As an additional study, effect of tyrosine nitration on the BCD of protonated and metalated peptides was investigated. Some fragment ions that were inhibited in the ECD of protonated peptides were liberated in the ECD of metalated peptides. By theoretical calculation of the cation-pi and cation-nitro group coordination using the metal ions nitrated phenol complex as a model, it is found that the metal ions might favor coordinating with the nitro group of the nitrated tyrosine residue in the peptides. / In order to improve the performance of the electron capture dissociation (BCD) mass spectrometry for structural analysis of peptides/proteins, BCD of peptides cationized with various transition metal ions was investigated. It was found that peptides adducted with different divalent transition metal ions generated different BCD tandem mass spectra. For Mn2+and Zn2+, the incoming low-energy electron would not favor being trapped by the metal ions and instead trigger the usual BCD dissociation channel(s) via "hot-hydrogen" or "superbase" intermediates to form a series of c-/z·- fragments. For other first row transition metal ions, including Fe2+, Co2+, Ni 2+and Cu2+, reduction of the metal ions occurs preferentially during the electron capture event and lead to the formation of usual "slow-heating" type of fragment ions, i.e. metalated a-/y-fragments & metalated b-/y- fragments. / To further compare the behavior of metal ions with the same electronic configuration, BCD of Group IIB metal ions adducted peptides were investigated. In contrast to the ECD behavior of Zn2+ adducted peptides, peptide radical cations (M+· ) and fragment ions corresponding to losses of neutral side chain from M+· were observed in the ECD spectra of Hg2+ and Cd2+ adducted peptides. The experimental observations appeared to depend on the balance of the ionization energy of peptide and the solvation modulated ionization energies of the metal atom. The reduction of divalent metal ions by the electron capture event could induce spontaneous electron transfer from the peptide moiety to the monovalent metal centre and generate hydrogen-deficient M +· species. / Chen, Xiangfeng. / Adviser: T.-W. Dominic Chan. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 131-139). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

自由電子雷射器和傅裡葉變換質譜儀的組合使之成為一種研究生物分子和一些水和離子的溶解動力學的有力工具。而理論方法作為實驗的輔助手段常用于判斷一些分子的結構。在本論文中，我運用密度泛函理論和第一性分子動力學方法研究了陽離子化的氨基酸和一些水合陰離子的實驗紅外多光子吸收譜。 / 第二章研究了氫離子和鹼金屬離子化的天冬醯胺酸的紅外多光子吸收譜。以前有文獻用簡諧近似的方法研究過這個團簇，不過這種方法忽略了分子的動力學和非諧效應。我用第一性分子動力學方法重新研究了這個體系，結果顯示這種陽離子化的氨基酸的分子結構非常柔軟，在有限溫度下可以通過二面角的轉動和離子與氨基酸中的氧和氮原子距離的振動可以相互的轉化。而這些構型的相互轉化可以解釋實驗紅外吸收峰的展寬和相對強度變化趨勢。 / 第三章研究了水合碳酸氫根陰離子的紅外多光子吸收譜。以前的文獻指出，對於這種團簇，僅通過對比實驗和簡諧近似的紅外譜圖不能夠判斷是否只有一種異構體存在。應用第一性分子動力學方法，我發現簡諧近似紅外譜和實驗譜的不吻合之處，特別是水分子個數小於等於5時，水分子中氫原子的左右搖擺振動和來回搖擺振動吸收峰在實驗譜中的缺失。通過計算一系列異構體的熱能，我發現一些含量較少的異構體仍然對吸收峰有比較大的貢獻，考慮了這些結構的貢獻我們就可以理解為什麼隨著團簇尺寸的增加，一些吸收峰的強度有一定的變化趨勢。 / 最後兩章研究了水合磷酸二氫根的紅外多光子吸收譜。這是第一次我們和實驗組合作成果。在這個專案裡，我負責分析和全部的理論計算。對於這種團簇，實驗上測量了紅外譜的低頻和高頻區(n=1-4)。有趣的是，特別是體系只包含一個水分子時，兩個穩定的異構體均不能單獨解釋低頻和高頻的實驗結果。基於分子動力學的研究發現，有一個過渡態的吸收峰出現在了高頻區。其原因是氫原子的零點能和隧穿效應。與n=1類似,對於存在多個水分子的體系，實驗譜也揭示了低溫下的異構體效應，而這個效應使得簡諧效應完全失效。 / The combination of the FEL with FTICR makes it a powerful tool in researching the biochemical molecules and solvation dynamics of small hydrated ions. And theoretical methods are often employed in the determination of the molecular structures as auxiliary tools. In this thesis, density functional theory and ab initio molecular dynamics method have been applied to study the experimental infrared multiphoton dissociation (IRMPD) processes for cationized amino acids and hydrated anions. / The second Chapter is the AIMD simulated IR spectra for Asparagine cationized by H⁺, Li⁺, Na⁺, K⁺, and Cs⁺. The previous work simulated these type clusters with harmonic approximation in which the dynamics and anharmonicity effects were missed. My result shows that M⁺(Asn) complexes are very flexible and they could convert into each other at finite temperatures by torsional rotation and stretching the distances between the ion and N, O atoms in Asn. The broaden features and shift of the relative intensities of the vibrational profiles for these conformers are dependent on the structural flexibility of the complexes. / The third Chapter is the IRMPD spectra of the hydrated bicarbonate anion clusters for n=1-7. For some clusters, as mentions in the former harmonic results, comparing the experimental and calculated spectra does not always identify a single isomer as being responsible for the spectrum. By using AIMD technique, I found discrepancies between the harmonic and experimental spectra, especially for the absence of water wagging and rocking mode in the experimental result for n=1-5. By calculating the thermal energies of various isomers of each cluster, I found that the less dominate conformer also shows its large contributions to the vibrational profiles and this could explain the peak intensity trend as the cluster size increase. / The vibrational spectra for (HO)₂PO₂⁻(H₂O)n=1-4, 6, and 8 are presented in the last two chapters. It is the first time we collaborate with experiment group. In these works, I have done all the theoretical simulations. For these clusters, both the low and high (n=1-4) frequency regions of IRMPD spectra are measured. Interestingly for n=1, both the two stable isomer cannot alone represent both the low and high frequency profiles. Base on the AIMD simulations, I found that the existence of an unstable transient state shows it absorption profile in the high frequency region due to the zero point energy and tunneling effect of hydrogen atom. Similar to n=1, the IRMPD spectra of larger clusters (n>1) also show evidence for isomerization at cryogenic temperatures which leads to a complete breakdown of the harmonic approximation. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Sun, Shoutian. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references. / Abstracts also in Chinese. / Sun, Shoutian.

