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Nanotechnology is more and more present in our world today and different fields are taking advantage of its possibilities. Among others, microscopists have been interested in using nanoparticles in combination with available techniques, one of which is fluorescence microscopy. Lanthanide-doped nanoparticles for example have been studied for many years now for their interesting luminescence and upconversion characteristics. This research presents the development of upconverting biolabels operating in the near-infrared (NIR) to eventually allow scientists to probe deeper into tissues using fluorescence microscopy. Two distinct types of nanoparticles were fabricated using the lanthanide ions Yb3+ and Tm3+ for their upconversion capabilities (from 980 to 800 nm) within the biological window (700 to 1000 nm). The first one, an annealed silica-coated LaF3:Yb,Tm nanoparticle, could not be used as a biolabel due to its lack of dispersibility in aqueous environment. However, the second type, a silica-coated NaYF4:Yb,Tm nanoparticles proved to be very promising. Two surface modifications of these particles were successfully performed. The first introduced NH2 groups while the second incorporated polyethyleneglycol (PEG). The latter was achieved using two distinct methods: one through a reaction with the amino groups and one through a second silica coating involving PEGsilanes. Stable dispersions of these PEGylated nanoparticles were obtained and imaging of ovarian cancer cells grown in their presence showed that they interact with the cells although the nature of this interaction is still to be determined.

This work presents the synthesis and characterization of a new family of bridging ligands, indigo diimines (Nindigos). Nindigos are bis(bidentate) N-donor type ligands derived from the dye indigo. These Nindigos have been synthesized via reaction of indigo with primary amines, using TiCl4 as a catalyst, in bromobenzene. A family of Nindigo ligands was prepared with p-tolyl, p-methoxyphenyl, p-chlorophenyl, mesityl, and tBu functional groups. The UV-Vis properties of the Nindigos were investigated. The λmax for these ligands occurs in the range of 580-640nm, with extinction coefficients in the order of 1x104 M-1 cm-1. These absorptions are similar to that of indigo itself, which also shows a λmax close to 600nm. The reactions of selected Nindigo derivatives with Pd(hfac)2 formed bimetallic complexes. Upon complexation with palladium, the major absorption of the Nindigo complexes was found to red-shift to ~ 910nm, while the extinction coefficient increased to approximately 2x104 M-1 cm-1. This demonstrates that both the Nindigos and their complexes are functional molecular dyes. The electrochemistry of the p-tolyl, p-methoxyphenyl, and mesityl complexes show two reversible oxidations, with E1/2 at approximately + 0.0V and + 0.50V. There is also a quasi-reverisble reduction at approximately -1.4V. The alkyl derivatized complex, tBu Nindigo showed only one reversible oxidation at +0.32 V and one irreversible reduction at ~ -1.7 V. The Nindigo complexes now represent a new class of redox active bridging ligands, and thanks to the facile derivatization, they have more options for electronic and steric control around the metal center, which ultimately means greater control over redox activity.

The synthesis of the cyclopentadiene-fused dimethyldihydropyrene, CpDI-IP(H) 44, from DHP 31 was achieved in a seven-step synthesis in an overall yield of 7%. Deprotonation of 44 gave the Cp anion fused CpDHP anion 28. The photochromic properties of 28 were studied. It is found that 28 is photochromic and its behavior is intermediate between the parent DHP 31 and the benzannelated DHP 36. The 1H-NMR data of 28 were also analyzed and showed that the Cp anion has similar bond fixing effect on the DHP ring as benzene does, but to a lesser extent. The complexation of anion 28 to various metal centers has been investigated. While the reactions of 28 with Re(CO)5Br, (Cp*RuCl2)„ and FeC12 yielded (CpDHP)Re(CO)3 51. Cp*Ru(CpDHP) 52 and (CpDHP)2Fe 54 respectively, the reactions with Mn. Y. Yb(III) or Zr precursors either gave the starting materials back or resulted in the decomposition of 28 to unidentified products. Reaction of the protonated form CpDHP(H) 44 with Yb[N(SiMe3)2I(thf)2 afforded Yb(CpDHP)2(thf)2 57.

