Synthesis and Characterization of New Metal-Organic Frameworks (MOFs) for Sensing and Catalysis Applications.

Abstract

Metal organic frameworks (MOFs) are an emerging class of porous materials that have earned a significant amount of attention due to their design flexibility from their building blocks of organic linkers and inorganic clusters. In order to enhance the performance and to develop novel applications using MOFs, we outline here the design and synthesis of new kind of MOFs using new type of linkers. From the proposed linkers, we will be able to prepare a set of new materials with unprecedented electrical, chemical, and topological properties for applications including sensing and catalysis. In our proposed research work, we aimed to synthesize new type of MOFs to be used in sensing and photocatalysis. To this end, a new series of Lanthanides Metal Organic Frameworks (LnMOFs) was synthesized via solvothermal reaction. The four new luminescent MOFs synthesized by mating LnNO3.6H2O where Ln is (La and Ce) cations with 1,5 dihydroxy-2,6-naphthalenedicarboxylic and 2,6-naphthalenedicarboxylic acid. In this project, AUBM-2(Ce) and AUBM-3(Ce) were selected for sensing the heavy toxic metals (Pb(II), Cr(IV), As(III), Cd(II), Hg(II)) and for paraquat. The hydroxyl-functionalized structures have shown to be promising luminescent sensory materials with high selectivity and sensitivity towards the detection of mercury. In a second part of our research work, our focus was on the development of new MOFs for photocatalysis applications. We report the successful incorporation of the photo-active bis(4̍-(4-carboxyphenyl)-terpyridine)Ruthenium(II) (Ru(cptpy)2 strut into a robust metal organic framework, AUBM-4. The single crystal X-ray analysis revealed the formation of a new one-dimensional structure of Ru(cptpy)2 complexes linked together by Zr atoms that are eight coordinated with O atoms. The chemically stable MOF structure was employed as an efficient photocatalyst for carbon dioxide conversion to formate under visible light irradiation. To the best of our knowledge, the obtained conversion rate was among the highest reported in the literature for similar systems. Our strategy of using the Ru(cptpy)2 complex as a linker to construct the MOF catalyst appears to be very promising in artificial photosynthesis.