Faster, cleaner, cheaper, better processes for industrially relevant chemicals is at the forefront of many areas of chemical research. The development of selective catalysts is important in many fields, classically; pharmaceutical chemistry and drug development, agricultural chemistry and biological activity, cosmetic chemistry and specific fragrances. But, selective catalysis is also important in many other areas including polymerisation and the fine tuning of a polystyrene, and of growing environmental importance; biodegradable and biocompatible plastics from sustainable sources. The former areas are looking towards heterogeneous systems that are tolerant to an array of substrates for a varied range of classic reactions, including asymmetric Michael reaction, Henry reaction, hydroformylation, hydrogenation, hydrosilylation reactions to name a few, to generate important chemical building blocks. An example of the latter point is the stereocontrolled production of polylactide via the ring-opening polymerisation (ROP) of the racemic cyclic ester lactide (rac-LA), with current industrial metal initiators chosen for the ROP of LA lacking chiral discrimination. This thesis, divided into four chapters, will investigate various ligands as homogeneous analogues containing a variety of transition metals for organically important reactions and the ROP of rac-LA. Chapter 1 introduces the importance of chirality and catalysis alongside the interests of heterogeneous systems. A review of the current literature is presented for the benchmark reactions undertaken in this thesis. Also introduced in this chapter is the ring-opening polymerisation of rac-LA, the importance of biopolymers, mechanism and methods involved in the preparation and characterisation of polylactic acid, alongside a review of the current literature. Chapter 2 investigates the preparation of an array of chiral pyridine containing Schiff base homogeneous ligands, as analogues to heterogeneous systems. The sterics about the chiral centre of the ligands have been varied. These ligands were trialled against benchmark reactions, and the activity and selectivity analysed. Furthermore, a selection of heterogeneous catalysts have been trialled for the same benchmark reactions. Chapter 3 describes the development of chiral Schiff base complexes, and Salalen based complexes, for the ROP of rac-LA, where the sterics and electronics of the ligand have been varied. The metal centre of these initiators includes titanium, hafnium, zirconium and aluminium, and the initiators investigated under solution and melt polymerisation conditions. Chapter 4 provides details of the reaction procedures for the synthesis of starting materials, ligands and complexes. Benchmark reaction conditions for the asymmetric Henry reaction and asymmetric hydrogenation reaction is detailed along with that of the polymerisation reaction.

Society is now dependent on the continued development and access to modern technology. Materials science therefore stands at the forefront of resolving and tuning functional materials properties, and designing technologies to improve our health, economy and environment. The content of this thesis covers a wide range of methods and approaches for understanding the chemical complexities, and tuneable properties of a unique subset of materials named metal-organic frameworks. The number of available precursor components for synthesising MOFs has led to a plethora of possible final crystal structures, with vast differences in observed material properties. The use of computational approaches in the prediction of potential functional frameworks, and also for resolving the origin behind observed phenomena, is essential for directing further work in the field. Work in this thesis includes the parameterisation of an approach that would allow a large-scale and cheap screening procedure of the thermodynamic properties of MOFs. Other work in this thesis includes the calculation of defective framework structures and the thermodynamics associated with their formation. Defects that occur in MOFs, when compared to inorganic binary materials such as oxides, can be considered as severe and non-dilute. The concentration and distribution of potential defects and the stability of the framework as a function of these factors, is a poorly understood area in the research field of MOFs. Finally, interfacing MOFs with surfaces is a relatively new approach for designing functional devices for applications such as gas absorption and photovoltaics. In this thesis we calculate interface binding sites and energetics of adhesion of an archetypal example of a MOF interfacing a metal oxide. Each approach and direction taken in the work forming this thesis were taken to resolve the theory behind observed phenomena in experiments, and to provide a platform for investigating the potential material properties of yet unsynthesised MOFs.

