Porphyrin-based MOFs for sensing environmental pollutants

Utilizing porphyrin molecules as the building blocks (ligands) of metal–organic frameworks (MOFs) leads to porphyrinic MOFs (including incorporation of functional materials into porphyrinic MOFs), whereas the immobilization of porphyrin molecules into porous MOFs afford porphyrin@MOFs. These two kinds, collectively regarded as porphyrin-based MOFs (PP-MOFs), are known to feature distinct photophysical and electrochemical properties lending towards several applications. This is because PP-MOFs can overcome the instability and self-quenching issues oft-encountered in porphyrins. Thanks to the ordered immobilization of porphyrins and electron-hopping mobility, this relatively new class of MOFs has received a surge of attention in sensing environmental pollutants. This review will explore the strengths and weaknesses of PP-MOFs in this context, as well as the influence of various sensory mechanisms associated with them. Libraries of porphyrinic MOFs and porphyrin@MOFs are reviewed herein, a number of them featuring the optimal selectivity and sensitivity for device fabrication. Finally, the challenges and prospects of PP-MOFs for environmental monitoring are critically interrogated.