by Lim Che Lau. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 79-84). / Title Page --- p.i / Table of Contents --- p.ii / List of Tables --- p.iv / List of Figures --- p.v / List of Schemes --- p.vii / Acknowledgments --- p.viii / Abstract --- p.ix / Chapter CHAPTER 1: --- INTRODUCTION / Chapter 1.1. --- Historical Background --- p.1 / Chapter 1.2. --- FTICR with External Ion Source --- p.2 / Chapter 1.3. --- High Mass Analysis in FTICR --- p.4 / Chapter 1.4. --- Outline of Present Work --- p.7 / Chapter CHAPTER 2: --- INSTRUMENTATION AND EXPERIMENTAL / Chapter 2.1. --- Instrumentation --- p.8 / Chapter 2.1.1 --- Ion Source --- p.10 / Chapter 2.1.1.1. --- Liquid Secondary Ion Mass Spectrometry --- p.11 / Chapter 2.1.1.2. --- Electrospray Ionization --- p.12 / Chapter 2.1.2. --- Electrostatic Ion Focusing System --- p.15 / Chapter 2.1.3. --- ICR Analyzer Cell and Magnet --- p.18 / Chapter 2.1.4. --- Data Acquisition and Handling System --- p.22 / Chapter 2.2. --- Experimental --- p.22 / Chapter 2.2.1. --- Liquid Secondary Ion Mass Spectrometry --- p.22 / Chapter 2.2.2. --- Electrospray Ionization --- p.23 / Chapter 2.2.3. --- Nozzle-Skimmer Dissociation --- p.24 / Chapter 2.2.4. --- Sustained Off-Resonance Irradiation Collision- Induced Dissociation --- p.24 / Chapter 2.2.5. --- Data Acquisition and Processing --- p.27 / Chapter 2.2.6. --- Mass Calibration --- p.27 / Chapter CHAPTER 3: --- STRUCTURAL CHARACTERIZATION OF TERPYRIDINE-BASED POLYETHER DENDRIMERS AND THEIR IRON(II) METALLOCOMPLEXES BY LIQUID SECONDARY ION MASS SPECTROMETRY AND ELECTROSPRAY IONIZATION MASS SPECTROMETRY / Chapter 3.1. --- Introduction --- p.28 / Chapter 3.2. --- Sample Preparation --- p.29 / Chapter 3.3. --- Results and Discussion --- p.30 / Chapter 3.3.1. --- Liquid Secondary Ion Mass Spectrometry Studies --- p.30 / Chapter 3.3.1.1. --- Dendrimers --- p.30 / Chapter 3.3.1.2. --- Metallodendrimers --- p.41 / Chapter 3.3.2. --- Electrospray Ionization Mass Spectrometry Studies --- p.47 / Chapter 3.4. --- Conclusions --- p.53 / Chapter CHAPTER 4: --- STUDIES OF LANTHANIDE(III) PORPHYRIN- PHTHALOCYANINE HETEROLEPTIC SANDWICH COMPLEXES USING ELECTROSPRAY IONIZATION / Chapter 4.1. --- Introduction --- p.54 / Chapter 4.2. --- Results and Discussion --- p.55 / Chapter 4.2.1. --- Molecular Weight Determination --- p.57 / Chapter 4.2.2. --- Structural Elucidation --- p.65 / Chapter 4.2.3. --- Charge-Transfer Processes --- p.72 / Chapter 4.3. --- Conclusions --- p.76 / Chapter CHAPTER 5: --- CONCLUSIONS --- p.77 / References --- p.79

Misturas poliméricas no campo tecnológico e científico vêm sendo desenvolvidas, diariamente, devido à possibilidade de gerar materiais com propriedades especiais para determinadas aplicações, sem a necessidade de se desenvolver novos processos de polimerização. O processo de mistura no estado fundido, por extrusão em dupla rosca, facilita à obtenção de misturas poliméricas, com destaque, às misturas ternárias. As misturas poliméricas possuem a vantagem de produzir materiais com propriedades intermediárias às dos seus componentes puros. Este trabalho teve como objetivo desenvolver uma mistura polimérica para ser aplicada na indústria calçadista capaz de substituir componentes produzidos a partir do copolímero de (etileno-co-acetato), EVA, em forma de espuma, sem a necessidade de reticulação. Para atingir este objetivo, misturas de POE/EVA/PVC em diferentes proporções, foram preparadas a partir de uma mistura básica de POE/EVA, á qual se adicionou diferentes % de PVC, preparadas em uma extrusora de dupla rosca corrotante, com configuração específica. As condições de processamento foram definidas a partir de um estudo de reometria oscilatória. As misturas foram caracterizadas quanto as suas propriedades térmicas, por DSC e TGA, quanto a sua resistência mecânica por medidas de tração uniaxial e dureza. A compatibilidade dos componentes foi avaliada por reometria oscilatória e espectroscopia de infravermelho com transformada de Fourier e a sua morfologia por MEV. Os resultados de FTIR aliados as análises térmicas e a microscopia indicam uma miscibilidade parcial entre os componentes nas composições estudadas. Os ensaios mecânicos de tração e dureza revelaram que a adição de PVC à mistura POE/EVA aumentou a rigidez do composto ternário, enquanto nas análises de fluidez, no