Orientador: Luiz Carlos da Silva Filho / Banca: Paulo Noronha Lisboa Filho / Banca: Waldemar Lacerda Junior / Resumo: O presente trabalho retrata o estudo do pentacloreto de nióbio (NbCI5) como ácido de Lewis em reações multicomponentes para a síntese de compostos derivados de 4-aril-3,4-di-hidrocumarinas. Estes compostos foram obtidos através de reação entre o derivado fenólico (3,5-dimetoxifenol), aldeídos aromáticos e malonato de dimetila ou dietila na presença do pentacloreto de nióbio, em um mesmo pot reacional. Foram estudados os tempos reacionais. Também foram avaliados os percentuais dos produtos formados. As reações se procederam primeiramente com a reação de condensação de Knoevenagel entre o malonato de dimetila ou etila com o aldeido aromático e em seguida ocorre a reação de hidroarilação do éster benzilidênico formado com o derivado fenólico seguida da reação de transesterificação intramolecular. Juntamente com os estudos de sistemática reacional, foi feita a caracterização estrutural completa de todos os compostos sintetizados por: Espectroscopia de Adsorção na Região do Infravermelho, Ressonância Magnética Nuclear de Hidrogênio, Ressonância Magnética Nuclear de Carbono 13 e espectrometria de massas de alta resolução. Foram realizadas também, avaliações sobre a mortalidade, a atividade motora e o pareamento de vermes adultos de Schistosama mansoni, agente causador da esquistossomose, devido à ampla faixa de atividade biológica que a classe de derivados cumarínicos apresenta / Abstract: The present work shows the study about of niobium pentachloride (NbCI5) as Lewis acid on multicompounds, were obtanied by the reaction between the phenolic derivative (3,5-dimethoxyphenol), aromatic aldehydes and dimethyl or diethyl malonate in the presence of niobium pentachloride, by one reaction. Reaction times were analysed. We also evaluated the yelds of the products obtained. The reactions procceded first by the Knoevenagel condensation between dimethyl malonate or diethyl and the aromatic aldehyde. Then, occur the hydroarylation of benzilidenic ester by the phenol used followed by the intramolecular transesterifiation reaction in the presence of niobium pentachloride. In addition to the synthetic studies a complete structural characterization of all compounds resonance of hydrogen, nuclear magnetic resonance of carbon 13 and high resolution mass spectroscopy . Were also performed, evaluations on mortality, motor activity and pairing of adult worms of Schistosoma monsoni, agent of schistosomiasis, due to the wide range of biological activity presented by coumarin derivates / Mestre

Made available in DSpace on 2014-06-11T19:30:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-22Bitstream added on 2014-06-13T20:00:22Z : No. of bitstreams: 1 santos_wh_me_bauru.pdf: 3137301 bytes, checksum: a0d58711df44de1efee5e340d28e47aa (MD5) / O presente trabalho retrata o estudo do pentacloreto de nióbio (NbCI5) como ácido de Lewis em reações multicomponentes para a síntese de compostos derivados de 4-aril-3,4-di-hidrocumarinas. Estes compostos foram obtidos através de reação entre o derivado fenólico (3,5-dimetoxifenol), aldeídos aromáticos e malonato de dimetila ou dietila na presença do pentacloreto de nióbio, em um mesmo pot reacional. Foram estudados os tempos reacionais. Também foram avaliados os percentuais dos produtos formados. As reações se procederam primeiramente com a reação de condensação de Knoevenagel entre o malonato de dimetila ou etila com o aldeido aromático e em seguida ocorre a reação de hidroarilação do éster benzilidênico formado com o derivado fenólico seguida da reação de transesterificação intramolecular. Juntamente com os estudos de sistemática reacional, foi feita a caracterização estrutural completa de todos os compostos sintetizados por: Espectroscopia de Adsorção na Região do Infravermelho, Ressonância Magnética Nuclear de Hidrogênio, Ressonância Magnética Nuclear de Carbono 13 e espectrometria de massas de alta resolução. Foram realizadas também, avaliações sobre a mortalidade, a atividade motora e o pareamento de vermes adultos de Schistosama mansoni, agente causador da esquistossomose, devido à ampla faixa de atividade biológica que a classe de derivados cumarínicos apresenta / The present work shows the study about of niobium pentachloride (NbCI5) as Lewis acid on multicompounds, were obtanied by the reaction between the phenolic derivative (3,5-dimethoxyphenol), aromatic aldehydes and dimethyl or diethyl malonate in the presence of niobium pentachloride, by one reaction. Reaction times were analysed. We also evaluated the yelds of the products obtained. The reactions procceded first by the Knoevenagel condensation between dimethyl malonate or diethyl and the aromatic aldehyde. Then, occur the hydroarylation of benzilidenic ester by the phenol used followed by the intramolecular transesterifiation reaction in the presence of niobium pentachloride. In addition to the synthetic studies a complete structural characterization of all compounds resonance of hydrogen, nuclear magnetic resonance of carbon 13 and high resolution mass spectroscopy . Were also performed, evaluations on mortality, motor activity and pairing of adult worms of Schistosoma monsoni, agent of schistosomiasis, due to the wide range of biological activity presented by coumarin derivates

