Novel zinc Metalloporphyrin based metal-organic framework for Quantitative & Reusable Sensing of nitrobenzene

Porphyrins and metalloporphyrins have been exploited for a wide range of applications including sensing and catalysis in both homogeneous and heterogeneous formats. An emerging class of porous materials that utilize porphyrins and metalloporphyrins for diverse applications are the metal organic frameworks (MOFs) containing porphyrins as guests within the MOF cavities or as integral components of the framework by serving as a metal node linker. Here, a novel metal metalloporphyrin framework (MMPF-X) was synthesized using a solvothermal method from a 4′,4″‘,4″“‘,4″““‘-(porphyrin-5,10,15,20-tetrayl)tetrakis(([1″“,1″“‘-biphenyl]-3,5-dicarboxylic acid)) (TDBP) ligand and zinc paddlewheel metal building blocks (MBBs), yielding C 2/m space group crystals with a cph pattern of crisscross metalloporphyrin lattices that result in complex interconnected channels. The MMPF-X functions as a heterogeneous sensor for nitroaromatics, exhibiting reversible fluorescence quenching in the presence of nitrobenzene. The level of detection (LOD) was determined and compared to ZnTDBP in solution, highlighting MMPF-x's potential for quantitative sensing of nitrobenzene and related compounds across a wide concentration range. The quenching mechanism was evaluated using a modified stern-Volmer analysis for fractional components consistent with the porosity of the MOF.