On-Surface-Assembled Single-Layer Metal-Organic Frameworks with Extended Conjugation

Single-layer metal-organic frameworks with extended conjugation (SL-cMOFs) exhibit electronic bands that lead to high conductivity or non-trivial quantum phases. Experimental realization of SL-cMOFs has been demonstrated using on-surface coordination self-assembly. The tunability and adaptability of coordination assembly offers rich opportunities for designing and fabricating SL-cMOFs with various geometric characteristics. In this Review, we discuss the recent experimental advances in on-surface synthesis of SL-cMOFs and characterization of their band structures. Special attention has been paid to the MOFs featuring Kagome lattices. Starting from the general principles of their structural design, the SL-cMOFs recently achieved via on-surface coordination self-assembly are subsequently divided into three categories, that is, M₃ L₂ , M₂ L₃ , and M₃ L MOFs (M for metal and L for ligand), and the corresponding works are overviewed. The current challenges and prospective directions are also discussed.