Carbon dioxide levels have been steadily increasing over the past decades; as of 2019 (411 ppm), CO2 levels are at their highest in over 40 years (330 ppm in 1977); consequently, regulations in certain areas require the reduction of CO2 emissions to combat this trend. For effective carbon capture, we require a sorbent that has high adsorption capacity, stability, and recyclability; in addition, an efficient and economical way to release the captured gas is needed as well. Metal-organic frameworks (MOFs) possess a high surface area for adsorption, but releasing the stored gases requires additional energy input that limits the overall efficiency of carbon capture. Ag/UiO-66 provides a thermally stable complex with a high surface for adsorption of CO2 while the silver nanoparticles utilize light-induced local heating to act as a photoswitch for dynamic release of CO2; visible light in the 400 nm spectrum is used to liberate the captured CO2.

Metal-organic frameworks (MOFs) are a class of highly crystalline nanoporous materials that self-assemble from inorganic metal oxide clusters and multitopic organic linkers. MOFs can be altered in terms of the types of metals and structures of organic linkers used, allowing for a high degree of customization and manipulation of the synergistic chemical or physical properties that arise from the precise coordination of their molecular components, including exceptionally large surface area and pore size. Zirconium-based MOFs, called UiOs in honor of their conception at the University of Oslo, also show remarkable chemical stability in both acidic and basic environments, making them excellent candidates for biomedical applications as drug delivery systems, where they can either function as molecular cargo ships, with drugs packed into their pores, or as controlled release systems, in which drug molecules are directly attached to their ligands for precise delivery. The objective of this work is to prepare water-stable MOFs whose linkers are decorated with functional groups that have potential compatibility in drug delivery systems and to explore the efficacy of certain synthesis conditions in terms of the crystallinity of the MOF product. Thus, we hope to establish a basis for the ligation of anticancer drugs and fluorescent tags to MOFs for their controlled release at a specified location within the body. These targeted release mechanisms represent new therapeutic possibilities in terms of cancer treatment as their specificity would mitigate damage to healthy tissues, thereby addressing one of the greatest weakness of present treatment options.

Metal–organic frameworks (MOFs) represent an important platform to immobilize and stabilize electroactive molecular catalysts due to their porosity, high surface area and well characterized three-dimensional structure. Most efforts in this area have been dedicated to the development of photocatalysts and traditional heterogeneous catalysts based on both precious and abundant transition metals. However, little work has been done to design nickel-based MOF electrocatalysts for organic synthesis. In this work we describe the synthesis of three linkers containing a bipyridine moiety, where two of the linkers are dicarboxylate extended linkers and one is a bispyrazole extended linker. The two dicarboxylate linkers are combined with zirconium clusters to build MOFs of the UiO-n family. The bispyrazole linker was used to synthesize copper-based MOFs. The developed MOFs function as support for the immobilization of nickel (II) species in isolated sites within the frameworks. Following this, the redox properties of these MOFs were studied by the means of electrochemistry. The structure of the organic linkers was confirmed by 1H NMR spectroscopy and mass spectrometry, and two of the linkers are new molecules never synthesized before. The synthesized MOFs were characterized by powder X-ray diffraction, where the MOFs of the UiO-n family showed small crystallite sizes. Similarly, the MOFs based on the bispyrazole linker showed low crystallinity. Metalation of the MOFs with a [Ni(phen)3]Cl2 complex was studied using UV-Vis spectroscopy and scanning electron microscopy, both techniques confirmed the immobilization of the nickel catalyst in the UiO-n MOFs. The electrochemical properties of the MOFs were studied using cyclic voltammetry. Both UiO-n MOFs showed a non-reversible event for the reduction of Ni(II) and the MOFs based on the bispyrazole linker showed a quasi-reversible event for the Cu(II)/Cu(I) couple.