The Amazing Chemistry of Metal-Organic Frameworks

Abstract

The interest in the study of metal-organic frameworks (MOFs) has been growing quickly and prominently in the last years, because such materials that have relevant properties such as porosity, high surface area, and the possibility of functionalization of their internal surfaces have enabled applications in different areas. This is a new research area in which, from the conceptual point of view, Coordination Chemistry and Solid-State Chemistry principles are strictly related. According to the official definition, MOFs are coordination polymers well defined with an open framework containing potential voids as the feature. Despite the pioneering article of Kinoshita published in 1959, the area did not gain notoriety until the late 1990s with the reporting of Omar Yaghi about a zinc(II) porous coordination solid of high structural stability, popularly named MOF-5. For the rational planning of these complex materials, in particular, this same group of research has developed the reticular synthesis approach in which it requires the use of secondary building units (SBUs) that are linked by means of strong covalent bonds throughout the crystal. A judicious choice of these building blocks can lead to the construction of complex networks containing different topologies, as well as specific functions and well-controlled morphologies for a wide variety of applications. In addition, we also highlight the main techniques for synthesis and characterization of MOFs and nano-MOFs, including different strategies to scalable batch and continuous production. Analogous MOF-based materials as, for example, bio-MOFs and Ln-MOFs, will also be presented in this chapter. Hence, the former concerns porous materials that are constructed by biologically compatible and renewable components such as bioelements, amino acids, or peptides, and for this reason, they have been widely used as drug carriers. The Ln-MOFs are lanthanide(III)-based MOFs with promising applications as luminescent sensors, light-emitting devices, biological markers, and so on. This chapter will also focus on recent advances in research on hierarchically structured meso-/macroporous and functionalized materials.