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The existence of complexes of that display non-innocence has been of interest in the field of coordination chemistry since the investigations of square-planar dithiolene complexes of the late transition metals in the 1960s. The ligands used in these systems are termed “non-innocent” when bound to a number of the late transition metals, because the orbital energy levels are similar to those of the central metal ion. This allows there to be significant electron delocalisation over the complex with the potential for the complexes to exist in a number of electronic states due to the combined electrochemical activity. In 1966, Jørgensen classified innocence as ligands that “allow oxidation states of the central atoms to be defined”, thus by this logic non-innocent ligands are defined as complexes where the precise oxidation states of the ligand and metal are ambiguously assigned. However it should be noted that no ligand is inherently non-innocent, but rather the ligand may behave in a non-innocent manner under the right circumstances. The qualification of non-innocence should therefore only be applied to combinations of metal and ligand that result in the aforementioned properties. In this thesis, the term “non-innocent” will be used to define ligands that often possess non-innocent behaviour when complexed to the metal centres they are bound to. A general form of ligand that displays non-innocent behaviour is that of the 1,2-bidentate moiety with an unsaturated carbon backbone. The chelating donor groups (X) are either O, NH, S, or a combination of the three. The central transition metal is generally a late metal that favours a square-planar geometry, because the planarity of the complex is crucial for electron delocalisation within the molecule and molecular interactions in the solid material. When the metal is nickel or platinum for example, their square-planar complexes with such ligands have shown threemembered electron-transfer series. Specific examples of ligands that have been shown to display non-innocent behaviour are those of catechol (1,2-dihydroxybenzene) and 1,2-diaminobenzene, where the unsaturated backbone is provided by a phenyl group. The electronic nature of these compounds has been extensively investigated by the groups of Pierpont and Lever, with focus on their redox and magnetic properties. The combined metal and ligand redox activity results in interesting magnetic behaviour, with potential for magnetic exchange interactions between a paramagnetic metal centre and the radical ligand or between two radical ligands mediated by a diamagnetic metal centre. This research has been advanced by Wieghardt and co-workers who have performed experimental and theoretical examination of non-innocent complexes of 1,2-substituted phenyl chelates, where the donor group is a combination of O and NH. These studies have focused on the understanding the nature of the metal-ligand interactions to apply to biological systems, such as those observed at the active site of enzymes that act upon molecules with similar moieties to the non-innocent ligands. Compounds of catechol may be referred to as dioxolenes in analogy to the sulfur-based dithiolenes. The deprotonated, dianionic form of catechol is known as catecholate (cat), which can be readily oxidised to the monoanionic o-semiquinone (SQ) and neutral o-benzoquinone (Q) forms. It has been seen that catecholate compounds can be described by localised electronic states with defined oxidation states, unlike many of the dithiolene class of molecules. However these states can exist in equilibrium with each other when the metal and ligand orbitals are close in energy, with differences in the charge and spin definition in what has been described as “valence tautomerism”. Therefore, although the complexes may not be seen as non-innocent by definition that their oxidation states are not ambiguous, it is still a useful description due to the potential for easily accessible charge states. Metal dithiolene complexes, where the metal is coordinated by one or more ligands with two S-donor atoms linked by a conjugated backbone, are one of the best researched of the non-innocent class of molecules. The square-planar bis-dithiolenes of the late transition metals have interesting magnetic, optical and electrical properties arising from the delocalised nature of the constituent metal and ligand orbitals, which has enabled their use for a wide range of applications such as non-linear optics, transistors and near-infrared switches. Of particular interest is the ability to fine tune the electrical properties to fit the application by changing the substituents on the core dithiolene moiety. For example, Anthopoulos has shown that by lowering the energy of the lowest unoccupied molecular orbital (LUMO), stable n-channel conductivity can be observed in field-effect transistors (FETs). Materials based on square-planar non-innocent complexes have been tested in FETs, and been seen to display field-effect mobilities as high as 10˗2 cm2 V˗1 s˗1 as with Ni bis(o-diiminobenzo-semiquinonate) complexes. Most of these molecules are based on conjugated, chelating ligands such as 1,2-diaminobenzene and the dithiolene class of molecules. Field-effects have also been observed in square-planar Pt complexes, where the conductivity is thought to arise from beneficial Pt-Pt bonds in addition to the π-stacking between molecules. Despite the similarity to the diaminobenzene and dithiolene counterpart, there are no reports of catechol-based materials displaying field-effect properties in the literature. Catechol compounds are well-researched in the field of biological chemistry due to the prevalence of the catechol moiety and enzymes with which it interacts in nature. However they have not been examined far beyond their simple coordination chemistry or chemical characterisation.

