Facile Synthesis of Metallosalphen‐Based 2D Conductive Metal‐Organic Frameworks for NO 2 Sensing: Metal Coordination Induced Planarization

Abstract As an emerging class of promising porous materials, the development of two‐dimensional conductive metal organic frameworks (2D c ‐MOFs) is hampered by the few categories and tedious synthesis of the specific ligands. Herein, we developed a nonplanar hexahydroxyl‐functionalized Salphen ligand (6OH‐Salphen) through a facile two‐step synthesis, which was further applied to construct layered 2D c ‐MOFs through in situ one pot synthesis based on the synergistic metal binding effect of the N 2 O 2 pocket of Salphen. Interestingly, the C 2 v ‐symmetry of ligand endows Cu‐Salphen‐MOF with periodically heterogeneous pore structures. Benefitting from the higher metal density and shorter in‐plane metal‐metal distance, Cu‐Salphen‐MOF showcased excellent NO 2 sensing performance with good sensitivity, selectivity and reversibility. The current work opens up a new avenue to construct 2D c ‐MOF directly from nonplanar ligands, which greatly simplifies the synthesis and provides new possibilities for preparing different topological 2D c ‐MOF based functional materials.