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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Metal–organic frameworks for organic electrocatalysis

Torres Méndez, Carlos Enrique January 2022 (has links)
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.

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