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Dujols, Virginie Elisabeth. "Rhodamine & anthracene-based chemosensors /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487941504294111.
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Cabell, Larry Allen. "Chemosensors and competition sensing assays /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Fang, Albert Geeson. "Development of novel fluorescent chemosensors /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3138822.
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Jin, Shan. "Development of Boronic Acid-Based Chemosensors." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_diss/31.
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It is well known that boronic acids can bind with diols and can be further applied as chemosensors for biomolecules such as carbohydrates and dopamine. Carbohydrates are known to mediate a large number of biological and pathological events. Small and macromolecules capable of carbohydrate recognition have great potentials as research tools, diagnostics, vectors for targeted delivery of therapeutic and imaging agents, and therapeutic agents.
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Santos, Carla Isabel Madeira dos. "Corroles : synthesis, functionalization and application as chemosensors." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/11959.
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Departamento em QuímicaO trabalho de investigação apresentado nesta dissertação foi desenvolvido tendo como objectivo a síntese e funcionalização de meso-triarilcorróis para utilização como quimiossensores. Este trabalho encontra-se apresentado ao longo de cinco capítulos. No primeiro capítulo são apresentadas as características gerais, as metodologias de síntese e de funcionalização de macrociclos de tipo corrólico, e descrevemse algumas aplicações em que têm sido utilizados. São ainda abordadas algumas das propriedades e características dos quimiossensores e os mecanismos de deteção de diversos analítos. No segundo capítulo, após uma pequena introdução às reações de Wittig e de Diels-Alder, escolhidas para a funcionalização do macrociclo corrólico, descreve-se o estudo efectuado para a obtenção do complexo de gálio(III) do 3- vinil-5,10,15-tris(pentafluorofenil)corrol e o seu comportamento como dieno, em reações de Diels-Alder na presença dos dienófilos 1,4-benzoquinona e 1,4- naftoquinona. Desses estudos resultaram dois aductos cuja habilidade sensorial, bem como a dos seus precursores, foi estudada, em solução, na presença de aniões esféricos (F-, Br-, Cl-), lineares (CN-) e volumosos (CH3COO-, H2PO4 -). Dos macrociclos estudados verificou-se que o corrol base-livre 5,10,15-tris(pentafluorofenil)corrol apresenta uma elevada sensibilidade para o anião fluoreto (F-), e que a coordenação do núcleo corrólico com gálio(III) diminui a afinidade para este anião. Em geral, todos os compostos mostraram afinidade para o anião cianeto (CN-) mesmo quando em suportes poliméricos. O gel de poliacrilamida revelou-se muito promissor na determinação de CN- em amostras de água. No terceiro capítulo é avaliada a reatividade do complexo de gálio(III) do 3- vinil-5,10,15-tris(pentafluorofenil)corrol ainda como dieno mas agora na presença de um dienófilo linear, o acetilenodicarboxilato de dimetilo. Desse estudo resultaram dois novos derivados corrólicos. A habilidade sensorial dos mesmos perante os aniões fluoreto, cianeto, acetato, e fosfato foi avaliada por espectroscopia de absorção e emissão tendo um dos aductos mostrado ser colorimétrico para o anião cianeto. No quarto capítulo descreve-se a síntese e caracterização de dois conjugados do tipo corrol-cumarina, resultantes de reações de Hetero-Diels-Alder entre o 3-vinil-5,10,15-tris(pentafluorofenil)corrolatogálio(III)(piridina) e orto-quinonasmetídeos gerados in situ a partir de reacções de Knoevenagel entre cumarinas e paraformaldeído. Realizaram-se estudos de afinidade sensorial para aniões e catiões com estes macrociclos, bem como com conjugados porfirinacumarina análogos. A inserção de uma unidade cumarina conferiu uma excepcional solubilidade tendo os novos derivados apresentado solubilidade em etanol. No quinto e último capítulo desta dissertação é avaliada a capacidade sensorial do 5,10,15-tris(pentafluorofenil)corrol e da sua espécie monoaniónica, para os catiões metálicos Na+, Ca2+, Cu2+, Cd2+, Pb2+, Hg2+, Ag+, Al3+, Zn2+, Ni2+, Cr3+, Ga3+, Fe3+ em tolueno e acetonitrilo. Os macrociclos corrólicos mostraram ser selectivos e colorimétricos para o catião Hg2+. Neste trabalho descreve-se ainda a síntese do derivado -iminocorrol, que após funcionalização com o 3-isocianatopropiltrimetoxisilano originou um derivado do tipo alcoxisilano, que foi, posteriormente, ancorado a nanopartículas comerciais de sílica. As novas nanopartículas ancoradas com o alcoxisilano corrol foram estudadas na presença de Cu2+, Hg2+ e Ag+. Na presença do catião Ag+ assistiu-se a uma mudança de cor, de verde para amarelo.
The work described in this dissertation was focused on the synthesis of mesotriarylcorroles and their functionalization for later use as chemosensors. This work is divided in five chapters. In the first chapter it is described the general features of corroles, synthetic methodologies, the functionalization procedures and the applications of this kind of macrocycles. Additionally, some considerations about chemosensors and the importance of analytes that will be evaluated is also discussed. In the second chapter the Wittig and Diels- Alder reactions were chosen as post-functionalization procedures to apply to corroles. In this way, by the use of a Wittig reaction, the derivative 3–vinil-5,10,15- tris(pentafluorophenyl)corrolatogallium(III) was synthetized, from the corresponding 3-formy-5,10,15-tris(pentafluorophenyl)corrolatogallium(III), and its behavior as diene in Diels–Alder reactions, in the presence of the dienophiles 1,4-benzoquinone and 1,4-naphthoquinone was evaluated. These studies afforded two Diels-Alder adducts whose sensorial ability, as well as of their precursors, was studied in solution in the presence of spherical( F -, Br -, Cl -), linear (CN-) and bulky (CH3COO-, H2PO4 -) anions. The 5,10,15- tris(pentafluorophenyl)corrole showed to be the most sensitive macrocycle to the fluoride anion (F-). Although all derivatives have interacted with this anion the coordination of the corrole core with gallium(III) decreased their affinity for this anion. In general, all compounds showed interaction with cyanide (CN-) anions. By these results two low cost polymers based on polymethylmethacrylate and polyacrylamide were prepared and used in the detection of CN- in water. The polyacrylamide gel proved to be very promising. In the third chapter the reactivity of the gallium(III) (pyridine) complex of 3-vinyl- 5,10,15-tris(pentafluorophenyl)corrole as a diene was extended to dimethyl acetylenedicarboxylate as dienophile. This study afforded two new corrole derivatives. The sensorial ability of the new macrocycles towards fluoride, cyanide, acetate and phosphate anions was carried out by absorption and emission spectroscopy. One of the derivatives showed to be colorimetric to cyanide, where a change of colour from green to colourless was visualized. In the fourth chapter is described the synthesis and characterization of two new derivatives resulting from hetero-Diels-Alder reactions between the gallium(III) (pyridine) complex of 3-vinyl-5,10,15-tris(pentafluorophenyl)corrole and oquinone methides (o-QM) generated in situ from Knoevenagel reactions of coumarins with paraformaldehyde. The sensing ability of the resulting compounds was studied in the presence of different anions and cations. These sensorial studies were extended to porphyrin-coumarin analogues. The insertion of a coumarin moiety conferred an unusual solubility to these conjugates in ethanol. In the last chapter is shown the sensorial ability of 5,10,15- tris(pentafluorophenyl)corrole and of its monoanionic species towards Na+, Ca2+, Cu2+, Cd2+, Pb2+, Hg2+, Ag+, Al3+, Zn2+, Ni2+, Cr3+, Ga3+, Fe3+ metal ions in toluene and acetonitrile. The photophysical studies towards metal ions were carried out by absorption and emission spectroscopy. These corroles showed to be selective and colorimetric for Hg2+. In addition a new - imine corrole was successful synthetized and further functionalized with 3-isocyanatopropyltrimethoxysilane resulting an alkoxysilane derivative. The grafting of alkoxysilane derivative, with optically transparent silica nanoparticles (SiNPs) was also performed. The new-coated silica nanoparticles with corrole were studied in the presence of Cu2+, Hg2+ and Ag+ as metal ion probes. In the presence of Ag+ was observed a change of colour from green to yellow.
