The B3LYP density functional has been used to calculate properties of organometallic complexes of Co(CO)3 and ReBr(CO)3, with the chelating ligand 2,3-bisphosphinomaleic anhydride, in 19- and 18-electron forms. The SBKJC-21G effective core potential and associated basis set was used for metals (Co/Re) and the 6-31G* basis set was used for all other elements. The differences of bond angles, bond distances, natural atomic charges and IR vibrational frequencies were compared with the available experimental parameters. The differences between the 19- and 18-electron systems have been analyzed. The results reveal that the 19th electron is mostly distributed over the ligand of 2,3-bisphosphinomaleic anhydride, although partially localized onto the metal fragment in 1 and 2*. Two different methods, IR-frequencies and natural atomic charges, were used to determine the value of δ. Present computed values of δ are compared with available experimental values, and predictions are made for unknown complexes.

A series of alkyldithiolatodiironhexacarbonyl complexes of the form &mu:-(RS2)Fe2(CO)6, where RS2 is: 1,2-ethanedithiolate (eth-cat), cis-1,2-cyclopentanedithiolate (pent-cat), cis-1,2-cyclohexanedithiolate (hex-cat), and 2-exo,3-exo-bicyclo[2.2.1]heptanedithiolate (norbor-cat), are reported. These complexes display structures and catalytic behavior toward production of molecular hydrogen with similarities to the active site of the diiron hydrogenase enzymes. Hydrogen production is desirable as an alternative fuel source and these catalysts are capable of producing H2 in the presence of weak acid under electrochemical conditions. Through understanding of the factors which control the catalytic activity of these catalysts it may be possible to contribute to the development of a hydrogen fuel economy.Significant scan-rate dependence under electrochemical conditions is observed, resulting in an initial 1-to-2 electron reduction depending on how quickly the singly reduced species can reorganize. The rate of this reorganization directly corresponds to the internal strain within the system and can be ranked in the following order of increasing rate of reorganization: pent-cat < norbor-cat < eth-cat < hex-cat. Additionally, these catalysts all successfully catalyze protons to molecular hydrogen under electrochemical conditions in the presence of acetic acid via an ECEC catalytic mechanism, where, E is an electrochemical step (reduction) and C is a chemical step (protonation).Density functional theory computations support the reported catalytic processes by calculating physically observable quantities, such as: pKa values, reduction potentials, adiabatic ionization energies and carbonyl stretching frequencies in the infrared (IR) region. These quantities were used to suggest reasonable reactive intermediates within the catalytic cycle. The electronic structure of each catalyst was examined using photoelectron spectroscopy and the global minimum cationic structure, in all cases, involves a structure with a bridging carbonyl ligand, akin to that of the enzyme active site.The most significant outcome of this work is the unprecedented diiron center rotation upon reduction. As conformational strain involving the dithiolate ligand increases, the rate of reorganization of the anion increases leading to cleavage of an iron-sulfur bond to provide an alternative protonation site, a key step toward molecular hydrogen formation. This site is less basic than the unrotated form and helps evolve H2 with thermodynamic favorability.

