Lanthanide-based Metal-organic Frameworks Offering Hydrogen Bonding Cavities: Luminescent Characteristics and Sensing Applications.

This work presents the synthesis and characterization of three isomorphous lanthanide-based metal-organic frameworks (Ln-MOFs) (Ln3+ = Eu (1), Tb (2), and Sm (3)) supported by a pyridine-2,6-dicarboxamide-based linker offering appended arylcarboxylate groups. Single crystal X-ray diffraction studies highlight that these Ln-MOFs present three-dimensional porous architectures offering large cavities decorated with hydrogen bonding (H-bonding) groups. These Ln-MOFs display noteworthy luminescent characteristics. The use of a mixed-metal strategy affords a series of Ln-MOFs exhibiting color-tunable emissions. The Eu-MOF was utilized for the nanomolar sensing of both nitrobenzene and 4-nitrophenol. The critical role of H-bonding in the detection of these analytes is validated through multiple spectroscopic, ξ potential, and molecular docking studies. The Eu-MOF illustrated notable anticounterfeiting as well as practical sensing applications.