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Synthesis and studies on transition metal complexes of antimony ligandsHill, Angela M. January 1997 (has links)
No description available.
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Rf coil design for multi-frequency magnetic resonance imaging & spectroscopyDabirzadeh, Arash 15 May 2009 (has links)
Magnetic Resonance Spectroscopy is known as a valuable diagnostic tool for
physicians as well as a research tool for biochemists. In addition to hydrogen (which is
the most abundant atom with nuclear magnetic resonance capability), other species (such
as 31P or 13C) are used as well, to obtain certain information such as metabolite
concentrations in neural or muscular tissues. However, this requires nuclear magnetic
resonance (NMR) transmitter/receivers (coils) capable of operating at multiple
frequencies, while maintaining a good performance at each frequency. The objective of
this work is to discuss various design approaches used for second-nuclei RF (radio
frequency) coils, and to analyze the performance of a particular design, which includes
using inductor-capacitor (LC) trap circuits on a 31P coil. The method can be easily
applied to other nuclei. The main advantage of this trapping method is the enabling
design of second-nuclei coils that are insertable into standard proton coils, maintaining a
near-optimum performance for both nuclei. This capability is particularly applicable as
MRI field strengths increase and the use of specialized proton coils becomes more
prevalent. A thorough performance analysis shows the benefit of this method over other designs, which usually impose a significant signal-to-noise (SNR) sacrifice on one of the
nuclei.
A methodology based on a modular coil configuration was implemented, which
allowed for optimization of LC trap decoupling as well as performance analysis. The 31P
coil was used in conjunction with various standard 1H coil configurations
(surface/volume/array), using the trap design to overcome the coupling problem
(degraded SNR performance) mentioned above. An analytical model was developed and
guidelines on trap design were provided to help optimize sensitivity. The performance
was analyzed with respect to the untrapped case, using RF bench measurements as well
as data obtained from the NMR scanner. Insertability of this coil design was then
verified by using it with general-purpose proton coils available. Phantoms were built to
mimic the phosphorus content normally found in biologic tissues in order to verify
applicability of this coil for in vivo studies. The contribution of this work lies in the
quantification of general design parameters to enable “insertable” second-nuclei coils, in
terms of the effects on SNR and resonance frequency of a given proton coil.
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Cucurbit[n]uril - a delivery host for anti-cancer drugsZhao, Yunjie, Physical, Environmental & Mathematical Sciences, Australian Defence Force Academy, UNSW January 2009 (has links)
No description available.
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Mononuclear and multinuclear salicylaldimine metal complexes as catalysts precursors in the oxidation of phenol and cyclohexeneVan Wyk, Juanita Lizélle January 2009 (has links)
Philosophiae Doctor - PhD / In this thesis typical homogeneous and dendritic immobilized catalysts derived from
salicylaldimines were investigated as catalysts for the oxidation of hydrocarbons using
hydrogen peroxide as oxidant under aerobic conditions. This research work thus describes
the synthesis of several new N-(aryl)salicylaldimines as well as peripheral functionalised
salicylaldimine poly(propyleneimine) dendrimers. The dendritic ligands were obtained by
modifying the peripheral groups of Generation 1 and Generation 2 poly(propyleneimine)
dendrimer, (DAB-(NH2)n) which are commercially available. Both types of ligands were
utilized to synthesize Cu(II) and Co(II) complexes using appropriate acetate salts. The
ligands systems and metal complexes prepared were fully characterized using a range of
physical techniques. The Cu(II) and Co(II) complexes were evaluated as catalysts for the oxidation of phenol
and cyclohexene using hydrogen peroxide as oxidant under an oxygen atmosphere. The
catalytic oxidation of phenol to the dihydroxybenzenes, catechol (CT) and hydroquinone
(HQ), was investigated in aqueous media at various pH values. All the complexes
investigated were active for the hydroxylation process producing CT as major product. The
pH of the reaction medium was found to have much more of an influence on the activity
and product selectivity of the Co(II) complexes as compared to the case for the Cu(II)
complexes. All the catalysts investigated were also found to exhibit good activity for the oxidation of cyclohexene producing predominantly the allylic oxidation products 2-cyclohexene-1-one and 2-cyclohexene-1-ol. However the formation of the epoxide, cyclohexene oxide was
also observed as minor product or in trace quantities. It was found that the cobalt catalysts
produced 2-cyclohexene-1-one as major product, however higher levels of 2-cyclohexene-
1-ol was produced by all catalysts in catalytic runs where the oxidant to substrate ratio was
reduced and when the metal loading was increased. In the case of the copper catalysts 2-
cyclohexene-1-ol was produce in slightly higher levels than 2-cyclohexene-1-one.