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Cheung, Sin Man. "Development of optical chemosensors for cation sensing." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/771.
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Rosa-Gastaldo, Daniele. "Supramolecular chemosensors for the detection of phenethylamines." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3425410.
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In this work I described and discussed the results of a research project which focused on both development and application of the NMR-chemosensing technique. This technique is based on the combination of gold nanoparticles 2 nm in diameter coated with specific thiols and particular NMR experiments, and it allows to “extract” from the NMR spectrum of a mixture of substances the single NMR spectrum of the analyte bound by the nanoparticle. Specifically, the main goal of my work was to demonstrate how this technique can be successfully used for designer-drug detection.
The majority of the new drugs that appear on the market every year belong to this category, i.e. they are structural analogs of already well-known drugs. Designer drugs represent a big health issue, because no studies on them are available, therefore the risks and potential long-term adverse effects are not known. Moreover, as reference standards are not available, their sensing with routine techniques is difficult. The technique that I will describe also works on real street samples, with no pretreatment, thus giving the possibility to get from the seizure of the powder to the characterization of the substance in a few hours.
I’ll also show that to improve the potentialities of NMR chemosensing in terms of detection limit and sensitivity one can work from two sides. First, it is possible to improve the design of the coating thiol, obtaining a monolayer with different affinities and different capability of magnetization transfer, both crucial aspects for the technique. On the other hand, it is possible to im-prove sensitivity by acting directly on the type of NMR experiment used as well, also in combination with tricks that exploit magnetization enhancement, such as using the water trapped in the monolayer as an additional magnetization source or using the capability of gold nanoparticles to self-assemble on silica nanospheres, in order to enhance the nanoreceptor’s size. Combining all the various things, I will demonstrate how it is possible to sense inorganic species too, such as K+, which do not have an NMR signal per se.
Finally, as NMR is not, as of now, a technique that is easy to apply for on-field analysis, in the last part of this paper I propose a point-of-care sensor developed in the form of an indicator strip in which a self-assembled supramolecular receptor composed of a cucurbituril and a dye can selectively sense the presence, or not, of a drug in a quick, safe and cheap way.In questa tesi ho descritto e discusso i risultati ottenuti nell’ambito di un progetto di ricerca focalizzato sull’applicazione e lo sviluppo della tecnica dell’NMR-chemosensing. Questa tecnica è basata sulla combinazione di nanoparticelle d’oro da 2 nm di diametro passivate con opportuni tioli e di particolari esperimenti NMR e consente di “estrarre” dallo spettro NMR di una miscela di composti lo spettro NMR dell’analita riconosciuto dalla nanoparticella. In particolare, lo scopo primario del mio lavoro è stato dimostrare come questa tecnica possa essere usata con successo per il rilevamento delle cosiddette “designer drugs”. La maggior parte delle nuove droghe immesse sul mercato ogni anno altro non sono che analoghi strutturali di droghe già diffuse. Ciò rappresenta un grave problema di salute pubblica, perché non essendo queste nuove sostanze mai state studiate, non se ne conoscono i potenziali rischi e gli effetti a lungo termine. In più, non esistendo standard di riferimento, la loro rilevazione con tecniche tradizionali risulta difficoltosa. La tecnica che verrà descritta è stata testata e funziona anche su campioni reali, senza bisogno di pretrattamento del campione, e dà la possibilità di arrivare dal sequestro alla caratterizzazione strutturale della sostanza stupefacente nel giro di poche ore. Dimostrerò anche che per migliorare le potenzialità dell’NMR-chemosensing in termini sia di sensibilità che versatilità si può agire su un doppio fronte. Da un lato, è possibile migliorare la struttura del tiolo che ricopre le nanoparticelle, ottenendo un monostrato con maggior affinità e maggior capacità di trasferimento della magnetizzazione, entrambi aspetti fondamentali della tecnica. Dall’altro, è possibile migliorare la sensibilità agendo direttamente sul tipo di esperimento utilizzato, anche in abbinamento ad astuzie che possano aumentare l’efficienza del trasferimento di magnetizzazione, quali ad esempio usare l’acqua intrappolata nel monostrato come fonte supplementare di magnetizzazione oppure sfruttare la capacità delle nanoparticelle d’oro di autoassemblarsi su nanosfere di silice per aumentare le dimensioni del nanorecettore. Combinando tutte queste accortezze, dimostrerò come sia possibile analizzare con questa tecnica anche specie inorganiche, come K+, che di per sé non possiedono alcun segnale NMR. Infine, visto che l’NMR non è, per ora, una tecnica di facile applicazione per analisi sul campo, nell’ultima parte di questo lavoro di tesi mi sono occupato anche un sensore point-of-care sviluppato sotto forma di cartina indicatrice, in cui un recettore supramolecolare autoassemblato composto da un cucurbiturile e un colorante può indicare selettivamente la presenza o meno di sostanza stupefacenti in modo rapido, sicuro ed economico.
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Kuntner, Jochen [Verfasser]. "Oil Condition Monitoring Using Physical Chemosensors / Jochen Kuntner." Aachen : Shaker, 2008. http://d-nb.info/1164342134/34.
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Grantham, Andrew James. "The development of portable chemosensors for atmospheric radicals." Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/20210/.
