The synthesis and properties of novel Metal Organic Frameworks were investigated and reported in this thesis. Thirteen new materials have been synthesized and their properties have been discussed with nine of the structures being solved. The most interesting and useful MOF among the thirteen materials is STAM-1, a copper-based Metal Organic Framework in which the starting linker (Benzene-1,3,5-tricarboxylic acid) undergoes selective in situ monoesterification during the synthesis. The monoesterified BTC can be recovered easily from the MOF, opening up MOF synthesis as a “protection” tool for unexpected selectivity in preparative chemistry that is difficult to accomplish using standard organic chemistry approaches. The selective linker derivatisation leads to the formation of a porous MOF with two types of accessible channel; one hydrophilic lined by copper and the other hydrophobic, lined by the ester groups. The unique structure of the pores leads to unprecedented adsorption behaviour, which reacts differently to gases or vapours of dissimilar chemistry and allows them to access different parts of the structure. The structural flexibility of STAM-1 shows significant differences in the kinetics of O₂ and N₂ adsorption, showing potential for new materials to be developed for air separation. Having two types of channel systems, adsorption can be switched between the two channels by judicious choice of the conditions; a thermal trigger to open the hydrophilic channel and a chemical trigger to open the hydrophobic channel. The storage and release capability of NO in STAM-1 was investigated for use in biomedical applications. Successful studies showed the strength of the antibacterial effects of NO loaded STAM-1, by using three different bacterial strains as a test of performance and were found to be bactericidal. Furthermore the antibacterial effects of NO free STAM-1 were also probed and found to be bactericidal even with low concentrations of the material such as 5 wt%. STAM-1 showed some complex magnetic behaviour by displaying strong antiferromagnetic properties at room temperature and ferromagnetic properties at lower temperatures. The antiferromagnetic coupling was observed within the dimer and ferromagnetic coupling between the dimers. This property of ferromagnetism can only be attributed to the corporation of magnetic dimers in the framework. STAM-2 displays a different magnetic behaviour than STAM-1 which shows paramagnetic properties at room temperature and antiferromagnetic properties at lower temperatures. Other novel MOFs were also successfully characterised and their properties were investigated for potential applications.

Metal Organic Framework (MOF) materials, consisting of metal ions with organic linkers, have a functional cavity structure which can be utilized in applications such as catalyst, micro sensing, and gas absorption. Due to MOF materials' selective gas adsorption property, interest in MOF materials has intensified in the last few years, particularly for CO, CO₂, N₂, CH₄, and H₂. MOF materials are typically synthesized by reaction under hydrothermal conditions which yields a highly crystalline product. However, reaction under solvothermal condition typically requires long reaction times - from 8 hours up to several days depending upon the particular MOF material and the reaction conditions, such as solvent, temperature, and concentration. Other synthesis methods that have been developed to address these issues include microwave synthesis, sonochemical synthesis, and mechanochemical synthesis. Reaction time can be reduced to minutes under the high energy conditions of a microwave synthesis method. A solvent free synthesis can be achieved using the mechanochemical synthesis. The sonochemical synthesis method provides an environmentally friendly process. However, all of these synthesis methods above are batch processes and meet several difficulties in scalability and controllability. Herein, we introduce a new synthesis method for MOF materials which utilizes a continuous flow reactor process. To reduce the reaction time and solvent usage, and to maintain a high degree of the crystallinity are the goals of this study. Cu-BTC (BTC = Benzene, -1,3,5-Tricarboxylate ) or HKUST-1 Metal Organic Framework material was chosen to demonstrate the continuous flow reactor process since it has a simple MOF structure, consisting of Cu⁺² ions and BTC linkers, and has been widely studied for catalyst applications. The continuous flow synthesis method shows successful results of reduced residence time as low as 5 minutes, high crystal quality obtained, size control, and high yield with recycle solvent cooperation. The particle size control of MOF material has been shown crucial contributions in absorption application and is accomplished by adjusting the system temperature, flow rate, and solvent composition ratio. A water/ethanol mixture as the solvent in Cu-BTC synthesis reaction is environmentally friendly and easy to separate from the MOF product. In addition, the composition of water in solvent is the most influential factor to the crystal growth rate specifically in crystallization rate and nucleation rate. BTC is used in excess to achieve a production yield of about 97% based on Cu ion consumption. Since the Cu-BTC particles have a low solubility in the ethanol/water solution, they can be obtained easily using a dispersion/sonication method. The BTC rich supernatant can be recycled for use in the feed stream to maintain a high production rate, which can be beneficial for quick economic production in laboratory, as well as, commercial scale applications. / Graduation date: 2012

Construction of polynuclear metal assemblies from discrete 0D clusters to extend 3D networks, comprised of metal ions and bridging organic/inorganic ligands has attracted immense attention, owing to their intriguing network topologies and interesting properties. Proper ligand design and the appropriate choice of the metal center are of vital importance to the design of such polynuclear assemblies. One of the various attributes of polynuclear metal assemblies is magnetism. Magnetic materials can be constructed by incorporating magnetic moment carriers such as paramagnetic metals(V, Cr, Mn, Fe, Co, Ni, Cu) in presence of bridging ligands. Though, one-atom oxo/hydroxo and two-atom cyanide bridges were of popular choices due to their short distance for transmitting strong magnetic coupling between the paramagnetic metal centers, it has been shown that, three-atom bridging ligands like carboxylate and azide (N3 ) are well-fitted moieties for this purpose since they offer a variety of magnetic interactions depending on their versatile bridging modes. It has been well known that incorporation of anionic bridging ligand in presence of azide anion is a challenging task due to the competition between the 2nd anionic ligand with azide in self-assembly process. Incorporating both azide and carboxylate functionalities, a series of polymeric complexes has been synthesized and conversion of 0D discrete clusters to extended networks with the retention of basic core by fine tuning the ligands has been achieved. Single-crystal to single-crystal transformation has received considerable attention in crystal engineering since it is difficult for crystals to retain single crystallinity after removal of the guest at high temperature. Interestingly single-crystal to single-crystal transformation was observed at high temperature for Co(II) formate-formamide complex and change in dimensionality from 3D to 0D was observed at high temperature for Cr(III) formate-formamide complex. Multiferroic materials are those where both ferroelectricity and ferromagnetism coexist in the same phase. In general the transition metal d-electrons which are essential for magnetism reduce the tendency for off-center ferroelectric distortion. First tetrazole based miltiferroic coordination polymer of Co(II) metal ion in presence of azide has been successfully synthesized whereas its analogous Mn(II) complex showed different structural topology with interesting magnetic behavior. It has been also established in the present study, the important role played by hydrazine ligand to prevent oxidation of paramagnetic Co(II) to diamagnetic Co(III) system with the formation of a metal-inorganic assembly of Co(II) which exhibited spin-canted behavior.