Orientador: Maria Helena Andrade Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-05T09:37:37Z (GMT). No. of bitstreams: 1 Oliveira_BergsonFogacade_M.pdf: 2498560 bytes, checksum: addf7bff0c71745fb9460b5f5e61fa49 (MD5) Previous issue date: 2005 / Resumo: A quitosana, um poliaminossacarídeo natural, tem atraído atenção considerável para uso na área de saúde como polímero com baixa toxicidade apresentando características favoráveis tais como biocompatibilidade, biodegradabilidade e mucoadesividade. A quitosana tem sido usada em diferentes aplicações com engenharia de tecidos bem como em sistemas de liberação controlada de fármacos e vacinas por diferentes vias de administração incluindo as vias oral e nasal. Para a maior parte das aplicações em sistemas de liberação controlada, devido às propriedades hidrofílicas da quitosana, a reticulação se torna uma estratégia para controlar propriedades desses sistemas como capacidade de adsorção de água, carga superficial, dentre outras que afetam diretamente a sua cinética de liberação. A reticulação da quitosana pode ser de natureza química, formada por ligações covalentes irreversíveis, e reticulação física, formada por várias ligações reversíveis (ligações iônicas, complexos de polieletrólitos). Nesse trabalho, sistemas de liberação modificada à base de quitosana (microesferas) foram obtidos empregando-se a técnica de spray drying. Estudou-se, a seguir, a reticulação química e física das mesmas: 1) reticulação química com diferentes aldeídos, gliceraldeído (GAL) ou glutaraldeído (GLU); 2) reticulação física com hialuronato de sódio (HNa). As partículas foram caracterizadas quanto às propriedades de intumescimento, carga superficial, área superficial, análise térmica, teor de umidade, cristalinidade, espectroscopia no infravermelho e análise elementar. Os resultados obtidos mostraram que a reticulação com GAL gerou propriedades de superfície tais como potencial zeta elevado e um melhor controle sobre o intumescimento. Essas microesferas foram testadas para a adsorção superficial de pDNA e analisadas quanto à capacidade de transfecção de células in vitro. Os resultados confirmaram a transfecção, apontando o uso potencial destas partículas como carreadoras de vacinas gênicas / Abstract: In recent years, chitosan, a natural cationic polysaccharide, has attracted considerable attention as a new non-toxic polymer having favourable characteristics such as biocompatibility, biodegradability and mucoadhesiveness. Chitosan has found several applications as a biomaterial in tissue engineering as well in controlling drug release by various routes of delivery including oral and nasal. For most of the drug delivery applications, due to its hydrophilic properties, chitosan crosslinking becomes a strategy to control properties of these systems such as sweling properties, superficial charge, among others that affect release kinetic. The chitosan crosslinking can be chemical, formed by irreversible covalent bounds, and physical crosslinking, formed by several reversibles bounds (ionic bounds, polyelectrolyte complex). In this work, modified delivery system made of chitosan (microspheres) had been obtained using spray drying technique. It was studied, to follow, chemical and physical crosslinking of that: 1) chemical crosslinking with different aldehydes, glyceraldehyde (GAL) ou glutaraldehyde (GLU); 2) physical crosslinking with sodium hyaluronate (HNa). The particles had been characterized by swelling properties, surface charge, surface area, thermal analysis, humidity quantification, crystalinity, infrared spectroscopy and elemental analysis / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