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The complex photochemical oxidation cycles involved in the degradative removal of anthropogenic and biogenic hydrocarbons from the atmosphere are mediated by a range of radical intermediates (e.g. peroxyl radicals). Thus these radicals are of particular interest in relation to air quality and human health. Speciated measurements of atmospheric radicals pose considerable challenges to analytical chemists. Owing to their low concentrations, high reactivity and short lifetimes, free radical species cannot be easily sampled; therefore direct offline analysis is extremely difficult. Issues such as selectivity, full structure determination, portability and cost (logistics, power, expertise) remain challenging obstacles to atmospheric radical analysis. Within this thesis, the synthesis and development of a series of novel chemosensors is presented. These are organic trapping compounds that can efficiently and selectively react with a range of radical species. The chemosensor is designed with the aim of radical addition to a double bond, resulting in the loss of a stable radical leaving group. The trapped radical structure is maintained in the reaction products, which are sufficiently stable for offline mass spectrometry. This approach allows for accurate determination of the radical structures and is different to traditional spin trapping, with the captured radical now converted to a stable non radical form. The developed chemosensors have been tested and evaluated in laboratory and chamber experiments by application to a range of atmospherically relevant systems (e.g. alkene ozonolysis and reactions of .OH with alkanes), giving key insights into radical selectivity and reaction mechanisms. They have also been applied to measurements of indoor and outdoor air, providing evidence for the function of this system at atmospheric radical concentrations.
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Figueira, Flávio Alberto da Silva. "Expanded porphyrins and their evaluation as anion chemosensors." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13247.
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Doutoramento em QuímicaExpanded porphyrins are synthetic analogues of porphyrins, differing from the last ones and other naturally occurring tetrapyrrolic macrocycles by containing a larger central core, with a minimum of 17 atoms, while retaining the extended conjugation features that are a tremendous feature of these biological pigments. The core expansion results in various systems with novel spectral and electronic features, often uniques. Most of these systems can also coordinate cations and/or anions, and in some cases they can bind more than one of these species. In many cases, these molecules display structural features, such as non-planar structures, that have no antecedents in the chemistry of porphyrins or related macrocyclic compounds. This work will discuss several synthetic approaches for the synthesis of expanded porphyrins, namely the construction of new building blocks by Michael addition, as well as potential synthetic routes towards expanded porphyrins. The synthesis of smaller oligopyrrolic compounds namely, bipyrroles and dipyrromethanes, not only were developed for the synthesis of expanded porphyrins as they were also used in Knoevenagel condensations furnishing chromogenic compounds able to recognize different anions in solution. Also, an approach to the synthesis of novel expanded porphyrins namely sapphyrins has been done by aza-Michael additions. Several synthetic routes towards the synthesis of pyridyl and pyridinium N-Fused pentaphyrins and hexaphyrins have been explored in order to achieve compounds with potential applications in catalysis and PDI, respectively. Studies on the synthesis of compounds with potential anion binding properties, led to the structural characterization and NMR anion binding studies of [28]hexaphyrins functionalized with several diamines in the para position of their pentafluorophenyl groups. These compounds allow NH hydrogen bond interactions with various anions. All synthesized compounds were fully characterized by modern spectroscopic techniques.
Porfirinas expandidas são análogos sintéticos das porfirinas, diferindo destes apenas por possuírem um core contendo no mínimo 17 átomos. A expansão do core resulta em vários sistemas com novas características electrónicas e espectrais, e numa extraordinária química de coordenação. Em muitos casos é também possível interação supramolecular com um ou vários aniões. Outra característica interessante é a possibilidade destes macrociclos acomodarem mais do que um estado de oxidação variando as suas características de aromaticidade e planaridade sem antecedentes na química de macrociclos tetrapirrólicos e derivados. Este trabalho discute diversas rotas de síntese de macrociclos expandidos e sua derivatização, bem como a síntese de precursores bipirrólicos sobejamente conhecidos pela sua utilização como precursores na síntese de Porfirinas expandidas. Para este fim, unidades do tipo bipirrolico foram funcionalizadas através de adições de Michael. Estes pequenos compostos foram também derivatizados através de condensações de Knoevenagel para aplicação em coordenação de aniões demonstrando reconhecimento de diferentes aniões mediante uma variação de cor específica. No seguimento destes estudos de reactividade por Diels-Alder e/ou adições de Michael obtiveram-se novos derivativos do tipo safirina com substituições no interior do macrociclo. Tendo em vista a síntese de compostos com reconhecimento de aniões e potencial aplicação em PDT/PDI e catálise, macrocrociclos do tipo pentafirina e hexafirina foram derivatizados com diversos nucleófilos. Neste último, a introdução de grupos amino na sua periferia conduziu a um aumento drástico da capacidade de interação com aniões em solventes polares. Estudos de RMN com os compostos capazes de reconhecer aniões possibilitou a sua total caracterização estrutural demonstrando estruturalmente os grupos que participam no reconhecimento de aniões. Todos os compostos presentes sintetizados foram caracterizados estruturalmente com recurso a diversas técnicas espectroscópicas, nomeadamente: à ressonância magnética nuclear de protão, carbono 13 e de flúor 19, à absorção no Ultravioleta-Visível, à espectrometria de massa e sempre que possível a análise de raio-X de monocristal.
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Mummolo, Liviana <1992>. "Nanostructured luminescent chemosensors for environmental and biomedical applications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9836/1/PhD_Thesis_XXXIIIcycle_LMummolo_upload2.pdf.
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Nanomaterials are nowadays widely recognised as advantageous sensing tools due to their unique properties.
Some natural nanomaterials, such as DNA or hyaluronic acid analysed in this PhD thesis, have an intrinsic biocompatibility that overcomes a series of issues in the field of sensing in biological environments.
Therefore, the main aim of this project was to derivatize HA chains with luminescent dyes - both organic and metal complexes - in order to obtain natural polymer-based optical sensors.
A derivatization of HA with these moieties was obtained and a photophysical characterization was provided. To prove their sensing ability towards nanomaterials, the interaction with. PluS Nanoparticles, featuring an outer PEG shell, was tested. It was mostly demonstrated that the main features of the luminophores used were present in the HA nanogels as well. For example, HA@Dansyl was proven to be a luminescent probe able to sense different environment polarities. Furthermore, in HA@PA the amount of excimers/monomers emission was found to be relatable to the degree of entanglement of HA chains, that changes upon interactions with nanoparticles.
Moreover, two ruthenium bipyridyl derivatives were linked to HA and it was found out that HA interacts with long DNA sequences.
Also, the presence of BPA, a small molecule of environmental concern, was detected using (i) an already studied hyaluronic acid derivative with rhodamine (HA@RB) , (ii) a dizinc ruthenium complex coordinating BPA to the metal centres, and (iii) a new probe constituted by PluSNPs@DEAC and HA@RB. Despite all the systems were found to be able to detect BPA, the latter probe presented advantages in terms of sensitivity.