Metal-Organic Materials (MOMs) represent an important division of coordination chemistry. They are self-assembled through the linking of metals with organic ligands. They gained their spotlight among scientists for their aptitude for design and facile synthesis via their multi-component coordination, and their readiness to functionalization. MOMs have been targeted for specific industrial and environmental applications such as gas storage, catalysis and CO2 sequestration. Throughout the past decade, studies have been conducted to develop systematic approaches toward the design and synthesis of functional MOMs. Their synthesis from targeted building units has facilitated their rational design and functionalization. The Molecular Building Block (MBB) approach was first developed to direct the design of MOMs from preset building blocks with specific connectivity amenable to form the overall MOM structure with the desired topology. These building blocks are easily constructed in situ through the chelation of multifunctional ligands (i.e, carboxylic acid, amine, etc) to single ion or cluster metals such as dinuclear copper paddlewheel, and basic zinc acetate. As complexity and applications for MOMs increased, a new approach was developed through the utilization of Supermolecular Building Blocks (SBBs) for the assembly of more complex and higher connected MOM structures. The SBB approach is implemented through the formation of highly coordinated metal-organic polyhedra (i.e, small rhombihexahedron, cuboctahedron, etc) which are further linked by organic ligands to construct functional porous materials with the desired net topology. In this work, we focus on the implementation of a new design approach based on utilizing targeted [M(R-BDC)]n 2D layers as building blocks, i.e Supermolecular Building Layers (SBLs). We target well-known 2D layers that are amenable to pillaring through organic building blocks with specific geometries (i.e quadrangular, hexangular) in order to rationally design and synthesize functional porous metal-organic materials. These SBLs are derived from multifunctional ligands capable of both directing the formation of the 2D layers and pillaring to construct the overall targeted 3D structures with the desired topology (i.e, tbo-MOMs, eed-MOMs, mmm-MOMs, bor-MOMs, and eef-MOMs). Ultimately, we construct isostructural, and isoreticular materials which show potential for many applications such as gas storage, gas separation, and catalysis. These materials have been targeted through the rational choice of specific ligands and proper metals which we recognized to have the capability and the functionality to direct the construction of the desired functional materials and to reach our research goals.

This work began with the synthesis and full characterization of a novel £^-diimine ligand, (2,6-iPr2C6H3N=CH)2C6H4, from the reaction of o-phthaladehyde and the bulky aniline, 2,6-diisopropylaniline. It was observed that any <i>di-ortho</i>-substituted aniline with less bulky groups than isopropyl groups resulted in formation of the corresponding iminisoindolines. Reaction of the £^-diimine ligand with PdCl2 did not result in a seven-membered coordination complex, but in non-palladacyclic complex, [(g-diimine)PdCl(Ý-Cl)]2. Whereas reaction with Pd(OAc)2 gave an S-shaped five-membered trinuclear palladacyclic complex, {1,2-(2,6-iPr2-C6H3N=CH)2-C6H3]Pd(Ý-OAc)2}2Pd. These complexes were found to be active precatalysts for Heck and Suzuki coupling reaction giving TONs of up to 104 and 86, for arylbromides and arylchlorides, respectively.<p> On the other hand, a series of neutral and cationic seven-membered aluminum coordination complexes were obtained from the reaction of £^-diimine with a variety of aluminum species (AlMe3, AlMe2Cl, AlMeCl2 and AlCl3). The synthesis and characterization of these complexes are exemplified.<p> Also illustrated in this thesis is the synthesis and characterization of a series of air- and moisture-stable iminoisoindoline-based palladacyclic compounds of the general formula, [(iminoisoindoline)Pd{Ý-OAc}]2. These six-membered palladacyclic complexes were obtained through a simple two-step protocol as analytically pure solids. Phosphine-ligated mononuclear palladacycles of the general formula, [Pd(iminoisoindoline)X(PR3)], X= OAc or Cl, R = Ph or Cy, are also described. Dinuclear palladacycles were also found to be active for the Heck and Suzuki C-C coupling reactions. TONs of up to 106, 105 and 60 were observed for coupling of iodobenzene, <i>p</i>-acetylbromobenzene and <i>p</i>-chlorobenzaldehyde, respectively in the Heck coupling reaction.

