Song, Xu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 92-96). / Abstracts in English and Chinese. / Table of Contents --- p.i / Acknowledgements --- p.iii / Abbreviations --- p.iv / Abstract --- p.v / Chapter Part I --- Carbon-Carbon Bonds Activation (CCA) of Ketones by Iridium(III) Porphyrins / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Carbon-Carbon Bonds Activation by Transition Metals --- p.1 / Chapter 1.2 --- Thermodynamic and Kinetic Considerations in CCA --- p.1 / Chapter 1.3 --- C-C Bonds Activation by Low Valent Transition Metal Complexes --- p.3 / Chapter 1.3.1 --- CCA in Strained System --- p.3 / Chapter 1.3.2 --- CCA Driven by Aromatization --- p.6 / Chapter 1.3.3 --- Chelation Assisted CCA --- p.8 / Chapter 1.4 --- C-C Bonds Activation by High Valent Transition Metal Complexes --- p.11 / Chapter 1.5 --- Previous Mechanistic Studies on CCA by High Valent Transition Metal Complexes --- p.14 / Chapter 1.6 --- Objective of the Work --- p.16 / Chapter Chapter 2 --- Carbon-Carbon Bonds Activation (CCA) of Ketones by Iridium(III) Porphyrins / Chapter 2.1 --- Introduction --- p.17 / Chapter 2.2 --- CCA of Aromatic Ketones with Iridium(III) Porphyrins --- p.17 / Chapter 2.2.1 --- CCA of Aromatic Ketones with Ir(III) Porphyrin Chloride --- p.17 / Chapter 2.2.2 --- CCA of Aromatic Ketones with Ir(III) Porphyrin Methyl --- p.20 / Chapter 2.2.3 --- Steric Effect on CCA with Ir(III) Porphyrins --- p.21 / Chapter 2.3 --- CCA of Aliphatic Ketones with Iridium(III) Porphyrins --- p.21 / Chapter 2.3.1 --- CCA of Unstrained Aliphatic Ketones with Ir(III) Porphyrins --- p.21 / Chapter 2.3.2 --- CCA of Cyclic Aliphatic Ketones with Ir(III) Porphyrins --- p.22 / Chapter 2.4 --- Summary --- p.23 / Chapter Chapter 3 --- Preliminary Mechanistic Studies of Carbon-Carbon Bonds Activation (CCA) / Chapter 3.1 --- Proposed Mechanism of CCA with Ir(III) Porphyrin Chloride --- p.24 / Chapter 3.2 --- Proposed Mechanism of CCA with Ir(III) Porphyrin Methyl --- p.27 / Chapter 3.3 --- Determination of CCA co-product in situ --- p.30 / Chapter 3.4 --- Summary --- p.31 / Experimental Section --- p.33 / References --- p.44 / List of Spectra I --- p.48 / Chapter Part II --- Supramolecular Chemistry of C6o with Ir(III) Porphyrin Methyl / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Supramolecular Interactions --- p.62 / Chapter 1.2 --- Introduction of C6o --- p.67 / Chapter 1.3 --- Supramolecular Interactions between C6o and Metalloporphyrins --- p.70 / Chapter 1.3.1 --- Discovery of Supramolecular Interactions between C6o And Metalloporphyrins --- p.70 / Chapter 1.3.2 --- Development of C6o-Metalloporphyrin Supramolecular Structure and Application --- p.71 / Chapter 1.3.3 --- Investigation on C6o-Metalloporphyrin Bonding Nature --- p.73 / Chapter 1.4 --- Objective of the Work --- p.76 / Chapter Chapter 2 --- Supramolecular Interaction between C60 and Ir(III) Porphyrin Methyl / Chapter 2.1 --- Synthesis of C60-Ir(ttp)Me Complexes --- p.77 / Chapter 2.2 --- X-ray Structure Analysis of C60-Ir(ttp)Me Complexes --- p.78 / Chapter 2.3 --- 1H NMR Analysis of C60-Ir(ttp)Me Complexes --- p.83 / Chapter 2.4 --- 13C NMR Analysis of C60-Ir(ttp)Me Complexes --- p.84 / Chapter 2.5 --- Binding Constant of C60-Ir(ttp)Me Complexes Using UV-Vis Analysis --- p.85 / Chapter 2.6 --- Summary --- p.87 / Experimental Section --- p.88 / References --- p.92 / Appendix --- p.97 / List of Spectra II --- p.101 / Reprint of OM Paper --- p.112 / Supporting Information for Organometallics Paper --- p.118

O trabalho abrange o estudo de biorreduções de cetonas por espécies vegetais, empregando-se homogenatos de células de tecidos de plantas já desenvolvidas (folhas) ou culturas de células de Rauwolfia sellowii e Cereus peruvianus em suspensão. Dentre os objetivos principais do trabalho estão: reduzir cetonas-modelo por culturas de células vegetais, avaliando a eficiência e estereosseletividade do processo. Desenvolver um procedimento de triagem por enzimas vegetais solúveis entre diversas espécies obtidas no campus \"Armando Salles de Oliveira\", através da manipulação de variáveis que sabidamente alteram a atividade enzimática. Este tipo de preparação enzimática é utilizado no estudo de rotas biossintéticas, mas o emprego de homogenatos de células vegetais na triagem por novos biocatalisadores é inovador, tendo sido demonstrado seu potencial como ferramenta