Furthermore, the chapter 2 of this thesis is focused on the detection of a NF-κB protein in PC3 cancer cells. via confocal microscopy by following a FRET signal variation on a triplex-hairpin derivatized with a FRET couple of dyes.
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Bokeloh, Frank. "Development of organic microelectromechanical chemosensors based on fiber optics." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2381.
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Un (bio)capteur classique est principalement composé de deux éléments essentiels : une couche réceptrice sensible à l’analyte à laquelle on s’intéresse et un transducteur qui permet de convertir une stimulation chimique / biologique en un signal physique mesurable. Dans le cas idéal, un capteur ne doit pas nécessiter de marquage de la cible, doit posséder de très grandes sensibilité et sélectivité envers elle, ne requiert qu’une faible quantité de cette dernière et doit présenter un temps de réponse très court. Au vu de ces critères, les microsystèmes électromécaniques (MEMS) sont des candidats très prometteurs dans le développement de capteurs. Les polymères fonctionnels, tels que les polymères à empreinte moléculaire (MIPs), sont une approche très intéressante dans l’utilisation des MEMS car ils peuvent être intégrés dans des technologies existantes de MEMS à base de silicium ou complètement remplacer ces technologies. Le but de cette thèse porte sur le développement d’un capteur MEMS composé de polymères (fonctionnels). Un chapitre initial (chapitre 2) introduit des nouveaux systèmes de fabrication de polymères fonctionnels. Des biopuces composées de MIPs imprimés par jet d’encre sont présentées ainsi qu’une technique basée sur la polymérisation radicale contrôlée qui permet le dépôt d’un fin enrobage de MIPs sur des microstructures. La deuxième partie de ce chapitre présente la fabrication de polymères à empreinte moléculaire par stéréolithographie deux-photons, qui peut être vue comme une extension de l’impression 3D. Afin d’illustrer cette technologie de prototypage rapide, deux capteurs composés de MIPs sont présentés : un capteur à grille de diffraction et un capteur en microlevier. Les deux principaux chapitres de ce manuscrit (chapitre 3 et 4) se focalisent sur le développement d’un nouveau concept de fabrication pour les capteurs MEMS. Ce concept est basé sur la polymérisation d’une poutre à fort ratio de forme à l’extrémité d’une fibre optique de télécommunication. Cette poutre a été mise en vibration à sa résonnance et a ainsi pu être utilisée comme un capteur à base de levier. Le capteur en polymère a permis l’intégration de MIPs comme élément récepteur et la reconnaissance sélective de l’antibiotique enrofloxacine. De plus, un nouveau système de mesure intégré est présenté dans le chapitre 4. Ce système de mesure intègre la fibre optique en guidant un rayon laser à travers elle ainsi qu’à travers le levier qui y est attaché.Le rayon lumineux sortant est ensuite focalisé sur une photodiode sensible à la position du rayon lumineux, permettant ainsi la mesure du spectre de résonance de la poutre en polymère. Ce système de mesure est caractérisé et ses performances sont présentées au travers de la détection de masse du levier en polymère et de mesures faites en milieu liquideA classical (bio)sensor consists of two key components: A receptor layer that detects the analyte of interest and the transducer which converts the chemical / biological stimuli into a physical measurable signal. Ideally a sensor is label-free, highly sensitive and selective towards the target, requires low sample amount and shows a fast response time. Regarding these criteria microelectromechanical systems (MEMS) offer great potential for the sensor development. One interesting approach for this development are functional polymer materials, such as molecularly imprinted polymers (MIPs), that can be either integrated to existing MEMS based on silicon or completely replace the silicon technology. The emphasis of this thesis is focused on the development of a MEMS sensor based on (functional) polymers. In an initial chapter (chapter 2) new fabrication schemes for functional polymers are introduced. Inkjet-printed biochips based on MIPs are presented and a technique based on controlled radical polymerization is shown that allows the deposition of thin MIP shells on a microfabricated pattern. In the second part of this chapter the fabrication of molecularly imprinted polymers by two-photon stereolithography is shown which can be seen as an extension of 3dimensional printing. As possible application of this rapid prototyping technology two sensors based on MIPs are introduced a diffraction grating sensor and a microcantilever sensor. The two main chapters of this manuscript (chapter 3 and chapter 4) report the development of a new fabrication concept for MEMS sensors. It is based on the polymerization of a high aspect ratio beam on the extremity of an optical telecommunication fiber which was actuated at resonance and thus could be used as a cantilever sensor. The polymer sensor allowed the integration of MIPs as sensing element and the selective recognition of the antibiotic enrofloxacin. Furthermore, is a new, integrated read-out scheme presented in chapter 4. This read-out scheme integrates the optical fiber, by guiding a probe laser beam through it and attached cantilever beam. The output light beam is then focused on a position sensitive photodiode and thus enabled to monitor the resonance spectra of the polymer beam. The read-out scheme is characterized and its performance is shown by demonstrating the mass sensitivity of the polymeric cantilever beam and by measurements in liquid environments
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Williams, James Anthony Gareth. "Luminescence behaviour of macrocycle metal complexes." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5313/.
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Luminescent complexes of lanthanide ions are of growing interest because the long lifetime of emission allows time-resolved detection procedures to be employed. A key step in the development of such systems lies in the preparation of highly luminescent complexes which display high stability in aqueous solution. A series of ligands based on 1,4,7,10-tetraazacyclododecane have been prepared, in which the nitrogen atoms are appended with coordinating phosphinate or amide groups, or a combination of both. The compounds obtained are octadentate ligands which form water-soluble lanthanide complexes of high stability. Complexes incorporating aryl groups in the pendent arms have been prepared and some display intense metal luminescence following excitation into the organic chromophores. A back energy transfer process occurs in the terbium complexes containing naphthyl or quinohnone groups. Measurements of the luminescence lifetimes in H(_2)O and H(_2)O show diat diere are no metal-bound water molecules in the tetrabenzylphosphinate complexes. Those incorporating one amide and three phosphinate groups display hydration states between 0 and 1. An attempt has been made to correlate this information with that obtained from an analysis of the nuclear magnetic resonance dispersion profiles of related gadolinium complexes. The complexes incorporating secondary amide groups display an additional deactivation pathway for the metal excited state involving energy transfer into N-H bonds. The luminescence behaviour of four macrocyclic tetraamide ligands incorporating naphthyl fluorophores has been studied. These compounds exhibit distinctive changes in luminescence in the presence of quenching (eg. Pb(^2+), Cu(^2+) and Ni(^2+)) and non- quenching ions (eg. Cd(^2+) and Zn(^2+)). This behaviour extends to non-aqueous solution. The protonated tetranaphthyl ligand forms an intramolecular excimer in which the excimer emission displays a sensitive dependence on the polarity of die solvent.
