Synthesis of Single‐Layer Two‐Dimensional Metal–Organic Frameworks M3(HAT)2 (M=Ni, Fe, Co, HAT=1,4,5,8,9,12‐hexaazatriphenylene) Using an On‐Surface Reaction

Abstract 1,4,5,8,9,12‐Hexaazatriphenylene (HAT) is one of the smallest polyheterocyclic aromatic building blocks for forming conjugated metal–organic frameworks (cMOFs). However, the strong inter‐molecular steric hindrance impedes the growth of HAT‐based cMOFs. Here we employ on‐surface synthesis to grow single‐layer two‐dimensional cMOFs of M 3 (HAT) 2 (M=Ni, Fe, Co). Using scanning tunnelling microscopy and density‐functional theory (DFT) analysis, we resolve that the frameworks comprise a hexagonal lattice of HAT molecules and a Kagome lattice of metal atoms. The DFT analysis indicates that Ni, Co and Fe carry a magnetic moment of 1.1, 2.5, and 3.7 μB, respectively. We anticipate that the small π‐conjugated core of HAT and strong bidentate chelating coordination give rise to appealing electronic and magnetic properties.