estado fundido, o índice de fluidez (melt flow index, IMF) diminuiu, indicando um aumento da viscosidade do sistema. As propriedades das misturas ternárias desenvolvidas capacitam as mesmas para uma aplicação tecnológica imediata em peças para solados de calçados, visto que, a depender da composição, geram materiais com interação entre as fases adequada para alcançar elasticidade, resiliência e rigidez necessárias, mesmo na ausência de reticulação, o que por sua vez, facilita o reuso do material. / Polymer blends in scientific and technological fields are being developed every day because of the possibility to generate materials with special properties for specific applications without a need to develop new polymerization processes. The mixing process in the melt by twin screw extrusion, facilitates the obtaining of polymer blends, especially at ternary mixtures. The polymer blends have the advantage of producing materials with properties intermediate those of their pure components. This study aimed to develop a polymer blend to be applied in footwear industry capable of replacing components produced from the copolymer of (ethylene-co-acetate), EVA, in the form of foam, without the need for crosslinking. To achieve this goal, blends of POE / EVA / PVC in different proportions were prepared from a basic mixture of POE / EVA, to which was added various% PVC prepared in a twin screw extruder co rotating with specific configuration. The processing conditions were defined from a study of oscillatory rheometry. The blends were characterized for their thermal properties by DSC and TGA, as their mechanical strength by uniaxial tensile measurements and hardness. The compatibility of the components was evaluated by oscillatory rheometry and IR spectroscopy The Fourier transform and its morphology by SEM. The results of analyzes combined FTIR microscopy and thermal indicate a partial miscibility between the components in the compositions studied. The properties of ternary mixtures developed enable the same to a technological application shown in parts for shoe soles, since, depending on the composition, generate materials with interaction between the phases to achieve adequate elasticity, resiliency and rigidity necessary even in the absence of crosslinking, which in turn facilitates the reuse of the material.

Neste trabalho, foi proposto um novo material adsorvente com base na modificação química do talo de açaí (AS) com brometo de hexadeciltrimetilamônio (CTAB), formando um novo material chamado AS-CTAB. Os dados da caracterização do adsorvente de AS-CTAB indicaram que a biomassa foi modificada quimicamente pelo surfactante. O material preparado foi utilizado com sucesso como adsorvente para a remoção de Direct Blue 15 (DB-15) e Direct Red 23 (DR-23) a partir de soluções aquosas. Para ambos os corantes, a adsorção seguiu o modelo cinético Avrami. O modelo da isotermica de Liu apresentando Qmax de 394,01 e 454,9 mg g-1 para DB-15 e DR-23, respectivamente, a 45 °C. Uma vez que o AS-CTAB não é um material poroso, a interação eletrostática foi o principal mecanismo envolvido no processo de adsorção para ambos os corantes. A reação de adsorção termodinâmica mostrou ser um processo espontâneo e endotérmico. O adsorvente AS-CTAB também foi testado no tratamento de efluentes de corantes sintéticos e apresentou uma boa performance. / In this work, it was proposed a new adsorbent material based on the chemical modification of aqai stalk (AS) by hexadecyltrimethylammonium bromide (CTAB), forming a new material called AS-CTAB. The characterization data of AS-CTAB adsorbent indicated that the biomass was chemically modified by the surfactant. The prepared material was successfully used as adsorbent for the removal of Direct Blue 15 (DB-15) and Direct Red 23 (DR-23) from aqueous solutions. For both dyes, adsorption followed the Avrami kinetic model. Liu isotherm model displayed Qmax of 394.01and 454.9 mg g-1 for DB-15 and DR-23, respectively at 45°C. Since the AS-CTAB is not a porous material, electrostatic interaction was the main mechanism involved in the adsorption process for both dyes. The thermodynamic adsorption reaction was shown to be a spontaneous and endothermic process. The AS-CTABadsorbent was also tested in the treatment of synthetic dye effluents and presented very good performance.