A new multi-step self-assembly route to polymer-semiconducting nanoparticle photonic structures is described. The multi-step self-assembly strategy targets complex hierarchical structures in which organization of cadmium sulfide (CdS) nanoparticles on progressively longer length scales is introduced via a series of three self-assembly steps. each involving building blocks of increasing structural complexity. Each self assembly step can be described as follows: 1) SA1: self-assembly of PS-b-PAA to form block ionomer reverse micelles, followed by synthesis of a single CdS semiconducting nanoparticle in each core, forming the hybrid building blocks PS-CdS: 2) SA2: self-assembly of blends of PS-CdS and PS-b-PAA stabilizing chains in DMF/water mixtures by addition of water to form spherical nanoparticle assemblies, termed large compound micelles (LCMs); 3) SA3: self-assembly of LCMs into ordered close packed arrays by slow water evaporation. The kinetic freezing of building blocks at each stage offers the potential for unique control of nanoparticle self-assembly step since each step is "locked in", allowing structural features determined by the subsequent step to be independently tuned through a new set of experimental variables. Chapter 2 and 3 of this thesis investigate aspects of size and polydispersity control of spherical nanoparticle assemblies in the SA2 self-assembly step. Chapter 4 demonstrates that LCMs can be further assembled (SA3 step) to form three-dimensional hierarchical arrays.

This work presents three new classes of 6-oxoverdazyl radicals. Each of these classes of radicals bears a different substituent in the 3-position of the verdazyl ring. These classes include N-heteroaromatic monoverdazyls, oligopyridine diradicals, and ferrocenyl-based verdazyl radicals and diradicals. With the exception of the ferrocenyl-based radicals, these verdazyl radicals have been designed to serve as ligands and the direct metal-radical interactions have been explored. The ferrocenyl verdazyls have been designed to investigate the indirect interactions between iron(II) and the covalently linked verdazyl radical. All verdazyl radicals and precursors were fully characterized and the metal-radical magnetic interactions were investigated where structural characterization was available. A series of bidentate verdazyl radical ligands were prepared and the metal-radical magnetic interactions have been investigated. The magnetic susceptibility data for the octahedral complexes indicates that cobalt(II) couples ferromagnetically (Jco_vd = +95 cm-l) and iron(II) antiferromagnetically (JFe_vd = -66 cm-1) to the verdazyl radical. The nature of these interactions appears to be dictated by orbital symmetry and is consistent with previously reported nickel and manganese verdazyl complexes. This work also demonstrates that imidizole-based verdazyl radicals are effective ligands in tetrahedral copper(I) complexes. Oligopyridine-based diradicals have been designed as ligands, but decompose in solution preventing metal complexation. An attempt was made to construct grids as a higher order molecular structure. To this end, a diradical ligand with the topology necessary to form discrete grid architectures was synthesized, but has not yet demonstrated the ability to coordinate to metal ions. Other monoverdazyl radicals that are symmetrically substituted in the N1 and N5 positions were also investigated as potential grid forming ligands. A series of ferrocenyl verdazyl and methylated ferrocenyl verdazyls were prepared to investigate the electronic and magnetic interactions between the ferrocene and verdazyl electrophores. As evidenced by UV-Vis and electrochemical solution measurements, the two electrophores exhibit mutual electronic perturbations. In the case of the methylated ferrocene derivatives the degree and pattern of methylation appears to have a regiospecific influence on the verdazyl electrochemistry. In the solid state Mössbauer data is consistent with a Fe2+ ground state and there is no evidence of Fe3+ at or below room temperature. Weak antiferromagnetic behaviour (|J| < -13 cm-1) was observed within and between pairs of ferrocenyl monoverdazyls in the solid state. In order to investigate the interactions between radicals separated by an organometallic spacer, a ferrocenyl verdazyl diradical was prepared. The ferrocene diradical demonstrated significant differences between the solid state and solution phase. While the ferrocene diradical and ferrocene monoverdazyl exhibited similar solution electronic properties, the magnetic properties were vastly different. In solution the spins associated with the diradical appeared to be weakly coupled, but in the solid state the diradical has been characterized as a strongly coupled antiferromagnetic π-dimer. This is the first example of a verdazyl π-dimer. The π-dimer appears to be diamagnetic with the lower limit of exchange estimated at Jinter ≈ 2000 cm 1.

