In duplex DNA, guanine radical cations react with water to form mainly 7,8-dihydro-8-oxoguanine (8-OxoG). Understanding for the mechanism for migration of a radical cation (hole) from the site of initial DNA oxidation to a remote guanine is an important step in the process that will lead to a thorough understanding of DNA damage and its repair. The vast majority of charge migration in DNA experiments utilize guanine oxidation as a monitor for charge transfer. The synthesis of a potential monitor for charge transfer through DNA that is independent of guanine oxidation is reported herein. The system is a carbazole moiety covalently attached to the 2O position of uridine which was successfully incorporated into a DNA strand. Carbazole has a low oxidation potential, and will create a deeper trap than guanine during DNA charge transfer. One electron oxidation of carbazole should lead to the formation of its radical cation. The high extinction coefficient of carbazole radical cation should make it clearly observable with UV analysis. Hence a monitor for charge migration in DNA independent of guanine oxidation is obtained.

A mechanism for the mass transfer of anthraquinone (AQ) into wood during alkaline pulping has been developed. Although the chemistry of action of AQ is well-developed, there has not been much work conducted on its diffusion properties. The discrepancies between different experiments with AQ indicate that something other than the chemistry is at work. Because most of the differences arise from differences in pulping conditions, it is likely that mass transfer is the source of these discrepancies. A model system was therefore developed to explore the mass transfer properties of AQ. It was shown that AQ must be reduced to anthrahydroquinone (AHQ) at the membrane surface before any permeation of a membrane can occur. It was also shown that increasing surface coverage of the membrane through AQ particle size reduction could improve the rate of membrane permeation. The mechanism described by the model system was then tested against pulping data. It was shown that the addition of surfactants increases the pulping efficiency of AQ. This is probably through better dispersion of AQ particles to cover more chip surface area. Bulk reduction effects were also tested, and it was shown that bulk phase reducing agents decrease the efficacy of AQ in pulping. This led to the development of the mechanism for AQ diffusion in alkaline pulping.

In this research the environmental effects related to the position of a redox moiety with the electrochemical double layer were studied. This project was made possible with the synthesis of a series of lengths of ferrocene derived alkanethiols, a series of lengths of ferrocene derived norbornylogous bridges and a series of lengths of anthraquinone derived norbornylogous bridges. The series of ferrocene derived alkanethiols were used to study the effect of gradually varying the polarity of the self-assembled monolayers (SAMs) surface on the standard electron transfer rate constant and formal potential. This was achieved by varying the portion of hydroxyl to methyl terminated alkanethiol diluent in the SAM preparation step. It was found that the formal potential increased with a decreasing proportion of hydroxyl terminated diluent and increasing length of the diluent. For pure hydroxyl terminated diluent the formal potential was relatively independent of length. It was found that the rate constant increased for short alkane chain lengths with decreasing proportion of hydroxyl terminated diluent. However, it decreased in magnitude with long alkane chain lengths for low proportions of hydroxyl terminated diluent. The norbornylogous bridges were shown to stand proud above the diluent with a similar tilt angle as the alkanethiol diluent. The ferrocene derived norbornylogous bridges showed hydroxyl terminated monolayers had a slower rate constant then methyl terminated diluents independent of length and that it is highly probable that an alkane bridged redox moiety is located very close to the surface of the monolayer. SAMs were created with the ferrocene of the ferrocene derived norbornylogous bridges located at various heights above the monolayers surface. This was done by using various lengths of hydroxyl terminated diluent. It was found that the rate constant and the formal potential decreased with height above the surface. Interfacial potential distribution was used to account for this and to estimate a ??true?? formal potential. The anthraquinone derived norbornylogous bridges were tested at various pH values and heights above the surface. It was found that an accurate estimate for the electron transfer mechanism can not be made for surface bound species due to the effects of interfacial potential distribution. They demonstrated a novel technique for estimating the point of zero charge of the electrode.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Este trabalho relata o estudo quÃmico do extrato hexÃnico e etanÃlico do caule de Senna cana H.S Irwin & Barneb, popularmente conhecida no Nordeste como candieiro preto e SÃo JoÃo, coletada em MucugÃ-BA. O estudo do Ãleo fixo do caule de Senna. cana resultou na identificaÃÃo de oito Ãcidos graxos, totalizando 83,13% da composiÃÃo do Ãleo fixo. Destacaram-se como componentes majoritÃrios os Ãcidos graxos dos Ãcidos saturados: palmÃtico (26,83%), lignocÃrico (18,60%) e o nonadecanÃico (11,18%). O tratamento cromatogrÃfico dos extratos hexÃnico e etanÃlico do caule da Senna cana, possibilitou o isolamento e caracterizaÃÃo de duas antraquinonas 1,8-diidroxiladas, crisofanol e fisciona, de um Ãcido carboxÃlico de cadeia longa denominado de Ãcido triacontanÃico e de dois triterpenos lupeol e friedelina, bem como a mistura β-sitosterol e estigmasterol. O potencial farmacolÃgico e biolÃgico de Senna cana, foi investigado atravÃs de ensaios de atividade antioxidante, anticolinesterÃsica e larvicida. Das amostras analisadas, o extrato etanÃlico foi o que apresentou melhor resultado, com o I.V 39,61%. As determinaÃÃes estruturais foram realizadas atravÃs de anÃlises espectroscÃpicas, tais como: espectroscopia na regiÃo do infravermelho, de ressonÃncia magnÃtica nuclear de hidrogÃnio-1 e carbono-13, espectrometria de massas e comparaÃÃo com dados da literatura. / This paper reports the chemical study of the hexane and ethanol extracts from the Senna cana H.S Irwin & Barneby, called in the Northeast of Brazil as "Candieiro preto" and "SÃo JoÃo", collected in MucugÃ-BA. The study of the fixed oil of the stem of Senna cana resulted in the identification of eight fatty acids, amounting to 83.13% of fixed oil composition. Stood out as the major components of fatty saturated acids: palmitic (26.83%), lignoceric (18.60%) and nonadecanoic (11.18%). The chromatographic treatment of the hexane and ethanol extracts of the stem from the Senna cana, allowed the isolation and characterization of two dyhydroxylated 1,8-anthraquinones, chrysophanol and physcion, a long chain carboxylic acid named triacontanoic acid, two triterpenes called lupeol and friedelin and the mixtures β-sitosterol and stigmasterol. The pharmacological and biological potencial from Senna cana was investigated by antioxidant activity, anticholinesterase and larvicide tests. The ethanol extract showed the best result with 39.61% IV. The structural determination was performed using spectroscopic analysis, such as infrared spectroscopy, hydrogen-1 and carbon-13 nuclear magnetic resonance, mass spectrometry and comparison with the results founded on the literature.