na seleção de enzimas vegetais para a biotransformação de xenobióticos. A metodologia é simples e confiável, possibilitando o estudo de biotransformações por enzimas diferentes daquelas expressas em culturas de células e oferecendo maior garantia de que a atividade enzimática observada é originária da espécie vegetal em estudo, e não de microorganismos endofíticos, que podem atuar nas biotransformações em que se utilizam partes de plantas desenvolvidas como biocatalisador / The work focuses on the study of the bioreduction of ketones by plant species, using homogenates of already developed plant tissues cells (leaves) or of Rauwolfia sellowii and Cereus peruvianus cell cultures suspensions. Among the main objectives of the study are the evaluation of the efficiency and stereoselectivity of the ketone-reduction process in plant cell cultures. It was employed a screening procedure for soluble enzymes from different plant species found on campus \"Armando Salles de Oliveira\", through the manipulation of variables known to be related to the enzyme activity. This type of enzyme preparation has been already reported in studies of biosynthetic routes, but the use of homogenates of plant cells to the screening for new biocatalysts is innovative. In this work we could demonstrate the potential of this approach as a tool in the selection of plant enzymes for the biotransformation of xenobiotics. The methodology is simple and reliable, allows the study of biotransformations by enzymes different from those expressed in cultured cells, and provides greater assurance that the enzymatic activity observed originated in plant species under study, rather than in endophytic microorganisms, which can act in biotransformations that employ parts of developed plants as biocatalyst.

A técnica de ressonância ciclotrônica de íons permite aprisionar numa cela adequada íons produzidos por impacto de elétrons sobre um gás a baixa pressão (10-7 - 10-4 Torr) . Os íons são mantidos na cela por tempos de 3 a 10 ms e dessa maneira podem reagir com moléculas neutras do gás do qual provém ou, de algum outro gás introduzido no espectrômetro. Resultam dessas reações produtos iônicos, que frequentemente foram observados reagirem novamente com moléculas neutras, dando origem a íons terciários. Todos os íons são detectados pela potência que absorvem de um campo de rádio-frequência conveniente, podendo ser registrado um espectro, no qual cada íon é caracterizado por sua massa, sendo a intensidade do pico correspondente proporcional à corrente iônica parcial do lon na cela. Contudo, a situação é tal que íons de massa maior permanecem por tempos mais longos na cela, de modo a reagirem em maior extensão e absorverem maior potência do oscilador de rádio-frequência. Essa discriminação de massa precisa ser levada em conta ao interpretar os espectros de ressonância ciclotrônica de íons e, para esclarecer a natureza das correções necessárias, as principais equações que descrevem o movimento dos íons na cela foram deduzidas e discutidas na primeira parte deste trabalho. Tais equações sugerem urna série de experiências, que tornam a espectroscopia de ressonância ciclotrônica de íons uma técnica muito versátil. Estas experiências foram todas apresentadas na primeira parte, devendo-se salientar a experiência de ressonância dupla, que permite identificar de maneira inequívoca o precursor de algum produto iônico, a experiência de ejeção de íons, que permite remover seletivamente um íon de dada espécie da cela, além de experiências que visam a obtenção de constantes de velocidade de reações de íons com moléculas. É justamente esta última grandeza mencionada, a saber, a constante de velocidade de uma reação, a que pode ser com parada com valores calculados a partir de modelos teóricos. Esses modelos baseiam-se em sua maioria na interação do íon, considerado como carga puntiforme, com a molécula neutra de certa polarizabilidade e momento dipolar (modelo de polarização) ou, na fragmentação de um complexo intermediário (modelos estatísticos). Os aspectos teóricos das reações entre íons e moléculas em fase gasosa foram analisados e os modelos mencionados, discutidos, além de modelos chamados \"diretos\" mais apropriados para comparações com resultados de experiências de feixes iônicos. A espectroscopia de ressonância ciclotrônica de íons foi utilizada para o estudo de reações de acilação