocyclic carbene (NHC) ligands possess the ability to stabilize metal-based nanomaterials for a broad range of applications. With respect to metal-hydride nanomaterials, however, carbenes are rare, which is surprising if one considers the importance of metal-hydride bonds across the chemical sciences. In this study, we introduce a bottom-up approach that leverages preexisting metal-metal m-center-n-electron (mc-ne) bonds to access a highly stable cyclic(alkyl)amino carbene (CAAC) copper-hydride nanocluster, [(CAAC)₆Cu₁₄H₁₂][OTf]₂ with superior stability compared to Stryker's reagent, a popular commercial phosphine-based copper hydride catalyst. Density functional theory (DFT) calculations reveal that the enhanced stability stems from hydride-to-ligand backbonding with the π-accepting carbene. This new cluster emerges as an efficient and selective copper-hydride pre-catalyst, thereby providing a bench-stable alternative for catalytic applications.