The fabrication of complex colloidal particles with anisotropic "patchy" e.g. Januslike, morphology will be studied. Known approaches towards "Janus particles" focus mostly on the micron-sized domain, with common fabrication routes based on monolayer modification or microfluidic production (restricts scale-up). We operate in the submicron regime (typically 100-500 nm) and use scalable emulsion polymerization strategies, in combination with entropic phase separation of swollen cross-linked latex particles and living radical polymerization, i.e. SET-LRP, to prepare our "patchy" amphiphilic particles. In this research, various Cross-linked densities (typically from 1 - 8wt%) poly(styrene) latexes (typically 100-500 nm) functionalized with tert-bromine functional groups, by batch or shot addition of (2-methacryloxyethyl -2- bromoisobutyrate) made via soap-free emulsion polymerization used as the precursor particles. Two synthetic pathways were investigated to make the targeted hairy Janus Particles. Approach one: in which we carried out the domain formation step prior to the fabrication of the polymer brushes, We found out that the effective synthetic way to make Janus hairy dumbbell particles in a reproducible manner is to start the synthesis with light cross-linked density of (1.9 to 3.0 wt% DVB) precursor poly(styrene) latex particles (150-250 nm diameter) made by shot addition method. The direct entropic phase separation from these latex particles leads to the formation of only one new domain with dumbbell shape morphology, when the swelling ratio used between monomer and latex is between 2.0 and 4.0, and with low DVB concentration in the swelling monomer (between 0.15-1.0wt%) using AIBN as initiator. Formation of hydrophilic polymer brushes by SET-LRP resulted in targeted hairy Janus particles with sub-micrometer diameter, in a reproducible manner. The length of the polymer brushes can be controlled by addition of water soluble ATRP initiator to produce shorter polymer brushes. The rate of SET-LRP was ultrafast and the rate can be reduced by addition of deactivator CuBr2. The second approach: water-soluble polymer brushes were grafted onto the surface of latex particles by SET-LRP. These “hairy” cross-linked colloids were swollen with additional monomers and initiator. Elevation of temperature causes entropic phase separation inducing new domains, which were polymerized. This approach leads to mainly popcorn and raspberry particles with some limited cases that are able to make hairy Janus Particles with non reproducible manner. The obtained complex particles show some interesting application such as a stabilization agent for Carbon Nanotubes (CNTs) in aqueous medium, Pickering emulsion stabilizer, and they self assembled upon addition of dilute electrolyte solution.

The work presented in this thesis is concerned with the growth and characterisation of III-NSb films by plasma-assisted molecular beam epitaxy (PA-MBE). The research was motivated by their application in technologically important regions of the IR spectrum. Homoepitaxial growth of GaSb films was conducted and characterised as a function of V:III ratio and growth temperature, permitting observation of morphology changes with growth conditions, also providing insight into surfaces of the ternary dilute nitride. Heteroepitaxial GaSb/GaAs growth has highlighted defect formation and propagation arising from lattice mismatched deposition. Films of GaNxSb1-x, a material of interest for device applications in the 2-5 μm spectral range, have been grown on GaSb(001) substrates. The results demonstrate the degree to which substitutional N content may be controlled through variation of the temperature and rate of deposition. Models based upon kinetic and thermodynamic principles and previously applied to GaNxAs1-x have been evaluated for N content of GaNxSb1-x films as a function of the rate and temperature used for growth. The growth of InNxSb1-x, an alloy of significance in the technologically important wavelength region of 8-12 μm, upon InSb(001) substrates is described. There is qualitative agreement with the temperature dependence of N content. Analysis of the substitutional N content as a function of growth rate, however, suggests a difference between GaNxSb1-x and GaNxAs1-x. An explanation is presented for the trend in the level of substitutional N uptake across III-V-N materials. Further experiments are proposed to extend the parameter space sampled in the investigation of GaNxSb1-x and InNxSb1-x films, with regard to the Sb:III ratio employed during growth. Initial results are reported from measurements undertaken with a pyrometer operating at 1.6 μm, suggesting that growth can be conducted at lower temperatures. Additional preliminary results are presented for the growth of GaxIn1-xNySb1-y films, demonstrating a tuneable band gap quaternary material, lattice matched to GaSb is possible.

