Metal ion detection using luminescent-MOFs: Principles, strategies and roadmap

Owing to their porosity and enriched host–guest chemistry, metal–organic frameworks (MOFs) applied extensively in detection of large variety of hazardous chemicals using different instrumental methods, especially metal ions by photoluminescence methods. Application of luminescent MOFs (LMOFs) in detection of metal ions demonstrates successes in this area along with some challenges. Contrary to versatile application of LMOFs as metal-ion sensor, there is not any review in this area. Also, there are some inconsistencies in this area needing right solution. Considering such vacancies, we tried to identify the successes and challenges of using MOFs as metal ion sensor. To this aim, for the first time in this review we present “structure-signal” and “mechanism-response” approaches through communicating between LMOFs structural features and their signal transduction and detection mechanism. In “structure-signal” approach we discuss how a LMOF with special organic linker and inorganic nodes can generate special kind of luminescence signal. In “mechanism-response” we explain that how a detection mechanism can produce selective and sensitive response toward special metal ion. Then, we address about some essential concepts in photoluminescence (PL) methods to avoid any misunderstandings. However, our goal is not giving a full explanation about PL principles because other reviews did this job very well. Finally, we discussed about sensing parameters and characterization techniques and offer a generalized updated roadmap for detection of metal ions.