Hydride-Mediated Electronic Stitching at Interfaces of Ligand-Protected Gold Nanoclusters

Abstract

Hydride-containing ligand-protected gold nanoclusters present a distinctive bonding problem: despite its negligible steric bulk, hydride can contribute to the stabilization of compact gold frameworks. Here we show that each kernel surface bridging hydride in gold nanohydride clusters forms a local three-center two-electron Au2H(2e) superatomic connector. Across four reported clusters, [Au20H3]3+, [Au22H3]3+, [Au24H3]3+, and [Au22H4]2+, hydride-bridged Au–Au contacts with the Au2H(2e) are contracted, the Au–H distances are longer than typical Au–H bond, and standard electron counting is compatible with electron-deficient Au2H connector. Pipek-Mezey localized orbitals further reveal continuous Au–H–Au three-center topology, while a simple Au2H+ reference model captures the essential orbital pattern of this local motif. Rather than replacing global superatomic electron counting, the Au2H connector picture provides a local bonding complement that explains how surface hydrides electronically assemble adjacent gold fragments at kernel interfaces. Exploratory hydride-containing model clusters illustrate the possible transferability of this motif. These results reposition surface hydrides from passive electron-counting ligands to atomically compact local connectors, providing a chemically intuitive framework for understanding hydride-stabilized gold nanoclusters.