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Pancholi, Jessica. "Novel 'click' generated sensors and molecular machines for fluorescent sensing of Zn2+." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/15017.
Full textAbstract:
Zinc is now firmly established as an essential trace element in the human body. Whilst it has many key structural and catalytic fixed roles, it is also found in 'mobile' pools in many essential organs and organelles that are readily chelatable. The presence and trafficking of these zinc pools are thought to contribute in some form to many human disease states associated with these organs, for example, Type 2 diabetes in the pancreas, some forms of cancer in the prostate, and even ischemic stroke, epilepsy and Alzheimer's disease. The exact role however, remains largely unknown and this is due to our current limitations with the methods in which we monitor the movement of this important element in our body. This thesis presents our efforts to develop novel Zn2+ selective chemosensors that can meet contemporary criteria for successful and simple imaging. Many efforts are being made to develop simple fluorescent molecular probes to monitor the trafficking and progress of Zn2+ through these cells and organs in real time via these chelatable 'mobile' pools. Chapter 1 will outline some successful efforts towards these and discuss their relevance and mechanisms of action, as well as outlining 'click'-chemistry and its role in chemosensing to date. Chapter 2 describes a novel 'click'-chemistry approach designed to aid with the simple construction of novel zinc-chelating probes in a facile and high yielding manner. This methodology was taken forward to the synthesis of 6 novel Zn2+-selective small molecule fluorescent probes that incorporate a cell organelle targeting motif in their structure. These are described in Chapter 3, and their successful testing both in-vitro and in-cellulo in murine pancreatic islet cells is presented and discussed. Finally, Chapter 4 discusses the development of some modified fluorescent [2]rotaxanes as molecularly interlocked architectures capable of binding and sensing metals, and will specifically focus on how small structural changes led to vast differences in their fluorescence properties, ultimately resulting in a Zn2+-selective [2]rotaxane in organic media.
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Turkewitsch, Petra. "The synthesis of fluorescent chemosensors responsive tocAMP and other nucleotides." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0018/NQ44611.pdf.
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You, Qihua. "Development of fluorescent chemosensors based on different signal transduction mechanisms." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/95.
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A series of fluorescent probes based on different signal transduction mechanisms for the detection of Fe3+, Zn2+, histidine and pH was designed and synthesized. Their photophysical properties, binding abilities and the further application in cell imaging were fully evaluated. Building on the groundwork of our previous study, molecular scaffold 19 has been appended to spirobenzopyran fluorophore to furnish a highly selective and sensitive Zn2+ sensor. To broaden the application scope of this trifunctional receptive molecule, 19 was incorporated onto rhodamine, antipyrine and coumarin moieties to give 20, 21 and 23, respectively. Probe 20 operative on a chelation-enhanced fluorescence mechanism exhibited highly selective response to Fe3+ with 2:1 stoichiometry of 20-Fe3+ complex. However, a possible tendency of probe 20 to hydrolyze induced by Fe3+ and the unsuccessful attempt of cell imaging would limit its application scope. Probe 21 with O-N-N-N-N-ligand showed a highly selective and sensitive detection of Zn2+. The probe displayed suppressed response to Cd2+ which is the most common interference ion in zinc metal detection. The binding of Zn2+ to probe 21 inhibited the photoinduced electron transfer process originating from the lone pair of the nitrogen atom in the antipyrine moiety to quinoline fluorophore. Therefore, a turn-on fluorescent probe was developed. A moderate binding constant with 1:1 stoichiometry of 21-Zn2+ complex was established by fluorescence titration. The binding mechanism was fully explained by 1H NMR titration. To our delight, probe 21 was successfully applied for recognizing Zn2+ in living cells. The preparation of probe 23 was achieved by appendage of 19 to coumarin derived fluorophore and the probe exhibited a good selectivity and fluorescent turn-off property to Cu2+. The 1:1 stoichiometry of 23-Cu2+ ensemble can serve as an efficient probe for the detection of histidine and biothiols. In the presence of NEM, the influence of biothiols could be eliminated. Furthermore, this sensing ensemble was also used in the detection of histidine in hard-to-transfect U87MG cells with very low cytotoxicity. Based on our group’s previous work on the spiropyran platform, a novel ratiometric near-infrared pH probe 27 operating on an excited-state intramolecular electron transfer mechanism was developed. The pKa was calculated to be 5.9 and the ring-opening/ring-closing mechanism triggered by protons was reasonably explained by 1H NMR titration. However, this spiropyran-based probe was found to be unsuitable for cell imaging. To continue the innovation of pH sensing and extend its application in bioimaging, a series of ratiometric pH probes 32 and 38 characterized by their high quantum yield working in the NIR range was developed. The appendage of N,O-disubstituted hemiaminal ether moiety onto coumarin fluorophore with C=C double bond conferred the sensory material with the ability to display a pH-dependent ratiometric output operating on the ring-opening/ring-closing mechanism. The pKa of 32 and 38 were 6.9 and 5.8 – 6.0, respectively, which rendered them suitable for pH measurement in near-neutral and acidic media. A preliminary work of intracellular pH measurement was also conducted and promising results were obtained
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Hull, Mark Q. "The role of semiochemicals in the behaviour and biology of Lepeophtheirus salmonis (Kroyer, 1837) : potential for control?" Thesis, University of Aberdeen, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310772.
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The role of semiochemicals in the behaviour and biology of Lepeophtheirus salmonis was investigated using a range of techniques. The potential use of semiochemicals in the behavioural ecology of mobile stages was examined using longitudinal monitoring and experimental manipulation of laboratory reared single cohort populations. The chronic and long term effects of separation from the host were also investigated using similar populations. The nature and chemosensory capability of the sense system of the parasite was assessed through morphological and ultrastructural studies. Finally, the nature of potential chemical stimuli during initial copepodid settlement, pair formation and mating, and host re-attachment of mobile stages, was examined using both in vitro and in vivo techniques. Longitudinal monitoring of populations created a model for mobile development and the timing and processes of pair formation and mating. There was evidence of a hierarchy of pair formation between female stages, periods of strong mate competition between males, and many factors within the processes were defined. Survival off the host was strongly related to the developmental stage and/or size of the louse; with adult females surviving for the longest and preadult I males for the shortest periods. The ability of adult males to re-attach and subsequently persist on the host was significantly reduced after only 72 hours of separation. Very few potential chemosensory setae were found on the appendages examined, the exception to this being the antennule. Two distinct populations of setae on the distal (14 setae) and proximal (27 setae) articles of the antennule demonstrated a wide range of morphology. The internal organisation, innervation and ultrastructure of these antennular setae was examined in detail. The setae could be divided into at least 6 distinct categories, when the internal data were combined with the external morphology.