O crescimento excessivo da frota veicular mundial tem feito com que milhares de toneladas de poluentes sejam lançadas na atmosfera diariamente em todo o globo, no Brasil a frota de veículos atingiu aproximadamente 54 milhões de unidades, e tem aumentado significativamente em vários estados, segundo o DETRAN (Departamento Estadual de Transito de São Paulo) o estado conta hoje com aproximadamente 19,5 milhões de veículos, 6,5 milhões só na capital, onde são emplacados aproximadamente mil veículos por dia, este crescimento tem causado episódios críticos de poluição do ar nos centros urbanos. Dentre os poluentes lançados na atmosfera de origem veicular, encontram-se os aldeídos e os ácidos carboxílicos, (objetos de estudo deste trabalho), essas substâncias são de suma importância para saúde humana, e participam nas reações fotoquímicas de formação de ozônio na baixa troposfera. Desde a implantação do PROCONVE (Programa de Controle de Poluição do Ar por Veículos Automotores) em 1988, medidas como a redução dos limites de emissão, novas tecnologias na fabricação de veículos automotores, redução da porcentagem de enxofre no diesel, combustíveis renováveis, entre outras, e programas como a Inspeção veicular na cidade de São Paulo criada a partir de 2009, tem sido tomadas visando à constante melhoria na qualidade do ar. Dentre os combustíveis renováveis atualmente utilizados, o biodiesel tem se destacado, tendo em vista o grande consumo de diesel utilizado como fonte de energia no Brasil. Atualmente foram incorporados 2% de biodiesel ao diesel comercial, e antecipando a meta para 2013, possivelmente já no ano de 2010 a porcentagem será de 5%. O objetivo deste trabalho é a caracterização preliminar de aldeídos e ácidos carboxílicos na emissão de veículos do ciclo Otto e do ciclo diesel, utilizando combustíveis fósseis e renováveis. Para a realização deste trabalho foram utilizados três veículos, sendo dois do ciclo Otto e um do ciclo diesel. Os testes foram realizados em dinamômetro de chassis conforme norma ABNT NBR 6601 e ABNT NBR 12026, o método para amostragem dos ácidos carboxílicos foi validado e estabelecido conforme item 6.2 deste trabalho. Nos veículos do ciclo Otto, foram utilizados como combustíveis, a gasolina pura, gasolina com 22% de AEAC (Álcool etílico anidro combustível) e AEHC (álcool etílico hidratado combustível). No veículo do ciclo diesel foram utilizados como combustíveis o diesel comercial com 2% de biodiesel e biodiesel puro de soja. Os resultados obtidos indicaram uma emissão de ácidos carboxílicos 2,5 vezes maior para os testes realizados com os veículos do ciclo Otto, e 5,5 vezes superior para os aldeídos nos resultados dos testes realizados com o veículo do ciclo diesel. A média de todos os resultados obtidos na realização deste trabalho com os veículos do ciclo Otto e do ciclo diesel, utilizando combustíveis fósseis e renováveis, indicaram emissão 3,2 vezes superior dos poluentes pesquisados na utilização de combustíveis renováveis. Estudos com maior número de amostras, e diversificações nas categorias dos veículos devem ser realizados a fim de se detalhar o perfil destes poluentes na emissão veicular com o uso de combustíveis fósseis e renováveis. / The global automotive fleet is emitting thousands of tons of air pollutants daily all over the planet; in Brazil, the domestic fleet reached 54 million vehicles. According to DETRAN (São Paulo state traffic department), the state of São Paulo has 19,5 million vehicles and 6,5 million in São Paulo city, where a thousand new vehicles daily are registered. This fleet growing up is causing critical air pollution situations in metropolitan areas. Among the major automotive air pollutants are aldehydes and carboxylic acids, both are the subject of this study. These substances play an important role for human health and they take place at photochemical reactions generating ozone in low troposphere. Since the beginning of PROCONVE (National Automotive Pollution Control Regulation) in 1988, measures has been taken like emission regulation, development of new automotive technologies, reduction of sulfur content in diesel fuel, renewable fuels and inspection of in use vehicles. Among the fuels from renewable sources currently in use, the biodiesel plays an important role, because diesel is the most used energy source. Currently, with the enforcement of the law number 11097, from January 13rd of 2005, 2% of biodiesel must be added in the commercial diesel and until 2013 this addition will rise to 5%. The subject of this study is the determination of emission profile of aldehydes and carboxylic acids in vehicles powered by Otto and diesel engines using fossil and renewable fuels. In this study were used three vehicles, two of them powered by Otto engines and one sample with diesel engine. The tests were performed in vehicle chassis dynamometer in accordance of the standards ABNT NBR 6601 and ABNT NBR 12026. The method for sampling and evaluation of carboxylic acids was validated and established in article 6.2 of this study. Otto vehicles were tested with 100% gasoline, gasoline plus 22% of anhydrous ethanol and 100% Ethanol. Diesel vehicle were tested with commercial diesel plus 2% biodiesel and 100% soy biodiesel. The results indicates an average 3,2 times higher emission of aldehydes and carboxylic acids when the samples were tested with renewable fuels. Tests with a higher number of samples and variation in vehicle types should be performed in order to provide a more precise profile of these pollutants emission using fossil and renewable fuels.