12 azo dye ligands LI-LI2 that are used in the inkjet printer industry have been synthesised and characterised. The dyes L5B and L3765 were supplied as gifts by the chemical company Avecia. All dyes were fully examined by IH NMR, 13e NMR, IR spectroscopy, electrospray mass spectroscopy, atomic absorption spectroscopy, UV-Visible spectroscopy and microanalyses. Melting points were also determined. pKa values have been determined by visible spectroscopy for the dyes PAN(Aldrich), L7, L3765, Ll, L5 and L5B. Stability constant measurements have been attempted for the Ni(II) complexes of PAN, LI and L5 using UV-Visible spectroscopy. Single wavelength stopped-flow kinetic studies of the reactions of Ni(II) with PAN(Aldrich), PADA(Aldrich), SUDAN I(Aldrich), L3765 and L7 were carried out. Multi wavelength stopped-flow kinetic studies of the reactions of Ni(II) with L 1, L 7, L5 and L5B were examined and rate constants for complex formation (kf ) were determined. Rates of dissociation of [Ni(PAN)2] using ligand exchange with either EDTA or 2,2' :6' ,2" -Terpyridine (Terpy) were investigated using UV -Visible spectroscopy. Relative stabilities of [Ni(II)(PAN)t, [Ni(II)(L 7)] and [Ni(II)(L3765)r have been determined. Dissociation of Ni(II) complexes of Ll, L5, L5B, L6, PAN, L7 and L3765 using excess Terpy have been studied using UV -Visible spectroscopy and relative stabilities have been compared.

A novel time-resolved velocity map ion imaging (TR-VMI) experiment has been constructed and successfully applied to the study of non-statistical dissociation processes. The photodissociation of NH3 following the population of the ν2 ’ = 4 umbrella vibrational mode of the first electronically excited, Ã1A2”, singlet state, was initially studied. It was clearly observed that the N-H dissociation timescale was inversely proportional to kinetic energy released to the H fragment. Assignment of different kinetic energy regions of the TR-VMI transients to corresponding bending vibrational modes (ν2) of the X2B1 state NH2 photoproduct clearly suggests that dissociation into the vibrationless NH2 occurs in < 50 fs. Low kinetic energy channels, show extended dissociation timescales, strongly indicative of adiabatic dissociation to the first electronically excited state of NH2 (Ã2A1). With an aim of modelling the photodissociation dynamics of adenine, the photodissociation of pyrrole, imidazole, 2-methylimidazole, 4-methylimidazole and 2,4-dimethylimidazole following excitation at 200 nm were studied using time-resolved mass spectrometry (TR-MS) and VMI. In all cases ultrafast H elimination was observed in < 130 fs, consistent with direct dissociation via the repulsive 1πσ* potential energy surfaces. The photodissociation of 1- methyimidazole at this wavelength was also studied. Once again ultrafast H elimination was observed, but with greatly reduced yields, strongly suggesting H elimination from the non-heteroatom co-ordinates (C-H) also partaking in the photodissociation dynamics at this wavelength. TR-MS and VMI have also been applied to the study of the photodissociation of adenine, 9-methyladenine and 6-dimethylaminopurine. In all measured kinetic energy spectra a high kinetic energy channel has been observed, strongly suggesting the participation of 1πσ* potential energy surfaces of both the azole and amino co-ordinates in H elimination following excitation at 200 nm. Power dependence studies at 266 nm suggest H elimination, but subsequent TR-MS measurements seem to suggest that this is not due to the participation of the 1πσ* potential energy surfaces at this excitation wavelength.

