Pour effectuer des opérations de régulation et de signalisation, les systèmes naturels mettent à profit des processus ioniques et photoniques. Certain aspects de ces processus peuvent être reproduits dans des systèmes artificiels, en combinant senseurs et récepteurs moléculaires photoactifs dans des nanocapsules ou des membranes auto-assemblées. Une série de molécules photoactives amphiphiles et non-amphiphiles a été synthétisée, notamment pour la complexation et la libération d'ions calcium. Ces derniers processus ont été étudiés à l’aide de différentes spectroscopies incluant la fluorimétrie et l’infrarouge. Le couplage du processus photomodulé d'éjection d'ion et sa détection, dans des domaines nanoscopiques et à l'interface membrane / liquide, a été étudié pour connaître l'efficacité du transfert d'ion en solution et milieu organisé, notamment au sein de vésicules de tailles différents. / Natural systems combine ionic and photonic processes in order to control, for example,signalling and regulation. Certain aspects of these processes can be achieved in artificialsystems, on combining photoactive molecular sensors / switches, molecular receptors andself-assembled nanocapsules or membranes. A range of novel amphiphilic andnon-amphiphilic synthetic photoactive molecules and molecular systems are reported, notablyfor the complexation and liberation of calcium ions. These processes are studied using a rangeof spectroscopies including fluorimetry, microscopy and IR-techniques. Coupling processes ofphotocontrolled ion ejection and detection in nanoscopic compartments and at liquid /membrane interfaces has been studied in order to assess the relative efficiency ofintermolecular ion transfer in solution and organized media, notably in vesicle nanodomains.

The rational design, synthesis and complexation characteristics of several monovalent cation-selective ligands are described. Molecular modeling employing a combination of dynamics, mechanics (AMBER94) and electrostatics was used to design ligands for the complexation of ammonium, potassium, sodium and lithium ions. A modular technique was used to synthesize an ammonium selective ionophore based on a cyclic depsipeptide structure (8). The ionophore was incorporated into a planar ion selective electrode (ISE) sensor format and the selectivity tested versus a range of metal cations. It was found that the membrane containing the polar plasticizer NPOE (nitrophenyloctylether) in the absence of ionic additive exhibited near-Nernstian behavior (slope = 60.1 mV/dec @ 37¢ªC) and possessed high selectivity for ammonium ion over lithium and the divalent cations, calcium and magnesium (logK = -7.3, -4.4, -7.1 for lithium, calcium and magnesium ions, respectively). The same membrane also exhibited sodium and potassium selectivity that was comparable to that reported for nonactin (logK = -2.1, -0.6 for sodium and potassium, respectively, compared to -2.4, -0.9 in the case of nonactin). N-(9-methylanthracene)-25,27-bis(1-propyloxy)calix[4]arene-azacrown-5 (10) was synthesized and tested as a fluoroionophore for the selective detection of potassium ions. Compound 10 acts as an ¡°off-on¡± fluorescent indicator for ion complexation as a result of photoinduced intramolecular electron transfer (PET). Studies demonstrate that 10 is selective for potassium over other alkali metal cations, with excellent selectivity over sodium and lithium (log K ¡ -3.5) and moderate selectivity over rubidium and cesium (log K ~ -1). N-(9-methylanthracene)-25,27-bis(1-propyloxy)-4-tert-butylcalix[4]arene-azacrown-3 (11) was synthesized and tested as a fluoroionophore for the selective detection of lithium cations. When exposed to lithium ions in a 75:25 dichloromethane/THF solvent mixture, the molecule, which operates on PET, exhibited a >106-fold enhancement in fluorescence emission intensity. Selectivity studies demonstrated that 11 effectively discriminates against sodium and potassium ions log K ¡ -3.8 and log K ¡ -2.3. A fluorescent sodium optode based on a fluoroionophore consisting of aminorhodamine B covalently-linked through an amide bond to a calix[4]arene has also been developed (12). The optode, fashioned by incorporation of the fluoroionophore into a single component polymer matrix, operates on the basis of PET. The fluorescence intensity increased linearly with increasing sodium ion concentration in the range 0.01 M to 2.0 M, exhibiting a three-fold enhancement over this range. The optode provides selectivity for sodium ions compared to potassium ions that is sufficient for clinical determinations of sodium ion concentration.

The drawbacks of nonactin, the current commercial standard receptor for ammonium ion necessitate the development of new ammonium ionophores. We have designed and attempted to synthesize fluoroionophores, I- III. Molecular modeling of I suggests superior selectivity over that of nonactin. III was synthesized as a selective ionophore for optical detection of ammonium ion. The synthetic strategies for III are two-fold: solid phase and solution phase. Solution phase synthesis was performed with two different protecting groups (t-butyl ester and benzyl ester). A methyl-amino substituted anthracene molecule will be covalently coupled to the secondary amine group to provide an optical signaling moiety that operates on the basis of an“off-on" fluorescence emission mechanism. Compound IV was also synthesized in order to provide a sample reaction for the covalent coupling of the chromophore and to provide a fast route to an ammonium fluoroionophore.

L'objet de ce travail est de fournir de nouveaux outils moléculaires pour la caractérisation physico-chimique des particules atmosphériques afin d'établir des liens entre leurs propriétés et leur toxicité pulmonaire. Nous nous sommes plus particulièrement intéressés à la détection, la quantification et le traçage du fer, élément majeur dans les particules industrielles du bassin dunkerquois. Pour ce faire, nous avons mis au point dans un premier temps, la synthèse rapide de nouvelles sondes fluorescentes par micro-ondes et ultrasons. L'étude des propriétés spectroscopiesde ces nouvelles sondes a été menée et a permis de mettre en avant un composé sélectif des ions ferriques en solution aqueuse non temponnée en présence d'autres ions métalliques. Dans un second temps, nous avons réalisé des supports solides contenant des entités chélatantes supramoléculaires ou bio-inspirées afin de séparer les traces de fer ferrique de matrices aqueuses complexes. / The aim of this work is to provide new molecular tools for the physico-chemical characterization of atmospheric particles in order to establish a link between their properties and their pulmonary toxicity. We particularly investigate the detection and quantification of iron, a major element in industrial particle of Dunkirk city, France. So, in a first hand, we have developed the efficient synthesis of new fluorescents chemosensors by ultrasounds and microwave irradiation. Then the study of these compounds was undertaken and has revealed a highly selective sensor of ferric iron in non-buffered aqueous solution in presence of other metallic cation. In the other hand, we have synthesized new solid supports which beard supramolecular chelatant or bio-inspired entities in order to separate iron traces from complex aqueous matrix.