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Computational and Spectroscopic Determination of Lithiated Benzylic Nitriles in THF/HMPA SolutionHarmon, Henry Jason 16 October 2008 (has links)
The synthetic utility of nitrile-stabilized carbanions as reactive intermediates for selective carbon-carbon bond formation has prompted numerous studies toward characterization of the solution structure of these nucleophiles. In hopes of eventually gaining a better understanding of the structural properties which may mediate reactivity and selectivity, researchers have designed elegant structure elucidation strategies. These studies have offered key advancements toward the characterization of these intermediates; however, contradictory evidence has hindered unambiguous structural determination—particularly for lithiated benzylic nitriles in low dielectric, ethereal media.
Chapter 1 of this dissertation presents a review of the synthetic utility of metalated nitriles and the spectroscopic and computational techniques employed to characterize their solution structure. Also reviewed herein are the controversial determinations drawn from these efforts. The research and data which follow in Chapters 2 and 3 focus on resolution of the conflicting structural determinations drawn from multinuclear magnetic resonance (NMR) and vibrational (IR and Raman) spectroscopy. Employing a strategy to slow the lithium-nitrogen exchange rate in low dielectric media, new 7Li, 31P, and 15N NMR spectroscopic evidence (with support from computational modeling) lead us to amend our previous assessments and propose that lithiated arylacetonitriles adopt an aggregated triple-ion structure in THF/hexane with sub-stoichiometric HMPA.
Due to the limitations of computer resources and the effect of non-linear scaling, theoretical modeling of aggregated and solvated lithiated benzylic nitriles became impractical at the 6-31+G(d) basis set. These limitations led to the use and comparative analysis of two alternative basis sets for the DFT analysis of lithiated benzylic nitrile derivatives' 6-31(+LiX)G(d) and 6-31â +â G(d). Defined upon the principal of resonance stabilization, these basis sets were constructed by application of varying levels of computational theory on a per-atom basis. By applying higher levels of theory only to the atoms most intimately involved in the electronic distribution, "accurate" replacement models for 6-31+G(d) structures were obtained with considerable savings in computational resources. This study in basis set economy is detailed fully within Chapters 4 and 5. / Ph. D.