Electrochemical processes suffer from a number of challenges that needs to be overcome for widespread industrial adaptation. The need for an excess amount of inert supporting electrolyte in conventional three electrode set-ups with a single electrolyte medium makes synthetic applications uneconomical in both resource and sustainability aspects, and adds further complexities when the resulting product needs to be purified from the mixture which may also include the electro-catalyst. From an electro-analytical stand-point, altering the sample with the addition of high concentrations of electrolyte salt can have unpredictable chemical effects which may be difficult to account for in the analysis. The following results of the thesis addresses these issues by i) utilising triple-phase boundary systems where the electro-active species are kept in a separate phase from the source of electrons and ions, ii) introducing methods of heterogenising the electro-catalyst from the reaction mixture by immobilising in immiscible oils or polymers of intrinsic microporosity, and iii) offer practical application of such systems through the use of economical and technically unsophisticated methodologies. In the introduction the concept of an Integrated Chemical System is introduced where components with different functions can be synergistically combined and arranged to achieve a more complex output. In the context of electrochemistry, modifying electrodes with materials to add or improve activity, stabilise performance and to substitute more expensive materials, is desirable for enhanced control over the activity of an electrode. The first chapter begins with a general overview of various electrode modification strategies pioneered throughout the last few decades as an introductory narrative for the approach taken in the thesis. Integrated Chemical Systems synthesized and investigated in the thesis are as follows. In chapter 3, electrospun carbon nanofiber based triple-phase boundary systems are utilised for ion-transfer voltammetry across the liquid-liquid interface. Chapter 4 introduces a more conveniently prepared carbon microsphere-polystyrene composite, where the carbon is mechanically held together into a porous structure by an electrically insulating polymer binder. The porous carbon structure is demonstrated to be an effective host for organic oil analysis, under a triple-phase boundary set-up. Chapter 5 is also a study of a carbon-polymer of intrinsic microporosity composite, the polymer functions as a binder as well as a porous host for electrocatalytic guest molecules. Chapters 6 and 7 presents a novel hydrodynamic technique and its use in modulating mass transport in solution, which can be used as a diagnostic tool to study electrode processes at both modified and unmodified electrodes. Chapter 7 demonstrates the method’s utility through a mechanistic analysis of the organic free radical catalyst utilised in chapter 5. It is the hoped that the series of studies presented in the thesis addresses the issues with electrochemical processes at least in part through utilising economic materials and simple methodologies. Whilst the final outcome and devices presented are not fully optimised, they demonstrate a proof-of-principle of the main advantages of employing the modified electrodes. In future, better materials are needed to address the weaknesses of the composites investigated in the thesis to extract the full benefits offered by the electrochemical approach of chemical synthesis and analysis.

Nano-emulsions are a centre of attention for many industrial applications in different fields such as pharmaceutical, cosmetic, food and agriculture due to their interesting physical properties such as transparency, larger surface area to volume ratio and long-term physical stability. This PhD project focuses on the preparation of stable nano-emulsions using different emulsification methods with an attempt to find the optimum formulation to produce stable nano-emulsions for food and healthcare applications. The emulsification methods studied in this project were rotor-stator homogeniser (Ultra-Turrax), Phase Inversion Temperature (PIT), dead-end and cross-flow membrane emulsification methods. The model system soybean oil/water/Brij 97 was used to investigate the emulsification methods. However, in the case of two membrane emulsification methods, it was decided to use Tween series surfactants as Brij 97 didn't work for our experiments. Our study showed that stable nano-emulsions containing 10 % (w/w) oil phase ratio can be produced by Homogeniser, PIT and dead-end membrane emulsification methods with droplet sizes in the range of 9 - 90 nm depending on the employed method, surfactant concentration and various experimental conditions. Cross-flow emulsification method failed to produce stable nano-emulsions in this study. PIT method yielded the smallest drop sizes in the range of 9 – 19 nm and lowest energy consumption (200 - 280 J g-1). However, for producing stable nano-emulsions by this method, the minimum amount of surfactant required were found to be 10.5 % (w/w). Dead-end membrane emulsification was also found to be a promising method for producing stable nano-emulsions with using surfactant concentration as low as 4 % (w/w) in oil, bearing also in mind that Tween series surfactants are more biocompatible than Brij 97. The only drawback for this method is its higher energy consumption than PIT method as Ultra-Turrax was used to prepare the premix. If a more energy efficient method for mixing the emulsion components is employed, this method could be a more suitable option than PIT method for food and healthcare applications. Nevertheless, PIT method could still be considered as the favourable choice when shear sensitive materials are used.