Han, Fangyuan. / Thesis submitted in: November 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 68-72). / Abstracts in English and Chinese. / Title Page --- p.I / Thesis Committee --- p.II / Acknowledgements --- p.III / Abstract --- p.IV / 摘要 --- p.V / Table of Contents --- p.1 / List of Figures --- p.4 / List of Tables --- p.6 / Chapter Chapter 1 --- Introduction --- p.7 / Chapter Chapter 2 --- Fourier Transform Spectroscopy --- p.10 / Chapter A. --- The Michelson Interferometer and the Interferogram --- p.10 / Chapter B. --- The Link between the Interferogram and the Spectrum: the Fourier Transform --- p.12 / Chapter C. --- "Resolution, Apodization and Spectral Folding" --- p.13 / Chapter D. --- Advantages and Disadvantages of FTIR Spectroscopy --- p.17 / Chapter E. --- Time-resolved FTIR Spectroscopy --- p.18 / Chapter (1) --- Time-resolved Rapid Scan Scheme --- p.18 / Chapter (2) --- Step-scan Scheme --- p.19 / Chapter F. --- Several Considerations in Step-scan Time-resolved Spectroscopy / Chapter Chapter 3 --- Molecular Fluorescence --- p.24 / Chapter A. --- Transitions Between Electronic States --- p.24 / Chapter B. --- Absorption and Vibrational Relaxation --- p.26 / Chapter C. --- Internal Conversion and Fluorescence --- p.26 / Chapter D. --- Intersystem Crossing and Phosphorescence --- p.27 / Chapter E. --- Fluorescence Lifetime and Quantum Yield --- p.29 / Chapter Chapter 4 --- Fourier Transform Spectroscopy of Zinc Phthalocyanine and Derivatives --- p.32 / Chapter A. --- Introduction --- p.32 / Chapter B. --- Apparatus --- p.35 / Chapter (1) --- VERTEX 70 FTIR Spectrometer --- p.35 / Chapter (2) --- Excitation Source --- p.38 / Chapter (3) --- Detectors and the Transient recorder --- p.38 / Chapter (4) --- Samples and Sample Cells --- p.39 / Chapter C. --- Experimental Setup --- p.40 / Chapter (1) --- Absorption Experiments --- p.40 / Chapter (2) --- Emission Experiments --- p.42 / Chapter D. --- Results and Discussion --- p.45 / Chapter (1) --- Absorption and Fluorescence Spectra --- p.45 / Chapter (2) --- Fluorescence Lifetimes and Quantum Yields --- p.51 / Chapter (3) --- Time-resolved Fluorescence Spectra --- p.54 / Chapter E. --- Some Experimental Details --- p.60 / Chapter (1) --- Choice of Windows for Regular Tests of the Instrument Performance --- p.60 / Chapter (2) --- Configurations of the Transient Recorder in OPUS --- p.61 / Chapter (3) --- Configurations of Detectors in OPUS --- p.61 / Chapter (4) --- The Standard Method of Extracting Time Slices --- p.62 / Chapter (5) --- Parameters that Easily Cause Problems --- p.63 / Chapter (6) --- Elimination of Background Noises --- p.64 / Chapter Chapter 5 --- Concluding Remarks --- p.66 / Reference --- p.68

We give congruences modulo powers of 2 for the Fourier coefficients of certain level 2 modular functions with poles only at 0, answering a question posed by Andersen and Jenkins. The congruences involve a modulus that depends on the binary expansion of the modular form's order of vanishing at infinity. We also demonstrate congruences for Fourier coefficients of some level 4 modular functions.

