The coordination chemistry of phosphine ligands was pioneered by Mann, Chatt, and others beginning in the 1930s.1 Currently, phosphine compounds are sought as one of the most important classes of L-type ancillary ligands for transition metal complexes, particularly, because of their applications in a wide range of synthetically and catalytically valuable transition metal systems. There have been numerous efforts to understand the stereo-electronic properties of phosphine ligands and the nature of metal–phosphine bonding.2 Despite extensive effort in this field, there is considerably less known about the coordination chemistry of the 12-membered tri-phospha macrocycles due to the difficulty of their synthesis. This thesis describes a detailed study of the chemistry of 1,5,9-trialkyl-1,5,9-triphospha cyclododecane ([12]-ane-P3R3)3 ligands with copper, ruthenium, iron and cobalt metals. Chapter 1, reviews the background chemistry of this research. The radical-initiated coupling of three facially capping allylphosphine ligands on a neutral (CO)3Mo(0) template leads to the tri-secondary macrocycle, [12]-ane-P3H3 which then undergoes a two-step reaction involves deprotonation followed by alkylation. The macrocycle is then liberated from the template by oxidation of Mo, stereospecifically as the syn-syn isomer. The coordination chemistry of 12[ane]P3Et3, with copper(I) halides, is discussed in Chapter 2, including a bimetallic Cu(I) species with a unique mono bridging halide atom. All the complexes have been fully characterized analytically and structurally. Chapter 3 explores the coordination chemistry of triphosphacyclododecane ligands with Fe(0) and Co(0), which led to a range of novel macrocycle complexes, which have been characterised by multinuclear NMR, infrared spectroscopy, mass spectrometry and elemental analysis. Chapter 4 discusses a series of novel bimetallic and monometallic Ruthenium(II) complexes, which were isolated and characterised in the course of reactions with the macrocycle ligands. The catalytic ability of one such complex (4.9) with respect to ring closing metathesis of diethyl diallylmalonate is described. GC-MS data provide insight to support conclusions drawn about the RCM reaction.

This thesis discusses the development and synthesis of ligands for coordination to dand f- block metal ions. The subsequent coordination chemistry to PtII and a range of LnIII metal ions is outlined, along with the photophysical properties of the resultant compounds towards bimodal imaging agents and probes for diagnostic and therapeutic applications. Chapter 2 presents the synthesis and characterisation of a range of PtII complexes using functionalised 2-phenylquinoline ligands. A range of products were synthesised by utilising a variety of ancillary ligands, including β-diketones, 8-hydroxyquinoline, 2,2′-bipyridine and pyridine, in order to investigate any effects on the photophysical properties. X-ray crystallography confirmed the anticipated structures of several compounds whilst 195Pt NMR was employed to probe the metal environment in the different complexes. Chapter 3 builds on the investigations in the previous chapter by altering the functionality of the 2-phenylquinoline ligand in order to tune the solubility. The second part of Chapter 3 exploits the facile coordination of pyridine, as found in Chapter 2, by introducing pendant pyridine-appended macrocycles encapsulating LnIII ions. This provided bimetallic complexes with good water solubility, which allowed relaxivity measurements to be carried out. Photophysical measurements also gave evidence of direct sensitisation of the LnIII ion by PtII based 3MLCT emission. Chapter 4 extends the 2-phenylquinoline functionality to incorporate naphthyl, anthracenyl and pyrenyl chromophores with suitable solubility in common organic solvents. The complexes were investigated to determine whether it was possible to observe interactions between the excited state of the chromophore and the metalcentred excited state. Low temperature and degassed steady state luminescence and lifetime measurements were obtained in order to build energy level diagrams to explain the interplay of excited states. Chapter 5 discusses the development of anthraquinone-based polypyridyl ligand scaffolds for the incorporation of LnIII ions. The ligands possess subtle differences that result in changes in the coordination sphere of the LnIII ion. This was confirmed by determining the inner-sphere hydration of the LnIII ions through observing the luminescence properties of the complexes.

