Synthesis of a Luminescent Aluminum-Based MOF for Selective Iron(III) Ion Sensing

In the search for new materials to open up creative pathways for industry and research, modification is one of the best methods to implement. Developing materials with high sensitivity and selectivity for specific applications, such as ion sensing, remains a significant challenge. This work aims to introduce a novel metal-organic framework (MOF) derived from the well-established 2-amino-[1,1'-biphenyl]-4,4'-dicarboxylic acid MOF by modifying its structure to enhance its properties and applications. A luminescent 2-naphthyl moiety was attached to the amino group of the linker to form the new luminescent Al-based MOF Al-BP-Naph with a surface area of 456 m² g^-1 and a pore volume of 0.55 cm³ g^-1. Al-BP-Naph showed high selectivity towards Fe³⁺ sensing due to the overlapping absorption and excitation spectra of both Fe³⁺ and MOF. The MOF demonstrated a detection limit of approximately 6 × 10^-6 mol L^-1 with a limit of quantification of about 19 × 10^-6 mol L^-1 and a very fast response time (less than 10 s). It also had a Stern-Volmer constant of approximately 0.09 × 10⁵ L mol^-1, distinguishing it from other ions. Our work contributes to the expanding repertoire of functional materials with promising applications in sensing technologies, offering a novel MOF with superior properties for iron(III) ion detection.