The planar-chiral C2-symmetrical dibromoferrocene derivatives, (S,S,Sp,Sp)-1,1'-dibromo-2,2'-di(2-butyl)ferrocene (88) and (S,S,Sp,Sp)-1,1'-dibromo-2,2'-bis{2-[1-(trimethylsilyl)propyl]} ferrocene (92), were synthesized using the well-established “Ugi’s amine” chemistry. The steric influences of the alkyl groups on ferrocenes 88 and 92 in salt-metathesis reactions were investigated. The reaction of 88 and 92 with iPr2NBCl2 yielded mixtures of bora[1]ferrocenophanes (bora[1]FCPs) 94 and 99 and 1,1'-bis(boryl)ferrocenes 95 and 100 respectively. Ferrocene 92 was expected to yield the highest product ratio of bora[1]FCPs to 1,1' bis(boryl)ferrocenes due to the significant amount of steric bulk on ferrocene from the alkyl groups; however, the product ratio was less than the product ratio obtained for the less bulky ferrocene 88. The product ratios for 88 and 92 were compared to the known product ratios for (Sp,Sp)-1,1'-dibromo-2,2'-di(isopropyl)ferrocene (78) and (Sp,Sp)-1,1'-dibromo-2,2'-di(3-pentyl)ferrocene (79) to determine the effects of the alkyl groups in salt-metathesis reactions. To gain more insight into the effects of the alkyl groups on ferrocenes 88 and 92, a series of conformational analyses of 78, 88, and 92 were performed using density functional theory (DFT) calculations. The DFT calculations aided in the explanation for the unexpectedly low product ratio obtained for ferrocene 92. In efforts to obtain new [1]ruthenocenophanes ([1]RCPs), the synthesis of the ruthenium analog of 78, (Sp,Sp)-1,1'-dibromo-2,2'-di(isopropyl)ruthenocene (105), was attempted. To accomplish this, (R,R)-1,1'-bis(α-N,N-dimethylaminoethyl)ruthenocene (109) was prepared using the same chemistry that was used to prepare its ferrocene analog. However, the synthesis of (R,R,Sp,Sp)-1,1'-dibromo-2,2'-bis(α-N,N-dimethylaminoethyl)ruthenocene (110) via the dilithiation of 109 was unsuccessful. The synthesis of dibromoferrocene derivatives using “Ugi’s amine” chemistry is a long and inflexible process. Therefore, a method to prepare dibromoferrocene derivatives through an alternative synthetic pathway was investigated. The synthesis of (Ss,Ss)-1,1'-bis(p-tolylsulfinyl) ferrocene (118) was accomplished by reacting dilithioferrocene•tmeda with (1R,2S,5R)-(-)-menthyl (SS)-p-tolylsulfinate (117). The diastereoselective dilithiation and subsequent silylation of 118 to obtain (Ss,Ss,Sp,Sp)-2,2'-bis(trimethylsilyl)-1,1'-bis(p-tolylsulfinyl)ferrocene (120) proved to be problematic.

This thesis describes the synthesis and characterisation of a variety of acetylide-bridged di- and trinuclear ruthenium acetylide complexes that were prepared in a controlled fashion, and the preparation and characterisation of the ruthenium(II) complexes required for these stepwise reactions. These precursor complexes, or building blocks, include dimethyl-, acetylidomethyl-, and bis(acetylido)ruthenium(II) complexes. An introduction to metal acetylide chemistry is presented in Chapter 1. The previous research in this area is briefly reviewed, and the potential applications of these complexes are highlighted. The primary aims of this course of work are outlined, namely, to develop a controlled synthetic approach to the synthesis of oligonuclear ruthenium acetylide complexes. The synthetic strategies for this aim are introduced in Chapter 2, and the synthetic routes to cis and trans-Ru(CH3)2(dmpe)2 (25/23) and cis and trans-Ru(CH3)2(depe)2 (26/24) are described. Characterisation of the novel, synthetically important trans-Ru(CH3)2(dmpe)2 (23) is completed by an examination of its X-Ray crystallographic structure. Chapter 3 describes the thermal and photochemical metathesis reactions of trans-Ru(CH3)2(dmpe)2 (23) with terminal acetylenes, and the preparation of a variety of acetylidomethylruthenium(II) complexes, trans-Ru(CH3)(C≡CR)(dmpe)2 (R = Ph (30), tBu (31), SiMe3 (32), C6H4-4-tBu (33), C6H3-3,5-tBu2 (34), C6H4-4-C≡CH (35), C6H4-4-OCH3 (36), C6H4-4-CH3 (37), C6H3-3,5-(CF3)2 (38)). The characterisation of these complexes by NMR spectroscopy, IR spectroscopy and X-Ray crystallography is presented. A clean and high yielding synthesis of the synthetically significant unsymmetrical bis(acetylido)ruthenium(II) complexes was developed via the reaction of an acetylidomethylruthenium(II) complex with an excess of a second terminal alkyne in a mixture of methanol and benzene. The characterisation of the novel complexes trans-Ru(C≡CR)(C≡CR′)(dmpe)2 (R = Ph, R′ = tBu (40), SiMe3 (41), C6H4-4-C≡CH (44); R = tBu, R′ = SiMe3 (42), C6H4-4-C≡CH (43), C6H4-4-tBu (45), C6H3-3,5-tBu2 (46)) by NMR and IR spectroscopy, mass spectrometry and X-Ray crystallography is described in Chapter 4. Additionally, Chapter 4 describes the synthesis and characterisation of symmetrical bis(acetylido)ruthenium(II) complexes, and a number of organic butenyne compounds, which were observed as by-products from the attempted synthesis of several of the bis(acetylido)ruthenium(II) complexes. Dinuclear ruthenium(II) complexes were prepared by the reaction of trans-Ru(C≡CR)(C≡CC6H4-4-C≡CH)(dmpe)2 (R = tBu (43) or Ph (44)) with an acetylidomethylruthenium(II) complex in toluene and methanol. Both symmetrical and unsymmetical dinuclear complexes could be prepared in this way, and were characterised by a range of techniques including NMR spectroscopy, IR spectroscopy, mass spectrometry and X-Ray crystallography, and are described in Chapter 5. In addition, an electrochemical study of one of the dinuclear complexes was undertaken using cyclic voltammetry. The symmetrical trinuclear ruthenium(II) complexes, trans,trans,trans- (RC≡C)Ru(dmpe)2(μ-C≡CC6H4C≡C)Ru(depe)2(μ-C≡CC6H4C≡C)Ru(dmpe)2(C≡CR) (R = Ph (80), tBu (81), SiMe3 (82)) was prepared by the reaction of two equivalents of an acetylidomethylruthenium(II) complex with the symmetrical bis(acetylido)ruthenium(II) complex, trans-Ru(C≡CC6H4-4-C≡CH)2(depe)2 (54), in toluene and methanol. These syntheses, and the subsequent characterisation of the products are also reported in Chapter 5. The primary aim of this thesis, viz. the synthesis and characterisation of acetylide bridged di- and trinuclear ruthenium acetylide complexes in a controlled fashion, was successfully achieved. Suggestions for future work are described in Chapter 6.

This thesis describes the synthesis and characterisation of a variety of acetylide-bridged di- and trinuclear ruthenium acetylide complexes that were prepared in a controlled fashion, and the preparation and characterisation of the ruthenium(II) complexes required for these stepwise reactions. These precursor complexes, or building blocks, include dimethyl-, acetylidomethyl-, and bis(acetylido)ruthenium(II) complexes. An introduction to metal acetylide chemistry is presented in Chapter 1. The previous research in this area is briefly reviewed, and the potential applications of these complexes are highlighted. The primary aims of this course of work are outlined, namely, to develop a controlled synthetic approach to the synthesis of oligonuclear ruthenium acetylide complexes. The synthetic strategies for this aim are introduced in Chapter 2, and the synthetic routes to cis and trans-Ru(CH3)2(dmpe)2 (25/23) and cis and trans-Ru(CH3)2(depe)2 (26/24) are described. Characterisation of the novel, synthetically important trans-Ru(CH3)2(dmpe)2 (23) is completed by an examination of its X-Ray crystallographic structure. Chapter 3 describes the thermal and photochemical metathesis reactions of trans-Ru(CH3)2(dmpe)2 (23) with terminal acetylenes, and the preparation of a variety of acetylidomethylruthenium(II) complexes, trans-Ru(CH3)(C≡CR)(dmpe)2 (R = Ph (30), tBu (31), SiMe3 (32), C6H4-4-tBu (33), C6H3-3,5-tBu2 (34), C6H4-4-C≡CH (35), C6H4-4-OCH3 (36), C6H4-4-CH3 (37), C6H3-3,5-(CF3)2 (38)). The characterisation of these complexes by NMR spectroscopy, IR spectroscopy and X-Ray crystallography is presented. A clean and high yielding synthesis of the synthetically significant