The H-atom detachment driven through the 1πσ* states of biological chromophores containing an X-H bond (where X = N or O) upon UV absorption is ubiquitous in nature. Understanding the role of this dissociative state in the chromophores and their respective amino acids following UV excitation would enable a step change towards establishing a better understanding of the mechanisms of photostability of larger peptides in the gas-phase. The work presented in this thesis focuses on the H-atom elimination of phenol and indole, the chromophores of the amino acids tyrosine and tryptophan, respectively. The H-atom elimination has also been carried out in tyrosine and its sub-units p-ethylphenol and tyramine upon excitation at 200 nm. In all these systems the O-H bond fission on the phenol ring results in a range of H-atoms kinetic energy release. Using a combination of femtosecond pump-probe spectroscopy, time-offlight mass spectroscopy (TOF-MS) and velocity map ion imaging (VMI) reveals that H-atom elimination in all these systems occurs on an ultrafast timescale (~200 fs) for both fast and slow H-atoms. This casts considerable doubt over the previously assigned statistical origin of the slow H-atoms and suggests direct pathways to their formation. The H-atom kinetic energy spectrum in tyrosine also implies that H-atom elimination is occurring through the same coordinate i.e. O-H bond as exhibited by it’s phenol chromophore, thus confirming the active participation of the 1πσ* states from the chromophore of the amino acid to the amino acid itself. These findings are of great importance enabling one to compare these results with existing calculations on the chromophores which often model the system in an isolated environment. These results also provide ground work for more complex calculation to be carried out, in particular on the amino acids and the di/tri peptides.

The synthesis and characterisation of RuII complexes of the form [(η6-arene)Ru(N,N')X]+ (where N,N' is a bidentate chelating ligand and X is a halogen) are described; including the X-ray crystal structures of four of these complexes. The hydrolysis rates at 310 K of the complexes vary over many orders of magnitude and in some cases are followed by partial arene loss. Density Functional Theory (DFT) calculations suggest that the aquation mechanism occurs via a more associative pathway. The significant cytotoxic activity towards A2780 human ovarian cancer cells of some of the complexes is found to be dependent on the chelating ligand. Selective binding to 9-ethylguanine (9-EtG) but not to 9- ethyladenine (9-EtA) is observed in aqueous solution at 310 K in all cases. The X-ray crystal structure of a RuII arene 9-EtG adduct is also described. DFT calculations show that the 9- EtG nucleobase adducts of all complexes are thermodynamically preferred compared to those of 9-EtA. Preliminary CT-DNA studies in cell-free media suggest that some of these complexes can interact with DNA. A family of piano-stool RuII arene complexes of the form [(η6-arene)Ru(N,N')(L)]2+ (where N,N' is a chelating ligand and L is a pyridine or a pyridine-derivative), that can selectively photodissociate the monodentate ligand (L) when excited with UVA or visible light is described. The X-ray crystal structures of five of these complexes are also discussed. Their photoactivation allows the formation of a reactive aqua species that otherwise would not form in the dark. Results from TD-DFT calculations suggest that all the RuII pyridine complexes follow a relatively similar L-ligand photodissociation mechanism, likely to occur from a series of 3MC triplet states. It is shown how light activation can be used to phototrigger binding of these complexes to nucleobases with specific preference towards 9- EtG over 9-EtA. CT-DNA studies suggest that photoirradiated complexes interact with DNA via a combined coordinative, intercalative, and monofunctional binding mode. Some of the complexes are also cytotoxic against A2780 human ovarian cancer cell line in the absence of irradiation. The possibility of photo(triggering) hydride-transfer reactions using RuII arene complexes, NAD+, and formate as the hydride source under biologically relevant conditions is shown. The reactions occur either upon the spontaneous hydrolysis of a Ru–Cl bond in complexes of the form [(η6-arene)Ru(N,N')Cl]+ (where N,N' is a bidentate chelating ligand) or upon the photolysis of a Ru–N(Py) bond in [(η6-arene)Ru(N,N')Py]2+ (Py is pyridine). A mechanism involving the formation of a stable formate adduct followed by a hydrogen β- elimination is proposed. It is also demonstrated how a hydride-transfer from 1,4-NADH to some RuII arene chlorido complexes can occur in aqueous solution. Neutral RuII arene complexes of the form [(η6-arene)Ru(NH3)Cl2] which are constitutional analogues of cisplatin were synthesised by a novel synthetic method. These analogues display extensive H-bond interactions in the solid state as shown by X-ray crystal structures determination and their biexponential hydrolysis rates at 310 K vary over many orders of magnitude. The complexes are found to readily form mono- and di-guanine adducts upon hydrolysis but are not cytotoxic against the A2780 human ovarian cancer cell line up to the maximum concentration tested (100 μM).

