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The complexation of calcium and zinc cations by pyrroglutamate analogs has been studied in the gas phase by means of electrospray ionization mass spectrometry (ESI-MS). Complexes were obtained from the solutions of calcium perchlorate and zinc perchlorate in acetonitrile. The complexes with calcium are singly and doubly charged with various stoichiometries while zinc complexes are singly charged except for one ligand. Solvation with acetonitrile and presence of perchlorate counter-ions are observed when the complexes are in the gas phase. The complexes formed with both metals are mainly L(2)M and LM species. All tested compounds are better complexing agents for calcium than for zinc.

The synthesis of novel [4+2] cycloadducts by Diels-Alder (DA) reaction between diethyl 1-phosphono-1,3-butadiene and cyclic C=C and N=N dienophiles, such as maleimide and 1,2,4-triazole-3,5-dione derivatives, is described. These phosphonated bicyclic frameworks feature a cage shape enabling metal chelation. Indeed, stable complexes were formed in solution with M(2+) and M(3+) metal cations, as evidenced by HRMS in the ESI mode (electrospray ionization). L(1):M (one ligand-one metal) and L(2):M (two ligands-one metal) complexes were identified depending on the nature of the cation. (C) 2011 Elsevier Ltd. All rights reserved.

To date, GC-MS and LC-tandem MS techniques emerged quite frequently in laboratory medicine. However, high-resolution mass spectrometric (HRMS) analyzers remain almost ignored, even though in academic environment, they become more largely used. The main objective of this work is to present and illustrate with several applications, current high resolution mass spectrometric systems which could be useful for clinical applications. Among these systems are the Time-of-Flight (TOF) and Orbitrap instruments. Orbitrap has the advantage of higher resolution but suffers from a slower data acquisition, whereas TOF systems display the opposite characteristics. Both systems could provide accurate mass data and possible structural elucidation, very useful in large scale screening, in different medical areas (clinical or environmental toxicology, anti-doping controls, …). Provided there are further improvements in quantification performances, there is no doubt such HRMS instruments will find their place in clinical laboratories.

In a world involving large amounts of new technologies, the search for new molecular switches for the optimisation of information storage and display setups becomes very challenging. In this context, N-salicylidene aminopyridines have revealed a more complicated structure-properties relationship than the one previously reported because of the combination of structural (associated to the molecular packing) and electronic factors, induced by the molecular architecture itself. A study of the influence of the molecular flexibility has led to consider new conditions needed to observe thermo- and photochromism (with short or long lifetimes). This study was performed with fluorimetry (observation of new radiative relaxations) and supported by a computational approach in order to simulate the thermo- and photo-induced phenomena appearing in the solid state materials. A second step of rationalisation and control of involved parameters was then investigated by using a supramolecular engineering approach based on 1,10-phenanthroline, 1,2,4-triazole and tetrazole moieties. These molecules allowed studying the role of each type of supramolecular interactions in the crystal structure. It also gave access to novel phenomena such as a ‘spring type’ effect involving a photo-switchable material which resists to applied light-induced constraints. These organic molecules were also studied after incorporation as ligands in inorganic complexes. The impact of the coordination as well as the nature of complexes components on the optical behaviours (tuning of the intensity of the thermo- and the photochromism and of the fluorescence of materials) was demonstrated experimentally and supported by a theoretical approach. Moreover, the use of spin transition ions paves interesting way to the observation of thermo- and/or photo-induced magnetic phenomena. We were also able to follow a thermo-induced spin crossover by temperature dependent fluorimetry via the use of a ligand acting as a local pro, Dans un monde imprégné de nouvelles technologies, la recherche de nouveaux matériaux moléculaires bistables pour l’amélioration des dispositifs de stockage et affichage de l’information devient une nécessité. Lors de ce travail, nous avons étudié de façon approfondie et pluridisciplinaire de nouveaux dérivés de la N-salicylidene aniline, connue pour ses propriétés de thermo- et de photochromisme à l’état solide. Les dérivés de type aminopyridine et aminométhylpyridine ont ainsi démontré la présence d’une relation structure/propriété plus complexe que précédemment proposé vu l’implication de facteurs structuraux, liés à l’empilement moléculaire, ainsi qu’électroniques induits par l’architecture moléculaire elle-même (présence de substituants, etc). Une étude de l’influence de la flexibilité moléculaire a également été réalisée, ce qui a conduit à s’interroger sur les pré-requis liés à l’observation des phénomènes de thermo- et de photochromisme (à court et long temps de vie). Cette étude a été soutenue par des mesures fluorimétriques (observation de nouvelles désexcitations radiatives) et via une approche théorique visant à modéliser les phénomènes thermo- et photo-induits au sein des matériaux en phase solide. Une seconde étape de rationalisation et de contrôle des différents paramètres impliqués a ensuite été envisagée via une approche d’ingénierie supramoléculaire développée à partir de motifs azotés de type 1,10-phénanthroline, 1,2,4-triazole et tétrazole. Ces composés nous ont donné la possibilité d’étudier le rôle des différentes interactions supramoléculaires présentes au sein des structures cristallographiques, permettant ainsi de mettre à jour des phénomènes inédits tel qu’un effet ressort impliquant un matériau photo-commutable qui résiste aux contraintes lumineuses appliquées. Ces molécules organiques ont également été étudiées après leur incorporation en tant que ligands au sein de complexes inorganiques. L’impact de la coordination ainsi que de la nature, (CHIM 3) -- UCL, 2010

