Studies on the synthesis of main group and late transition element frameworks

Abstract

Metal organic frameworks (MOFs) are metal-ligand compounds that extend into one, two or three dimensions via metal-ligand bonding that have found numerous technological applications, associated with their open pores and large internal surface area. The work developed in this doctoral thesis consists in the study of methodologies and systematic development of ligands or organic spacers for the synthesis of novel metal organic frameworks. An introduction to the chemistry, structural features and diverse applications of metal organic frameworks is provided in Chapter 1. The following chapter, chapter 2 involves the synthesis of gallium, indium and thallium metal organic frameworks using pyrazine, and pyrazine-2-carboxylic acid as organic spacers.^The change in the pore size of the synthesized frameworks was studied in correlation with the atomic radii of the selected triel elements.^Chapter 3 describes the work with the flexible, multidentate heteroelemental dipodal ligands: bis(2-pyridylthio)methane, bis(2-pyrimidylthio)methane and bipyrimidyldisulfide. These ligands were reacted with a series of copper halides or pseudo halides for the isolation of cubane clusters and polymers depending on the flexibility of the selected ligands, the stereochemical requirements of the metal center and the preferred coordination modes of the corresponding halide or pseudo halide. The fourth chapter deals with the use of 2-pyridinephosphonic acid (2PyPOH2), 4-pyridinephosphonic acid (4PyPOH2) and 4-pyridinemethylphosphonic acid (4PyCH2PO3H2) for the synthesis of aluminum and gallium phosphonate cages. The isolation of these cages was achieved under careful control of the hydrolytic conditions of the corresponding reaction media.^Chapter 5, details the results of the studies with the ligand aminomethylphosphonic acid (ampa) for the construction of MOFs.^The reaction of ampa with salts of Zn, Cd, Hg, Pb, Ag, Cu and Pb afforded new metal-phosphonate polymers with unique structural features and includes the synthesis of a bimetallic MOF containing Ag and Cu. Finally, chapter 6 analyzes the ligand 5-pyrimidyl phosphonic acid (5-PymPO3H2) in the synthesis of homo and heteroelemental MOFs based on its possession of a phosphonate moiety for coordination and two heterocyclic nitrogen atoms at the opposite end to the PO3H2 to promote multi-site coordination. As a consequence it was possible to synthesize six coordination polymers, including a two dimensional, Cu/Ag polymer. All of the MOFs obtained throughout these studies have been characterized by X-ray crystallography along with other spectroscopic techniques, including NMR, IR, UV/Vis, and MS.