Gold catalysts have been found to be efficient for many oxidation reactions. The performance of these catalysts depends strongly on the particle size of the Au nanoparticles. However, other factors also have a strong influence on the catalytic activity such as the preparation method and choice of support. The effect of support and the preparation methods has been investigated with regard to the selectivity and the activity of Au catalysts. The disproportionation of benzyl alcohol has been identified as a source of toluene formation in the solvent free oxidation of benzyl alcohol using supported gold palladium catalysts. The disproportionation reaction of benzyl alcohol oxidation has been performed in a conventional glass stirred reactor. Oxidation and disproportionation reactions respond slightly differently to the changes in reaction parameters, such as oxygen concentration and pressure. When MgO supported gold-palladium catalysts were used for this reaction, the toluene selectivity reduced substantially at the cost of conversion. The synthesis of bimetallic nanoalloys is of great practical importance as they exhibit size-dependent functional properties, which can be exploited in fields such as catalysis. Conventional chemical impregnation routes for generating supported bimetallic nanoparticles are facile, but often generate materials having broad particle size distributions, which typically exhibit core–shell morphologies and significant compositional variations from particle-to-particle. More complex sol-immobilisation synthesis techniques offer much better control over particle size distribution, but retain stabilising ligands on the surface, which can be deleterious for catalysis. Here, a convenient excess anion modification and post reduction step prior to the impregnation method has been used, which permits the reproducible preparation of supported bimetallic AuPd nanoparticles with a tight particle size distribution comparable to that found for sol-immobilisation materials, but without the complication of ligands adsorbed on the particle surface. These advantageous features of the modified impregnation materials resulting in higher activity and stability compared to the catalysts prepared using both conventional impregnation and sol-immobilisation methods. Detailed STEM combined with EDX analyses of individual particles have revealed that an increase in anion concentration increases the gold content of individual particles in the resultant catalyst, thus providing a method for controlling/tuning the composition of the nanoalloy particles. The improved activity and stability characteristics of these new catalysts are demonstrated using: (i) the solvent-free aerobic oxidation of benzyl alcohol and (ii) the direct synthesis of hydrogen peroxide as case studies. The study has examined using this modified impregnation catalyst in different Au:Pd ratios for the solvent-free aerobic oxidation of benzyl alcohol. These modified impregnation catalysts have been found to be exceptionally active, mainly with a Aurich composition, when compared to reduced conventional impregnation catalysts. Moreover, these modified impregnation catalysts have been found to be exceptionally active and stable when evaluated for crotyl alcohol in mild conditions when compared to sol-immobilisation methods. This new preparation protocol could be beneficial for both the academic research community and the industrial community, with a very convenient and reproducible methodology for preparing supported Au-Pd nanoalloy catalysts with high activity and stability, without using any ligands or stabilisers, while not compromising their catalytic activity.

The effect of light on plants is fundamental to our understanding of the biological world. Photo-activated processes within botanical cells are controlled by two distinct colours; red light provides the energy required for photosynthesis, and blue light stimulates responses of the cell (growth, stomatal opening, etc.) necessary for biological progression. The key step in blue-light controlled processes has recently been determined to be the formation of a covalent bond between a tightly-bound molecule of flavin and a conserved cysteine residue within a photosensitive protein domain, which causes a physical change to the protein structure upon irradiation. This research was undertaken to examine light-stimulated covalent bond formation in phototropic proteins using two approaches. Firstly, two analogues of riboflavin (5-deazariboflavin and 1-deazariboflavin) were chemically synthesised, converted to the appropriate cofactor form (flavin mononucleotide; FMN), and incorporated into the photosensitive domain. The results of this were startling; while 1-deazaFMN inactivated the photosensitive domain to all wavelengths of light, 5-deazaFMN allowed control of the domain’s behaviour using two separate wavelengths of light, creating a biophotonic nanoswitch. The second approach was based upon mutagenesis of the amino acid responsible for bond formation, introducing several alternative residues in place of the reactive cysteine. All mutants were found to be inactive to irradiation (including those incorporating either of the deazaFMN analogues), providing further evidence to support the current “radical pair” mechanism of photoadduct formation. During the synthesis of the flavin analogues, several reactions were found to be inefficient, and a large number of alternative reactions were studied. Additionally, a new route to several flavin analogues was devised and tested, and while unsuccessful, provides a foundation upon which to base a future examination of their synthesis. Finally, the synthesis of a novel riboflavin analogue (5-deaza-8-demethyl-riboflavin) was completed, allowing comparison with the synthesis of 5-deazariboflavin.