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Synthèse et étude de la complexation de nouveaux benzoxaboroles multivalents / Synthesis and study of the complexation of new multivalent benzoxaborolesLarcher, Adèle 22 October 2018 (has links)
Les benzoxaboroles (qui sont les dérivés cycliques des acides boroniques) s’imposent comme une nouvelle classe de molécules intéressantes, pour la formulation de nouveaux agents thérapeutiques (notamment avec la commercialisation de l’AN2690, dérivé fluoré du benzoxaborole, en tant qu’antifongique), tout comme la formation de matériaux fonctionnels. A ce jour, il n’y a pas eu de mise au point de synthèse systématique de petites molécules benzoxaboroles multivalentes, limitant ainsi leur utilisation. Dans le cadre de cette thèse, différentes approches de synthèse ont été développées et ont permis l’obtention de 12 nouveaux composés bi- ou tri-valents. La principale réactivité de ces composés est leur capacité à complexer les cis-diols. Étant donné que la force de l’interaction est dépendante de la nature du substrat, il est important de pouvoir l’analyser en détail. La complexation entre les benzoxaboroles avec les diols est généralement réalisée par la méthode spectrofluorimétrique qui est controversée, particulièrement dans le cas des molécules organoborées multivalentes. Pour analyser en détail la stœchiométrie de ces complexations, une méthode RMN multinucléaire en solution a ici été développée. Les composés bi- ou tri-valents ont ensuite été testés en tant qu’agent thérapeutique. En effet, récemment, l’activité d’inhibition contre l’anhydrase carbonique de motifs benzoxaboroles monovalents a été discutée dans la littérature. La multivalence nos molécules pouvant être un avantage, leur constante d’inhibition contre l’anhydrase carbonique ont été mesurées. Enfin, dans un tout autre domaine, la réactivité avec les diols et la multivalence de nos composés ont été mises en avant par la formation de nouveaux complexes moléculaires. / Benzoxaboroles (which are cyclic derivates of boronic acids) are emerging as an interesting class of molecules for the design of news therapeutic agents (in particular with the commercialization of AN2690, which is a fluorinated derivative of benzoxaborole, as an antifungal agent), as well as for the formation of functional materials. However, to date, only few syntheses of small molecules of multivalent benzoxaborole have been described in the literature. In this thesis, different approaches were explored to isolate 12 new bi- or tri-valent benzoxaboroles. The main reactivity of these compounds is their ability to bind to cis-diols. Given that the strength of interaction between an organoboron molecule and a diol depends on the nature of the interacting counterparts, it is important to be able to measure it in detail. The complexation between benzoxaboroles and cis-diols is usually studied by a spectrofluorimetric method, which is controversial, especially in the case of multivalent benzoxaboroles. To analyse in detail the stoichiometry of these complexation, a multinuclear NMR method in solution was developed in this thesis. The di- or tri-valent benzoxaboroles were then tested as therapeutic agents. Indeed, recently, the activity of monovalent benzoxaborole against carbonic anhydrases was discussed in the literature. Since the multivalence of our molecules could be a benefit, the measurement of their inhibition constants against carbonic anhydrases was performed. Finally, in a completely different type of application, their reactivity toward cis-diols and their multivalence was put forward to create new complexes.
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On Thallium (III) and binuclear platinum-thallium complexes with N-donor ligands in solution and in solidMa, Guibin January 2001 (has links)