The purpose of this investigation was the synthesis of some 1,4-naphthoquinones and 1,4-anthraquinones. It will be shown that some of these substituted quinones exhibit physiological properties.

Yes / Structural features from the anticancer prodrug nemorubicin (MMDX) and the DNA-binding molecule DRAQ5™ were used to prepare anthraquinone-based compounds, which were assessed for their potential to interrogate cytochrome P450 (CYP) functional activity and localisation. 1,4-disubstituted anthraquinone 8 was shown to be 5-fold more potent in EJ138 bladder cancer cells after CYP1A2 bioactivation. In contrast, 1,5-bis((2-morpholinoethyl)amino) substituted anthraquinone 10 was not CYP-bioactivated but was shown to be fluorescent and subsequently photo-activated by a light pulse (at a bandwidth 532–587 nm), resulting in punctuated foci accumulation in the cytoplasm. It also showed low toxicity in human osteosarcoma cells. These combined properties provide an interesting prospective approach for opto-tagging single or a sub-population of cells and seeking their location without the need for continuous monitoring.

This thesis summarizes the outcome of work performed withthe objective to contribute to the knowledge and development ofthe kraft cooking process using spectrophotometricinterfaces. In kraft cooking, it is desirable to maximize the removal oflignin in the cook without loss of pulp strength. Theselectivity can be improved by exchanging some of the hydrogensulfide ion in the white liquor for polysulfides. Paper Ipresents a spectrophotometric method for in-line monitoring ofthe electrochemical production of polysulfide using anATR-probe for the UV-Vis range. A linear relation existsbetween the ATR-probe response and the concentration ofabsorbing species. Thus the process can be followed by simplemonitoring of a few wavelengths. A spectrophotometric monitoring system using a durableNafion ionomer membrane interface for continuous on-linemeasurement of sulfide and dissolved lignin during kraftcooking has previously been developed by our group. In paperII, the permeation of low molecular weight anions from liquorshaving high ionic strengths through a membrane in Na+ form hasbeen studied. A general relation between penetration and ionsize approximated by molecular weight has been established. Thepenetration of different anions can be explained as a diffusionthrough the winding membrane channels. Further the differentanions transport independently without being interfered by thesample matrix. In light of this validation, we applied the membraneinterface to the determination of anthraquinone-2-sulfonate(AQ-S) in alkaline pulping liquor. In paper III, a simple andrapid spectrophotometric method was developed and implementedon real samples. Interferences from other compounds penetratingthe membrane were minimized by reduction of the penetrated AQ-Sand measurement at 520 nm. This method is quick and can be usedon-line. Further, we extended the method to determination ofanthraquinone (AQ) in pulping liquor (paper IV). Although AQ isregarded as insoluble, it was found that the apparentsolubility of AQ in alkaline solutions increases considerablyin the presence of lignin, reaching 0.14 g/L at 90 oC. Thismakes the calibration of AQ possible. Time-resolvedmeasurements of dissolved AQ in 3 kraft-AQ pulping processeswere performed. The results show that the membrane has great potential aspart of a selective interface in applications where theconcentrations of small anions are to be monitored in mediawith high ionic strength. Keywords: Kraft cooking, On-line, Sulfide, Lignin,Polysulfide excess sulfur, Anthraquinone-2-Sulfonate (AQ-S),Anthraquinone (AQ), Nafion Membrane, UV-Vis, ATR-probe,Spectrophotometric.

