Crystallography as a Path-Finding Tool to Understand Functionality in Coordination Polymers

Because of their potential applications, coordination polymers (CPs) are at an exalted position in the field of chemical and material science. Porous coordination polymers, popularly known as metal–organic frameworks (MOFs), have large surface area with functional pore environment, permanent porosity, tailorability in pore size, dimension and volume, which make them promising for interesting functionalities. In this review, we show how the mixed-ligand CPs/MOFs are very important in tuning the functionality of such systems and how the X-ray structure illuminates their functionalities. Here, we discuss the application of mixed-ligand functional MOFs for CO2 storage and separation by fine-tuning their pore size and dimension along with their polar pore surfaces using different functional dicarboxylates and N,N′-donor ligands. We also discuss the nature of conductivity and fabrication of Schottky barrier diode for CPs, where free organic ligands are in their pores. In addition, we also present the variation of their interesting chemical reactivity, e.g. framework-assisted in situ redox transformation.