Ions play pivotal roles both biologically and environmentally. The effects felt from the impact of ions, much like their relative charge, can be positive or negative. Ions are responsible for catalyzing and executing precise control over many of the essential processes that occur in our bodies. Ions can also be major contributors as environmental pollutants having catastrophic effects. There is a great deal of interest in better understanding the role and effect of ions in the surrounding environments. The ability to study ions of interest relies on efficient recognition and sensing of these targets. The field of supramolecular chemistry is particularly well suited for this task as it utilizes non-covalent molecular interactions in much the same way natural system involving ions operate. Broadly, this body of research seeks to explore the subtle interactions of various targeted ions with supramolecular receptors. This research is an effort to further understand the nature of these interactions for potential recognition and sensing applications as well as better understanding the highly complex systems found in biology. Chapter I provides a brief overview of various mechanisms of ion coordination in supramolecular chemistry and emphasizes some key examples demonstrating the importance of the various types of coordination as it pertains to the research presented herein. Chapter II highlights a unique class of phosphine oxide-based tripodal ditopic receptors and presents studies on their interactions with alkali metals and halides. Chapter III covers the synthesis and study of anionic binding trends for a series of heteroaromatic-containing urea-based receptors and discusses the influence of anion binding on receptor conformation. Chapter IV provides preliminary results on the application of the bipyridal bisurea-based anion receptor, presented in Chapter III, as ligand for metal salts. Chapter V focuses on a series of pyridal bisurea-based receptors with regard to their ability to serve as chloride sensitive probes in cellular environments. This dissertation contains both previously published and unpublished co-authored material. / 10000-01-01

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We investigate the coupling of a single trapped ion to a miniature optical cavity operating in the ultraviolet. Our cavity provides a source of single photons at a high rate into a single spatial mode. Using our apparatus, we have demonstrated the highest atom-cavity coupling rate achieved with a single ion by an order of magnitude. When the ion is continuously excited, we observe phase-sensitive correlations between emission into free-space and into the cavity mode, which can be explained by a cavity induced back-action effect on a driven dipole. We demonstrate coherent manipulation of a hyperfine qubit and ultra-short optical π rotations, which are essential tools for creation and detection of spin-photon entanglement. To this end, we have developed optical fibre-based Fabry-Perot cavities in the ultraviolet spectral range. These cavities operate near the primary dipole transition of Yb at 370 nm, and allow us to couple a pure atomic two-level system offered by a single trapped ion to the cavity mode. A new Paul trap apparatus in an ultra-high vacuum chamber has been built which allows for the integration of these cavities at very small ion-mirror separations. In order for independent operation of the trap, a compact system of diode lasers has been built which are stabilised to low-drift optical reference cavities. Coherent control of the hyperfine qubit in Yb 171 is achieved through application of microwave radiation, and ultra-short optical π rotations are performed with resonant light pulses derived from a frequency-doubled mode-locked titanium-sapphire laser. The experiment is controlled through a system of hardware and software which has been developed in a modular fashion and will allow for efficient control on the nanosecond time-scale when several such systems are interconnected. The success of our system opens the door to future experiments with trapped ions which will reach the strong coupling regime with a single ion. Furthermore, when operated in the fast-cavity regime, systems based on our approach will enable high-efficiency collection of photons from the ion into the single mode of an optical fibre. These systems will allow for the generation of distributed entanglement and will prove ideal as nodes in a larger quantum network of trapped ions.