<p>This thesis summarizes the outcome of work performed withthe objective to contribute to the knowledge and development ofthe kraft cooking process using spectrophotometricinterfaces.</p><p>In kraft cooking, it is desirable to maximize the removal oflignin in the cook without loss of pulp strength. Theselectivity can be improved by exchanging some of the hydrogensulfide ion in the white liquor for polysulfides. Paper Ipresents a spectrophotometric method for in-line monitoring ofthe electrochemical production of polysulfide using anATR-probe for the UV-Vis range. A linear relation existsbetween the ATR-probe response and the concentration ofabsorbing species. Thus the process can be followed by simplemonitoring of a few wavelengths.</p><p>A spectrophotometric monitoring system using a durableNafion ionomer membrane interface for continuous on-linemeasurement of sulfide and dissolved lignin during kraftcooking has previously been developed by our group. In paperII, the permeation of low molecular weight anions from liquorshaving high ionic strengths through a membrane in Na+ form hasbeen studied. A general relation between penetration and ionsize approximated by molecular weight has been established. Thepenetration of different anions can be explained as a diffusionthrough the winding membrane channels. Further the differentanions transport independently without being interfered by thesample matrix.</p><p>In light of this validation, we applied the membraneinterface to the determination of anthraquinone-2-sulfonate(AQ-S) in alkaline pulping liquor. In paper III, a simple andrapid spectrophotometric method was developed and implementedon real samples. Interferences from other compounds penetratingthe membrane were minimized by reduction of the penetrated AQ-Sand measurement at 520 nm. This method is quick and can be usedon-line. Further, we extended the method to determination ofanthraquinone (AQ) in pulping liquor (paper IV). Although AQ isregarded as insoluble, it was found that the apparentsolubility of AQ in alkaline solutions increases considerablyin the presence of lignin, reaching 0.14 g/L at 90 oC. Thismakes the calibration of AQ possible. Time-resolvedmeasurements of dissolved AQ in 3 kraft-AQ pulping processeswere performed.</p><p>The results show that the membrane has great potential aspart of a selective interface in applications where theconcentrations of small anions are to be monitored in mediawith high ionic strength.</p><p>Keywords: Kraft cooking, On-line, Sulfide, Lignin,Polysulfide excess sulfur, Anthraquinone-2-Sulfonate (AQ-S),Anthraquinone (AQ), Nafion Membrane, UV-Vis, ATR-probe,Spectrophotometric.</p>