After irradiation at 254 nm of aqueous solutions of the antipsychotic drug flupentixol, the structures of the photodegradation products were determined by ultra high performance liquid-chromatography linked to mass spectrometry. Fragmentation patterns of the parent ions were established on a hybrid linear ion trap-orbitrap mass spectrometer allowing accurate mass measurements of both parent and daughter ions. This allowed to propose plausible structures for the main photolysis products of flupentixol. A total of nine photoproducts were detected after irradiation of the drug. The main photoproduct is generated following the addition of a hydroxyl group on the double bond adjacent to the thioxanthene ring. Secondary photoproducts were also observed. (C) 2010 Elsevier B.V. All rights reserved.

H-1 and C-13 NMR chemical shifts of coumarin derivatives have been determined using first principles approaches with and without accounting for the effects of the solvent and compared to experiment in order to assess their reliability. Good linear relationships are obtained between theory and experiment, which allows correcting the calculated values for systematic errors. This is particularly the case when using the PCM scheme to model the solvent effects because the delta values larger than 150 ppm are more difficult to reproduce. The final accuracy of the method amounts to about 1 ppm for C-13 and 0.05 ppm for H-1.

Conjugated linoleic acids (CLA) are a group of molecules that has attracted strong interest in medicine because of the important physiological functionalities of some of their isomers. The discovery of their beneficial properties has led to an escalating interest on the production of commercial CLA preparations, which is mostly carried out by chemical synthesis. Consequently, there has been an increasing on the demand of suited techniques to analyze CLA. This thesis evaluates the potential of Fourier transform Raman spectroscopy (FT-Raman) for the determination of conjugated linoleic acids in samples containing complex blends of positional and geometrical CLA isomers. To take into account the spectral interferences between CLA isomers and further test the capabilities of FT-Raman spectroscopy to distinguish them, samples of I2-photoisomerized linoleic acid were analyzed. This photochemical method of synthesis was selected because of its capacity of producing samples with a complex CLA isomeric profile but without a dominant CLA isomer. Our results show that the information contained in the band corresponding to the symmetric stretching vibration of the C=C groups can be reliably used for the determination of total CLA by FT-Raman spectroscopy. In addition, other experiments demonstrate that FT-Raman spectroscopy coupled with PLS regression analysis is a reliable technique to monitor a single isomer in blends containing a dominant CLA isomer. To our knowledge, the present study is the first successful attempt to determine the total CLA content of oils and fats by Raman spectroscopy., (AGRO 3) -- UCL, 2010

