In this work the magnesium, zinc, nickel and cobalt MOFs of the MOF-74 isostructural family are used to probe metal-dependent adsorbate interactions with water and with carbon monoxide because of their ability to generate open metal sites upon activation. An isostructural family is used so that the only variable from one MOF to another is the metal incorporated into the framework. For water adsorption isotherms with humidities up to 90%, the observed trend at 298K and 1 bar is Mg-MOF-74 > Zn-MOF-74 > Co-MOF-74 > Ni-MOF-74. This observed trend is due to Lewis acid-base interactions. When the weight effect is removed, differences are still observed, especially below 40% relative humidity, thereby confirming that there is a metal effect. These studies revealed that PXRD alone cannot indicate the level of structural decomposition and that none of the four isostructures fully retain their structural integrity on exposure to humidified air because of microstrain and/or the presence of oxygen; more studies examining the extent of structural decomposition need to be undertaken. For carbon monoxide adsorption the general observed trend for P < 4 bar and temperatures of 298, 313 and 333K is Co-MOF-74 > Ni-MOF-74 > Zn-MOF-74 > Mg-MOF-74. This trend is based on π-backbonding interactions. Here again, differences remain after removal of the weight effect, confirming the metal dependence. Notably, Co-MOF-74 has the highest CO loading at 298K and 1 bar reported so far. Both the Toth and Virial Isotherms were used to fit the CO adsorption data followed by the use of the Clausius-Clapeyron equation to find the isosteric heats of adsorption, qst. The results from the Toth isotherm are more reliable and showed that qst remains constant as loading increases for Mg-MOF-74, decreases for Zn-MOF-74 and increases with loading for Co-MOF-74 and Ni-MOF-74; Ni-MOF-74 had the highest heat of adsorption at all loadings. It appears that using the Clausius-Clapeyron equation to calculate qst is an inappropriate method for Ni-MOF-74 so other methods such as calorimetry are recommended. It is also recommended to model the data of all the MOFs with other isotherm models such as Sips equation and to investigate the possibility of chemisorption for the cobalt and nickel isostructures. Finally, Henry’s constant results reveal that Ni-MOF-74 has the highest affinity for CO at low coverages.

The aim of this thesis was to examine the ability of metal organic frameworks (MOFs) to store and controllably release biologically significant amounts of nitric oxide (NO). Initial work involved the synthesis of a series of isostructural MOFs, known as M-CPO-27, which display coordinatively unsaturated metal sites (CUSs) when fully activated (guest solvent molecules both coordinated and uncoordinated to the metal atom are removed). Two of these frameworks (Ni and Co CPO-27) displayed exceptional performance over the entire cycle of activation, storage and delivery showing the largest storage and release of NO of any known porous material (up to 7 mmolg⁻¹). These frameworks would therefore be considered for initial research into the formulation of MOFs, for possible use in medical applications. It was shown that they still release large amounts of NO even when placed inside porous paper bags, creams or hydrocolloids. The other versions of M-CPO-27 also displayed significant adsorption of NO however they show poor total NO release. It was also shown that it is possible to synthesise both Ni and Co CPO-27 using microwave synthesis without any detrimental effect to the porous structure. Several iron-based MOFs were also investigated for NO storage and release. The results showed that Fe MIL-88 based structures adsorb good amounts of NO but only release a small amount of the irreversibly adsorbed NO. Two successfully amine grafted giant pore MOFs were then investigated to attempt to improve the NO adsorption and release. This result was not observed however, due to the poor total amine grafting coverage and pore blockage resulting from the amines. In-situ IR studies reveal that when exposed to NO, activated Fe MIL-100 forms a chemical bond with the NO. The studies also displayed that when water is then allowed to attempt to replace the NO that only a small amount of NO is actually released, the majority of the NO either remains chemically bonded to the Fe atom or forms N₂O in conjunction with a Fe-OH group. Other MOFs were also successfully synthesised and characterised for NO storage and release. Both Ni succinate and Ni STA-12 display good adsorption and excellent release of NO. This indicates that Ni based MOFs show the best results for NO adsorption and release. In the conclusion of the thesis I am able to categorise the NO release ability of MOFs based on composition and formulate a theory as to why this happens.