This thesis describes the synthesis, structure, equilibriaand other properties of novel thallium(III) monomeric andplatinum-bonded complexes with nitrogen donor ligandsethylenediamine, diethylenetriamine, triethylenetetramine,porphyrin, 2,2'-bipyridine and 1,10-phenanthroline in solutionand in solid. The existence of three complexes withthe general formula[Tl(en)n]3+(n = 1-3) and their overall stability constantshave been established in pyridine. All three complexes wereidentified by their205Tl and1H NMR chemical shifts and205Tl-1H coupling constants. The formation process of thecomplexes was followed by1H NMR spectroscopy. The crystal structure of[Tl(en)3](ClO4)3was determined; the thallium(III) ion isN-coordinated in a distorted octahedral geometry. Two [Tl(dien)n]3+(n = 1-2) complexes were proved to exist insolution and the structure of the bis-complex [Tl(dien)2]2+inu-facialisomers was determined in solid. In addition,crystal structures of [Tl(en)2CN](ClO4)2with cyanide bridging between two Tl(en)2units forming an infinite chain structure and of[Tl(tren)2(CN)2](ClO4) with a distorted pseudo-octahedral coordinationaround thallium were determined. Thallium(III) complexes with2,2'-bipyridine and 1,10-phenanthroline have been studied inDMSO using205Tl,13C and1H NMR spectroscopy. In addition, aseven-coordinated thallium was found in the crystal structureof [Tl(bipy)3(dmso)](ClO4)3, and six-coordinated thallium in pseudo-octahedralgeometry in [Tl(phen)2Cl2](ClO4). The solvated complex [Tl(dmso)6]3+has been prepared using concentrated aqueoussolution of Tl(ClO4)3by a solvent replacement reaction in DMSO, and thewater-free solid compound [Tl(dmso)6](ClO4)3was crystallized from DMSO. The structure of thecomplex [Tl(dmso)6]3+is a regular octahedron with the Tl-O bonddistance 2.224(3) Å. It represents an easy and secure wayto introduce water-free Tl(III) into organic phase withoutreduction. Through several reactions, novel heteronuclear Pt-Tlcomplexes with the composition [(NC)5Pt-Tl(tpp)]2-, [(NC)5Pt-Tl(thpp)]2-, [(NC)5Pt-Tl(bipy)n](n = 1-2), [(NC)5Pt-Tl(en)n-1](n = 1-3) and [(NC)5Pt-Tl(phen)n](n = 1-2), have been synthesized in solution.Multinuclear NMR (195Pt,205Tl,13C and1H), Raman spectroscopy and X-ray diffraction dataare fully compatible with formation of unsupported Pt-Tl bondedcomplexes both in solution and in solid. The huge1J(195Pt-205Tl) spin-spin coupling constants (48-66 kHz) wereobserved by both195Pt and205Tl NMR spectroscopy in solution and they providea strong evidence of formation of the Pt-Tl bond in solution.In all six determined crystal structures of the Pt-Tl compoundsa very short Pt-Tl bond is found with distances2.6117(5)-2.6375(5) Å. The calculated values of Pt-Tlforce constants (1.38-1.91 N/cm) are characteristic for asingle metal-metal bond. In the Pt-Tl compounds, the oxidation state of the metalions is intermediate between the stable states PtII/PtIVand TlIII/TlI, respectively, and this is reflected by their195Pt and205Tl chemical shifts. It turns out that N-donorligands can really stabilize the Pt-Tl bond both in solutionand in solid. The character of the metal-metal bond anditstheoretical basis are discussed. <b>Keywords:</b>Thallium, Platinum, Cyanide, N-donor ligand,Metal-metal bond, Multinuclear NMR, Raman spectroscopy, X-raydiffraction, Equilibrium, Spin-spin coupling.
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On Thallium (III) and binuclear platinum-thallium complexes with N-donor ligands in solution and in solidMa, Guibin January 2001 (has links)
<p>This thesis describes the synthesis, structure, equilibriaand other properties of novel thallium(III) monomeric andplatinum-bonded complexes with nitrogen donor ligandsethylenediamine, diethylenetriamine, triethylenetetramine,porphyrin, 2,2'-bipyridine and 1,10-phenanthroline in solutionand in solid.