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Turkewitsch, Petra. "The synthesis of fluorescent chemosensors responsive to cAMP and other nucleotides /." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37551.
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The overall objective of this study was to develop a fluorescent chemosensor for cAMP by creating recognition sites for cAMP, that contain a fluorescent molecule, in a polymer matrix by molecular imprinting. Such a fluorescent molecularly imprinted polymer may, therefore, serve as both the recognition element and the measuring element for the fluorescent detection of cAMP in aqueous media.Two new fluorescent molecules, known as 4-(p-dimethylaminostyryl)pyridinium salts or dyes, were synthesized as possible fluorescent components of a chemosensor. Upon excitation at 469 run, dye 1, trans-4-( p-N,N-dimethylaminostyryl)-N-vinylbenzyl-pyridinium chloride, displays a dramatic quantum yield enhancement in an emission band centered at ∼600 nm, with concomitant slight red shift of the emission maximum, in the presence of the cyclic nucleotides, cAMP and cGMP, in aqueous solution. Other purine nucleotides (AMP, ADP and ATP) and adenosine induce fluorescence quantum yield enhancements of lesser magnitude than those observed for cyclic nucleotides. The pyrimidine nucleotides, CMP and UMP, have almost no effect on the fluorescence of 1, suggesting a specificity of 1 for purine over pyrimidine analytes. Equilibrium association constants for 1 with the purine analytes, in aqueous solution (pH 7.2) range from 13.9 M --1 for cAMP to 0.15 M--1 for adenine. We conclude that the interaction of 1 with these analytes requires the presence of a purine base, and is enhanced by the presence of ribose and phosphate moieties. Dye 1 and a structurally-similar dye 2, trans-4-(p-N,N-dimethylaminostryl)-N-phenethylpyridinium bromide, also display dramatic fluorescence enhancements in the presence of DNA and proteins, suggesting that they also interact with these biomolecules. The environmentally-sensitive fluorescence of dyes 1 and 2 suggests that such compounds may be useful for developing fluorescent chemosensors for purine nucleotides, especially cAMP, and for the fluorescence detection or staining of DNA and proteins.
To increase the recognition ability of 1 for cAMP, we prepared recognition sites for cAMP that contain fluorescent dye 1 in a polymer matrix by molecular imprinting. This is a novel design for such template-selective sites, since dye 1 forms an integral part of the recognition cavity, thereby serving as both the recognition element and the measuring element for the fluorescence detection of cAMP in aqueous media. The polymer displays a concentration-dependent decrease in fluorescence in the presence of aqueous cAMP, whereas almost no effect is observed in the presence of the structurally-similar molecule, cGMP. An association constant of ∼105 M--1 was calculated for cAMP binding. Such fluorescent molecularly imprinted polymers could serve as a starting point in the development of highly effective synthetic fluorescent sensors for cAMP as well as other important biological molecules.
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Wang, Hao. "Development of fluorescent chemosensors : mercury sensing and biological molecules sensing probes." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/890.
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Fan, Li-juan. "Design, synthesis and photophysics of fluorescence "turn-on" conjugated polymer chemosensors." Diss., Online access via UMI:, 2006.
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Nolan, Elizabeth M. (Elizabeth Marie) 1978. "Fluorescent chemosensors for exploring zinc metalloneurochemistry and detecting mercury in aqueous solution." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36266.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2006.Vita.
Includes bibliographical references.
Chapter 1. An Introduction to Zinc Metalloneurochemistry and Zinc Detection in Biology. This chapter presents an overview of zinc neurophysiology and pathology, which provides motivation for the design of new tools and tactics for zinc detection in vivo. A historical account of biological zinc detection is also given, followed by a summary of recent progress in the development and use of fluorescent Zn(II) sensors for in vivo studies. A summary of project goals and thesis organization is also included. Chapter 2. Zinc Sensors Based on Monosubstituted Fluorescein Platforms I: Routes to Electronic Variation, Syntheses and Spectroscopic Characterization. In this work, a convergent synthetic approach for the assembly of fluorescent zinc sensors from aniline-derivatized ligands and a fluroescein carboxaldehyde platform is presented. These sensors are based on the previously reported ZP4 motif and incorporate a di(2-picolyl)amine moiety in the aniline-based ligand framework. The effects of electronic variation, achieved by halogenation of either the zinc-binding unit or the fluorophore platform, on the fluorescence properties and aniline nitrogen atom pKa values are considered.
(cont.) Chapter 3. Spectroscopic Characterization and Biological Applications of Halogenated Zinpyr Sensors. In this chapter, the effects of fluorescein halogenation on the photophysical properties and protonation equilbria of symmetrical Zinpyr derivatives, which contain two di(2-picolyl)amine-based ligand appendages, are considered. These sensors have sub-nM affinity for Zn(II) and are selective for Zn(II) over biologically relevant alkali and alkaline earth metals. Fluorescein halogenation influences background fluorescence, dynamic range, tertiary amine pKa, and both excitation and emission wavelengths. Extensive biological work, including cytotoxicity assays and confocal imaging, are also presented. Studies in a number of cell lines, including neurons, show that ZP3 is a versatile Zn(II) imaging tool. Chapter 4. Zinc Sensors Based on Monosubstituted Fluorescein Platforms II: Modulation of Zinc Affinity and Biological Applications. To access ZP sensors with lower Zn(II) affinity, pyrrole moieties were incorporated into an aniline-based ligand unit to give sensors ZP9 and ZP10. The photophysical characterization and metal binding properties of these sensors are described.
(cont.) The pyrrole-for-pyridyl substitution affords Zn(II) sensors with improved Zn(II) selectivity and sub-[M dissociation constants. Biological imaging studies revealed that asymmetrical ZP probes, including ZP4, are cell permeable and Zn(II) responsive in vivo. Both ZP4 and ZP9 detect endogenous Zn(II) in acute hippocampal slices from the adult rat. Chapter 5. The Zinspy Family of Fluorescent Zinc Sensors: Syntheses and Spectroscopic Investigations. Four fluorescent sensors designed for Zn(II) detection and which contain a fluorescein reporting group and a pyridyl-amine-thioether derivatized ligand moiety were prepared and their photophyiscal properties characterized. These "Zinspy" sensors are water soluble and generally display -1.4 to -4.5-fold fluorescence enhancement upon Zn(II) coordination, depending upon fluorescein halogenation and the number and nature of the Zn(II)-binding appendages. The Zinspy sensors exhibit improved selectivity and lower affinity for Zn(II) compared to the di(2-picolyl)amine-based Zinpyr family members. Chapter 6. Zinspy Sensors with Enhanced Dynamic Range: Imaging Zinc Uptake and Mobilization with a Low Affinity Probe.