The purpose of this investigation was to study the known methods of forming acetals and find one or several that could be used in further investigation. In connection with the reactions, the use of various catalysts was pertinent. Some of the catalysts used were hydrogen chloride, calcium chloride, ferric chloride, aromatic sulfonic acids, and other. There was no data available comparing the sulfonic acids with the inorganic salts and mineral acids. For that reason one of the subsidiary problems of this investigation was such a comparison. In order to investigate stability, several acetals were subjected to conditions intended to produce ring acetylation. These conditions are the same imposed by a Friedel Crafts reaction or a Fries rearrangement.

No description available.

Possible mechanisms for the formation of isovaleraldehyde from l-leucine and isobutyraldehyde from l-valine in bananas are described. These aldehydes are key intermediates for the development of the branched-chain alcohols and esters, which are prominent components of banana flavor volatiles. When amino acids were incubated with dopamine and banana enzyme extract, these aldehydes were formed. Greater amounts of aldehydes were produced when hydrogen peroxide was included in the reaction mixture. It is proposed that the reaction mechanism involves oxidation of dopamine to o-quinones catalyzed by polyphenoloxidase and peroxidase, followed by the nonenzymic reaction of the quinone with the amino acid to form the corresponding aldehyde. At levels of leucine, polyphenoloxidase (PPO) and dopamine tested, aldehyde production increased with leucine concentration (up to 75 mM) and tended to peak at relatively low levels of PPO (0.1 units/ml) and dopamine (0.5 mM). / Master of Science

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2015. / Ovahimba people from Kunene region, northern Namibia, are known for covering their bodies with red ochre mixed with clarified butterfat, traditionally known as otjize to give them a distinct red appearance. Ochre refers to a clay-like earth pigment which contains some form of iron-containing mineral. A mixture of traditional herbs with clarified butterfat, otjizumba, is also applied around the necks as a perfume. This study was prompted by ethnographic interviews amongst the Ovahimba people which revealed functional uses of the traditional cosmetics, specifically the red ochre-derived cosmetic, as a mosquito repellent. Several analytical techniques were used to determine the presence of mosquito repellent compounds in the red ochre- derived cosmetic and the aromatic plant derived-cosmetic. GC-MS was used to identify the presence of compounds which have previously been found to have mosquito repellent capabilities. GC-MS analysis identified mostly oxygenated compounds which include ketones (2-dodecanone, 2-nanonone, 2-undecanone and 2-tridecanone), aldehydes (heptanal and nonanal) and carboxylic acids (hexanoic acid and heptanoic acid) in dichloromethane extracts of otjize and mostly hydrocarbons (o-cymene, α-pinene, limonene, and squalene) and less oxygenated compounds (terpinen-4-ol and α-campholenal) in plant derived cosmetic extracts. The chemical composition of the cosmetics was also analyzed using FTIR. FTIR analysis for organics in both cosmetics showed presence of vibrational motions including O-H, C=O, C-H, C=C and C-C which affirmed the presence of organic functional groups including aldehydes, ketones, esters, alkenes and alkanes. Peak patterns observed using GC-FID showed that the mixture of red ochre and clarified butterfat released higher quantities of volatiles than when individual samples were analyzed. Mineralogical composition of red ochre was determined by PXRD, supported by FTIR which revealed as significant amount of hematite (Fe2O3), the primary mineral responsible for the red hue of the ochre. Other major minerals including quartz (SiO2), kaolinite (Al2(Si2O5)(OH)4, calcites (CaCO3) and chalconatronite(Na2Cu(CO3)2.3H2O) were found to