Orientador: Elidiane Cipriano Rangel / Banca: Aldo Eloizo Job / Banca: Sandra Andrea Cruz / Resumo: Os elastômeros termoplásticos (TPE) têm sido bastante empregados em substituição às borrachas tradicionais, por terem custo reduzido de matéria prima, facilidade no processamento e serem recicláveis. Apresentam propriedades mecânicas semelhantes, porém quando utilizados em componentes de vedação apresentam limitada resistência à corrosão em água clorada. Assim, o desenvolvimento de tratamento superficial que não modifique as características originais, mas tornem o material mais resistente são desejáveis. Para tanto, este trabalho pretende desenvolver uma metodologia a plasma para melhorar esse quesito. O elastômero termoplástico de copoliéster (COPE) foi escolhido por ser o mais empregado em componentes de vedação. O tratamento a plasma de baixa pressão com hexafluoreto de enxofre (SF6) foi empregado visando tornar a superfície do COPE hidrofóbica através da incorporação de grupos fluorados. A implantação iônica por imersão em plasmas (IIIP) de argônio foi utilizada para criar uma camada superficial mais coesa e entrelaçada, além da possibilidade de torná-la hidrofóbica após envelhecimento. Para o tratamento com SF6, os parâmetros de excitação do plasma (12 Pa e 80 W) foram mantidos, variando-se o tempo do tratamento entre 2 e 180 minutos de modo a encontrar uma condição ótima para esse processo. Para a IIIP de Ar os parâmetros de excitação do plasma (5 Pa e 60 min) foram mantidos e a potência da radiofrequência foi variada entre 10 e 150 W. A energia de superfície e ângulo d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Thermoplastic elastomers have been widely used in substitution for conventional rubber, given that the feedstock is cheaper, easier to process and recyclable. Its mechanical properties are similar, but when applied to sealing components its resistance is limited due to the chlorine present in water, therefore, it is interesting to develop a surface treatment that do not alter the original characteristics, but make the material more robust. To achieve such result, we chose to submit the copolyester thermoplastic elastomer (COPE) to plasma. This material was naturally chosen, once it is widely used for sealing purposes in this specific industry. By using low pressure plasma with sulfur hexafluoride, we expect to alter COPEs surface by incorporating fluorine groups, thus making it hydrophobic. We also submitted the sample to a second treatment, by submersion to argon plasma, making the outer layer less defective and more entangled with aging, as observed in previous experiments. For SF6 treatment, the exiting plasma parameters (12Pa and 80W) were kept and the treatment time was varied between 2 to 180 minutes in order to find the optimal treatment time. For Argon IIIP, the plasma exciting parameters (5Pa and 60 min) were maintained, while the radio frequency variation was between 10 to 150W. Surface energy and contact angle were obtained by and automatic goniometer, through the sessile drop method ... (Complete abstract click electronic access below) / Mestre

This thesis details the use of aromatic ions, especially aminocyclopropenium ions, as empowering design elements in the development of new chemical reactions, organic catalysts and polymeric materials. A particular focus is placed throughout on understanding the relationship between the structure of aromatic ions and their performance in these novel applications. Additionally, the benefits that aromatic ions provide in these contexts are highlighted. The first chapter briefly summarizes the Lambert Group's prior efforts toward exploiting the unique reactivity profiles of aromatic ions in the context of new reaction design. Also provided in the first chapter is a comprehensive literature review of aminocyclopropenium ions, upon which the majority of advances described in this thesis are based. To set the stage for the first application of aminocyclopropenium ions, Chapter 2 provides an account of existing highly Brønsted basic functional groups, including guanidines, proazaphosphatranes and iminophosphoranes. The provided review on the synthesis and use in asymmetric catalysis of these bases indicates that there is a high need for conceptually new Brønsted basic functional groups. To address this need, the development of chiral 2,3-bis(dialkylamino)cyclopropenimines as a new platform for asymmetric Brønsted base catalysis is described in Chapter 3. This new class of Brønsted base is readily synthesized on scale, operates efficiently under practical conditions, and greatly outperforms closely related guanidine-based catalysts. Structure-activity relationship studies, mechanistic experiments and computational transition