Le domaine du proche infrarouge a une importance majeure pour l'imagerie optique en raison de la faible autofluorescence des systèmes biologiques et de la diffusion limitée de la lumière permettant l’amélioration du rapport signal-sur-bruit et une pénétration plus profonde dans les tissus. Les sondes fluorescentes proche-infrarouges les plus couramment utilisées à ce jour sont les fluorophores organiques ou les nanocristaux semi-conducteurs qui sont affectés par un certain nombre d’inconvénients. Plusieurs cations lanthanide possèdent des propriétés optiques uniques comme des bandes d'émissions étroites dont les longueurs d'ondes sont très peu sensibles à l’environnement, de grandes différences d’énergie entre longueurs d’onde d’excitation et d'émission et une forte résistance au photoblanchiment. Afin de bénéficier de la luminescence des lanthanides, les faibles absorbances des cations lanthanides libres doivent être compensées par l'utilisation de groupes chromophores appropriés fonctionnant comme sensibilisateurs. On parle d’effet d’"antenne". Nous présentons dans ce travail plusieurs familles de sondes à base de lanthanides (i) de petites molécules, plus spécifiquement des complexes monométalliques constitués par la coordination de Ln³⁺ par un ligand de type TTHA-anthraquinone et des métallacrowns polymétalliques Ln³⁺/Zn²⁺ auto-assemblés; (ii) de nouveaux nanomatériaux basés sur des billes de polystyrène possédant deux types de chargements différents, à savoir (i) un complexe bimétallique d-f Cr³⁺-Ln³⁺ ainsi que (ii) des antennes dérivées d’hydroxyanthraquinone et des cations lanthanide libres; (iii) des macromolécules de type dendrimère polyamidoamine de génération 3 fonctionnalisés avec sensibilisateurs aza-BODIPY en leurs périphéries et qui encapsulent des lanthanide luminescents. Les propriétés photophysiques, la cytotoxicité et l'incorporation cellulaire ont été décrites et discutées pour chacun des types de sondes. En outre, ces sondes ont été testées en imagerie in vitro visible et/ou proche-infrarouge par des expériences de microscopie confocale et d’épifluorescence. L’ensemble des sondes décrites dans ce travail, en raison de leurs propriétés avantageuses et nouvelles, constituent des avancées majeures pour le développement de nouvelles générations d'agents d'imagerie optique. / The near-infrared (NIR) region has a significant importance for optical imaging due to the minimal autofluorescence and reduced light scattering thus allowing for improved signal-to-noise ratio and deeper penetration through tissues. Nowadays, the most commonly used NIR-emitting fluorescent probes rely mainly on organic fluorophores or quantum dots and exhibit drawbacks. Several lanthanide(III) ions (Ln³⁺) possess unique optical properties e.g. sharp emission bands the wavelengths of which have minimal sensitivity to the microenvironment, large differences between excitation and emission wavelengths and strong resistance toward photobleaching. In order to obtain the luminescence of lanthanides, the low absorbances of the free Ln³⁺ have to be overcome by the use of appropriate chromophoric groups functioning as a sensitizing “antenna”. We present here several families of Ln³⁺-based probes: (i) small molecules, in particular monometallic complexes constituted by the TTHA-anthraquinone moiety and Ln³⁺, and polymetallic self-assembled Ln³⁺/Zn²⁺ metallacrowns; (ii) novel nanomaterials based on polystyrene beads with two different loadings, i.e. d-f bimetallic Cr³⁺- Ln³⁺+ complex and hydroxyanthraquinone antennae and Ln³⁺ ; (iii) macromolecular generation-3 polyamidoamine dendrimers functionalized with aza-BODIPY sensitizers at their periphery and encapsulating the luminescent Ln³⁺. The photophysical properties, cytotoxicity and cellular uptake were reported and discussed for each of the presented types of Ln³⁺-based probes. Moreover, these probes were successfully tested for visible and/or NIR in vitro imaging by confocal or epifluorescence microscopy experiments. Finally, the reported Ln³⁺-based probes, due to the number of advantageous properties, represent significant breakthroughs toward the developments of new generations of optical imaging agents.

L’étude de plantes utilisées en médecine traditionnelle camerounaise contre le paludisme a révélé des activités antiprotozoaires pour des espèces du genre Psorospermum conduisant à l’isolement d’anthranoïdes prénylés. De nouveaux fractionnements basés sur des techniques chromatographiques en polarité de phase inverse et de partage centrifuge ont permis d’isoler 9 vismiones de l’écorce de P. glaberrimum qui ont montré de fortes activités antileishmaniennes (30 nM < CI50 < 827 nM). Un protocole d’isolement à l’échelle du gramme de ces molécules, sensibles aux conditions classiques de purification, a été développé pour fournir les quantités nécessaires à une démarche d’hémisynthèse et pour comprendre leur mécanisme d’action. La répartition de ces molécules dans les organes de 10 espèces de Psorospermum a été étudiée. Une approche de synthèse organique a également été développée afin d’obtenir des analogues, déterminer leurs activités antiprotozoaires et leurs relations de structure-activité. / The screening of plants used in Cameroonian traditional medicine against malaria revealed significant antiprotozoal activities for species belonging to the Psorospermum genus and led to the isolation of prenylated anthranoids. Further fractionations based on reversed-phase and centrifugal partition chromatography allowed us to isolate 9 vismiones from the bark of P. glaberrimum. All these compounds exhibited strong antileishmanial activities (30 nM<IC50<827 nM).A gram-scale isolation protocol of these highly unstable compounds, when traditional ill-suited purification processes are used, has been developed to provide enough starting material for further hemisynthesis steps and to investigate their mechanism of action. The repartition of these metabolites in different parts of 10 Psorospermum species has been studied. A synthetic approach has also been developed to obtain anthranoid analogues to investigate their antiprotozoal activities and explore structure-activity relationships.