A consensus model is a statistical approach that uses a family of signals or in our case, a family of images to generate a predictive model. In this thesis, we consider a family of images that are represented as tensors. In particular, our images are (2,0)-tensors. The consensus model is produced by utilizing the quantum Fourier transform of a family of images as tensors to transform images to images. We write a quantum Fourier transform in the numerical computation library for Python, known as Theano to produce the consensus spectrum. From the consensus spectrum, we produce the consensus model via the inverse quantum Fourier transform. Our method seeks to improve upon the phase reconstruction problem when transforming images to images under a 2-dimensional consensus model by considering images as (2,0)-tensors.

Tese de mestrado. Faculdade de Engenharia. Universidade do Porto. 1998

Documento confidencial. Não pode ser disponibilizado para consulta / Estágio realizado na CeNTI e orientado pela Mestre Joana Branquinho e Doutor José Santos / Tese de mestrado integrado. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 2010

The present studies which have been performed in the work-group C-2 (Prof. W. Kiefer) within the program of the Sonderforschungsbereichs 347, deal with the FT-Raman and –IR spectroscopy on new organometallic complexes, synthesized in the work-groups B-2 (Prof. W. Malisch), B-3 (Prof. W. A. Schenk), D-1 (Prof. H. Werner) and D-4 (Prof. D. Stalke). The FT-Raman spectra recorded at 1064 nm led to very useful and interesting information. Furthermore, the DFT calculations which are known to offer promise of obtaining accurate vibrational wavenumbers, were successfully used for the assignment of the vibrational spectra. For the first time it has been possible to ascribe exactly the n(RhC) stretching mode in the vinylidene rhodium(I) complex trans-[RhF(=C=CH2)(PiPr3)2] by using isotopic substitution, in conjunction with theoretical calculations. This is also true for the complexes trans-[RhF(CO)(PiPr3)2], trans-[RhF(C2H4)(PiPr3)2], trans-[RhX(=C=CHPh)(PiPr3)2] (X = F, Cl, Br, I, Me, PhCºC) and trans-[RhX(CN-2,6-xylyl)(PiPr3)2] (X = F, Cl, Br, I, CºCPh). In addition, the comparison between the n(RhC) wavenumbers of the complexes trans-[RhF(=13C=13CH2)(PiPr3)2] and trans-[RhF(CO)(PiPr3)2], containing the isoelectronic ligands 13C=13CH2 and CO, which have the same reduced mass, indicated that the Rh-C bond is stronger in the carbonyl than in the vinylidene complex. Besides, the n(RhF) stretching mode, which has been observed at higher wavenumbers in the FT-Raman and -IR spectra of trans-[RhF(CO)(PiPr3)2], showed that the carbonyl ligand is a better p-acceptor and a less effective s-donor than the vinylidene one. Moreover, the comparison of the n(CºC) and n(Rh-C) modes from the FT-Raman spectrum of the complexes trans-[Rh(CºCPh)(L)(PiPr3)2] (L = C=CHPh, CO, CN-2,6-xylyl) point out that the p-acceptor ability of the ligand trans to CºCPh should rise in the order C=CH2 < CO < CN-2,6-xylyl £ C=CHPh. The investigated sensitivity of the n(RhC), n(CC), n(CO) and n(CN) vibrational modes to the electronic modifications occuring in the vinylidene, carbonyl, ethylene and isonitrile complexes, should allow in the future the examination of the p-acceptor or p-donor properties of further ligands. Likewise, we were able to characterize the influence of various X ligands on the RhC bond by using the n(RhC) stretching mode as a probe for the weakening of this. The calculated wavenumbers of the n(RhC) for the vinylidene complexes trans-[RhX(=C=CHR)(PiPr3)2], where R = H or Ph, suggested