The denitration of 2,4,6-trinitrotoluene (TNT) can produce mono- or dinitro aromatic compounds susceptible to microbial mineralization. In the present study, denitration of TNT and other nitro aromatic compounds was investigated with a solid-phase extract obtained from the culture supernatant of Pseudomonas aeruginosa ESA-5 grown on a chemically defined aerobic medium. When the C18 solid-phase extract containing extracellular catalysts (EC) was incubated with TNT and NAD(P)H, we observed a significant release of nitrite. The concentration of nitrite released in the reaction medium was strongly dependent on the concentration of NAD(P)H and EC. Denitration also occurred with two TNT-related molecules, 2,4,6-trinitrobenzaldehyde, and 2,4,6-trinitrobenzyl alcohol. The release of nitrite was coupled with the formation of two polar metabolites, and mass spectrometry analyses indicated that each of these compounds had lost two nitro groups from the trinitro aromatic parent molecule. During this process, the production of toxic reduced TNT metabolites was minimal. The incubation of EC with TNT, NAD(P)H, and specific scavengers of reactive oxygen species suggested the involvement of superoxide radicals (O2*-) and hydrogen peroxide in the denitration process. Results obtained in this study reveal for the first time that extracellular small-molecular-weight substance(s) of bacterial origin can serve as green catalyst(s) to initiate TNT denitration. In addition, this study gives clear evidence for the production of a TNT metabolite bearing a single nitro groupfollowing a denitration reaction with catalyst(s) of biotic origin.

The aim of this study was to investigate the photodegradation of the antiemetic drug metoclopramide. Metoclopramide aqueous solutions were photoirradiated at 254 nm under argon atmosphere. Irradiated metoclopramide solutions were analyzed by high performance liquid chromatography–ion trap mass spectrometry in order to characterize photolysis products. Rapid decrease in metoclopramide purity, following first-order kinetic, was observed following irradiation. The structures of 18 photolysis products were tentatively identified based on their mass spectra and fragmentation. The main degradation mechanism was scission of the chlorine which could be followed by polymerization of the resulting products since dimeric and trimeric products were observed.

Only few data exist on the metabolites produced during the biotransformation of anthraquinonic dyes by white rot fungi (WRF). During the biotransformation of an anthraquinonic dye Acid Blue 62 (ABu62) using Pycnoporus sanguineus MUCL 41582 strain, it was previously demonstrated that the blue colour of the medium turned to red before complete dye decolourisation. To better understand the phenomenon, this study carried out ABu62 biotransformation with five different WRF strains (Coriolopsis polyzona MUCL 38443, Perenniporia ochroleuca MUCL 41114, Perenniporia tephropora MUCL 41562, P. sanguineus MUCL 38531 and Trametes versicolor MUCL 38412) and compared with P. sanguineus MUCL 41582 previously described. A multi-methodological approach (using capillary electrophoresis, mass spectrometry, HPLC, UV, NMR and IR spectroscopies) was developed to characterise the metabolites involved and monitor their apparition. Seven metabolites were commonly found with all strains, suggesting a common metabolic pathway for ABu62 biotransformation. During the first days, dimer and oligomers of the initial ABu62 molecule were observed: the main one absorbed in the 500nm region, explaining the red colour appearance of the medium. This main metabolite was made up of two molecules of ABu62 linked by an azo bond, minus a cyclohexyl moiety. After a longer incubation time, breakdown products were observed. Based on these products characterizations, a bioconversion pathway was proposed.