Histone H2A.Z is a highly conserved replication-independent histone variant that is essential for survival in diverse organisms including Tetrahymena thermophila, Drosophila melanogaster, Xenopus laevis, and Mus musculus. H2A.Z has been shown to play a role in many cellular processes including, but not limited to, gene expression, chromosome segregation, cell cycle progression, heterochromatin maintenance and epigenetic transcriptional memory. However, the mechanism by which H2A.Z and its post-translationally modified forms participate in these diverse cellular events and their subsequent effects on chromatin structure and function are not entirely clear. A thorough review of H2A.Z is provided in Chapter 1. We have isolated native non-acetylated and acetylated forms of H2A.Z and characterized nucleosome core particles (NCPs) reconstituted with these proteins using the analytical ultracentrifuge (Chapter 2). We report that NCPs reconstituted with native non-acetylated H2A.Z exhibit a slightly more compact conformation compared to those reconstituted with H2A. Furthermore, we show that acetylation of H2A.Z in conjunction with acetylation of the histone complement, results in NCPs that are less compact and less stable than H2A.Z-containing NCPs reconstituted with non-acetylated histones. Acetylated H2A.Z NCPs are nevertheless more compact and stable than acetylated H2A-containing NCPs. We have also identified the presence of two H2A.Z protein isoforms in vertebrates, H2A.Z-1 and H2A.Z-2, and characterized the sites and abundances of their N-terminal peptide acetylation. Further characterization of the human H2A.Z isoforms is presented in Chapter 3 and indicates that they are expressed across a broad range of human tissues, and that they exhibit a similar but non-identical distribution within chromatin. Our results suggest that H2A.Z-2 preferentially associates with H3 trimethylated at lysine 4 compared to H2A.Z-1, and the phylogenetic analysis of the promoter regions of H2A.Z-1 and H2A.Z-2 indicate that they have evolved separately during vertebrate evolution. Overall, these data suggest that the two isoforms of H2A.Z present in vertebrates may have acquired a degree of functional independence. In Chapter 4, we show that H2A.Z and an N-terminally acetylated form of H2A.Z associate with the prostate specific antigen (PSA) gene promoter and the levels of these proteins are reduced upon induction of the gene with androgen. Furthermore, H2A.Z protein levels increase in response to treatment with androgen which correlates with an increase in the mRNA expression levels of the H2A.Z-1 gene. Preliminary Western Blot and quantitative PCR analysis of H2A.Z (-1 and -2) levels in a tumor progression model of prostate cancer indicate that increased H2A.Z expression may be involved in the development of androgen independent prostate cancer. Collectively, our results contribute to our understanding of H2A.Z biology in vertebrates and support a role for this protein and its acetylated forms in poising promoter chromatin for subsequent gene transcription.

Wilms' tumor suppressor protein (WTI) is a key regulatory factor involved in controlling the development and normal physiology of the genitourinary tract. Mutations within WT1 result in multiple syndromes affecting the kidney and gonads with the most severe effects being Wilms' tumor, a pediatric kidney cancer. The WTI protein is composed of two distinct functional domains; the amino terminus is a proline and glutamine rich regulatory domain, while the carboxyl terminus is a DNA binding domain which contains four C2H2 zinc fingers. Although the zinc finger motif is small in size, proteins containing zinc fingers are extremely diverse in their functions. The functional diversity of WT1 is exemplified through its interactions with a wide range of ligands, such as DNA, RNA and proteins. The interaction between WT1 and DNA has been well characterized, while the interactions with RNA and proteins still require intensive investigation. Recent studies have identified a diverse group of WT1 protein partners but the characterization of the protein-protein interactions has been limited and inconclusive. Therefore, the experiments conducted in this study focused on investigating the mechanism of interaction between WTI with the protein ligands Ciao 1, p53, par4, and U2AF65. To identify which WTI zinc finger(s) are critical in protein binding, a series of finger swap and deletion mutant proteins were created using site directed mutagenic PCR. The effects the mutant proteins had on the protein interactions were analyzed qualitatively using GST pulldown assays. Two different approaches were used for the GST pulldown assays. The first approach utilized bacterially expressed and purified proteins. None of the mutant WTI proteins exhibited a decrease in protein binding in these assays. Numerous pulldown trials involving various zinc fmger proteins revealed non-specific protein-protein interactions were occurring. The second approach employed in vitro translated 35S-labelled proteins. The results from these assays demonstrate a clear role for WT lzf3, and a possible role for WTI zf4 in the WT 1-par4 interaction. The replacement of WT 1 zinc fingers 3 and 4 with those from YY1 caused a distinct reduction in binding to par4 which was exclusive for the WT1-par4 interaction. YY1 is a transcription factor from yeast that contains four C2H2 type zinc fingers. A decrease in binding between the chimeric proteins WTI :YY1 and the protein partners Ciao 1 and U2AF65 was also observed, although to a much lesser extent. This difference in binding ability may indicate that the interactions between WT1 and its protein ligands involve different zinc fingers.

