Abstract
Magnesium metal-organic frameworks (Mg-MOFs) are a relatively new field of research. Currently, only a small number of Mg-MOFs exist, and most of them have not been studied very extensively. This work investigates three new magnesium structures made with a pre-existing ligand used for MOF synthesis.
Chapter one of this thesis details information about MOFs generally with specific focus on certain parts of their structures and capabilities. This includes a brief overview of different types of MOFs, including, multiwalled and lightweight MOFs. This is followed by a more in-depth literature review of the synthesis and applications of a number of Mg-MOFs.
Chapter two focuses on the synthesis and characterisation of the pre-existing ligand, 2-(4- carboxy-1, 1’-biphenyl)imidazo(4, 5-f)-1, 10-phenanthroline (L1). This includes the characterisation of L1 by single crystal X-ray crystallography. This was followed by the synthesis and characterisation of a new ligand 2-(3, 5-biscarboxy-1, 1’-biphenyl)imidazo(4, 5-f)-1, 10-phenanthroline (L2). The methylated version of L2 was characterised via single crystalX-ray crystallography due to the low solubility of the non-protected L2. Attempts were made to produce ruthenium-ligand complexes with L1 and L2, but these processes were unsuccessful.
Chapter three focuses on how L1 and L2 were used to create a number of new metal-organic structures. These structures were, three separate magnesium MOFs, a cadmium MOF, and two sodium coordination polymers. L1 was also used to produce a zinc MOF that had recently been published. The three magnesium-L1 MOFs were synthesised, characterised, and compared to determine why and how they were produced. The first Mg-MOF was a simple one-dimensional chain with two sets of L1 bound to each magnesium ion metal node in opposite directions (Mg MOF-1). The second Mg-MOF formed as a two-dimensional layered sheet framework with large 1D pores. The framework was held together by secondary building units (SBUs) with four magnesium ions bound together by formate bridging ions and the carboxylate groups of L1 (Mg-MOF-2). The third Mg-MOF formed was a much more intricate 1D chain, with each chain-link comprising of multiple L1 ions and magnesium ions bound together with formate bridging (Mg-MOF-3). The structure of Mg-MOF-3 indicates that it may have been a partially formed version of Mg-MOF-2.
Chapter four presents an overview of the future work that can be investigated regarding the structures that have been made with L1 and L2. This includes a more comprehensive investigation into the materials that have been produced such as their gas adsorption and photophysical properties. It also includes the planned production and analysis of isoreticular analogues of the already produced material. Finally, it includes the synthesis of ruthenium-ligand complexes via literature methods and the potential bimetallic MOFs that could be synthesised with those complexes.