The aim of this study is to evaluate the specificities of the irradiation of drugs in frozen aqueous solution. The structures of the degradation products were determined to gain insight into the radiolysis mechanisms occurring in frozen aqueous solutions. Metoclopramide hydrochloride and metoprolol tartrate were chosen as models. The frozen solutions were irradiated at dry ice temperature by high energy electrons at various doses. The drug purity (chemical potency) and the radiolysis products were quantified by HPLC-DAD. Characterization of the degradation products was performed by LC-APCI-MS-MS. The structures of the radiolysis products detected in irradiated frozen aqueous solutions were compared to those detected in solid-state and aqueous solutions (previous studies). For both metoclopramide and metoprolol, solute loss upon irradiation of frozen aqueous solutions was negligible. Five radiolysis products present in traces were identified in irradiated metoclopramide frozen solutions. Three of them were previously identified in solid-state irradiated metoclopramide crystals. The two others were formed following reactions with the hydroxyl radical (indirect effect). Only one fragmentation product was observed in irradiated metoprolol frozen solutions. For both drugs, radiosterilization of frozen solutions, even at high doses (25kGy), was found to be possible.

The fragmentations of hydroxylated flavanones, chalcones and dihydrochalcones were investigated by direct loop injection using an ion trap mass spectrometry equipped with atmospheric pressure chemical ionization (APCI) probe. Some of them have been isolated from the leaves of Piper hostmannianum var. berbicense and standards were used to confirm their fragmentation behaviour. In negative ion mode, fragmentations of these three types of flavonoids revealed specific diagnostic ions which allowed us to identify aglycones in a crude plant extract. The major fragment ion obtained in MS/MS experiment for methoxylated chalcones is the neutral loss of a methyl radical whereas a H(2)O molecule is lost in the case of methoxylated dihydrochalcones. Methoxylated chalcones and flavanones isomers could be differentiated by the relative intensity ratio of [M-H-CH(3)]*(-) and [M-H-C(2)H(2)O](-) ions. Based on UV and MS data, a decision tree that includes UV lambda(max) absorptions and MS/MS diagnostic ions was built in order to obtain structural information of unknown compounds present in the extract. This tree was used to identify flavonoids in the ethyl acetate extract of P. hostmannianum var. berbicense leaves after analysis by high-performance liquid chromatography-diode array detection-atmospheric pressure chemical ionization ion trap multistage mass spectrometry. A total of 11 flavonoids were tentatively characterized based on the MS fragmentations pattern observed in MS(n) experiments.

The aim of this study was to assess the feasibility of radiosterilization of drugs aqueous solutions and to evaluate the effects of some additives, such as mannitol, nicotinamide and pyridoxine, which might protect the drug from degradation. Metoclopramide was selected as a model drug. The structures of the degradation products were determined to gain insight on the radiolysis mechanisms in aqueous solution in order to design strategies to lower the drug degradation. Metoclopramide hydrochloride aqueous solutions with and without excipients were irradiated either with gamma rays or high-energy electrons. HPLC-DAD was used to measure the loss of chemical potency and to quantify the degradation products which were also characterized by LC–APCI–MS-MS. Metoclopramide recovery for gamma and electron beam-irradiated solutions containing either mannitol, pyridoxine or nicotinamide meets the pharmacopoeial specifications for metoclopramide content up to a 15 kGy irradiation so that metoclopramide solutions containing these excipients might be radiosterilized at 15 kGy either with gamma rays or high-energy electrons. Structures are proposed for the majority of radiolysis products. Similar radiolysis products were detected for gamma and electron beam irradiations but the chromatographic profiles were different (differences in the distribution of radiolysis products).