that the strength of the Rh=C bond increases along the sequence X = CºCPh < CH3 < I < Br < Cl < F. For the series of carbonyl compounds trans-[RhX(CO)(PiPr3)2], where X = F, Cl, Br and I, analogous results have been obtained and confirmed from the model compounds trans-[RhX(CO)(PMe3)2]. Since, the calculated vibrational modes for the ethylene complex trans-[RhF(C2H4)(PiPr3)2] were in good agreement with the experimental results and supported the description of this complex as a metallacyclopropane, we were interested in getting more information upon this class of compounds. In this context, we have recorded the FT-Raman and -IR spectra of the thioaldehyde complexes mer-[W(CO)3(dmpe)(h2-S=CH2)] and mer-[W(CO)3(dmpe)(h2-S=CD2)] which have been synthezised by B-3. The positions of the different WL vibrational modes anticipated by the DFT calculations, were consistent with the experimental results. Indeed, the analysis of the band shifts in the FT-Raman and –IR spectra of the isotopomer mer-[W(CO)3(dmpe)(h2-S=CD2)] confirmed our assignment. The different stereoisomers of complex mer-[W(CO)3(dmpe)(h2-S=CH2)] were investigated too, since RMN and IR-data have shown that complex mer-[W(CO)3(dmpe)(h2-S=CH2)] lead in solution to an equilibrium. Since the information on the vibrational spectra of the molybdenum and tungsten complexes Cp(CO)2M-PR2-X (M = Mo, W; R = Me, tBu, Ph; X = S, Se) is very scarce, we extended our research work to this class of compounds. We have tried to elucidate the bonding properties in these chalcogenoheterocycle complexes by taking advantage of the mass effect on the different metal atoms (W vs. Mo). Thus, the observed band shifts allowed to assign most of the ML fundamental modes of these complexes. This project and the following one were a cooperation within the work-group B-2. The Raman and IR spectra of the matrix isolated photoproducts expected by the UV irradiation of the iron silyl complex Cp(CO)2FeSiH2CH3 have been already reported by Claudia Fickert and Volker Nagel in their PhD-thesis. Since no exact assignment was feasible for these spectra, we were interested in the study of the reaction products created by irradiation of the carbonyl iron silyl complex Cp(CO)2FeCH2SiH3. Although the calculated characteristic vibrational modes of the metal ligand unit for the various photoproducts are significantly different in constitution, they are very similar in wavenumbers, which did not simplify their identification. However, the theoretical results have been found to be consistent with the earlier experimental results. Finally, the last part of this thesis has been devoted to the (2-Py)2E- anions which exhibit a high selectivity toward metal-coordination. All di(2-pyridyl) amides and -phosphides which were synthesized by D-4, coordinate the R2Al+ fragment via both ring nitrogen atoms. This already suggests that the charge density in the anions is coupled into the rings and accumulated at the ring nitrogen atoms, but the Lewis basicity of the central nitrogen atom in Et2Al(2-Py)2N is still high enough to coordinate a second equivalent AlEt3 to form the Lewis acid base adduct Et2Al(2-Py)2NAlEt3. Due to the higher electronegativity of the central nitrogen atom in Me2Al(2-Py)2N, Et2Al(2-Py)2N and Et2Al(2-Py)2NAlEt3, compared to the bridging two coordinated phosphorus atom in Me2Al(2-Py)2P and Et2Al(2-Py)2P, the di(2-pyridyl)amide is the hardest Lewis base. In the phosphides merely all charge density couples into the rings leaving the central phosphorus atom only attractive for soft metals. These results were confirmed by using DFT and MP2 calculations. Moreover, a