The synthesis of yttrium phenalenide complexes 129-132 was achieved by salt metathesis reactions between ligand anions and YCI3. Ytterbium phenalenide complexes 133-137 were synthesized by protonolysis reactions between neutral ligands and Yb[N(SiMe3)2]2(THF)2. The solid state structure of (Pni1Bu)2Yb(THF) 136 reveals a unique n3 bonding pattern, however the electrons of the phenalenide ligand remain delocalized even when bonded to the metal center. Mono-alkyl complexes (PCpR)2Y(CH2SiMe3)(THFSiMe3)(THF) 147-149 (R = Me. Ph. H) and bis-alkyl complexes (PCp*)Y(CH2SiMe3)2(THF) 150 and (sCp)Y(CH2SiMe3)2(THF) 152 were synthesized by direct protonolysis reactions between Y(CH2SiMe3)3(THF)2 and neutral ligands. When treated with phenylsilane, complex 148 generated the crowded hydride dimer [(PCpPh)2Y(u-H)]2 161. Complexes 150 and 152 undergo acid-base. metallation. insertion reactions and polymerization of small substrates. A variable temperature `H NMR study of 150 and 152 at low temperature reveals an equilibrium between 150/152-THF and 1501152. The THF-free complexes. 150/152-THF. appear to undergo inversion of a pyramidal ground state structure to generate a C2 symmetric intermediate. The X-ray structures of 136, 147, 150. 152, (sCp)Y(CH2SiMe3)2(bipy) 154, 161. [PCp*Y(CCSiMe3)(THF)]2(u2-CCSiMe3)2] 167, acetylide cluster 169 and bis-(Me3Si)2Cp yttrium chloride dimer 176 were determined and structural features discussed.

A series of para-dioxolene bridging ligands with bis-tridentate or bis-bidentate coordination pockets have been prepared. These ligands were designed to serve as building blocks in the preparation of functional metallosupramolecular structures. The bis-tridentate dipyridyl-diazaanthraquinones have topologies suitable for the preparation of [2 x 2] grids or larger extended structures. Employing a double condensation reaction between 1,3-diamino-4,6-benzenedicarboxaldehyde and 2-acetyl pyridine successfully afforded a cisoid binding diazaanthraquinone. The redox activity of the latter revealed it is more easily reduced than structurally similar 1,5- and 1,8-diazaanthraquinones. The synthesis of an analogous ligand displaying transoid coordination pockets proved challenging. Several approaches were attempted however the preparation of key intermediates 1,4-dinitro-2,5-benzenedicarboxaldehyde and 2,5-diamino-1,4-(hydroxyI-methyl) benzene were unsuccessful. A collection of bis-bidentate 2,5-bis(phosphino)1,4-dioxolenes were prepared with diphenyl, diisopropyl and diethoxy substituents at the phosphorus center. 2,5- Dibromo-1,4-dimethoxybenzene was reacted with the appropriate chlorophosphine under lithiation conditions to afford the dimethoxy compound, which was subsequently deprotected to the hydroquinone state with a Lewis acid. The diphenylphosphino hydroquinone was oxidized using phenyliodonium bisacetate, however efforts to oxidize other hydroquinone precursors to the targeted quinone state proved challenging. Diphenyl and diisopropyl phosphino hydroquinones were successfully coordinated with diamagnetic palladium hexafluoroacetylacetonate precursors. The resulting bimetallic bis(phosphino) dianion complexes were subsequently oxidized to the semiquinone state using silver (I) hexafluorophosphate and studied to determine the distinctive features of the semiquinone ligand.