(cont.) This chapter describes the preparation and characterization of Zinspy sensors containing non-coordinating thiophene heterocycles in the metal-binding unit. These probes show improved dynamic range relative to thioether-containing ZS sensors, low M dissociation constants for Zn(II) and improved Zn(II) selectivity. Stopped-flow kinetics investigations indicate fast association rates and reversible Zn(II) coordination with kon > 1.8 x 106 M'-s- and koff > 3 s-1 at 25 C. ZS5 is cell permeable, Zn(II)-responsive in vivo and localizes to the mitochondria of certain cell types. ZS5 can detect Zn(II) released from neurons following nitrosative stress. Chapter 7. QZ1 and QZ2, Rapid Reversible Quinoline Derivatized Fluoresceins for Sensing Biological Zinc. Two fluorescein-based dyes derivatized with 8-aminoquinoline were prepared and their photophysical, thermodynamic and zinc-binding kinetic properties determined. Because of their low background fluorescence and highly emissive Zn(II) complexes, QZ1 and QZ2 display a large dynamic range, with -42- and -150-fold fluorescence enhancements upon Zn(II) coordination, respectively.
(cont.) These sensors have micromolar dissociation constants for Zn(II), improved selectivity and bind Zn(II) rapidly and reversibly with kon values >106 M-'s-1 and koffvalues of ~150 s-1. Biological imaging studies with ZP3 and QZ2 show that binding affinity is an important parameter for metal ion detection in vivo. QZ1 and QZ2 also respond to two-photon excitation and two-photon microscopy was used to visualize Zn(II) with QZ2 in live HeLa cells. Chapter 8. A "Turn-On" Fluorescent Sensor for the Selective Detection of Mercuric Ion in Aqueous Media. This chapter describes the synthesis, photophysical characterization and metal-binding properties of mercury sensor 1 (MS1). This sensor is based on a fluorescein platform and has a thioether-rich metal-binding unit, which conveys high selectivity for Hg(II). To the best of our knowledge, MS1 was the first reversible fluorescent Hg(II) sensor to give fluorescence turn-on in water. MS1 can detect low ppb levels of Hg(II) in aqueous solution at neutral pH. Chapter 9. Selective Hg(II) Detection in Aqueous Solution with Thiol Derivatized Fluoresceins. The syntheses and photophysical properties of MS2 and MS3, two asymmetrically derivatized fluorescein-based dyes designed for Hg(II) detection, are described.
(cont.) These sensors each contain a single pyridyl-amine-thiol metal-binding moiety, form 1:1 complexes with Hg(II) and exhibit selectivity for Hg(II) over other Group 12 metals, alkali and alkaline earth metals, and most divalent first-row transition metals. Both dyes display superior brightness ( x ) and fluorescence enhancement following Hg(II) coordination in aqueous solution. At neutral pH, electron transfer (PET) quenching of the free dye is enhanced, and the Hg(II)-induced turn-on also benefits from alleviation of this pathway. MS2 can detect ppb levels of Hg(II) in aqueous solution, demonstrating its ability to identify environmentally relevant concentrations of Hg(II). Chapter 10. MS4, A Seminaphthofluorescein-Based Chemosensor for the Ratiometric Detection of Hg(II). The synthesis and photophysical characterization of MS4, an aniline-derivatized seminaphthofluorescein-based dye that contains a pyridyl-amine-thioether ligand analogous to that employed in the Zinspy Zn(II) sensor family (Chapter 5) are reported. Sensor MS4 provides single-excitation, dual-emission ratiometric detection of Hg(II) in aqueous solution. An -4-fold ratiometric change (624/524) is observed upon introduction of Hg(II) to an aqueous chloride-containing solution of MS4 at pH 8.
(cont.) In this milieu, MS4 shows selectivity for Hg(II) over a background of alkali and alkaline earth metals, a number of divalent first-row transition metals and its Groupl2 congeners Zn(II) and Cd(II). Chapter 11. Turn-On and Ratiometric Mercury Sensing in Water with a Seminaphthofluorescein-Based Probe. The synthesis and characterization of MS5 are presented in this chapter. This sensor incorporates the aniline-derivatized thioether ligand used in the preparation of MS1 and the seminaphthofluorescein platform described in the design of MS4. MS5 gives selective fluorescence turn-on for Hg(II) at pH > 7. At pH > 8, single-excitation dual-emission ratiometric Hg(II) detection is possible by comparison of the (624 / 524) ratio before and after Hg(II) coordination. Studies of the pH dependence suggest that the seminaphthofluorescein dianion is critical for generating the ratiometric response. X-ray crystallographic studies with a salicylaldehyde-based model complex are presented to help elucidate the nature of Hg(II) coordination to MS1 and MS5. MS5 can respond to Hg(II) added to natural water samples, which points to its potential utility in the field.
(cont.) Appendix 1. Miscellenous Fluorescein-Based Ligands. This appendix details the preparation and, in some cases, characterization of potential fluorescein based sensors for either Zn(II) or Hg(II) detection that were not described in earlier chapters. Many of these compounds give fluorescence turn-off or no fluorescence change with analyte binding. Sensors ZP11 and MS6 are lower-affinity probes that give fluorescence turn-on for Zn(II) and Hg(II), respectively. Appendix 2. Theoretical Investigations of Fluorescein Derivatives. In this chapter, we present the results from DFT and TDDFT calculations on fluorescein and its derivatives. These studies include establishing protocols for fluorescein pKa determination and TDDFT analysis. The absorption spectra of the fluorescein dianion and monoanion were assigned and a detailed molecular orbital analysis for a fluorescein dianion analog was conducted. These studies indicate that oxygen atoms in the xanthenone moiety influence the amount of C1 character in the donor and acceptor molecular orbitals responsible for fluorescein absorption.
by Elizabeth M. Nolan.
Ph.D.
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Vance, David Howard. "Convergency in the synthesis of anthracene-based fluorescent chemosensors and Dephosphorylation reagents /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487847309050039.
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Kutuk, Ilker. "Design And Synthesis Of Near-ir Emitting Fluorescent Chemosensors For Transition Metal Ions." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609561/index.pdf.
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Supramolecular chemistry is an emerging field of chemistry which has attracted much attention in recent years as a result of its broad applicability in many areas. Thus, the design of functional supramolecular systems is strongly in demand in this field. For this purpose, we have developed near-IR emitting ratiometric fluorescent chemosensors for transition metal ions. Judicious placement of dithiodioxaazamacrocycles on the BODIPY chromophore generates this chemosensor which is selective for Hg(II) ions and both absorption and emission spectra display large changes that would allow ratiometric sensing.
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Weis, Jonathan G. (Jonathan Garrett). "Manipulating Conjugation in electronic polymers and graphitic materials: chemosensors, precursor routes, and self-assembly." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98786.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references.