Described herein is research into the production of hydrocarbons suitable for various industrial applications via α-olefin trimerisation. This work has been split into three principal chapters that each describe a different aspect of the research carried out. In addition, a comprehensive review is presented into the development of selective oligomerisation, with an emphasis on the role of metallacyclic intermediates. α-Olefin Trimerisation: Catalyst Synthesis and Optimisation The synthesis and characterisation of eight novel chromium triazacyclohexane catalysts is described, including a series of catalysts containing alternative abstractable anions. All were shown to be active towards trimerisation, with optimisation resulting in exceptional selectivities of over 95 w%, with the remainder consisting of isomerised LAO and dimer. Investigation of the ‘halogen’ effect indicated the inducement of catalyst decomposition via oxidation. Mechanistic Insights into α-Olefin Trimerisation The proposed metallacyclic mechanism was investigated using a variety of techniques. The regioisomers of the trimer were identified down to an abundance of 0.1% with the use of 13C labelling. All matched those expected, allowing the relative abundance of differently substituted intermediates to be determined. 2H labelling identified competition between elimination pathways, which can only occur for metallacyclic intermediates. Characterisation of the catalyst activation products supported the mechanism, while chain transfer reactions were also identified. Air sensitive mass spectrometry led to observation of peaks matching those expected for proposed intermediates. Ethylene Trimerisation: Process Optimisation and Product Identification Optimisation of experimental procedures and increasing the catalyst bulk led to selectivities of 93 w% and activities beyond 250,000 mol(C2H4) mol(Cr)-1 h-1. Kink kinetics resulted in three distinct periods of differing ethylene consumption for which a mechanism has been proposed. Tetramerisation was detected for these systems for the first time alongside several co-trimerisation products. The C10 species were most abundant and have been fully characterised, supporting the proposed co-trimerisation mechanism.

Flavin catalysis has been developed as an environmentally benign route to novel redox chemistry, and the utility of these catalytic systems as simple models of flavoenzyme mechanism has been discussed. A system for oxidising aldehydes to carboxylic acids under flavin catalysis using a Bayer-Villiger type mechanism has been developed, which shows similarities to the enzyme bacterial luciferase. An oxidation of primary amines, using alloxan as co-catalyst and a sulfide as reducing agent, was developed. This was found to work efficiently using air as terminal oxidant, and by extensive mechanistic studies involving EPR spectroscopy, kinetics and UV/visible spectroscopy we propose a radical mechanism. The similarities in some kinetic properties of our system to monoamine oxidase (B isozyme) led us to re-evaluate some previously published pKa dependence data. The catalytic activity of alloxan itself was evaluated, in conjunction with a Cu(I) co-catalyst, and was found to be effective in oxidation of amines, including oxidative cross-coupling, as well as for diimide-like reductions of alkenes and alkynes with hydrazine. Finally, flavin-indole charge transfer chemistry was found to promote selective C3-deuteration of indoles. The CT complex was isolated and found to form a flavin-indole covalent bond under certain conditions. Additionally, we found that in situ DCl generation was a viable method for indole deuteration with very short reaction time and high selectivity compared to previous methods.

The reduction of oxygen in high saline media was investigated using Tafel analysis and platinum microwire electrodes and the effect of high pressures was also explored. Digital simulations coupled with experimental data of current-time transients were used to simultaneously determine the concentration and diffusion coefficients of protons and oxygen in increasing saline media. Glucose oxidation in varying neutral phosphate buffer solutions was explored using platinum microwire electrodes and electrothermal annealing cleaning process; a simple microfuel cell was created which produced 2 nW power in 0.5 M glucose. 3D-printed steel electrodes were modified using platinum to create a highly catalytic electrode for methanol oxidation in acidic electrolyte.

The work described herein involves the exploration of sequential reaction processes involving catalytic C-H functionalisations and Pd-catalysed cross-couplings in both batch and continuous-flow operation, in an effort to improve overall reaction efficiencies.

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