No description available.

No description available.

Many experiments have been performed with the Warburg apparatus, or variations of this manometric technique, since Warburg's experiments (52, 53) where the effects of cyanides upon dark reactions and of urethanes upon light reactions of photosynthesis were demonstrated. The same basic techniques were utilized in this research in attempting to determine the effects of some coordination complexes upon the apparent photosynthetic rate of Chlorella pyrenoidosa. A second goal of the present paper was to investigate the potential of the Warburg apparatus as a tool for screening algicidal compounds.

This thesis provides the first example of coordination of a 1,2,3-dithiazolyl (1,2,3-DTA) ligand through a N, O bidentate pocket that is reproducible in high purity and bulk quantities. More importantly, it reports the first magnetometry measurements on metal complexes of a 1,2,3-DTA ligand. The radical ligand 1,2,3-dithiazolyl-6,7-dimethyl-1,4-naphthoquinone (6,7-Me2DTANQ) has been prepared and fully characterized. Coordination complexes of 6,7-Me2DTANQ have also been prepared and the resulting species’ structural and magnetic properties are presented. The transition metal ions Ni2+ and Mn2+ produce volatile trinuclear M(hfac)2-Rad-M(hfac)2-Rad-M(hfac)2 complexes. The spin ground state of the trinuclear Mn complex ST = 13/2 results from antiferromagnetic (AFM) coupling. Short sulfur-sulfur contacts and sulfur-oxygen contacts between trinuclear complexes produce weak AFM coupling interactions between trimer units. The lanthanide ions Nd3+, Gd3+ and Dy3+ produce volatile [Ln(hfac)3-Rad]n complexes. The spin ground state of the Gd polymer is ST = 3 per monomeric unit due to Gd3+‒radical AFM coupling.

Proteoglycans containing Heparan Sulfate (HS), a sulfated glycosaminoglycan (GAG), play a major role in the cell signaling process, interacting with many different proteins. HS is over expressed on the surface of many cancer cells. Enzymatic cleavage of HS-GAGs by heparanase causes release of angiogenic growth factors leading to tumor cell migration. Heparanase is also over-expressed in tumors with significant correlation between metastatic potential and heparanase activity. Proteoglycans and their associated enzymes are thus significant drug targets of high biological relevance. A functional consequence of strong PPC-HS binding has been shown in proof-of-concept studies confirming inhibition of the model pentasaccharide, Fondaparinux, by bacterial Heparinase. Such metalloshielding by PPCs may also protect HS from enzymatic cleavage by the mammalian heparanase; preventing growth factors from binding to HS and/or preventing release of bound growth factors and thus inhibiting the metastatic response in the cancer cells. HS-GAGs are also receptors for cellular accumulation of cationic Polynuclear Platinum Complexes (PPCs) through high-affinity binding to the highly anionic HS. PPCs competitively inhibit uptake of TAMRA-R9, a fluorescent nona-arginine derivative, in CHO cells. The previously reported series of Pt(II) complexes were investigated as DNA binders, initiating the apoptotic cascade. The result of PPC-DNA binding produces long range inter and intra-strand cross-links, that produce structural and conformational changes. Hydrogen bonding between phosphate oxygens and square planar Pt(II) nitrogen results in bidentate complexes by either backbone tracking or groove spanning of DNA. This complex forms a clamp like structure, called a phosphate clamp, similar to that of the arginine fork. Understanding this clamp allows us to investigate the structurally similar sulfate binding between metal complexes and target HSPG. HSPGs may allow significant research into both a novel cellular internalization of principal metals and “metalloshielding” of heparin by these compounds. Previous studies have shown that a wide range of metal ions have high affinity to heparin. The trend of metal/heparin affinity is believed to be dependent on parameters consisting of the metal’s overall size, spatial orientation of the ligands attached to each metal, the net charge and oxidation state of these metals, and number of binding sites. Studies have shown relative affinities of sulfate and carboxylate groups for the metal ions. These metal cations play an important role in the affinity, specificity, and stability of many protein/heparin interactions. The study of simple coordination compounds, like Pt, Mn, V, Ru and Co, will allow preliminary results which will extend into the PPCs mode of binding. This thesis focuses on the concept of metalloglycomics and reviews the interactions of various metal complexes with heparin. The covalent and non-covalent interactions of metal complexes with heparin resulting in strong bonding are explained through spectroscopy and calorimetry. The cleavage inhibition of heparanase by metal complexes is also described. Sulfate cluster anchoring shields the sulfates from loss as seen in mass spectrometry. The study of metalloglycomics offers potential understanding into the relevance of metal-heparin interactions and possibilities into the development of new compounds as therapeutic agents.

No description available.

Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The number of coordination complexes utilizing bis-pyridyl diamide ligands has increased significantly over the past decade. This is attributed to the relatively easy synthetic procedure of the ligands and interesting structural features such as helicity, water clusters and porosity that the coordination complexes possess. In the first part of this study, the following eight structurally related bis-pyridyl diamide ligands: • N,N'-bis(pyridin-4-ylmethyl)isophthalamide (ISO); • N,N'-bis(pyridyl-4-ylmethyl)terephthalamide (TER); • N,N'-bis(pyridin-4-ylmethyl)hexanediamide (ADI); • N,N'-bis(pyridin-4-ylmethyl)butanediamide (SUC); • N,N'-bis(pyridin-4-ylmethyl)biphenyl-4,4'-dicarbonyl dicarboxamide (DIP); • N,N'-dipyridin-2-ylpentanediamide (GLUT); • (2E)-N,N'-bis(2-pyridin-4-ylmethyl)but-2-enediamide (FUM); • 4-(pyridin-4-ylmethyl)aminocarbonyl benzoic acid (TER-A). were synthesized and characterized by NMR, FTIR, MS and SCD. In the second part, the synthesized ligands were reacted with a variety of transition metal salts to yield fifteen novel coordination polymers and one discrete complex. SCD analysis showed that of the sixteen complexes thirteen formed 1-D chains, two formed 2-D networks, and one formed a discrete unit. Hydrogen bonding interactions between water molecules, the counterions and the amide groups resulted in connection of the lower dimension entities into higher dimension networks. The synthesized ligands were co-crystallized with trimesic acid and a novel co-crystal consisting of ADI and trimesic acid was obtained. SCD analysis showed that the co-crystal featured the amide homosynthon as well as the pyridine/carboxylic acid heterosynthon. / AFRIKAANSE OPSOMMING: Die aantal koördinasie komplekse met dipiridieldiamied ligande het noemenswaardig vermeerder oor die afgelope dekade. Hierdie groei kan toegeskryf word aan die eenvoudige sintetiese prosedure en interessante strukturele eienskappe van dié koördinasie komplekse, wat o.a. helikse, waterbondels en poreuse materiale vorm. In die eerste deel van hierdie studie is die agt onderstaande struktureel verwante dipiridieldiamied ligande se sintese en karakterisering deur kernmagnetieseresonansie, Fourier transform infrarooi, massaspektrometrie en enkel kristal X-straal diffraksie (SCD) beskryf: • N,N'-bis(piridien-4-ielmetiel)isoftalamied (ISO); • N,N'-bis(piridien-4-ielmetiel)tereftalamied (TER); • N,N'-bis(piridien-4-ielmetiel)heksaandiamied (ADI); • N,N'-bis(piridien-4-ielmetiel)butaandiamied (SUC); • N,N'-bis(piridien-4-ielmetiel)bifeniel-4,4'-dikarbonieldikarboksamied (DIP); • N,N'-dipiridien-2-ielpentaandiamied (GLUT); • (2E)-N,N'-bis(2-piridien-4-ielmetiel)but-2-eendiamied (FUM); • 4-(piridien-4-ielmetiel)aminokarboniel bensoësuur (TER-A). In die tweede gedeelte is bg. ligande met 'n reeks oorgangsmetaalsoute gereageer om vyftien nuwe koördinasiepolimere, asook een diskrete kompleks, te lewer. SCD analise toon dat van hierdie sestien komplekse vorm dertien 1-D kettings, twee vorm 2-D netwerke en slegs een vorm 'n diskrete eenheid. Waterstofbindings tussen die water molekules, die teen-ione en die amied groepe het laer dimensie (1-D) eenhede verbind om hoër dimensionele netwerke (2-D) te vorm. Mede-kristallisasie van die gesintetiseerde ligande met trimesielsuur het 'n nuwe mede-kristal tussen ADI en triemesielsuur opgelewer. Enkelkristal diffraksie toon dat die mede-kristal beide die amied homosinton en die piridien/karboksielsuur heterosinton bevat.

O entendimento das propriedades de complexos metálicos é de fundamental importância para o desenvolvimento de fármacos. No entanto, tanto do ponto de vista experimental quanto no de modelagem teórica, ainda temos muitas dificuldades de simular e mensurar as mudanças que a complexação com um metal causa em um composto. Este trabalho apresenta estudos de simulacões ab initio de complexos de Epiisopiloturina com Cu e Zn. Foram realizadas otimizações de estrutura, simulaçoes de espectroscopia vibracional, NMR e EPR além de estudos de reatividade. Obtivemos uma geometria otimizada condizente com a da forma cristalizada. Além disso, os resultados espectroscópicos mostram que as estruturas dos com plexos permanecem intactas em solução. Por fim, os estudos de reatividade conrmam que o complexo de Cobre aumenta a reatividade da molécula. / Understanding the properties of metal complexes is fundamental goal in the development of drugs. However, both from the experimental point of view and theoretical modeling, many diculties in the simulation and evaluatio of the changes that the metal causes upon complexation still remains. This work presents ab initio computational simulations of Epiisopiloturin com plexes with Cu and Zn. We make structural optimizations, simulations of vibrational spectroscopy, NMR and EPR, as well as reactivity studies. We obtain an optimized geometry that corresponds to that of the crystallized form. In addition, the spectroscopic results conrm that the complexes remain intact in solution. Finally, the reactivity studies conrm that the copper complex increases the reactivity of the molecule.

