In-Architecture X-ray Assisted C–Br Dissociation for On-Surface Fabrication of Nanodiamond Chains

The fabrication of well-defined, low-dimensional diamondoid-based materials is a promising approach for tailoring diamond properties such as superconductivity. On-surface self-assembly of halogenated diamondoids under ultrahigh vacuum conditions represents an effective strategy in this direction, enabling reactivity exploration and on-surface synthesis approaches. Here, we demonstrate through scanning probe microscopy, time-of-flight mass spectrometry, and X-ray photoelectron spectroscopy that self-assembled layers of dibromodiamantanes on gold can be debrominated by X-ray irradiation (Al Kα at 8.87 Å and Mg Kα at 9.89 Å) at low temperatures, without affecting their well-defined arrangement. The resulting ‘in-architecture’ debromination enables the fabrication of the diamantane dimer from self-assembled precursors in close proximity, which is otherwise inaccessible through annealing on metal surfaces. Our work introduces an approach for the fabrication of nanodiamond chains, with significant implications for in-architecture, layer-by-layer synthesis, and photolithography at the atomic limit.