unsymmetrical bis(acetylido)ruthenium(II) complexes was developed via the reaction of an acetylidomethylruthenium(II) complex with an excess of a second terminal alkyne in a mixture of methanol and benzene. The characterisation of the novel complexes trans-Ru(C≡CR)(C≡CR′)(dmpe)2 (R = Ph, R′ = tBu (40), SiMe3 (41), C6H4-4-C≡CH (44); R = tBu, R′ = SiMe3 (42), C6H4-4-C≡CH (43), C6H4-4-tBu (45), C6H3-3,5-tBu2 (46)) by NMR and IR spectroscopy, mass spectrometry and X-Ray crystallography is described in Chapter 4. Additionally, Chapter 4 describes the synthesis and characterisation of symmetrical bis(acetylido)ruthenium(II) complexes, and a number of organic butenyne compounds, which were observed as by-products from the attempted synthesis of several of the bis(acetylido)ruthenium(II) complexes. Dinuclear ruthenium(II) complexes were prepared by the reaction of trans-Ru(C≡CR)(C≡CC6H4-4-C≡CH)(dmpe)2 (R = tBu (43) or Ph (44)) with an acetylidomethylruthenium(II) complex in toluene and methanol. Both symmetrical and unsymmetical dinuclear complexes could be prepared in this way, and were characterised by a range of techniques including NMR spectroscopy, IR spectroscopy, mass spectrometry and X-Ray crystallography, and are described in Chapter 5. In addition, an electrochemical study of one of the dinuclear complexes was undertaken using cyclic voltammetry. The symmetrical trinuclear ruthenium(II) complexes, trans,trans,trans- (RC≡C)Ru(dmpe)2(μ-C≡CC6H4C≡C)Ru(depe)2(μ-C≡CC6H4C≡C)Ru(dmpe)2(C≡CR) (R = Ph (80), tBu (81), SiMe3 (82)) was prepared by the reaction of two equivalents of an acetylidomethylruthenium(II) complex with the symmetrical bis(acetylido)ruthenium(II) complex, trans-Ru(C≡CC6H4-4-C≡CH)2(depe)2 (54), in toluene and methanol. These syntheses, and the subsequent characterisation of the products are also reported in Chapter 5. The primary aim of this thesis, viz. the synthesis and characterisation of acetylide bridged di- and trinuclear ruthenium acetylide complexes in a controlled fashion, was successfully achieved. Suggestions for future work are described in Chapter 6.

The scope of the palladium catalysed allylic substitution reaction is reviewed with particular reference to stereocontrol. The use of enantiopure oxazolines and acetals in asymmetric synthesis is briefly outlined. The work presented is concerned with the design and construction of enantiopure ligands which are able to impart very high levels of enantioselectivity in the aforementioned palladium-catalysed allylic substitution reaction. The ligands exploit the stereochemistry-controlling properties of the oxazoline moiety, whilst incorporating a secondary donor atom. The ligands rely upon an electronic disparity between these two atoms to direct nucleophilic addition.

The use of rare and expensive noble metals in the chemical industry as organometallic catalysts has grown exponentially in the past few decades due to their high activity, selectivity and their ability to catalyze a wide range of reactions. With this growth in use has also come a proportional growth in concern as these toxic metals inevitably leach into the environment and their negative effects on public health and our ecosystems are becoming better understood. First-row transition metal catalysts provide both environmental and economic benefits as alternatives to these noble metals due to their lower toxicity and cheaper costs. The two-electron chemistry that makes the noble metals so attractive however, is more challenging to accomplish with first-row transition metals. Intelligently designing the ligand scaffold which surrounds the metal can mitigate or even eliminate some of the shortfalls of these first-row metals. Some key features that should be considered when designing a ligand are: 1) a strong chelating ability so the ligand can stay attached to the metal, 2) incorporation of strong donors to favour low-spin complexes, 3) inclusion of hemilabile groups to allow for substrate activation