New 1,2,3,5-dithiadiazolyl (DTDA), 1,2,3,5-diselenadiazolyl (DSDA) radicals and their resulting metal complexes were synthesized and characterized. The overarching theme of this thesis is the utility of intermolecular interactions for facilitating previously unseen magnetic behaviours in thiazyl radical-metal complexes. This thesis contains the first examples of thiazyl radical metal complexes acting as molecule based magnets. The 4-benzoxazol-2′-yl-1,2,3,5-dithiadiazolyl (boaDTDA) radical and its selenium analogue 4-benzoxazol-2′-yl-1,2,3,5-diselenadiazolyl (boaDSDA) were coordinated to several paramagnetic metal ions including transition metal ions Mn(II), Co(II) and Ni(II). The Ni(hfac)2(boaDTDA) and Ni(hfac)2(boaDSDA) complexes are isomorphous and both demonstrate step like π-stacking leading to additional ferromagnetic (FM) intermolecular interactions. The Mn(hfac)2(boaDTDA) (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato) complex was the first DTDA metal complex to conclusively show that intermolecular S(DTDA)…O(hfac) contacts can lead to intermolecular anti-ferromagnetic (AF) interactions which, in turn, can lead to a large spin ground state. Based on the magnetic properties of the Mn(hfac)2(boaDTDA) complex, a new DTDA biradical ligand, 4,6-bisDTDApyrimidine (bisDTDApym), was developed and coordinated to Mn(hfac)2. The resulting dinuclear Mn(II) complex, [Mn(hfac)2]2(bisDTDApym), is arranged in the solid state by short S(DTDA)…O(hfac) interactions forming two dimensional ferrimagnetic sheets. These ferrimagnetic sheets AF couple to one another, giving rise to AF ordering below 4.5 K. The [Mn(hfac)2]2(bisDTDApym) is the first thiazyl metal complex to magnetically order and is a unique example of a molecular coordination complex which magnetically orders. This thesis also presents the synthesis and characterization of precursor materials of the form Ln(hfac)3(DME) (DME = dimethoxyethane) for coordination reactions to thiazyl radical ligands. The Dy(hfac)3(boaDTDA) and Dy(hfac)3(pyDTDA) (pyDTDA = 4-(2′-pyridyl)-1,2,3,5-DTDA) complexes demonstrate single molecule magnetism with energy barriers of 100 K and 70 K respectively. Ten-coordinate Ln(hfac)3(pyDTDA)2 (Ln = La, Ce, Pr) complexes demonstrate phase transition behaviour between dimerized and undimerized phases and were studied by X-ray crystallography and magnetometry. The aforementioned compounds are some of the over 50 new compounds which have been synthesized and fully characterized in this thesis.

xvii, 147 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. / Supramolecular chemistry is a relatively new and exciting field offering chemists simplistic approaches to generating complex assemblies through strategically designed ligands. Much like the many spectacular examples of supramolecular assemblies in nature, so too are chemists able to construct large, elegant assemblies with carefully designed ligands which bind preferentially to target metal ions of choice. An important concept of supramolecular chemistry, often subtle and overlooked, is secondary bonding interactions (SBIs) which in some cases, act as the glue to hold supramolecular assemblies together. This dissertation examines SBIs in a number of systems involving the pnictogen elements of arsenic and antimony as well as aromatic interactions in self-assembled monolayers. The first half of this dissertation is an introduction to the concepts of supramolecular chemistry and secondary bonding interactions and how they are used in the self-assembly process in the Darren Johnson laboratory. Chapter I describes how secondary bonding interactions between arsenic and aryl ring systems and antimony and aryl ring systems assist with the assembly process. Chapter II is a continuation of the discussion of SBIs but focuses on the interactions between arsenic and heteroatoms. The second half of this dissertation will describe work performed in collaboration with Pacific Northwest National Laboratory (PNNL) in Richland, WA. This work was performed under the guidance of Dr. R. Shane Addleman in conjunction with Professor Darren W. Johnson of the University of Oregon. This portion describes novel systems for use in heavy metal ion remediation from natural and unnatural water sources. Chapters III-V describe functionalized mesoporous silica for use in heavy metal uptake from contaminated water sources. Chapter V describes a new technology invented during this internship at PNNL which utilizes weak bonding interactions between aryl ring systems to produce regenerable green materials for toxic metal binding. This work is ongoing in the Darren Johnson lab. This dissertation includes my previously published and co-authored material. / Committee in charge: Michael Haley, Chairperson, Chemistry; Darren Johnson, Member, Chemistry; Shih-Yuan Liu, Member, Chemistry; James Hutchison, Member, Chemistry; Eric Johnson, Outside Member, Biology