similar behaviour has been observed and described for the benzothiazolyl complex [Me2Al{Py(Bth)P}], where complementary investigations are to be continued. The DFT calculations carried out on the model compounds analysed in these studies supply very accurate wavenumbers and molecular geometries, these being in excellent agreement with the experimental results obtained from the corresponding isolated complexes. / Die vorliegende Arbeit wurde im Rahmen des Sonderforschungsbereichs 347 „Selektive Reaktionen Metall-aktivierter Moleküle“ im Teilprojekt C-2 (Prof. W. Kiefer) „Laserspektroskopie zur Charakterisierung der Struktur und Dynamik Metall-gebundener Moleküle“ durchgeführt. Diese befaßt sich mit den Infrarot- und Raman-spektroskopischen Untersuchungen an Übergangsmetallverbindungen, die in den Teilprojekten B-2 (Prof. W. Malisch), B-3 (Prof. W. A. Schenk), D-1 (Prof. H. Werner), D-4 (Prof. D. Stalke) synthetisiert wurden. Durch den Einsatz der FT-Raman-Spektroskopie mit langwelliger Laseranregung im NIR-Bereich und zum Teil von isotopenmarkierten Molekülen konnten aussagekräftige Spektren erhalten werden. Die Dichtefunktionnaltheorie stellte sich als geeignetes Mittel zur Vorhersage und Interpretation der Schwingungsspektren heraus. Abhängig von der Größe der betrachteten Komplexe waren jeweils Rechnungen nötig, die auf sehr unterschiedlichen theoretischen Niveaus basierten. Zum ersten Mal wurde mit Hilfe der Isotopenmarkierung und der Dichtefunktionaltheorie die Valenzschwingung n(Rh=C) in trans-[RhF(L)(PiPr3)2] (L = C=CH2, 13C=13CH2) charakterisiert. Diese zeigte sich als eine starke Raman-Bande und konnte ebenfalls im trans-[RhF(CO)(PiPr3)2] identifiziert werden. Darüber hinhaus erkannte man beim Vergleich von trans-[RhF(13C=13CH2)(PiPr3)2] und trans-[RhF(CO)(PiPr3)2] eine Verschiebung nach höheren Wellenzahlen der Valenzschwingung n(RhC) für den Carbonyl-Komplex. Einerseits haben beide Liganden 13C=13CH2 und CO die gleiche reduzierte Masse, was die elektronische Natur der n(RhC)-Verschiebung zeigt, welche eine Verstärkung der RhC-Valenzkraftkonstanten im Fall des Carbonyls belegt. Anderseits weist die Verschiebung der n(RhF)-Streckschwingung nach höheren Wellenzahlen im Carbonyl-Komplex für deren Ligand bessere p-Akzeptor- und schlechtere s-Donor-Eigenschaften gegenüber dem Vinyliden auf. Durch die aus solchen Untersuchungen gewonnenen n(RhC)- und n(CºC)-Verschiebungen in den verschiedenen untersuchten Komplexen ergibt sich die folgende Reihe abnehmender p-Akzeptorstärke: C=CHPh ³ CN-2,6-xylyl > CO > C=CH2. Die Empfindlichkeit der Valenzschwingungen n(RhC), n(CC), n(CO) und n(CN) gegenüber Veränderungen der elektronischen Verhältnisse in Vinylidene-, Carbonyl-, Ethylene- und Isonitrile-Komplexen läßt sich ihrerseits als „Sonde“ zur Untersuchung der p-Akzeptor-bzw. p-Donor-Eigenschaften anderer Liganden nutzen. Die Beeinflussung, vor allem die Schwächung der RhC-Bindung durch einen trans-ständigen Liganden konnte dadurch an den Komplexen trans-[RhX(13C=13CH2)(PiPr3)2] (X = F, Cl, Br, I), trans-[RhX(C=CHPh)(PiPr3)2] (X = F, Cl, Br, I, Me, PhCºC), trans-[RhX(CO)(PiPr3)2] (X = F, Cl, Br, I, PhCºC) und trans-[RhX(CN-2,6-xylyl)(PiPr3)2] (X = F, Cl, Br, I, PhCºC) untersucht werden. Die FT-Raman Spektroskopie zeigte sich als eine nützliche Methode zur Untersuchung des Trans-Einflusses. MO- und NBO-Berechnungen waren dabei sehr hilfreich, um diesen Effekt zu charakterisieren. Eine weitere Substanzklasse der hier untersuchten Übergangsmetallverbindungen stellen die verschiedenen Molybden- und Wolframkomplexe dar, die in den Teilprojekten B-3 und B-2 synthetisiert wurden. In