This thesis extends investigations into renewable amines for photochemical CO2 reduction by the Carpenter group. This work is motivated by a desire to provide solutions for green energy production. Modifications to the tricyclic amine, 20, were studied computationally using DFT calculations. These studies suggest that there are no simple modifications to this class of amines that will offer significantly improved properties for CO2 reduction. A second class of amines is then proposed in which radical stabilization groups can be introduced to promote the desired photochemistry. From this class of amines the phenyl derivative, 34, was identified as the best candidate. Rate calculations predict that distonic radical cation formation will not present a bottleneck in the reaction scheme. A synthesis of this class of amines is proposed and supporting DFT calculations indicate that it is a viable synthesis. Using the leads from computational studies synthetic work was undertaken to find a synthetic route to amines, 14+ 66. The routes developed are capable of producing the desired amines but need to be optimized for full_scale photochemical studies. The final chapter presents a tool named Quantum Chemistry Interface that is designed mainly as a teaching tool for computational chemistry. It facilitates rapid generation of libraries of substituted molecules. It also understands a simple language for describing reaction steps to automate calculations of reaction thermodynamic parameters. Its utility is shown with a small project with an undergraduate student.

The nuclear fuel cycle represents the nuclear power generation process, from mining the uranium ore to the treatment of waste. The fuel cycle is divided into two parts, the front end of the process and the back end of the process, with the nuclear power station being in the middle1. The processes before reaching the nuclear power station consist of uranium exploration, mining, refining, isotope enriching and fuel element fabrication1. Uranium is mined in twenty countries, but 52% of the world supply of uranium comes from just 6 countries. These countries are Canada, Australia, Russia, Kazakhstan, Namibia and Niger. Uranium is mined in several different types of mine. These include an open pit mine, an underground mine or in-situ leaching mine. In an open pit mine the ore lies close to the surface and the overlying layer of rock is removed creating a large pit where the ore is easily extractable. An underground mine is used when the ore lies deeper under the surface and the construction of access shafts and tunnels under the ground are needed to gain access to the uranium ore. The uranium ore is sometimes contained in ground water or a porous material, such as sand. In this case, a process called in-situ leaching is used to extract the uranium ore. Either acid or alkali (depending on the nature of the groundwater) is added to the ground water to dissolve the ore, and the resulting solution is pumped out. The ore then undergoes a milling process to extract the uranium oxides needed for fuel fabrication. Milling is normally carried out close to the mine where the ore has been extracted. The ore is crushed and then leached with sulphuric acid in order to dissolve the uranium oxides.

Syntheses, spectroscopic and microporosity analysis of novel phthalocyanines and porphyrin containing molecules and polymers were carried out. For this purpose, various bulky substituents were introduced on to the aromatic core in order to provide an awkward shape and hence avoid co-facial aggregation and efficient packing. Firstly, novel phthalocyanines containing dioxy-di-tert-butyl-dimethyltriptycene substituents were synthesised. UV-vis absorption spectra of these Pcs showed band broadening depending on concentration and solvent suggesting aggregation; although this aggregation was not found to be as significant as that of various phthalocyanines reported in the literature. Apparent BET surface areas of these materials were found to be in the range of 400 to 500 m2 g-1. For comparison, the spectroscopic behaviour of the related, literature based octa-tert-butyltetra-2,3-triptycenotetraazaporphyrins were examined which form discrete co-facial dimers in pentane solution. It was found that this high specific dimerisation can be prevented by introducing methyl substituents onto the bridgehead positions of the triptycene subunits. A third category of compounds, tetratriptycenoporphyrins were synthesised using the commercially available tetrakis(pentafluorophenyl)porphyrin precursor and dihydroxy-di-tert-butyl-dimethyltriptycene. UV-vis absorption and luminescence measurements showed these complexes to be non-aggregating and were found to be microporous with BET surface areas ranging from 450 to 600 m2 g-1. The synthesis and analysis of novel phthalocyanine and porphyrin based network polymers prepared via cyclotetramerisation of bis or tris phthalonitrile containing substituents of contortion (spirobisindane, ethanoanthracene and triptycene) or via nucleophilic aromatic substitution reaction starting from a preformed phthalocyanine or porphyrin precursor, was performed. UV-vis absorption measurements of these polymers proved difficult due to solubility issues, however nitrogen adsorption analysis revealed BET surface areas ranging from 300 to 1000 m2 g-1.