This work began with the synthesis and full characterization of a novel £^-diimine ligand, (2,6-iPr2C6H3N=CH)2C6H4, from the reaction of o-phthaladehyde and the bulky aniline, 2,6-diisopropylaniline. It was observed that any <i>di-ortho</i>-substituted aniline with less bulky groups than isopropyl groups resulted in formation of the corresponding iminisoindolines. Reaction of the £^-diimine ligand with PdCl2 did not result in a seven-membered coordination complex, but in non-palladacyclic complex, [(g-diimine)PdCl(Ý-Cl)]2. Whereas reaction with Pd(OAc)2 gave an S-shaped five-membered trinuclear palladacyclic complex, {1,2-(2,6-iPr2-C6H3N=CH)2-C6H3]Pd(Ý-OAc)2}2Pd. These complexes were found to be active precatalysts for Heck and Suzuki coupling reaction giving TONs of up to 104 and 86, for arylbromides and arylchlorides, respectively.<p> On the other hand, a series of neutral and cationic seven-membered aluminum coordination complexes were obtained from the reaction of £^-diimine with a variety of aluminum species (AlMe3, AlMe2Cl, AlMeCl2 and AlCl3). The synthesis and characterization of these complexes are exemplified.<p> Also illustrated in this thesis is the synthesis and characterization of a series of air- and moisture-stable iminoisoindoline-based palladacyclic compounds of the general formula, [(iminoisoindoline)Pd{Ý-OAc}]2. These six-membered palladacyclic complexes were obtained through a simple two-step protocol as analytically pure solids. Phosphine-ligated mononuclear palladacycles of the general formula, [Pd(iminoisoindoline)X(PR3)], X= OAc or Cl, R = Ph or Cy, are also described. Dinuclear palladacycles were also found to be active for the Heck and Suzuki C-C coupling reactions. TONs of up to 106, 105 and 60 were observed for coupling of iodobenzene, <i>p</i>-acetylbromobenzene and <i>p</i>-chlorobenzaldehyde, respectively in the Heck coupling reaction.

Abstract Methyldiphenylphosphonium cyclopentadienylide, C5H4PMePh2 (II), has been synthesized and characterized spectroscopically and crystallographically, and has been found to exhibit properties consistent with the zwitterionic structure IIb. New group 6 complexes, (η5-C5H4PMePh2)M(CO)3, have been synthesized and fully characterized. Comparisons of ν(CO) of these complexes with those of the isoelectronic (η6-C6H6)M(CO)3 and [(η5-C5H5)M(CO)3]- suggest that the electron donating ability of the ylide is between that of the cyclopentadienyl anion (Cp-) and benzene, but closer to Cp-. The electronic structures of II and of (η5- C5H4PMePh2)Cr(CO)3 have been investigated using ab initio methodologies. Thermal and photochemical substitutions of the CO ligands of (η5-C5H4PMePh2)M(CO)3 (M = Cr, Mo) by equimolar amounts of PMe3 and PPh3 were not observed, but the ylide is displaced photochemically from (η5-C5H4PMePh2)Mo(CO)3 by excess PMe3 to form fac- Mo(CO)3(PMe3)3 while (η5-C5H4PMePh2)Mo(CO)3 reacts with I2 to form [(η5- C5H4PMePh2)Mo(CO)3I]I. One electron oxidations of (η5-C5H4PMePh2)M(CO)3 (M = Cr, Mo, W) have been performed to give the cationic radicals [(η5-C5H4PMePh2)M(CO)3]+, which undergo dimerization to give dicationic metal-metal bonded dimers ((η5-C5H4PMePh2)M(CO)3)2 2+ in the solid state. These complexes have been fully characterized spectroscopically and crystallographically. It has been determined that the chromium dimer ((η5- C5H4PMePh2)Cr(CO)3)2 2+ undergoes dissociation extensively in solution to the persistent radical cation monomer (η5-C5H4PMePh2)Cr(CO)3 +, but that the heavier metal analogues iii ((η5-C5H4PMePh2)M(CO)3)2 2+ (M = Mo, W) dissociate very little, if at all. The Cr-Cr bond distance of the chromium complex is 3.3509(7) Å, which is the longest Cr-Cr bond distance known for a compound not containing some type of ligand bridging the metalmetal bond. The hitherto unknown indenyl-derived ylide, C9H6PMePh2, has been synthesized and characterized spectroscopically and