diesem Zusammenhang wurden die FT-Raman- und –IR-Spektren von den polykristallinen Thioaldehyd-Komplexen mer-[W(CO)3(dmpe)(h2-S=CR2)] (R = H, D) aufgenommen und mit Dichtefunktionalrechnungen verglichen. Die Isotopenmarkierung lieferte eine klare Zuordnung der n(WC) und n(CS) Valenzstreckschwingungen, welche den partialen CS-Doppelbindungscharakter in diesen Verbindungen zeigte. Zudem konnte eine vollständige Analyse dieser Komplexe mit Hilfe der DFT-Rechnungen erlangt werden. NMR- und IR-Daten zeigten, daß bei einer Lösung von mer-[W(CO)3(dmpe)(h2-S=CH2)] ein Gleichgewicht stattfindet. Infolgedessen wurden die Energien der unterschiedlichen Stereo-Isomere von mer-[W(CO)3(dmpe)(h2-S=CH2)] untersucht, welche in sehr guter Übereinstimmung mit dem experimentellen Befund standen. Die Umsetzung der Phosphenium-Komplexe Cp(CO)2M=PR2 (M = W, Mo; R = tBu, Ph) mit Schwefel oder Selen lieferte entsprechende stabile [2+1]-Cycloaddukte in guten bis sehr guten Ausbeuten. FT-Ramanspektren von solchen Verbindungen wurden auf der Basis von Dichtefunktionalrechnungen aufgenommen und diskutiert. Diese Untersuchungen fanden in Zusammenarbeit mit Teilprojekt B-2 statt und hatten die Aufklärung der Bindungseigenschaften des Dreirings in diesen Komplexen zum Ziel. Die wichtigsten n(M-L) Valenzschwingungen konnten ebenso charakterisiert werden. Bei der UV-Bestrahlung von Cp(CO)2FeSiH2Me und Cp(CO)2FeCH2SiH3 sind verschiedene Photoprodukte bzw. Intermediate zu erwarten. In den Dissertationen von Claudia Fickert und Volker Nagel sind Veränderungen an den Raman- bzw. IR-Spektren der UV-Bestrahlungexperimente der matrixisolierten Substanzen vorgestellt und diskutiert worden. Dabei wurde die a-H-Umlagerung nach photochemischer Decarbonylierung als stabilstes Intermediat postuliert. Jedoch konnten keine eindeutigen Aussagen getroffen werden. Aufgrund dessen wurde die theoretische photochemisch induzierte Decarbonylierung und anschließenden Umlagerungen von Cp(CO)2FeSiH2Me und Cp(CO)2FeCH2SiH3 mit Hilfe der Dichtefunktionaltheorie behandelt und in einem Kapitel der vorliegenden Dissertation dargestellt. Im letzten Teil dieser Arbeit wurden Raman-Spektren und quantenchemische Rechnungen an Di(2-Pyridyl)systemen durchgeführt, die im Teilprojekt D-4 synthetisiert wurden. Die Py2E--Anionen weisen eine außergewöhnliche Selektivität bezüglich der Metallkoordination auf. Um geeignete Vorläufermoleküle zur Darstellung dünner III/V-Schichten mittels MOCVD-Experimente darzustellen, wurde Py2NH und Py2PH mit Et3Al bzw. Me3Al umgesetzt. Ein deutlicher Unterschied zwischen Amid und Phosphid ist in der Reaktivität gegenüber einem weiteren Lewis-säuren Äquivalent Et3Al bzw. Me3Al zu erkennen. Das bivalente amidische Stickstoffatom ist im Gegensatz zum Phosphoratom zu einer weiteren Koordination befähigt, was mittels DFT- und MP2-Rechnungen belegt wurde. Der Py(Bth)P--Ligand in [Me2Al{Py(Bth)P}] kann als doppelter Hart/Weich-Chelatligand bezeichnet werden. Das Me2Al+-Fragment koordiniert über die „harte Seite“ des Liganden (den Pyridylstickstoffatomen), während die „weiche Seite“ als P-S-Chelatligand weiterhin in der Lage sein sollte, weiche Übergangsmetallkomplexfragmente [M] zu stabilisieren. Diese Verbindung wurde zum Teil mit den obengenannten Methoden charakterisiert und sollte in weiter untersucht werden. Die durchgeführten DFT-Rechnungen lieferten nicht nur eine Möglichkeit der Interpretation von Schwingungsspektren, sondern erlaubten auch den Vergleich berechneter Molekülgeometrien mit Daten von Kristallstrukturanalysen und lieferten wichtige Antworten zu verschiedenen Problemstellungen.

No description available.