We report on the grafting of coumarin chromophores on flat silicon surfaces and in regions of nanometric dimensions drawn on silicon surfaces. The coumarin derivative was grafted by using the quaternization of a tertiary amine group of the chromophore with a ((chloromethyl)phenylethyl)-dimethylchlorosilane (CMPDCS) grafted on silicon. Complete characterization of the grafted layer was performed as a function of reaction time by X-ray photoelectron spectroscopy, X-ray reflectometry, atomic force microscopy, fluorescence spectroscopy and laser-scanning confocal microscopy. The results indicate that about one chromophore molecule is grafted every second CMPDCS molecule, resulting in a surface density of coumarin of slightly more than one coumarin per nm2. A broadening of the distribution of the fluorescence lifetimes was observed, suggesting that the grafted molecules experience a larger distribution of environments in the grafted layer than in solution. Since this reaction is fully compatible with silicon processing technology, the grafting could also be performed in nano-regions of size as small as 250 nm defined by combining electron-beam lithography with silanization. In such nano-sized regions the distribution of fluorescence lifetimes was narrower, suggesting a possible influence of the confinement on the organization of the molecules.

In this work, the radiolysis mechanisms in solids as well as in liquid and frozen aqueous solutions have been studied. Liquid chromatography tandem mass spectrometry has evolved so that mass spectral information can now be used to determine the most probable structures of radiolysis products, even those present in traces amounts. Theoretical routes explaining the formation of radiolysis products can be deduced from their structures. The development of strategies to limit the degradation of the active pharmaceutical ingredient during irradiation of the drug requires a better knowledge of the radiolysis mechanisms responsible for the drug degradation. Metoclopramide, an antiemetic drug, has been selected as a model, due to the variety of its chemical bonds. In the solid state, radiation-induced degradation of the drug was very low (<0.1%) and only four radiolysis products were detected in traces. The "major" radiolysis product was formed after the loss of the chlorine by dissociative electron capture. For metoclopramide liquid aqueous solutions, the loss of the drug was important (~30% loss at 25 kGy) and several radiolysis products were detected. The majority of the degradation products were generated following the attacks of hydroxyl radicals and aqueous electrons. The loss of metoclopramide could be lowered up to acceptable levels (<10% loss) provided that radioprotective additives were added and the irradiation dose was limited to 15 kGy, which could be sufficient to reach the required SAL. The selected excipients were mannitol (which reacts mainly with the hydroxyl radical), nicotinamide and pyridoxine that react with both the aqueous electron and the hydroxyl radical. The irradiation of frozen aqueous solutions allowed to minimize the loss of active substance even for a 25 kGy dose. This approach seems to be the most promising method for terminal sterilization of aqueous solutions by ionizing radiations. The major radiolysis product was formed after the attack o, (FARM 3)--UCL, 2007

Fractionation of an antitrypanosomal lipophilic leaf extract from Strychnos spinosa led to the isolation of eight triterpenoids and sterols in this plant part for the first time. Two of these were found to possess in vitro antitrypanosomal activity, namely, saringosterol (14) and 24-hydroperoxy-24-vinylcholesterol (15), with IC(50) values of 7.8 +/- 1.2 and 3.2 +/- 1.2 microM, respectively. The latter compound was isolated from a plant source for the first time. A comparative study on the antitrypanosomal activity of the isolated triterpenoids and sterols and some related compounds has indicated that the presence of an oxygenated function at C-28 or an oxygenated side chain at C-17 seems to be important for the antitrypanosomal activity of triterpenoids and sterols, respectively.

