[Ni-8((CNBu)-Bu-t)(12)][Cl]: A nickel isocyanide nanocluster with a folded nanosheet structure

摘要

The reaction of 1.75 equiv of (BuNC)-Bu-t with Ni(1,5-COD)(2), followed by crystallization from benzene/pentane, resulted in the isolation of [Ni-8((CNBu)-Bu-t)(12)][Cl] (2) in low yields. Similarly, the reaction of Ni(1,5-COD)(2) with 0.6 equiv of [Ni((CNBu)-Bu-t)(4)], followed by addition of 0.08 equiv of I-2, resulted in the formation of [Ni-8((CNBu)-Bu-t)(12)][I] (3), which could be isolated in 52% yield after work-up. Both 2 and 3 adopt folded nanosheet structures in the solid state, characterized by two symmetry-related planar Ni-4 arrays, six terminally bound (BuNC)-Bu-t ligands, and six (BuNC)-Bu-t ligands that adopt bridging coordination modes. The metrical parameters of the six bridging (BuNC)-Bu-t ligands suggest that they have been reduced to their [(BuNC)-Bu-t](2-) form. In contrast to the nanosheet structures observed for 2 and 3, gas phase Ni-8 is predicted to feature a compact bisdisphenoid ground state structure. The strikingly different structural outcomes reveal the profound structural changes that can occur upon addition of ligands to bare metal clusters. Ultimately, the characterization of 2 and 3 will enable more accurate structural predictions of ligand-protected nanoclusters in the future.