em cetonas, reações bastante gerais (foi verificado que ocorrem também em outros sistemas carbonílicos) e que podem ser representadas pela equação RCOR\'+ + RCOR\' &#8594; RCO+ (RCOR\') + R\'. Estudos de variação das correntes iônicas relativas de todos os íons das cetonas, em função da pressão de cetona neutra, possibitaram a dedução de um mecanismo de formação desses íons acilados. Os resultados estão de acordo com um esquema no qual esse produto é formado pela fragmentação de um dímero intermediário, para o qual se supõe existirem condições de estado estacionário. Esta fragmentação se dá de maneira análoga à fragmentação dos íons moleculares de cetonas em espectroscopia de massa usual, tratando-se então de uma fragmentação induzida por uma espécie neutra. A pressões elevadas, nas quais o dímero pode sofrer colisões não-reativas e relaxar o excesso de energia interna, o mesmo é estabilizado, fornecendo um pico no espectro. Cetonas de polarizabilidade maior têm uma afinidade maior para o grupo acila; isto foi concluído, quando foram observadas reações de transferência de grupos acila, como por exemplo a transferência de CH3CO+ da cetona para a butanona num sistema formado pela mistura dessas duas cetonas. Estudos de basicidade relativa de álcoois, ácidos, ésteres e cetonas revelaram que há uma relação de proporcionalidade entre a basicidade desses compostos e seu potencial de ionização. Isto havia sido mostrado anteriormente para o caso das aminas, por outros pesquisadores. O conhecimento da basicidade de álcoois, ácidos e ésteres permitiu analisar reações de esterificação e transesterificação sob o ponto de vista termoquímico. Trata-se de reações entre moléculas protonadas das espécies mencionadas, que podem ser consideradas análogas às reações catalisadas por ácidos em solução. O fato de uma reação ser exotérmica não significa que ela ocorra. Assim, foi observado que ácido fórmico não é esterificado por metanol ou etanol nas condições reinantes numa cela de ressonância ciclotrônica de íons, enquanto quê ácido acético o é. A ordem relativa de basicidades em fase gasosa foi determinada como sendo HCOOH < ( CH30H < C2H5OH < CH3COOH. Dessa maneira os resultados estão de acordo com um ataque nucleófilo por parte do álcool no ácido protonado; porém, se este é menos básico que o álcool, ocorre a transferência de próton e não a esterificação. Reações de transesterificação não foram observadas de maneira alguma, mas uma outra reação entre ésteres e álcoois foi encontrada e que pode ser exemplificada pela equação (CH3)2CHOH2+ + HCOOC3H7 &#8594; HCO2(C3H7) (C3H7)+ + H2O. Esta reação só se dá com álcoois capazes de produzir íons de carbônio mais estáveis que os primários; portanto metanol e etanol não reagem. O produto formado pode fragmentar novamente O que revelou que o grupo alquila proveniente do álcool retém um excesso de energia na sua ligação, pois na decomposição é esta a ligação que rompe. Em todos estes estudos, isto é, nos de acilação de cetonas e de esterificação, bem como nos estudos de basicidade, foi sempre salientada a importância de examinar essas reações em fase gasosa, pelo fato de serem reações mais simples, uma vez que se dão na ausência de solventes e portanto revelarem propriedades intrínsecas das espécies envolvidas. Finalmente foram descritas algumas modificações realizadas no espectrômetro de ressonância ciclotrônica de íons, para poder operá-lo de forma pulsada. Com isso é possível manter os íons por tempos maiores na cela (500 ms) e, o que é mais importante, esses tempos podem ser definidos com grande precisão, o que torna viável a obtenção de resultados quantitativos (constantes de velocidade de reação) melhores. / Ions can be trapped for times as long as 10 ms by the combined action of magnetic and electric fields in the cell of an ion cyclotron resonance spectrometer. Despite the low operating pressure (10-7 - 10-4 Torr), the ions experience many collisions during this time, some of which may be reactive, leading to product ions. The ion cyclotron resonance spectrum thus displays a series of peaks corresponding to the various primary, secondary, and eventually tertiary ions; the peak heights, after suitable mass correction, yield ion currents. The double resonance technique allows one to establish unambiguously the precursor ions of a given product ion, by accelerating the suspected reagent ions and