and metal stabilization throughout various oxidation states, 4) redox activity to be able to donate or accept electrons, and 5) inclusion of Lewis base functionalities which are able to assist the substrate activation. Ligands which incorporate these features are known as bifunctional ligands as they can accomplish more than one function in the catalytic cycle. Developing first-row transition metal complexes containing these ligands may enable these species to replicate the reactivity and selectivity generally associated with the precious metals. Being able to replace the noble metals used in industry with these catalysts would have tremendous environmental and economic benefits. The objective of this thesis is to advance the field of bifunctional catalysis by examining the behaviour of two sterically svelte, tridentate SNS ligands containing hard nitrogen and soft sulphur donors when bonded to cobalt. Previous work with iron provides a template of the ligand behaviour to which cobalt can be compared, allowing us to contrast the effects exerted by the different metals. After an introduction to bifunctional catalysis in Chapter 1, Chapter 2 describes the reactivity of the amido ligand, SMeNHSMe, with precursors ranging from Co(I) to Co(III), all of which yielded the 19e- pseudooctahedral cobalt(II) bis-amido complex, Co(SMeN-SMe)2 characterized by 1H NMR spectroscopy, single-crystal X-ray crystallography and cyclic voltammetry. Although this complex has a similar structure as the Fe analogue, the cobalt bis-amido complex did not exhibit the same hemilabile behaviour that allowed for simple ligand substitution of one of the thioether groups. Instead it reacted reversibly with 2,2’-bipyridine while 1,2-bis(dimethylphosphino)ethane (DMPE) and 2,6-dimethylphenyl isocyanide both triggered additional redox chemistry accompanied by the loss of protonated SMeNHSMe. In contrast, protonation gave the cobalt(II) amido-amine cation, [Co(SMeNSMe)(SMeNHSMe)](NTf2), which allowed for substitution of the protonated ligand by acetonitrile, triphenylphosphine and 2,2’-bipyridine based on 1H NMR evidence. The ability of Co(SMeNSMe)2 to act as a precatalyst for ammonia-borane dehydrogenation was also probed, revealing that it was unstable under these conditions. Addition of one equivalent of DMPE per cobalt, however, resulted in better activity with a preference for linear aminoborane oligomers using ammonia-borane and, surprisingly, to a change in selectivity to prefer cyclic products when moving to methylamine-borane. Chapter 3 delves into the chemistry of the thiolate ligand, SMeNHS, which formed a new 18e- cobalt(III) pseudooctahedral complex, Co(S-NC-)(SMe)(DEPE), from oxidative addition of the Caryl-SMe bond. Scaling up this reaction resulted instead in formation of an imine-coupled [Co(N2S2)]- anion which was characterized by 1H NMR/EPR spectroscopy, single-crystal X-ray diffraction, cyclic voltammetry and DFT studies. The latter revealed an interesting electronic structure with two electrons delocalized in the ligand, demonstrating the non-innocent nature of the N2S2 ligand. While the analogous iron complex proved to be an effective pre-catalyst for the hydroboration of aldehydes with selectivity against ketones, this behaviour was not observed with [Co(N2S2)]- which gave a slower rate and less selectivity. The knowledge acquired from this thesis work has advanced the field of bifunctional catalysis by extending the application of these two SNS ligands from iron to cobalt, revealing unpredictable differences in reactivity between the metals. By comparing the behaviour of these ligands with iron and cobalt, we gain a better understanding of the chemistry that is accessible by these ligands and the applications for which they may be used. This increased knowledge contributes to our long-term goal of replacing expensive and toxic noble metals with more benign first-row transition metals, improving the sustainability of the chemical industry.