be present in the ochre powder. Elemental analysis of the ochre determined using EDXRF and ICP-OES supported mineralogical composition as iii Ovahimba red ochre exhibited high content of iron (Fe) and silicon (Si) and a significant amount of aluminum (Al), calcium (Ca) and copper (Cu). Based on % weight, presence of transition metals in red ochre powder identified using ICP-OES was observed in the descending order; Fe> V> Cu> Au> Ti> Zr. Based on the analysis carried out in this study, it is suggested that red ochre provides catalytic role, due to its diverse metal content especially the presence of transition metals including Fe and Cu, which might be influencing the production of secondary products during autoxidation of fatty acids present in otjize, specifically ketones and aldehydes. It was also concluded that the composition of clarified butterfat could be attributed to the release of mosquito repellent compounds in the red ochre derived cosmetic because when animal fat (kudufat) was used as an organic binder, the mixture did not release any of the identified possible mosquito repellent compounds. Keywords: Aldehydes, autoxidation, clarified butterfat, fatty acids, ketones, mosquito repellents, and red ochre

Chapter I deals with novel approaches for α-amino acids. This chapter has been divided into three sections. Section A describes the synthesis of α-amino acids via the Beckmann rearrangement of carboxyl-protected β-keto acid oximes. The synthesis of α-amino acids using the Beckmann rearrangement involves the preparation of the Z-oxime and efficient protection of the carboxyl group. Various 2-substituted benzoylacetic acids were synthesized, in which the carboxyl function was masked as a 2,4,10-trioxaadamantane unit (an orthoacetate), and were converted to their oximes (Scheme 1).1 The oximes were converted to the their mesylates, which underwent the Beckmann rearrangement with basic Al2O3 in refluxing CHCl3. The corresponding 2-substituted-N-benzoyl-α-amino orthoacetates were obtained in excellent overall yields. In Section B, the synthesis of α-amino acids via the Hofmann rearrangement of carboxyl-protected malonamic acids is described. The Hofmann rearrangement involves the migration of the alkyl moiety of the amide onto the N-centre. Various 2-substituted malonamic acids (malonic acid mono amides) were synthesized with the carboxyl group masked as a 2,4,10¬trioxaadamantane unit (an orthoacetate). These underwent the Hofmann rearrangement with phenyliodoso acetate and KOH/MeOH (Scheme 2). The resulting (N-methoxycarbonyl)¬trioxaadmantylmethylamines (carbamates) were formed in yields > 90%, and are α-amino acids with both carboxyl and amino protection.2 In Section C, an approach to chiral amino acids via the reductive amination of ketones, involving the hydride reduction of 1-(S)-phenethyl amine derived Schiff bases of C-protected α¬keto acids is described. An efficient synthesis of α-amino acids has thus been developed in high diastereoselectivity. Various 1-acyl-2,4,10-trioxaadamantanes were prepared from the corresponding 1-methoxycarbonyl derivatives, via conversion to the N-acylpiperidine derivative followed by reaction with a Grignard reagent in refluxing THF (Scheme 3). These α-keto orthoformates were converted to corresponding imines with 1-(S)-phenethyl amine (TiCl4/Et3N/toluene/reflux), the Schiff bases being reduced with NaBH4 (MeOH/0 °C) to the corresponding 1-(S)-phenethyl N-alkylamines (diastereomeric excess by NMR ~ 90:10).3 Hydrogenolysis of the phenethyl group (Pd-C/H2/MeOH) finally led to the (aminoalkyl)trioxaadamantanes, which are chiral C-protected α-amino acids, in excellent overall yields. Here a mild, inexpensive and efficient hydride reducing agent for the reductive amination of α-keto acids has been developed. Chapter II deals with the enantioselective synthesis of piperidines and its applications in the synthesis of piperidine alkaloids.4 This chapter has been divided into two sections. In Section A, the enantioselective