examining the effect on the product ion. Ions can also be selectively ejected from the cell. These techniques, which were described in this thesis after an outline of the basic principles of ion cyclotron resonance spectroscopy, allow, one to unravel the gaseous ion chemistry in any chemical system. Rate constants of ion-molecule reactions can be determined by ion cyclotron resonance spectroscopy. The necessary equations, based on the equations relating measured peak intensities to ion currents, were derived and their limitations, as well as those of the experimental procedures for obtaining the input parameters for the expressions, were discussed. Rate constants can also be calculated theoretically and there are a few microscopic models which treat the collision of an ion with a polarizable neutral molecule (polarization model) or the unimolecular fragmentation of an intermediate complex (statistical models). Direct models, although more suitable for comparison with results from beam experiments, were presented together with the above mentioned models, and their importance for the interpretation of the basic aspects of ion-molecule chemistry was discussed. The ion cyclotron resonance spectrometer was used to study an acylation reaction in ketones, which seems to be general for carbonyl compounds. RCOR\'+ + RCOR\' &#8594; RCO+ (RCOR\') + R\'. Pressure plots of the ion currents in ketones allowed us to propose a mechanism according to which the acylated ketones are formed by the fragmentation of an excited dimer ion, in a fashion analogous to the fragmentation of ketone parent ions in ordinary mass spectroscopy. Steady state conditions prevail for the excited dimer, which can be stabilized at pressures high enough for the ion to collide with a neutral in a time short compared to his life time, thus relaxing excess energy. The acyl group can be transferred from a ketone of lower polarizability to one of higher polarizability; thus CH3CO+ is for instance transferred from acetone to butanone in a mixture of these two compounds, as detected by double resonance. Relative proton affinities of alcohols, acids, esters, and ketones were determined and the results are in agreement with the assumption of constant hydrogen affinity within a homologous series, as has been shown previously for the case of amines by others. Of particular interest is the following order of proton affinities: HCOOH < ( CH30H < C2H5OH < CH3COOH. The positive ion spectra of mixtures of acetic acid with methanol or ethanol revealed that this acid reacts with the alcohols yielding a protonated ester, in a process apparently analogous to the acid catalized esterification in solution. On the other hand,formic acid was found not to behave in this way, although the reactions are all exothermic. These results could be rationalized assuming that a nucleophilic attack takes place on the protonated acid by the alcohol. If the alcohol is more basic, only proton transfer is observed. Transesterification reactions were not detected, but this failure was compensated by a reaction which all higher alcohols, namely those capable of producing a secondary or tertiary carbonium ion, undergo with the esters. This reaction can be exemplified by (CH3)2CHOH2+ + HCOOC3H7 &#8594; HCO2(C3H7) (C3H7)+ + H2O. Although in this particular reaction both alkyl groups seem equivalent, they are not so with respect to internal vibrational energy; this was demonstrated by the decomposition reactions which the ionic products like the one in the reaction above undergo: the alkyl group originally in the alcohol is always eliminated. All the reactions mentioned above, namely, acylation of ketones, proton transfer, and esterification, show the importance of ion-molecule reaction studies in the gas phase, where the intrinsic properties of the reacting species can be examined, free from solvation effects. This point has been repeatedly stressed. In a last chapter in this thesis the necessary modifications of the ion cyclotron resonance spectrometer, in order to operate it in a pulsed mode, were described. With this kind of operation a bunch of ions is formed by a pulse of the electron beam and the ions react for a known period of time, after which they are removed from the cell. Kinetic studies can be more easily carried out in this way than in the conventional one. Some preliminary results were shown.