</p><p>The existence of three complexes withthe general formula[Tl(en)<sub>n</sub>]<sup>3+</sup>(n = 1-3) and their overall stability constantshave been established in pyridine. All three complexes wereidentified by their<sup>205</sup>Tl and<sup>1</sup>H NMR chemical shifts and<sup>205</sup>Tl-<sup>1</sup>H coupling constants. The formation process of thecomplexes was followed by<sup>1</sup>H NMR spectroscopy. The crystal structure of[Tl(en)<sub>3</sub>](ClO<sub>4</sub>)<sub>3</sub>was determined; the thallium(III) ion isN-coordinated in a distorted octahedral geometry. Two [Tl(dien)<sub>n</sub>]<sup>3+</sup>(n = 1-2) complexes were proved to exist insolution and the structure of the bis-complex [Tl(dien)<sub>2</sub>]<sup>2+</sup>in<i>u-facial</i>isomers was determined in solid. In addition,crystal structures of [Tl(en)<sub>2</sub>CN](ClO<sub>4</sub>)<sub>2</sub>with cyanide bridging between two Tl(en)<sub>2</sub>units forming an infinite chain structure and of[Tl(tren)<sub>2</sub>(CN)<sub>2</sub>](ClO<sub>4</sub>) with a distorted pseudo-octahedral coordinationaround thallium were determined. Thallium(III) complexes with2,2'-bipyridine and 1,10-phenanthroline have been studied inDMSO using<sup>205</sup>Tl,<sup>13</sup>C and<sup>1</sup>H NMR spectroscopy. In addition, aseven-coordinated thallium was found in the crystal structureof [Tl(bipy)<sub>3</sub>(dmso)](ClO<sub>4</sub>)<sub>3</sub>, and six-coordinated thallium in pseudo-octahedralgeometry in [Tl(phen)<sub>2</sub>Cl<sub>2</sub>](ClO<sub>4</sub>).</p><p>The solvated complex [Tl(dmso)<sub>6</sub>]<sup>3+</sup>has been prepared using concentrated aqueoussolution of Tl(ClO<sub>4</sub>)<sub>3</sub>by a solvent replacement reaction in DMSO, and thewater-free solid compound [Tl(dmso)<sub>6</sub>](ClO<sub>4</sub>)<sub>3</sub>was crystallized from DMSO. The structure of thecomplex [Tl(dmso)<sub>6</sub>]<sup>3+</sup>is a regular octahedron with the Tl-O bonddistance 2.224(3) Å. It represents an easy and secure wayto introduce water-free Tl(III) into organic phase withoutreduction.</p><p>Through several reactions, novel heteronuclear Pt-Tlcomplexes with the composition [(NC)<sub>5</sub>Pt-Tl(tpp)]<sup>2-</sup>, [(NC)<sub>5</sub>Pt-Tl(thpp)]<sup>2-</sup>, [(NC)<sub>5</sub>Pt-Tl(bipy)<sub>n</sub>](n = 1-2), [(NC)<sub>5</sub>Pt-Tl(en)<sub>n-1</sub>](n = 1-3) and [(NC)<sub>5</sub>Pt-Tl(phen)<sub>n</sub>](n = 1-2), have been synthesized in solution.Multinuclear NMR (<sup>195</sup>Pt,<sup>205</sup>Tl,<sup>13</sup>C and<sup>1</sup>H), Raman spectroscopy and X-ray diffraction dataare fully compatible with formation of unsupported Pt-Tl bondedcomplexes both in solution and in solid. The huge<sup>1</sup>J(<sup>195</sup>Pt-<sup>205</sup>Tl) spin-spin coupling constants (48-66 kHz) wereobserved by both<sup>195</sup>Pt and<sup>205</sup>Tl NMR spectroscopy in solution and they providea strong evidence of formation of the Pt-Tl bond in solution.In all six determined crystal structures of the Pt-Tl compoundsa very short Pt-Tl bond is found with distances2.6117(5)-2.6375(5) Å. The calculated values of Pt-Tlforce constants (1.38-1.91 N/cm) are characteristic for asingle metal-metal bond.</p><p>In the Pt-Tl compounds, the oxidation state of the metalions is intermediate between the stable states Pt<sup>II</sup>/Pt<sup>IV</sup>and Tl<sup>III</sup>/Tl<sup>I</sup>, respectively, and this is reflected by their<sup>195</sup>Pt and<sup>205</sup>Tl chemical shifts. It turns out that N-donorligands can really stabilize the Pt-Tl bond both in solutionand in solid. The character of the metal-metal bond anditstheoretical basis are discussed.</p><p><b>Keywords:</b>Thallium, Platinum, Cyanide, N-donor ligand,Metal-metal bond, Multinuclear NMR, Raman spectroscopy, X-raydiffraction, Equilibrium, Spin-spin coupling.</p>
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Elucidation of Structure-Property Relationship Based on Multinuclear Metal Complexes and Development into Metal Complex Nanotubes / 多核金属錯体を基盤とした構造-物性相関の探索と金属錯体ナノチューブへの展開Aoki, Kentaro 23 March 2022 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第23715号 / 理博第4805号 / 新制||理||1688(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 吉村 一良, 教授 竹腰 清乃理 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
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Studies on Synthesis and Host-Guest Chemistry of Cycloparaphenylenes / シクロパラフェニレンの合成法とホストゲスト化学に関する研究Iwamoto, Takahiro 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18298号 / 工博第3890号 / 新制||工||1597(附属図書館) / 31156 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 山子 茂, 教授 中條 善樹, 教授 村田 靖次郎 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
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