Dans le but d'augmenter la sensibilité de senseurs fluorescents, nous avons connecté deux fluoroionophores dans une même molécule pour obtenir une sonde dichromophorique. Les molécules de ce travail sont réparties en deux familles: les premières sont dérivées de la coumarine 343, les autres d'une 7-aminocoumarine portant un groupement trifluorométhyle en position 4. De par leur structure, ces coumarines sont destinées à complexer efficacement le magnésium. Ce sont des sondes à transfert de charge intramoléculaire et donc, en présence de cations, leurs spectres d'absorption et d'émission sont déplacés vers les grandes longueurs d'onde. Ces chromophores sont reliés à un noyau aromatique central soit par un lien amide soit par un lien éther. Les analogues monochromophoriques de ces sondes ont également été synthétisés à titre comparatif. Tout d’abord, les propriétés photophysiques de ces sondes et de leurs complexes ont été étudiées dans l'acétonitrile par spectrophotométrie et fluorimétrie. Ces techniques d’analyse nous ont permis de visualiser la formation des complexes, mais également de proposer des stoechiométries pour ceux-ci et d’obtenir leurs constantes de formation. Ensuite, les déclins de fluorescence de ces mêmes ligands et de leurs complexes ont été étudiés. Nous avons ainsi approfondi notre connaissance de la photophysique des ligands et de leurs complexes et nous avons obtenu divers paramètres cinétiques de l’état excité tels que les constantes de vitesse de formation et de dissociation des complexes à l’état excité. Enfin, nous avons réalisé diverses expériences RMN pour obtenir plus d’informations sur la structure des complexes. Nous avons également étudié certains complexes par spectrométrie de masse afin de confirmer leurs stoechiométries., (CHIM 3) -- UCL, 2007

La production de b-lactamases est la principale cause de résistance bactérienne aux antibiotiques de type b-lactame. Ces enzymes inactivent les antibiotiques en hydrolysant la liaison amide du cycle b-lactame. Notre laboratoire s'intéresse à la synthèse et l'évaluation biologique d'inhibiteurs potentiels des b-lactamases des classes A, B, C et D. La cristallisation de BS3, une b-lactamase de la classe A, dans un tampon citrate a révélé le rôle inattendu de ce composé qui est parfaitement positionné dans la cavité enzymatique. Le citrate est un inhibiteur de toutes les b-lactamases de la classe A, actif au niveau micromolaire. Ces observations récentes effectuées au Centre d'Ingénierie des Protéines (Université de Liège) nous ont permis de considérer le citrate comme un lead pour la conception de nouveaux inhibiteurs sélectifs et de hautes affinités des b-lactamases. Tout d'abord, nous avons essayé d'augmenter l'affinité dans la cavité enzymatique en remplaçant la fonction alcool par une fonction amine sur laquelle nous pouvons fixer une variété de chaînes latérales. Le replacement d'une (ou deux) fonctions acides carboxyliques par les acides phosphoniques et l'allongement d'une ou deux chaînes acides pour créer de nouvelles interactions ont aussi été envisagées. Différents dérivés aminés du citrate et de l'iso-citrate ont été synthétisés et une évaluation de leur activité biologique a été effectuée sur différentes b-lactamases et sur R39. Le complexe entre l'aminocitrate et BS3 a été analysé par diffraction des rayons X. Plusieurs dérivés aminophosphoniques et bis-phosphoniques ont été synthétisés et leur potentiel inhibiteur a été évalué sur différentes PBPs. Finalement, la capacité complexante de certaines des molécules synthétisées a été évaluée par spectrométrie de masse., The production of b-lactamases represents the most widespread and often the most efficient mechanism devised by bacteria to escape to the lethal action of b-lactam antibiotics. Our research focuses on the synthesis and the biological evaluation of potential inhibitors of classes A, B, C and D b-lactamases. The crystallization of class A b-lactamase BS3 from a citric acid buffer revealed the unexpected role of this compound which is perfectly located in the enzymic cavity. The citrate is an inhibitor of all class A b-lactamases at the micromolar level. These recent observations carried out in the Centre d?Ingénierie des Protéines (université de Liège) led us to consider the citrate as a lead for the design of new selective and high affinity inhibitors of b-lactamases. We tried to increase the binding in the enzymic cavity by replacing the alcohol function by an amine function on which we could fix a variety of lateral chains. We have also considered the replacement of one (or two) carboxylic functions with the bioisoster phosphonic acids and the lengthening of one or two acidic chains to create novel interactions. Several derivatives of the amino-bioisoster of citric acid have been synthesized with carboxylic or ester functions and the biological activity of aminocitrate derivatives has been evaluated against PBPs (Penicillin Binding Proteins). The complex between the aminocitrate and BS3 has been analysed by X-Ray diffraction. The amino phosphonic and bis-phosphonic derivatives have been synthesized and the biological evaluation has been achieved against PBPs. Finally, the complexing capacity of several molecules has been evaluated by mass spectrometry., (CHIM 3) -- UCL, 2007