本論文主要探討銠卟啉和銥卟啉絡合物，分別與酮類與醛類進行的鍵活化化學。 / 第一部分主要介紹由β-乙基羥基銠卟啉絡合物(Rh{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH)與酮類進行的羰基碳及α-碳(C(CO)-C(α)) 鍵活化(下稱碳碳鍵活化)。於室溫至50ºC時，在非溶劑的條件下，Rh{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH選擇性地斷裂芳香酮和脂肪酮類的C(CO)-C(α)鍵，生成相對應的銠卟啉酰基絡合物(Rh{U+1D35}{U+1D35}{U+1D35}(ttp)COR, R = 烷基或芳基)，產率最高可達80%。作為銠卟啉羥基絡合物(Rh{U+1D35}{U+1D35}{U+1D35}(ttp)OH)的前體，Rh{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH的活性展示出Rh{U+1D35}{U+1D35}{U+1D35}(ttp)OH是碳碳鍵活化的重要中間體。 / 第二部分主要介紹由β-乙基羥基銥卟啉絡合物(Ir{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH)與芳香醛類進行，具選擇性的醛碳氫鍵活化。在160ºC和非溶劑的條件下，Ir{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH與芳香醛類反應，生成相對應的銥卟啉酰基絡合物(Ir{U+1D35}{U+1D35}{U+1D35}(ttp)COAr)作為碳氫鍵活化產物，產率最高可達72%。銥卟啉羥基絡合物(Ir{U+1D35}{U+1D35}{U+1D35}(ttp)OH)和乙烯配位銥卟啉絡合正離子((CH₂=CH₂)Ir{U+1D35}{U+1D35}{U+1D35}(ttp)⁺)被推斷為醛碳氫鍵活化的可能中間體。 / This research focuses on the bond activation chemistry by rhodium and iridium porphyrin complexes with ketones and aldehyde respectively. / Part 1 describes the C(CO)-C(α) bond activation (CCA) of ketones by Rh{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH (ttp = 5,10,15,20-tetratolylporphyrinato dianion). Rh{U+1D35}{U+1D35}{U+1D35}(ttp)- CH₂CH₂OH selectively cleaved the C(CO)-C(α) bond of aromatic and aliphatic ketones in solvent-free conditions at room temperature to 50ºC, giving the corresponding rhodium(III) porphyrin acyls (Rh{U+1D35}{U+1D35}{U+1D35}(ttp)COR, R = alkyl or aryl) up to 80% yield. The activity of the Rh{U+1D35}{U+1D35}{U+1D35}(ttp)OH precursor, Rh{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH, demonstrates Rh{U+1D35}{U+1D35}{U+1D35}(ttp)OH as the key intermediate in the CCA of ketones. / [With images]. / Part 2 describes the selective aldehydic carbon-hydrogen bond activation (CHA) of aryl aldehydes by Ir{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH. Ir{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH reacted with aryl aldehydes in solvent-free conditions at 160ºC to give the corresponding iridium(III) porphyrin acyls (Ir{U+1D35}{U+1D35}{U+1D35}(ttp)COAr) as the CHA products up to 72% yield. Ir{U+1D35}{U+1D35}{U+1D35}(ttp)OH and (CH₂=CH₂)Ir{U+1D35}{U+1D35}{U+1D35}(ttp)⁺ were proposed as the possible intermediate for the CHA reaction. / [With images]. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chan, Chung Sum. / "November 2012." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Abstracts also in Chinese. / Abstract --- p.i / Acknowledgement --- p.iii / Table of Contents --- p.iv / Abbreviations --- p.vii / Structural Abbreviations of Porphyrin --- p.viii / Chapter Part 1 --- Carbon-Carbon Bond Activation of Ketones with Rhodium(III) Porphyrin β-Hydroxyethyl --- p.1 / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Properties of Ketones --- p.1 / Chapter 1.2 --- Carbon(CO)-Carbon(α) Bond Activation (CCA) of Ketones --- p.2 / Chapter 1.2.1 --- CCA of Ketones by Transition Metal Complexes --- p.2 / Chapter 1.2.2 --- CCA of Ketones by Metalloporphyrins --- p.5 / Chapter 1.3 --- Porphyrin Ligands and Rhodium(III) Porphyrins --- p.7 / Chapter 1.3.1 --- Porphyrin Ligands --- p.7 / Chapter 1.3.2 --- Rhodium(III) Porphyrins --- p.8 / Chapter 1.4 --- Rhodium(III) Porphyrin Hydroxide --- p.10 / Chapter 1.4.1 --- Nature of Bonding in Late Transition Metal Hydroxides --- p.10 / Chapter 1.4.1.1 --- Hard-Soft Acid-Base principle --- p.11 / Chapter 1.4.1.2 --- dπ-pπ Interaction Model --- p.11 / Chapter 1.4.1.3 --- E-C Model --- p.12 / Chapter 1.4.2 --- Attempted Preparation of Rhodium(III) Porphyrin Hydroxides --- p.13 / Chapter 1.4.3 --- Chemistry of Rhodium(III) Porphyrin Hydroxides --- p.15 / Chapter 1.5 --- Rhodium(III) Porphyrin β-hydroxyethyl as Rhodium(III) Hydroxide Precursor --- p.18 / Chapter 1.6 --- Objective --- p.20 / Chapter Chapter 2 --- Carbon-Carbon Bond Activation of Ketones with Rhodium(III) Porphyrin β-Hydroxyethyl --- p.21 / Chapter 2.1 --- Preparation of Starting Materials --- p.21 / Chapter 2.1.1 --- Synthesis of Porphyrin --- p.21 / Chapter 2.1.2 --- Synthesis of Rhodium(III) Porphyrins --- p.21 / Chapter 2.2 --- CCA of Diisopropyl Ketone by Rh{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH --- p.22 / Chapter 2.3 --- Optimization of Reaction Conditions --- p.22 / Chapter 2.3.1 --- Atmosphere Effect --- p.22 / Chapter 2.3.2 --- PPh3 Effect --- p.23 / Chapter 2.3.3 --- Solvent Effect --- p.24 / Chapter 2.4 --- Substrate Scope --- p.26 / Chapter 2.4.1 --- CCA of Isopropyl Ketones --- p.26 / Chapter 2.4.2 --- CCA of Non-Isopropyl Ketones --- p.28 / Chapter 2.5 --- Proposed Mechanism --- p.29 / Chapter 2.6 --- Comparison on CCA of Ketones by Different Rh{U+1D35}{U+1D35}{U+1D35}(por)OH Sources --- p.31 / Chapter 2.6.1 --- Reaction Conditions --- p.31 / Chapter 2.6.2 --- Substrate Scope --- p.32 / Chapter 2.6.3 --- Regioselectivity --- p.33 / Chapter 2.7 --- Comparison on Bond Activation of Carbonyl Compounds by Rhodium Porphyrin β-Hydroxyethyl --- p.34 / Chapter 2.8 --- CCA of Ketones with Ir{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH --- p.36 / Chapter 2.9 --- Conclusion --- p.37 / Chapter Chapter 3 --- Experimental Sections --- p.39 / References --- p.54 / List of Spectra I --- p.59 / Spectra --- p.60 / Chapter Part 2 --- Aldehydic Carbon-Hydrogen Bond Activation with Iridium(III) Porphyrin β-Hydroxyethyl --- p.63 / Chapter Chapter 1 --- Introduction --- p.63 / Chapter 1.1 --- Properties of Aldehydes --- p.63 / Chapter 1.2 --- Carbon-Hydrogen Bond Activation (CHA) of Aldehydes --- p.64 / Chapter 1.2.1 --- CHA of Aldehydes by Transition Metal Complexes --- p.64 / Chapter 1.2.2 --- Aldehydic CHA by Metalloporphyrins --- p.74 / Chapter 1.3 --- Iridium(III) Porphyrins --- p.77 / Chapter 1.4 --- Iridium(III) Porphyrin Hydroxide --- p.78 / Chapter 1.4.1 --- Attempted Preparation of Iridium(III) Porphyrin Hydroxides --- p.78 / Chapter 1.4.2 --- Chemistry of Iridium(III) Porphyrin Hydroxides --- p.81 / Chapter 1.5 --- Iridium(III) Porphyrin β-hydroxyethyl as Iridium(III) Hydroxide Precursor --- p.83 / Chapter 1.6 --- Objective --- p.85 / Chapter Chapter 2 --- Aldehydic Carbon-Hydrogen Bond Activation with Iridium(III) Porphyrin β-Hydroxyethyl --- p.86 / Chapter 2.1 --- Preparation of Iridium(III) Porphyrins --- p.86 / Chapter 2.2 --- Aldehydic CHA of Benzaldehyde by Ir{U+1D35}{U+1D35}{U+1D35}(ttp)CH₂CH₂OH --- p.87 / Chapter 2.3 --- Optimization of Reaction Conditions --- p.87 / Chapter 2.3.1 --- Temperature Effect --- p.87 / Chapter 2.3.2 --- Solvent Effect --- p.88 / Chapter 2.3.3 --- PPh₃ Effect --- p.90 / Chapter 2.4 --- Substrate Scope --- p.93 / Chapter 2.5 --- Proposed Mechanism --- p.94 / Chapter 2.6 --- Conclusion --- p.96 / Chapter Chapter 3 --- Experimental Sections --- p.97 / References --- p.108 / List of Spectra II --- p.112 / Spectra --- p.112

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-02-15T17:02:45Z No. of bitstreams: 1 2009 - William Pereira.pdf: 3794972 bytes, checksum: 64fbf9758bbf44329031caf3b369b79a (MD5) / Made available in DSpace on 2017-02-15T17:02:45Z (GMT). No. of bitstreams: 1 2009 - William Pereira.pdf: 3794972 bytes, checksum: 64fbf9758bbf44329031caf3b369b79a (MD5) Previous issue date: 2009-10-22 / CAPES / The present study has two specific phases: Early, was studied the isathine irradiation with the presence of diisopropil-phosphoril-dimethylidrazone (diisopfh), in chloroform, at room temperature and 300nm. The structure of photo-product was elucidated by GC/MS, IR, NMR 1H, 13C and 31P, as well as hety-cosy, homo-cosy and other techniques. The proposal mechanism involve a bi-radical from triplet excited state of isathine that react with C=N of the diisopfh and has a ring expansion. The successive pass would be thermal and with propanone elimination, as thermal rearrangement on phosphoric derivates described in the literature. In a second phase was studied, by Laser Flash Photolysis, the kinetic effect of the six aromatic derived of phosphoril-hidrazone (H, p-Cl, p-NO2, p-CN, p-NMe2 e p-CO2H) on the triplet excited state of four aromatic ketones: Xanthone, Tioxanthone, Benzophenone and Benzyl. The observed process to quencher, in all cases, was energy transference, because the rate constants are in the order of 1010M-1s-1. In this form was possible to estimate the energy of triplet excited state of these six phosphoril-hidrazone derivates. / O presente estudo divide-se em duas etapas bem distintas: Inicialmente, estudou-se a irradia??o de isatina na presen?a de diisopropil-dimetilfosforilidrazona (diisopfh) em clorof?rmio, a temperatura ambiente e comprimento de onda de 300nm. H? forma??o de um produto majorit?rio cujo peso molecular corresponde ? soma dos reagentes, diminu?do de 58g/mol. A estrutura deste produto foi elucidada por CG/EM, IV e RMN de 1H, 13C e 31P, al?m de t?cnicas como homocosy, hetycosy e outros. Prop?e-se um mecanismo via bi-radical formado a partir do estado excitado triplete da isatina com a liga??o C=N do composto diisopfh e conseq?ente expans?o do anel isat?nico; levando ? forma??o de um prov?vel produto fotoqu?mico prim?rio resultante de cicloadi??o. Numa segunda etapa, por processo t?rmico de elimina??o de propanona, similar