crystallographically. The chromium tricarbonyl complex of this ligand, (η5-C9H6PMePh2)Cr(CO)3, has been synthesized and characterized spectroscopically and crystallographically. This complex is a mixture of two isomers exhibiting planar chirality generated upon coordination of the ligand. This complex represents the first structurally characterized phosphorus noncyclopentadienylide coordinated in an η5 manner. The spectroscopic and crystallographic behaviour of C9H6PMePh2 demonstrates that this ylide behaves much like the related cyclopentadienylides. / Thesis (Ph.D, Chemistry) -- Queen's University, 2007-09-07 11:46:39.391

This thesis documents the successful syntheses of six novel 2,2':6',2"-terpyridine-amine based polydentate ligands and a range of mono-, di-, and polynuclear complexes derived from them. The ability of some dinuclear complexes to affect the rate of hydrolysis of the phosphate diester group in the DNA model compound, bis-p-nitrophenyl phosphate (BNPP) has also been explored. Owing to the presence of two potential ligating groups in each polydentate ligand, a number of dinuclear, tetranuclear and serendipitous supramolecular architectures have been produced and characterised during this research. The polydentate ligands were synthesised by stepwise functionalisation of the progenitor ligand, 4'-(2"'-toluyl)-2,2':6',2"-terpyridine (L2.1), at its ortho methyl position via free radical bromination, and where various amine groups were appended by nucleophilic substitution reactions. The detailed ligand syntheses, and characterisation are discussed in Chapter 2, along with the crystal structures of some ligands. Chapter 3 describes coordination chemistry of 4'-(2"'-toluyl)-2,2':6',2"-terpyridine with transition metal ions. Thirteen new complexes of Ni(II), Cu(II), Zn(II) and Ag(I) are reported, where Ag(I) produced a striking spiral shaped polymer with L2.1 having unusual „hyperdentate‟ nitrogen atoms. Two polydentate ligands, 4'-[2"'-{(2-pyridylmethyl)aminomethyl}phenyl]-2,2':6',2"-terpyridine, L2.3, and 4'-[2"'-{bis(2-pyridylmethyl)aminomethyl}phenyl]-2,2':6',2"-terpyridine, L2.4, produced six different dinuclear and tetranuclear metal complexes (Chapter 4). The Zn(II) dinuclear complexes were used to study kinetics of hydrolysis of BNPP, and the enhanced rates were reported compared to the analogous mononuclear complexes. The detailed experimental methodology and results are discussed in Chapter 5. The most interesting outcome of this research was formation of the box and wheel shaped complexes, where the ligand L2.3 binds with different metal ions via different coordination modes. The box shaped tetranuclear complexes were synthesised deliberately via structural control over the coordination chemistry of terpyridine-type site of L2.3, where the coordination flexibility of the pendent picolylamine-type site of the ligand was used to bind with other metal ions. The tetranuclear [M¹₂M²₂(L2.3)₄X₂]⁶⁺ box shaped complexes were formed when two divalent M¹ ions bridge between the ligands to produce octahedral bis-terpyridine type complex M¹(L2.3)₂, and then two divalent M² ions link two M¹(L2.3)₂ units together through picolylamine binding sites, where X = Cl⁻, Br⁻, CH₃COO⁻; M¹ = Fe(II), Zn(II), Ni(II); M² = Zn(II), Cu(II). The bis-bidentate bridging ligand terephthalate was also deliberately encapsulated in the middle of Fe₂Zn₂L2.3 box to produce the complex where X₂ = terephthalate. These structures invite speculation that it may be possible to bind and react molecules within these boxes. In a more fortuitous outcome, Ni(II) ions were found to bind to both sites of L2.3 to give, exclusively, an unprecedented decanuclear wheel-shaped structure. A halide ion occupies the central position in the wheel, with Br⁻ being preferred over Cl⁻. The detailed crystal structures, and properties of the wheels shaped Ni₁₀(L2.3)₁₀ complexes are discussed in Chapter 6.