This thesis describes the use of both sulfuric acid and triflic acid, to promote hydroamination and hydroalkoxylation cyclisations for the formation of N- and Oheterocycles. Chapter 2 describes the synthesis of 2,2,6-trisubstetuted piperidine. A wide range of protecting groups has been employed in the cyclisation. A new, general and flexible method for the highly enantioselective synthesis of chiral piperidine and spiropiperidine has been developed. The main advantages of this synthetic method lie in the readily availability of the precursors. There is no reason why this reaction cannot find further application in natural product synthesis. Chapter 3 describes a miscellany of cascade and transannular cyclizations. The hydroamination has also been used to form the sterically crowded bridged isoquinuclidines through a transannular cyclisation, which would have rearranged to the less hindered products. We have also applied acid-catalyzed intramolecular cascade methodology to the synthesis of polycyclic hydroquinolines. Oxygen-centered transannular cyclisation has been compared with nitrogen-based examples, by acid-catalyzed hydroalkoxylation cyclisation to give only the sterically crowded bridged cineoles. Chapter 4 describes a new discovery of a novel N-to-O transfer reaction.

This thesis describes the synthesis and characterisation of a series of new azamacrocyclic ligands (L1-L3, L1O, L11, L14, L16-Ll9), which have been N-functionalised with pendant pyridylmethyl- (pyCH2-), bipyridylmethyl(bipyCH2-) and terpyridylmethyl- (terpyCH2-) arms. Some of the coordination chemistry of these ligands with transition metal ions is reported. A sexidentate tris(2,2'-bipyridyl) chelating ligand, 1,4, 7-tris(2,2'-bipyridyl-5'-ylmethyl)-1,4,7-triazacyclononane (Ll) has been developed, and the crystal structures of the mononuclear complexes [M(L1H)]3+ (M = Ru, Cu) are reported. In [M(L1H)]3+, the azamacrocyclic nitrogen atoms are non-coordinating to M, but have a high affinity for a single proton trapped in the macrocyclic cavity. An analogous nonadentate ligand (Ll7) has been developed based on 9N3 with three N-pendant terpyCH2- arms, and complexes of Ll7 with Eu(III) and La(III) are reported. The complex [Eu(L17H)](PF6)4 is found to be strongly fluorescent in acetonitrile and methanol/water solution. Ligands with potential use as fluorescent pH and transition metal ion sensors have been developed by reacting the azamacrocyclic N-pendant bipyCH2 arms of LLL3, LlO and Lll with cis-[Ru(bipYnCI2] to give macrocycles with up to four attached [Ru(bipY)3]2+ groups (LS-L7, L12, L13).

The bromination of alkene/epoxide mixtures leads to the fonnation of B,B'-dibromoethers (BrCR2CR20CR2CR2Br) [R=H,Me] and dibromoalkanes. The amount of B,B' -dibromoether fonned was optimised relative to the amount of dibromoalkane fonned by carrying jout the reaction in pentane at -78°C. The reaction is believed to proceed via a three step mechanism, two steps of which (the opening of bromonium ion by epoxide, and the opening of oxonium ion by Br) have been shown to occur stereospecifically. (Cinnamaldehydeanil)/tricarbonyliron(O) (4), (PhCHCHCHNPh)Fe(COh, a representative (l-azadiene )tricarbonyliron(O) complex can be prepared in 41 % yield by heating cinnamaldehydeanil (5) (PhCHCHCHNPh) with Fez(CO)9 (17). This yield could be improved to 82% by the use of ultrasound, or to 80% via a transfer reaction from a (l-oxadiene)tricarbonyliron(O) complex. l-Azadiene complexes could themselves be used as a source of -Fe(COh for a transfer reaction to butadiene ligands, the first reported use of (azadiene)tricarbonyliron(O) complexes in this way. (l-Azadiene)tricarbonyliron(O) was found to be unreactive with respect to Diels-Alder reactions. (2-Azadiene)tricarbonyliron(O) complexes (109) have never been reported. A series of 2-azadiene ligands (ArCHNCHCHCH3) [Ar = Ph- (114); Ar = 4-CIC6H4- (116); Ar = 4-MeOC6H4- (115)] were prepared, but complexation with Fe2(CO)9 (17) or Fe(CO)s (26) did not produce a tricarbonyliron(O) complex. Complexation of (115) with Fe2(CO)9 (17), however, produced a Fe2(CO)6 containing compound (118) [(4-MeO-C6H3-CH2NCHCHCH3)-Fe2(CO)6] in 10% yield.