a processo descrito na literatura por Olah, levaria a forma??o do fotoproduto detectado (derivado fosforil-benzodiazep?nico). Numa segunda etapa, estudou-se, por Fot?lise por Pulso de laser, o efeito cin?tico da presen?a de seis derivados arom?ticos de fosforilidrazona (H, p-Cl, p-NO2, p-CN, p-N (CH3)2 e p-CO2H) sobre o estado excitado triplete de quatro cetonas arom?ticas: tioxantona, xantona, benzofenona e benzil, todos em solu??o de acetonitrila. As constantes de velocidades obtidas (da ordem de difus?o da acetonitrila 1,9x1010 M-1s-1) indicam que o processo de supress?o de estado excitado se faz por transfer?ncia de energia. Desta forma foi poss?vel estimar a energia de estado excitado triplete destes derivados arom?ticos de fosforilidrazona.

<p>Odor discrimination ability was tested in four female South African fur seals (<em>Arctocephalus pusillus pusillus</em>) using a food-rewarded two-choice instrumental conditioning paradigm. The seals’ ability to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-heptanone) and alcohols (1-butanol to 1-heptanol) was assessed. The results showed that three out of four seals successfully discriminated between all of their stimulus combinations in both classes of odorants. One seal succeeded to reach the discrimination criterion with all 2-ketones but failed with all 1-alcohols.</p><p>No significant correlation between odor discrimination performance and structural similarity of the odorants in terms of differences in carbon chain length was found in either of the two chemical classes. Furthermore, it was found that the 2-ketones were significantly better discriminated than the 1-alcohols. The fact that both classes of odorants are known to be present in the natural environment of seals provides a possible explanation as to why most of the seals were able to successfully discriminate between them. The results of the present study support the notion that the sense of smell may play an important role in behavioral contexts such as social communication, foraging and reproductive behavior of fur seals.</p>

<p>This thesis contains seven papers dealing with iridium and ruthenium based catalytic asymmetric reductions, either of ketones into chiral alcohols, or olefins into chiral alkanes. The first part of the thesis describes how we have designed and evaluated new bicyclic ligands containing either <i>N</i>,<i>S</i> or <i>N</i>,<i>N</i> chelating atoms. The ligands have been evaluated in the asymmetric Ir-catalyzed transfer hydrogenation of acetophenone. The complexes evaluated induced good enentioselectivity of the product. Moreover we have also utilized a commercially available chiral diamine (QCD-amine) as a ligand in the Ru-catalyzed hydrogenation of prochiral ketones, with excellent enantioselectivity for some of the substrates used. As part of this work we investigated, both theoretically and experimentally, the mechanism of this hydrogenation. Based on these results we have proposed a new reaction mechanism for this type of hydrogenations which involves active participation of the solvent in the catalytic cycle. The last part of the thesis describes the design, synthesis and evaluation of <i>N</i>,<i>P</i> and <i>N</i>₂<i>C</i>-carbene,<i>N</i> ligands for the Ir-catalyzed hydrogenation of carbon-carbon double bonds. The selectivities obtained in these investigations are among the best reported so far for a broad variation of substrates. A selectivity model for this hydrogenation has been derived and used in the rationalization of the results. As a part of this work we have synthesized and evaluated a new class of substrates, vinyl silanes, and showed that the scope of the hydrogenation reaction can be expanded to this new substrate class.</p>

Palladium-catalyzed reactions have found widespread use in contemporary organic chemistry due to their impressive range of functional group tolerance and high chemo- and regioselectivity. The pioneering contributions to the development of the Pd-catalyzed C-C bond forming cross-coupling reaction were rewarded with the Nobel Prize in Chemistry in 2010. Today, this is a rapidly growing field, and the development of novel methods, as well as the theoretical understanding of the various processes involved are of immense importance for continued progress in this field. The aim of the work presented in this thesis was to develop novel palladium(0)- and palladium(II)-catalyzed reactions. The work involved in achieving this aim led to the development of a Mo(CO)6-mediated carbonylative Stille cross coupling reaction for the