Redox-Active Metal-Organic Frameworks (MOFs) and their Potential Applications

Abstract

This thesis focuses on design and synthesis of redox-active metal-organic frameworks (MOFs). The potential applications of these materials in photothermal, hydrocarbon purification and carbon capture were explored. Fundamental investigations and density functional theory (DFT) modelling were carried out to elucidate structure–function relationships alongside crystallographic, electrochemical, spectroscopic and spectroelectrochemical techniques.

In chapter 3, a nickel-dithiolene based MOF (Zn1) underwent an efficient photothermal conversion when illuminated with a low-power-density near-infrared (NIR) laser. The new photothermal MOF was then transferred into self-healing composites which could recover from dynamic damage by photostimulus.

In chapter 4, an olefin addition reaction was demonstrated in a novel 3D MOF (Zn2) containing nickel-dithiolene ligands. The reactions were analysed by a series of spectroscopic measurements which revealed the innate charge transfer interactions and elucidated the structural transformations upon the cyclopentene addition.

In chapter 5, electrochemical CO2 capture in a redox-active quinone system was fundamentally studied through a series of electrochemical and spectroelectrochemical measurements. The impact of protons on the electrochemical CO2 capture process was investigated. Furthermore, a UiO-type anthraquinone-based MOF was anticipated to exemplify electrochemical CO2 capture in solid-state materials.

Overall, this thesis highlights the utility of redox-active ligands in formulating porous materials with flexible applications in an energy efficient manner. The unique combination of redox activity with the structural versatility of MOFs allows these materials to occupy a unique niche within manufacturing and separations processes.