An Unprecedented Two-Dimensional Pattern in Gold Nanoclusters Bred by Interlocking Au₄ Blocks

Atomically precise metal nanoclusters with a two-dimensional (2D) structure have not been documented in the library of metal nanoclusters with rich structural diversity. Herein, we construct a novel Au₇₆(p-MBT)₄₂ (p-MBT = p-methylbenzenethiol) nanocluster with such an unforeseen 2D configuration by assembling tetrahedral Au₄ blocks into an interlocked gold kernel. Notably, these kernel gold atoms, together with gold atoms from surface staples, engage in building the 72-gold-atom 2D pattern (represented as 6 × 6 × 4) with a highly symmetric C₄ axis and a four-atom thickness. Interestingly, the interlocking Au₄ assembly in the gold kernel contributes to the structural stability of Au₇₆(p-MBT)₄₂ from geometric and electronic aspects. This nanocluster shows exceptional catalytic performance for the electroreduction of CO₂ to CO in both acidic and alkaline media, outperforming most metal nanoclusters reported under comparable conditions. More generally, our study reveals that the Au₇₆(p-MBT)₄₂ nanoclusters might serve as active seeds to grow into larger-scale topology along distinct directions to further attain splendid nanostructures, which will provide a conceptual blueprint for developing mechanically interlocked manipulation to construct topological nanocrystals with high atomic precision.