This thesis deals with the reactions of two high-valent metal complexes. [UO2]2+ and [W(CN)8]3- in their excited states in which their one-electron reduction potentials are increased greatly, i.e. sufficiently for them to remove an electron from water. The studies with uranyl ion cover the following, (i) the ground state interaction with some simple amino acids, (ii) the excited-state interaction with a variety of amino acids including some containing sulphur, which gave results of particular interest and, in following up the latter, (iii) the excited state interaction with some simple organosulphur compounds. These three inter-related topics form Chapters 8, 9 and 10 of this thesis. In more detail, in Chapter 8 we characterise optically, three new complexes of 1:4 stoichiometry between [UO2]2+ and glycine and α- and β-alanine in acidic aqueous solution. The x-ray crystal structure of the glycine complex confirms it as tetrakis (glycine) dioxouranium (VI) nitrate. Chapter 9 covers the kinetics of luminescence quenching of *[U02]2+ by amino acids (indicating the level of reactivity) and the quant yields of [U(IV)] which indicate the degree of charge separation from the initial radical-pair configuration, while cryogenic ESR data reveal the nature of the primary ligand-derived radical. Interestingly we find that while much the greatest kinetic reactivity towards *[UO2]2+ is shown by the sulphur-containing amino acids, these show very low yields for [U(IV)] production. This pattern is repeated in our study of the photo-oxidation of dialkyl sulphides by excited uranyl ion, in which we believe to have demonstrated that a. recent report of high quantum yields in this system and published in Inorganic Chemistry is erroneous. Our brief study of the aqueous [W(CN)8]3- system confirms the quantum yields for [W(CN)8]4- of Samotus et al., as opposed to the earlier data of Balzani and Carassiti and characterises, using ESR, IR and UV-vis spectroscopy, new W(V)-cyanide 4 complexes obtained during irradiation into the C-T bands of [W(CN)8]4- and [W(CN)8]3- in aqueous solution. Three publications have resulted hitherto from the above work in the following journals: Chapter 8: J. Chem. Soc., Dalton Trans., 1985, 517. Chapter 9:, Inorgý Chim. Acta, 1986, 114, 215. Chapter 10: Inorg. Chem., 1986, 21, 3840. The results from the final chapter together with data from the photoreduction of [W(CN)8]3- 81 with many organic systems obtained by Dr. D. Rehorek during his visit to the Department, have been compiled and submitted for publication to the Journal of the Chemistry Society, Dalton Transactions (paper 6/2444).