The use of bimetallic bases to effect highly stereoselective organic transformations via Directed ortho Metalation (DoM) is an important synthetic tool and requires thorough investigation to maximise efficiency and develop a mechanistic understanding. This thesis begins with a discussion of the history of DoM covering firstly monometallic lithium bases before moving to bimetallic magnesiate, zincate, aluminate, manganate bases and finally covering cuprate bases, which are the focus of this thesis. A description of the techniques employed in this project, which focuses on X-ray crystallography as the primary characterisation tool, follows. The experimental procedures and the associated characterisation data are also presented. These demonstrate that the addition of 2 equivalents of an amido or phosphido lithium to a copper(I) salt results in the crystallisation of a series of bis(amido)- and bis(phosphido)cuprates, and phosphidocopper compounds, many of which are suitable Directed ortho Cupration (DoCu) reagents. Syntheses involving phosphido ligands lead to the isolation of only one lithium cuprate species, Gilman-type [(Cy2P)2CuLi • 2THF], 11, which forms a polymer in the solid-state and is an ineffective DoCu agent. Alternative pathways which yield interesting novel phosphidocopper compounds [(Ph2P)6Cu4][Li • 4THF]2, 9, and Ph2PCu(CN)Li • 2THF, 10, are also investigated. The solid-state structures of all three species are discussed in detail. In situ preparations of bis(amido)cuprate bases from CuICl are shown to be effective in the deprotocupration of halopyridines. Reactions carried out with and without LiCl present in the mixture demonstrate that Lipshutz-type formulation bases are the active species. Analogous preparations from CuIBr are also effective in ortho deprotonation although do not provide consistently high-yields. In the solid-state, both bases are shown to form Lipshutz-type cuprates, [(TMP)2Cu(X)Li2 • THF]2 (X = Cl, Br). The effects of changing the donor solvent to the weaker Lewis base diethyl ether on the syntheses of Lipshutz-type cuprates are investigated, resulting in the isolation of [(TMP)2Cu(X)Li2 • Et2O]2 (X = CN, Hal). The results show that the solid-state structures are very similar to the analogous THF-solvated species. However, when the recrystallisation step is carried in bulk Et2O Lipshutz-type cuprates form, unlike when THF is employed which results in the formation of the Gilman-type cuprate [(TMP)2CuLi]2, 2. Changing the amido ligand to the less sterically demanding cis-2,6-dimethylpiperidine (HDMP) results in the formation of a remarkable new pentametallic structural motif, [(DMP)2CuLi • OEt2]2LiX (X = Hal), which can be viewed as an adduct between monomeric Lipshutz- and Gilman-type cuprates. The isolation of [(DMP)2CuLi • 2THF]2LiBr, 23 shows that adduct-type cuprates form regardless of the nature of the donor solvent and plausible explanations for the preference of DMP-based cuprates to form adduct-type species rather than Lipshutz-type species are presented. Reactivity studies demonstrate that 23 is an effective DoCu agent and theoretical studies explore possible mechanisms as well as the relative energies of the three cuprate structure types. The thesis is completed with a summary of the conclusions drawn and suggestions for further work. Ideas for further solid-state (including extensive investigations into the effects of sterics on the formation of cuprates), solution-state, reactivity and theoretical studies are put forward along with the rationale behind them.

The reaction of [BrRe(CO)₄]₂ with 2-(diphenylphosphino)pyridine (PN) and 6-(diphenylphosphino)-2-formylpyridine (PON) was investigated. The reactions were regiospecific and exclusively produced the phosphorus-coordinated products, BrRe(CO)₄(κᵖ-PN) and BrRe(CO)₄(κᴾ-PON). The kinetics for the chelate ring closure (κᴾ→ κᴾᴺ) in BrRe(CO)₄(κᴾ-PN) were confirmed to occur by dissociative CO loss. The reaction of [BrRe(CO)₄]₂ with 2-(diphenylphosphino)pyridine (PN) was modeled computationally by DFT calculations. The preferred reaction pathway for the substitution reaction was determined to occur by direct attack of the pnictogen donor on the dimer and formation of the κᴺ isomer as the kinetic substitution product occurs. The κᴺ kinetic product then rapidly isomerizes to the κᴾ thermodynamic product by way of a reversible ligand dissociation. Treatment of the tetrahedral cluster H₂Ru₃(CO)₃(μ₃-S) (1) with 2-(diphenylphosphino)thioanisole (PS) furnishes the cluster H₂Ru₃(CO)₇(κ²-PS)(μ₃-S) (2). Cluster 2, which exhibits a chelated thiophosphine ligand (κ²-PS), exists as a pair of diastereomers with Keq = 1.55 at 298 K that differ in their disposition of ligands at the Ru(CO)(κ²-PS) center. The PS ligand occupies the equatorial sites (Peq, Seq) in the kinetic isomer and axial and equatorial sites (Pax, Seq) in the thermodynamically favored species. The reversible first-order kinetics to equilibrium have been measured experimentally by NMR spectroscopy and HPLC over the temperature range 293-323 K. The substitution reaction involving 1 and the isomerization of the PS ligand in 2 were investigated by DFT calculations. The computational results support a phosphine-induced expansion of the cluster polyhedron that is triggered by the associative addition of the PS donor to 1. The observed isomerization of the PS ligand in 2 is best explained by a tripodal rotation of the CO and PS groups at the Ru(CO)(κ²-PS) center that is preceded by a regiospecific migration of one of the edge-bridging hydrides to the non-hydride-bridged Ru-Ru bond in 2. The chiral clusters 1,2-Ru₃(μ-H)₂(μ₃-S)(CO)₇(μ-1p1,2p2-POP) (A) and 1,2-Ru₃(μ-H)₂(μ₃-S)(CO)₇(μ-1p2,2p1-POP) (B) were formed were formed from reaction of Ru₃(μ-H)₂(μ₃-S)(CO)₉ with 1-diphenylphosphino-2-[2-(diphenylphosphino)ethoxy]benzene (POP). Chiral clusters A and B were fully characterized by IR and NMR spectroscopy. Additionally, the molecular structure of A was solved by X-ray crystallography. Chiral cluster A was resolved into its enantiomers by preparative HPLC with a chiral column. The enantiomers were characterized by electronic circular dichroism (ECD) spectroscopy and their absolute stereochemical configuration was determined by X-ray crystallography.