The adults of the leaf beetle Platyphora kollari (Chrysomelidae) are able to metabolise the oleanane triterpene beta-amyrin (1) into the glycoside 3-O-beta-D: -glucopyranosyl-(1-->4)-beta-D: -glucuronopyranosyl-hederagenin (2) that is stored in their defensive glands. The aim of this study was to test the hypothesis that oleanolic acid (3) is an intermediate in the conversion of 1 into 2 and to check whether the sequestration of pentacyclic triterpenes is selective in favour of beta-amyrin (1). To this end, adults of P. kollari were fed with Ipomoea batatas leaf disks painted with a solution of [2,2,3-(2)H(3)]oleanolic acid or [2,2,3-(2)H(3)]alpha-amyrin and the secretion of their defensive glands analysed by HPLC-ESIMS. The data presented in this work indicated that the first step of the transformation of beta-amyrin (1) into the sequestered glycoside 2 is its oxidation into oleanolic acid (3) and that this conversion is selective but not specific in favour of beta-amyrin (1).

The assessment of the glycemic index (GI) seems to be an important parameter to take into account in order to better understand the physiologic effects of foods with high carbohydrate levels. Among cereals, which are major sources of carbohydrates, spelt (Triticum spelta L.) has been considered as particularly interesting from a nutritional point of view. The aim of this study was to evaluate in vivo the GI of white spelt bread in healthy subjects. The wheat (Triticum aestivum L.) white bread was used as reference food. To avoid differences in the production of both breads, spelt and wheat breads were baked under the same controlled conditions. Results showed that the glycemic profile of spelt white bread was not different from that of wheat white bread (GI of 93 9). The area under the glycemic curve significantly and negatively correlated to fasting glycemia and carbohydrate intake during evening meals preceding the test. In conclusion, the glycemic response to spelt bread was similar to that of wheat bread. However, in order to avoid more inter-individual variability, our data supports the importance to propose standardised carbohydrate content for the last meat before evaluating the GI of food. (c) 2005 Elsevier Ltd. All rights reserved.

The biocatalytic elimination of the endocrine disrupting chemicals (EDC) nonylphenol (NP) and bisphenol A (BPA) and the personal care product ingredient triclosan (TCS) by the enzyme preparation from the white rot fungus Coriolopsis polyzona was investigated. Analysis of variance methodology showed that the pH and the temperature are statistically significant factors in the removal of NP, BPA and TCS. The elimination of NP and TCS was best at a temperature of 50 °C and the disappearance of BPA at 40 °C, whereas the most suitable pH for all three micropollutants was 5. After a 4-h treatment of the three target compounds at concentrations of 5 mg l−1 all of the NP and BPA were eliminated. In the case of TCS, 65% was removed after either a 4 or an 8-h treatment. The utilisation of 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) in the laccase/mediator system significantly increased the efficiency of the enzymatic treatment. The elimination of NP and BPA was directly associated with the disappearance of the estrogenic activity. Mass spectrometry analysis showed that the enzymatic treatment produced high molecular weight metabolites through a radical polymerization mechanism of NP, BPA and TCS. These oligomers were produced through the formation of C–C or C–O bonds. The polymerization of NP produced dimers, trimers, tetramers and pentamers which had molecular weights of 438, 656, 874 and 1092 amu respectively. The polymerization of BPA produced dimers, trimers and tetramers which had molecular weights of 454, 680 and 906 amu. Finally, the polymerization of TCS produced dimers, trimers and tetramers which had molecular weights of 574, 859 and 1146 amu.