Chapter One gives an overview of molecule-based magnetic materials, and a summary of topics of current interest in this field such as spin crossover (SCO), molecule-based magnets (particularly three room temperature metallo-organic magnets), Metallo-organic frameworks (MOFs), free radical magnets and single molecule magnets (SMMs). There is a brief introduction of key examples and developments in the specific topics, and a perspective at the end. Chapter Two introduces a family of optically pure Fe(II) polymeric chain complexes of formula {FeL2(μ-pz)}∞ and {FeL2(μ-bpy)}∞. [L = bidentate Schiff base ligands obtained from (R)-(+)-α-phenylethanamine and 4-substituted salicylaldehydes]. The structural and magnetic properties of the polymeric products are determined by single crystal X-ray diffraction and SQUID magnetometry. By fitting magnetic data of these complexes with the Bonner- Fisher 1-D chain model, the magnitudes of their magnetic exchanges are rationalised on the basis of substituent electronic properties and bridging ligand identity. Chapter Three describes two Fe(II) coordination polymers containing pyridineconjugated Schiff base isomer ligands. The isomerism of the two ligands leads to a change from trans to cis coordination in the [FeL2] SBU and thus from a tetrahedral diamond-like 3 D network exhibiting a gradual SCO to a 2 D hard magnet. Furthermore, we have also sythesised another four Cu(II) complexes based on these two ligands. Crystallographic studies reveal their structures ranging from 1 D zigzag chains and 2 D mat while their magnetic properties are transformed from ferro- to ferrimagnetic behavior. Chapter Four focuses on three pyrrole-2-ketone bidentate ligands. Three transition metal ions Mn2+, Fe2+ and Co2+ were studied, based on which twelve complexes have been made. The system is structurally diverse, with 1 D, 2 D, monometallic, trimetallic “sandwich” structures and a high nuclearity cluster being observed depending on the use of cations and solvents. Unusual magnetic phenomena are discovered, including a system in which SCO and ferromagnetic coupling are present. Chapter Five details the experimental procedures used to carry out the work in this thesis.

By asymmetric transfer hydrogenation, substituted quinolines, which are generally regarded as challenging substrates for reduction, were successfully converted into tetrahydroquinolines using "tethered" Ru(II) and "tethered" Rh(III) complexes in formic acid/triethylamine. An ether-linked "tethered" catalyst was successfully synthesized through a sequence that avoids the use of a Birch reduction for the formation of a 1,4-cyclohexadiene moiety. The ether link is incorporated between the basic amine of the ligand and the η6- arene ring, giving results comparable to the alkyl-"tethered" complexes. N-alkylated complexes containing a straight-chain substituent attached to a hydroxyl, ether or ester function can act as effective catalysts for the reduction of ketones, and also contains the required functionality for attachment of the catalyst to a heterogeneous support.

Clay platelets and silica nanoparticles are used as Pickering stabilizers in the fabrication of hybrid armored polymer particles through a Pickering emulsion polymerization process. A variety of hydrophobic comonomers (i.e., styrene-co- (n-butyl acrylate) (Sty:BA), methyl methacrylate-co-(n-butyl acrylate) (MMA:BA)), styrene-co-(2-ethyl hexyl acrylate) (Sty:2-EHA), vinyl acetate (VAc) and vinyl pivalate (VPiv) are used as organic film forming components. Polymerization kinetics and particle size distributions were examined as a function of monomer conversion. Additionally, key mechanistic features of the polymerization process by quantitatively analyzing the concentration of silica nanoparticles in the water phase during monomer conversion by disc centrifugation are unraveled. It is also showed the crucial role of Laponite clay discs in the particle formation (nucleation) of the Pickering emulsion polymerization process. Increasing amounts of clay nanodiscs leads to smaller average particles sizes, but broader particle size distributions. Polymer films of poly(styrene-co-n-butyl acrylate) armored with Laponite clay were studied as a function of clay amount. Improvements in mechanical, thermal and surface topography provided by clay platelets are reported. In addition, advantages are shown in use of hybrid polymer particles in comparison with simple blend mixtures of polymer particles plus inorganic particles. Humidity properties of poly(styrene-co-n-butyl acrylate) films as a function of clay content are investigated. It is demonstrated that the presence of Laponite clay improves the water storage capacity of polymer films. Also water barrier properties are improved when clay platelets are applied. Finally, a versatile two step Pickering emulsion polymerization for the fabrication of core-shell particles armored with Laponite clay XLS is developed. The obtained particles contain a "hard" core and a "soft" shell armored with clay. The different in the refractive indexes between the core and shell makes these core-shell particles interesting for possible use as colloidal crystals.