preparation of various deoxybenzoins. The protocol utilized convenient gas-free conditions to facilitate the carbonylative coupling of benzyl bromides and chlorides with aryl and heteroaryl stannanes. Mo(CO)6-assisted conditions were then used in the development of a general protocol suitable for the aminocarbonylation of aryl triflates. Both electron-poor and electron-rich triflates were coupled with primary, secondary and aryl amines. In addition, DMAP was found to be a beneficial additive when using sterically hindered or poorly nucleophilic amines. An efficient and convenient method for the synthesis of styrenes from arylboranes was developed, employing the relatively inexpensive vinyl acetate as the ethene source under Pd(II)-catalyzed conditions. The reaction mechanism was studied using ESI-MS, and a plausible catalytic cycle was proposed. A method for the oxidative Heck reaction employing aryltrifluoroborates and aryl MIDA boronates was also developed. Electron-rich and electron-poor olefins were regioselectively arylated under microwave-assisted conditions. Various arylboron species were identified in an ongoing reaction using ESI-MS.    Further investigations led to the development of a direct method for the synthesis of arylamidines from aryltrifluoroborates and cyanamides. Under Pd(II)-catalyzed conditions it was possible to insert the aryl into primary, secondary and tertiary cyanamides. Finally, a desulfitative method for the synthesis of aryl ketones was developed. A variety of aryl sulfinates were effectively inserted into alkyl- and aryl nitriles. The mechanism was further investigated using ESI-MS and a plausible catalytic cycle was proposed.

This thesis contains seven papers dealing with iridium and ruthenium based catalytic asymmetric reductions, either of ketones into chiral alcohols, or olefins into chiral alkanes. The first part of the thesis describes how we have designed and evaluated new bicyclic ligands containing either N,S or N,N chelating atoms. The ligands have been evaluated in the asymmetric Ir-catalyzed transfer hydrogenation of acetophenone. The complexes evaluated induced good enentioselectivity of the product. Moreover we have also utilized a commercially available chiral diamine (QCD-amine) as a ligand in the Ru-catalyzed hydrogenation of prochiral ketones, with excellent enantioselectivity for some of the substrates used. As part of this work we investigated, both theoretically and experimentally, the mechanism of this hydrogenation. Based on these results we have proposed a new reaction mechanism for this type of hydrogenations which involves active participation of the solvent in the catalytic cycle. The last part of the thesis describes the design, synthesis and evaluation of N,P and N2C-carbene,N ligands for the Ir-catalyzed hydrogenation of carbon-carbon double bonds. The selectivities obtained in these investigations are among the best reported so far for a broad variation of substrates. A selectivity model for this hydrogenation has been derived and used in the rationalization of the results. As a part of this work we have synthesized and evaluated a new class of substrates, vinyl silanes, and showed that the scope of the hydrogenation reaction can be expanded to this new substrate class.

Odor discrimination ability was tested in four female South African fur seals (Arctocephalus pusillus pusillus) using a food-rewarded two-choice instrumental conditioning paradigm. The seals’ ability to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-heptanone) and alcohols (1-butanol to 1-heptanol) was assessed. The results showed that three out of four seals successfully discriminated between all of their stimulus combinations in both classes of odorants. One seal succeeded to reach the discrimination criterion with all 2-ketones but failed with all 1-alcohols. No significant correlation between odor discrimination performance and structural similarity of the odorants in terms of differences in carbon chain length was found in either of the two chemical classes. Furthermore, it was found that the 2-ketones were significantly better discriminated than the 1-alcohols. The fact that both classes of odorants are known to be present in the natural environment of seals provides a possible explanation as to why most of the seals were able to successfully discriminate between them. The results of the present study support the notion that the sense of smell may play an important role in behavioral contexts such as social communication, foraging and reproductive behavior of fur seals.