Molecular assemblies capable of harvesting light and using the absorbed energy have attracted great interest in recent years because of their applicability in such domains as light emitting diodes, fluorescent labelling of biological molecules, and photonic devices. Nature has also developed in plants and photosynthetic bacteria several examples of photonic nanostructures which guide light over small distances and harvest light energy, using resonance energy transfer (RET). For some time, researchers have tried to mimic the spatial arrangements of high energy transfer efficiency found in Nature. Recent progress in the application, creation and manipulation of individual or small groups of molecules are opening new perspectives for further developments in this field. These recent advances are commonly considered to lie at the root of what is being called "Nanotechnology". Although the definitions of nanotechnology are diverse, it is commonly admitted that this new domain of Science draws ideas and concepts from disciplines including engineering, physics, chemistry, biology, mathematics and computer science. The central dogma of the "bottom up" version of nanotechnology is the notion of self-assembly, which is the spontaneous assembly of materials into predetermined ordered structures or complexes. Presented here is an example from a field of nanotechnology that utilizes self-assembly onto nano-patterned surfaces to generate nano-structured systems and devices. More precisely, in the present case we target photo-active devices based on Fluorescence Resonance Energy Transfer (FRET), taking inspiration from photosynthetic light harvesting systems, where concentric nanometric rings of chromophores funnel light energy to a reaction center. Here, we synthesize nano-patterned chromophore surfaces which are able to collect light energy over a large surface and funnel it in regions of ~100 nm size. Our results indicate that an efficient collection and transfer of light energy, (CHIM 3)--UCL, 2006

Au cours de ce travail, nous nous sommes intéressés au blocage et déblocage de la fonction amine par le groupement photosensible arylsulfonamide. Plus qu'une simple photodéprotection, notre projet a aussi l'originalité de vouloir promouvoir une photodéprotection énantiosélective par dédoublement cinétique des groupements arylsulfonyles, afin d'obtenir des amines chirales. L'utilisation de sensibilisateurs dérivés de la structure du BINOL a permis de mettre au point une méthode douce et catalytique de photodéprotection des arylsulfonamides, optimisée dans le méthanol et le DMF. L'efficacité et la sélectivité observées lors des essais de photodéprotection sur divers substrats ont permis de valoriser cette méthode, la rendant très compétitive par rapport aux procédés assez drastiques habituels pour cliver le groupement arylsulfonamide. Les observations expérimentales ont permis de déterminer que les dérivés du BINOL sensibilisent la réaction à partir, quasi exclusivement, de l'état triplet. Les différentes tentatives, à partir de différents sensibilisateurs et différents arylsulfonamides, de réactions de photodéprotection énantiosélectives n'ont pas été concluantes. Le suivi de l'excès énantiomérique en fonction de la variation de la conversion en arylsulfonamide a montré la présence d'un mélange de racémates. De nouvelles structures de sensibilisateurs, dérivés du naproxène ou de naphthol modifiés chiraux, ont eux aussi montré une bonne réactivité pour la réaction de photodéprotection des arylsulfonamides, mais là-encore, aucun enrichissement en l'un des énantiomères d'une amine déprotégée n'a été observée. Enfin, l'étude préliminaire du mécanisme de clivage du radical anion du tosylamide a démontré que l'espèce intermédiaire finale formée est une espèce anionique. Jusqu'à présent, le mécanisme de formation de cet intermédiaire anionique n'a pas été déterminé., (CHIM 3)--UCL, 2006

Escherichia coli grew aerobically with 2,4,6-trinitrotoluene (TNT) as sole nitrogen source and caused TNT's partial denitration. This reaction was enhanced in nongrowing cell suspensions with 0.516 mol nitrite released per mol TNT. Cell extracts denitrated TNT in the presence of NAD(P)H. Isomers of amino-dimethyl-tetranitrobiphenyl were detected and confirmed with U-15N-labeled TNT.