The aim of this project has been to develop the field of group 4 indenyl metallocene complexes based upon highly methylated ligands. Previous studies have shown that these compounds can be extremely active ethylene polymerisation catalysts, and, as such, are of both significant academic and commercial interest <strong>Chapter One</strong> introduces metallocene chemistry, discussing developments within the field and the effects of permethylation on indenyl rings. A synopsis of the rise of the ansa-bridge is provided, in addition to highlights from recent zirconocene chemistry. A feature on olefin polymerisation is included, spanning heterogeneous catalysts, homogeneous metallocenes and post metallocenes, as well immobilised complexes and their supports. <strong>Chapter Two</strong> charts updates to syntheses of bridged and unbridged permethylindenyl ligands. The developments have allowed for their use as viable industrial procedures. <strong>Chapter Three</strong> is an account of the group 4 organometallic chemistry of the indenyl ligands from Chapter Two. Four bridged metallocenes, including rac-SBI*ZrCl₂ and meso-EBI*Zr(CH₂Ph)₂, are reported. In addition, six unbridged analogues comprising rac/meso-Ind^#<sub style='position: relative; left: -.8em;'>2</sub>MCl₂ (M = Zr, Hf) and rac/meso-Ind^#<sub style='position: relative; left: -.8em;'>2</sub>(CH₂Ph)₂ are described as well as a half-metallocene. The complexes are characterised by single crystal X-ray diffraction and variable temperature NMR spectroscopy. DFT calculations have been performed, with representations of their optimised geometries and frontier MOs given. <strong>Chapter Four</strong> describes a reliable, reproducible procedure for immobilising group 4 complexes on the surface of solid supports; in total 19 catalysts are prepared. In addition to SSMAO, two new inorganic supports (LDHMAO and Solid MAO) are utilised. The latter has never previously been described in the academic literature. These catalysts have been characterised by IR, UV/visible and solid-state NMR spectroscopy in addition to SEM imaging. Zr K-edge EXAFS experiments were conducted and exceptionally clear data are reported. <strong>Chapter Five</strong> investigates the aforementioned complexes as both solution- and slurry-phase ethylene polymerisation catalysts. Numerous parameters are tested including temperature and time dependence and all of the catalysts produce high molecular weight polymer in the range 150-300,000 daltons. The activity of rac SBI*ZrCl₂ in solution exceeds 22,500 kg_PE/mol_Zr/h/bar, and 7,500 kg_PE/molZr/h/bar immobilised on Solid MAO. meso-EBI*Zr(CH₂Ph)₂ displays double the activity of its dichloride analogue. 1-hexene co polymerisation is carried out as part of a high throughput screening study and activities in excess of 30,000 kg_PE/molZr/h/bar are reported. Scale-up polymerisation runs are also disclosed. The resultant polymer has been characterised by GPC, as well as X-ray diffraction, SEM, ¹³C NMR and IR spectroscopy. <strong>Chapter Six</strong> provides the experimental details and characterising data for the previous chapters. An Appendix consists of crystal structure data while the Electronic Appendix contains the CIFs, DFT output files and the raw polymerisation data.