xvi, 233 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The coordination chemistry of iron with N 2 is becoming increasingly important as chemists try to find alternative routes to the production of ammonia. Current biological and industrial processes use iron to catalyze the formation of ammonia from N 2 ; however, huge amounts of energy are required for this conversion. Understanding how dinitrogen and other intermediates of dinitrogen reduction interact with iron could lead to energy efficient processes for the production of ammonia. This dissertation explores the synthesis and reactivity of an iron dinitrogen complex that reacts with acid to produce ammonia at room temperature and pressure. This dissertation also explores the progress toward determining the mechanism of this reaction in hopes of improving the yields of ammonia. Chapter I describes both the biological nitrogen fixation process and the industrial production of ammonia and provides an in-depth look at progress toward an alternative route to ammonia using iron complexes described in the literature thus far. Chapter II details the synthesis, characterization, and reactivity of dihydrogen and dinitrogen complexes of iron. These complexes are precursors to the active ammonia producing complex and are among a handful of dihydrogen and dinitrogen complexes that have been structurally characterized. Chapter III explores the synthesis and stability of Fe(DMeOPrPE) 2 N 2 . This complex produces ammonia and hydrazine upon protonation with a strong acid. Optimizing the yield of ammonia from this protonation is also described. Chapter IV discusses the synthesis and reactivity of several complexes of iron containing intermediates relevant to dinitrogen reduction, including diazene (N 2 H 2 ), hydrazine (N 2 H 4 ), and ammonia. By studying these intermediates, a mechanism of ammonia formation from the protonation of Fe(DMeOPrPE) 2 N 2 is proposed that may also provide insights into the mechanism of nitrogenase. Chapter V provides a summary of this research. This dissertation includes previously published and unpublished co-authored material. / Committee in charge: Darren Johnson, Chairperson, Chemistry; David Tyler, Advisor, Chemistry; Michael Haley, Member, Chemistry; Kenneth Doxsee, Member, Chemistry; Scott Bridgham, Outside Member, Biology

Ligand design in general enables the formation of coordination compounds with multiple functionalities within a single framework. To date, two of the most widely studied ligands are 2,2′:6′,2′′-terpyridine (terpy) and acetylacetone (acac), whose tridentate and bidentate coordination pockets, respectively, enables the formation of metallic complexes with various geometries. The Brusso group had been incorporating imidoyl amidine (ImAm) ligands to build different materials such as organic radicals and fluorescent materials. In particular, the ligands N-2-pyridylimidoyl-2-pyridylamidine (Py2ImAm) and N-2-pyrimidylimidoyl-2-pyrimidylamidine (Pm2ImAm) were recently synthesized and have great appeal to build metallic complexes, as they poses two coordination sites similar to those in terpy and acac. The work presented herein represents the first studies involving the coordination of Py2ImAm and Pm2ImAm as discrete ligands. Our results demonstrate the versatility of these ligand frameworks, in which discrete mononuclear complexes, homometallic and heterometallic polynuclear complexes may be realized. Chapter one serves as a brief introduction to transition metal chemistry and has a comprehensive review of the coordination chemistry of the ImAm ligand framework. In chapter two, the selective coordination of first row transition metals into the bidentate or tridentate sites of Py2ImAm is explored. The formation of these mononuclear complexes is acid-base driven, where a weak acid induces coordination to the tridentate site and a weak base leads to coordination in the bidentate site. Coordination to both sides of Pm2ImAm with manganese or iron is explored in chapter three. The results show the formation of unusual tetranuclear complexes with the metal ions in both low spin and high spin configurations. Chapter four covers the coordination to cobalt, and the formation of polynuclear complexes with different geometries using Pm2ImAm. The magnetochemistry of these cobalt polynuclear complexes is also presented and reveal a single molecule magnet behaviour for one of the complexes. Finally, in chapter five, a one-pot synthesis of copper-manganese heterometallic complexes is presented. Overall, these imidoyl amidine ligands are able to build complexes with different geometries, different electronic configurations (i.e. low or high spin), and different metal ions. These results show a great versatility of ImAm ligands and suggest the future use of these ligands by other research groups.