synthesis of 2-substituted piperidines and its applications in the synthesis of (R)-(-)-coniine and (R)-(+)-anatabine are described. Various N-tert-butylsulfinyl imines were synthesized, which upon allyl Grignard addition followed by N-allylation gave the diallyl compound with good diastereoselectivity (Scheme 4). The diallyl compound underwent ring closing metathesis with Grubbs’ first generation catalyst and subsequent reduction of the double bond with H2-Pd/C, furnished N-sulfinyl-2-susbstituted piperidines. Using this methodology (R)¬(-)-coniine hydrochloride and (R)-(+)-anatabine were synthesized. In Section B, the enantioselective synthesis of (S)-tert-butyl 2-(2¬hydroxyethyl)piperidine-1-carboxylate and its elaboration to the synthesis of (S)-(+)-δ-coniceine and (S)-(+)-pelletierine are described. The (S)-tert-butyl 2-(2-hydroxyethyl)piperidine-1¬carboxylate is a synthon used for the synthesis of various 2-substituted piperidine natural products. Using the above methodology (S)-tert-butyl 2-(2-hydroxyethyl)piperidine-1¬carboxylate was synthesized starting from (S)-(+)-2-methyl-2-propanesulfinamide and 3¬(benzyloxy)propanal (Scheme 5). This alcohol was further elaborated to furnish two piperidine alkaloids (S)-(+)-pelletierine and (S)-(+)-δ-coniceine. Scheme 5. Enantioselective synthesis of (S)-tert-butyl 2-(2-hydroxyethyl)piperidine-1¬carboxylate, (S)-(+)-pelletierine and (S)-(+)-δ-coniceine. Chapter III deals with the formation of barbituric acid in an aprotic medium and related mechanistic studies. The generally accepted mechanism for the formation of barbituric acid involves the nucleophilic attack of urea anion on diethyl malonate.5 This is debatable for at least two reasons: (1) the normally employed base, sodium ethoxide, is too weak to deprotonate urea and (2) diethyl malonate is more acidic than urea, so the initial deprotonation by base has to be from diethyl malonate. When diethyl malonate (DEM) enolate was treated with urea in DMF, barbituric acid was formed in 61% yield. The reaction was also extended to several 2-substituted DEM derivatives, the corresponding substituted barbituric acids being formed in reasonable yields. The reaction between diethyl 2-(ethoxycarbonyl)malonate and urea, with potassium carbonate in refluxing ethanol, led to the formation of barbituric acid. This is apparently facilitated by hydrogen bonding involving the enolate oxygen atom, which renders one of the carbonyl groups relatively electrophilic (Scheme 6). Meldrum’s acid failed to react with urea, despite its greater acidity, indicating that the reaction requires the formation of the E from of the s-trans enolate ion, in which the hydrogen bonding interaction and nucleophilic attack can occur in concert. Scheme 6. Proposed transition state for formation of Barbituric acid. Chapter IV deals with an improved Erlenmeyer synthesis with 5-thiazolone and catalytic manganese (II) acetate for aliphatic and aromatic aldehydes. A serious limitation to the classical Erlenmeyer reaction is that it generally fails in the case of aliphatic aldehydes. This chapter describes a convenient approach to this problem that extends the scope of the Erlenmeyer synthesis. The present study was aimed at developing milder conditions for the synthesis of 4¬arylidene and alkylidenethioazlactones. Thus, N-(thiobenzoyl)glycine was treated with DCC in DCM at room temperature for 10 min., according to a reported procedure, to form the thioazlactone.6 The same reaction mixture was treated with catalytic Mn(II) acetate and an equivalent of an aromatic aldehyde, to furnish the corresponding 4-arylidenethioazlactones in good yields. The scope of the reaction was extended to alphatic aldehydes also under similar reaction conditions, to obtain the 4-alkylidene thioazlactones in good to moderate yields (Scheme 7). Scheme 7. The Erlenmeyer synthesis with 5-thiazolone and manganese acetate. (for figures & structural formula pl refer pdf file)

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy