Trimethyltin-mediated covalent Gold–Carbon bond formation

We study the formation of covalent gold–carbon bonds in benzyltrimethylstannane (C10H16Sn) deposited on Au in ultra-high-vacuum conditions. Through X-ray photoemission spectroscopy and X-ray absorption measurements, we find that the molecule fragments at the Sn–benzyl bond when exposed to Au surfaces at temperatures as low as −110 °C. The resulting benzyl species is stabilized by the presence of Au(111) but only forms covalent Au–C bonds on more reactive Au surfaces like Au(110). We also present spectroscopic proof for the existence of an electronic “gateway” state localized on the Au–C bond that is responsible for its unique electronic properties. Finally, we use DFT-based nudged elastic band calculations to elucidate the crucial role played by the under-coordinated Au surface in the formation of Au–C bonds.