state modeling are all discussed in the context of asymmetric glycinate imine Michael reactions in order to arrive at a working model for cyclopropenimine chemistry. Cumulatively, this chapter provides a "user's guide" to understanding and developing further applications of 2,3-bis(dialkylamino)cyclopropenimines. The use of our optimal chiral 2,3-bis(dialkylamino)cyclopropenimine catalyst to promote asymmetric Mannich reactions of glycinate imines and N-Boc-aldimines is described in Chapter 4. The products of this transformation are optically enriched diamino acid derivatives, an important motif widely utilized in medicinal and synthetic chemistry. Importantly, unlike existing methods, our technology promotes reactions between tert-butyl glycinate and aliphatic N-Boc-aldimine substrates. A preparative-scale reaction is demonstrated and derivatization of its product to several valuable chiral compounds is shown. Chapter 5 describes the use of tris(dialkylamino)cyclopropenium (TDAC) ions as a new class of onium-like catalyst. A simple TDAC chloride salt is prepared on a 75-gram scale and its use as a phase transfer catalyst for a variety of reactions is demonstrated. This same salt is also utilized as an epoxide opening catalyst for a variety of transformations, including the fixation of carbon dioxide. Chapter 6 briefly highlights several continued applications of the chemistry advanced throughout this thesis. First, the work of other members of the Lambert Group toward the continued development of cyclopropenimine chemistry is described. Second, a broad initiative between the Lambert and Campos Groups at Columbia University focused on the synthesis and application of TDAC-based polymers is introduced. Lastly, the identification of a previously unknown equilibrium between fulvenes and imines/aldehydes in the context of a new mode of catalysis is presented.

Dans cette thèse, nous avons exploré toute une palette de composés à base de métaux de transition et de polyanions carboxylates (oxalates, malonates et carbonates) préparés via des procédés éco-efficaces. La synthèse du composé oxalate de fer (III) (Fe2(C2O4)3·4H2O) dont nous en avons élucidé pour la première fois la structure cristalline en combinant les techniques de diffraction des rayons X et neutrons, fait l'objet de la première partie de cette étude. Ce composé cristallise dans une maille triclinique (P -1) et il présente des propriétés électrochimiques intéressantes (98 mAh/g à 3.35 V vs. Li+/Li0). Dans cette quête pour de meilleurs matériaux, nous avons exploré la famille des oxalates Na2M2(C2O4)3·2H2O, dont la synthèse avait été déjà rapportée, mais sans qu'aucune activité électrochimique ne puisse être détectée. En revanche, le remplacement du groupement oxalate par un groupement malonate nous a permis d’obtenir pour la première fois plusieurs membres de la famille (Na2M(H2C3O4)2·nH2O (n=0, 2), M= Mn, Fe, Co, Ni, Zn et Mg) dont nous avons résolu leurs structures cristallines correspondantes. Cependant, comme dans le cas des oxalates, ces phases ne dévoilent aucune activité électrochimique vis-à-vis du lithium, bien qu'elles présentent des propriétés magnétiques intéressantes. Enfin nous avons conclu ce travail par la synthèse de composés appartenant à la famille des fluorocarbonates KMCO3F (M= Ca et Mn) en utilisant la voie tout solide. La phase au calcium, déjà rapportée dans la littérature, a fait l'objet d'une étude en température qui nous a permis de mettre en évidence pour la première fois la formation d'une phase haute température (KCaCO3F-HT), pour T≥320°C, dont nous avons résolu la structure. Finalement, l'utilisation du Mn au lieu du Ca a conduit à l'obtention d'une nouvelle phase (KMnCO3F) qui cristallise dans une maille hexagonale (P -6 c 2) / This thesis has focused on the exploration of new compounds based on 3d-metal and carboxylate polyanions (oxalates, malonates and carbonates) prepared through different sustainable synthetic approaches. In the first part, we report a new synthetic route to prepare the iron (III) oxalate compound (Fe2(C2O4)3·4H2O) and solve its crystal structure through combined X-ray and neutron powder diffraction. The compound crystallizes within a triclinic cell (P-1) and exhibits attractive electrochemical properties (98 mAh/g at 3.35 V vs. Li+/Li0). Motivated by this finding we pursued our quest for new positive electrode materials. We prepared by hydrothermal synthesis single crystals of sodium 3d-metal oxalates Na2M2(C2O4)3·2H2O, which are widely investigated in the literature for their magnetic properties. Unfortunately, these phases are electrochemically inactive versus lithium. Thereafter, we extended the synthesis towards the malonate family and we reported for the first time several members (Na2M(H2C3O4)2·nH2O (n= 0, 2), M= Mn, Fe, Co, Ni, Zn et Mg). These systems present rich crystal chemistry together with interesting antiferromagnetic properties but as in the case of the oxalates, they are not electrochemically active versus lithium. Finally, we synthesized two members of fluorocarbonates compounds KMCO3F (M= Ca and Mn) using solid state process. We succeeded in the preparation of the calcium member, already reported in the literature and we identified for the first time a phase transition at 320°C. The crystal structure of the high temperature phase (KCaCO3F-HT) was solved using neutron powder diffraction. A new manganese phase (KMnCO3F) was synthesized using the same technique and its crystal structure was solved by combining TEM, XR and neutrons powder diffraction techniques. This compound crystallizes within a hexagonal unit cell (P -6 c 2)

"November 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 206-213). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

No presente trabalho implantamos Íons de Sb, Sn e Ag no fotoresiste AZ1350 (polímero novolak) e usamos a técnica de retroespalhamento de Rutherford a fim de estudar os seguintes asp ectos: a) alcances projetados dos Íons i'mplantados e os correspondentes desvios estatísticos em função da energia de implantação; b) variação na estabilidade térmica do fotoresiste como conseqüência de imo plantações rasas destes elementos (até rv500 A) ; c) difusividade térmica dos íons implantados. Nossos experimentos forneceram os seguintes resultados. Encontramos que os parâmetros de alcance, extraídos dos perfis experimentais, estão em bom acordo com as predições teóricas obtidas a partir da teoria de Ziegler, Biersack e Littmark. No entanto, verificamos que o perfil da perda de oxigênio ocorrida durante o processo de implantação não corresponde ao perfil de danos obtido teoricamente. Com respeito a estabilidade térmica, encontramos que implantações rasas de Sb e Sn tornam o fotoresiste mais resistente quanto a perda de material, sendo o Sb mais eficiente que o Sn. Implantações com a Ag, por sua vez, não tem influência na estabilidade térmica do fotoresiste implantado. O processo de estabilização térmica pode ser devido a dois fatores: a) danificação ocasionada pelo processo de implantação; b) efeitos químicos de ligações dos Íons implantados com os componentes do fotoresiste. Finalmente, os estudos de difusividade mostram que Íons de Sb e Sn difundem regularmente sendo que a energia de ativação para o processo é de rvl80 meV. A Ag por sua vez segrega como conseqüência do tratamento térmico. Comparação dos nossos resultados com estudos prévios realizados com implantações de Au e Bi no fotoresiste AZ1350, nos levam à conclusão que aqueles elementos que difundem regularmente (Bi, Sn e Sb) protegem o fotoresiste, ao contrário dos elementos que não difundem regularmente como Au e Ag, que segregam como conseqüência do tratamento térmico. / In the present work we have implanted Sb, Sn and Ag in the photoresist AZ1350 and used the Rutherford backscattering technique in order to study the following features: a) range and range straggling of the implanted ions as a function of implantation energy; h ) variation in the thermal stability of the photoresist as a consequence of shallow o Ag, Sn and Sb implantations ( "'500 A); c) thermal diffusivity behavior of the implanted íons. Our results have shown the following features. We found that the experimental range parameters are in good agreement with the theoretical predictions by Ziegler, Biersack and Littmark. However the oXYgen profile loss, which arises as a consequence of the implantation process does not agree with the theoretical damage profile. We also found 'that the thermal stability of the photoresist increases as a consequence of the Sb and Sn implantations. On the other side the Ag implantations do not improve the thermal stability of the implanted photoresist. The thermal stabilization process can be attributed to two main process: a) radiation damage due to the implantation process; b) chemical effects due to the creation of bonds between the implanted ion and the components of the fotoresist. Finally it should be stated that the Sb and Sn íons diffuse in a regular way following an Arrhenius plot being the activation energy of the order of 180 meV. On the other side it is shown that Ag segregates as a consequence of the thermal treatment. A comparison of the present and previous results for Au and Bi implanted into the same photoresist allow us to draw the following conclusion. The thermal stability of the AZ1350 photoresist is enhanced by those elements which diffuse regulary (Sn, Sb and Bi) . On the contrary Au and Ag (which segregate) do not bring any beneficiai effect.