Radical-promoted room-temperature terminal alkyne activation on Au(111)

Exploring on-surface reactions of terminal alkyne derivatives are of primary importance for controlled synthesis of graphyne and graphdiyne-type materials. In this study, room-temperature (RT) adsorption of ethynyl-phenanthrene (EP) and ethynyl-iodophenanthrene (EIP) precursors on Au(111) were investigated by combined scanning tunneling microscopy and density functional theory (DFT) modeling. In contrast to inert adsorption of EP on Au(111), RT deposited EIP molecules are partially deiodinated, which gives rise to various kinds of reaction products. Surprisingly, polymeric chains with length up to ∼ 15 nm were identified. Our DFT modeling evidences that the alkyne activation and covalent coupling on Au(111) are more favored for the deiodinated precursors.