In Chapter 1, we synthesize dithienobenzotropone-based conjugated alternating copolymers by direct arylation polycondensation. Post-polymerization hydride reduction furnishes cross-conjugated copolymeric hydrogels that undergo phosphorylation and subsequent ionization upon exposure to chemical warfare agent (CWA) mimics. The resulting conjugated, cationic copolymer is intensely colored and facilitates spectroscopic and colorimetric detection of CWA mimics in solution and as a thin film. Similarly, we report the incorporation of CWA-responsive units into random copolymers prepared by ringopening metathesis polymerization (ROMP) to create highly modular, chromogenic thin films. In Chapter 2, we explore homoconjugated polynorbornadienes possessing various electron-withdrawing groups as polymeric precursors to electron-accepting poly(cyclopentadienylene vinylene) derivatives. Tungsten oxo alkylidene catalysts were utilized to polymerize a variety of 7-isopropylidene- and 7-oxa-2,3-disubstituted norbornadienes in a cis-highly tactic fashion by ROMP. We further demonstrate the excellent scope of tungsten oxo complexes by polymerizing norbornadienes that are unreactive with traditional molybdenum-, tungsten-, and ruthenium-based catalysts. In Chapter 3, we employ atomic force microscopy (AFM) and scanning tunneling microscopy (STM) to examine graphene oxide (GO) samples with gradations of (de)oxygenation. We analyze the roughness of the apparent height in STM topographic measurements - i.e. the "apparent roughness" - and report a correlation between increasing deoxygenation and decreasing surface roughness. The "apparent roughness" therefore serves as a supplemental technique for analyzing samples of GO. Furthermore, we report the first example of using an STM tip to locally reduce GO without local destruction of the graphene sample. In Chapter 4, we exploit the extraordinary self-recognition properties of deoxyribonucleic acid (DNA) to assemble single-walled carbon nanotubes (SWCNTs) in a controllable manner. Networks of SWCNTs with three-way junctions could be constructed in solution or sequentially on a surface. We envision that more complex nanoscale architectures and circuits can be prepared in this bottom-up manner. In Chapter 5, we introduce halogen bonding in SWCNT-based chemiresistive gas sensors. These chemiresistors were prepared by ball milling of SWCNTs and selectors, compression into a pellet, and mechanical abrasion between gold electrodes on paper. We demonstrate that sensing responses reflect halogen bonding trends, with some exceptions. The predominant signal transduction mechanism is likely attributed to swelling of the insulating haloarene matrix.
by Jonathan G. Weis.
Ph. D.
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Mello, Jesse Vincent. "Biarylpyridine fluorescent chemosensors : synthesis, structural studies, and combinatorial discovery of a Hg(II) sensor /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3129954.
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Wong, Joseph Kwun-Hoi. "Cyclam and Metal-Cyclam Complexes for Sensing and Therapeutic Applications." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16312.
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A variety of cyclam and metal-cyclam-based systems have been investigated for potential in the sensing of metal ions or biological binding events, and antibacterial applications. In Chapter two, an efficient synthesis of 1,8-bis-(2-azidoethyl)cyclam has been developed and used to prepare 1,8-disubstituted cyclam conjugates. UV/visible and fluorescence emission spectra, zinc binding experiments, fluorescence quantum yield and lifetime measurements and pH titrations of the bis-naphthalimide ligands reveal complex photophysical behaviour and differences arising from the inclusion of two fluorophores in the one probe and from the variation of triazole substitution pattern. In Chapter three, mono-substituted mercury- and zinc-cyclam-triazole-phenyl conjugates are described as model systems to investigate the use of NMR spectroscopy for studying the mechanism of target-activated metal complexes. A click-deuteration protocol has also been used to access deuterated-triazole systems. Ligand-induced displacement of the pendant triazole from the metal centre of these complexes was utilised to simulate changes to metal coordination environment as were observed upon the binding of biotinylated cyclam complexes to avidin. Utilising the methodology developed in Chapter two, Chapter four describes the synthesis of a small library of bis-substituted cyclam conjugates which were screened for activity against Mycobacterium tuberculosis. These compounds demonstrate promising activity against the growth of Mycobacterium tuberculosis. Chapter Five describes the serendipitous discovery of an effective and efficient method for the removal of the BF2 moiety from F-BODIPY derivatives. This has been achieved in near-quantitative yield using two common Brønsted acids (TFA and HCl). Compared to existing methods, these conditions are relatively mild and operationally simple, requiring only reaction at room temperature for six hours (TFA) or overnight (HCl).
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Marques, Elisabete De Jesus Oliveira. "New fluorescent chemosensors based on bio-inspired ligands and macrocycles: from single molecules to nanoparticles." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/5386.
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Dissertação apresentada para obtenção do grau de Doutor em Biotecnologia pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia. A presente dissertação foi preparada no âmbito do protocolo de acordo bilateral de educação avançada (ERASMUS) entre a Universidade de Vigo e a Universidade Nova de LisboaProject PTDC/QUI/66250/2006. Project VICOUK914122P64702. Project 09CSA04338PR (in Biomedicine)
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Sargenti, Azzurra <1986>. "Study of Magnesium Homeostasis and Intracellular Compartmentalization in Human Cells by Fluorescent Chemosensors and Synchrotron X-Ray Fluorescence." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7496/1/Sargenti_Azzurra_tesi.pdf.
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In this study, we investigated the analytical capabilities of DCHQ5, a new fluorescent chemosensor, belonging to the family of diaza-crown-hydroxyquinolines, for the quantitative assessment of total intracellular magnesium content, and its biological applications. We performed a comparative study of DCHQ5 and DCHQ1, the latter being the mother probe of the series, which showed preliminary encouraging results comparable to atomic absorption spectroscopy. We demonstrated that DCHQ5 is able to accurately quantify the total amount of Mg in a very “small” cellular population, by using a simple spectrofluorimetric assay. Furthermore, DCHQ5 demonstrated to be a versatile tool for different applications: its higher intracellular retentions allow to perform cytofluorimetric assays and two-photon confocal microscopy on whole and viable cells; its photochemical characteristic make it excitable in both UV and visible spectra, and the presence of different lifetimes allow to perform fluorescence life time imaging of intracellular Mg.
DCHQ5 was also exploited for studying the involvement of magnesium in the commitment of human adipose-derived mesenchymal stem cells (hASCs) with a mixture of hyaluronic, butyric and retinoic acids (HBR). We found that in normal magnesium availability, hASCs precommitment is associated by an increase of total magnesium content during time and by a block in the G2/M phase of the cell cycle. Moreover, our results demonstrated that magnesium deprivation triggers multilineage enrichments of HBR-induced preconditioning of hASCs.
The second part of this research was aimed at comparing single cells elemental analysis performed with synchrotron-based fluorescence and cell population analysis carry out by DCHQ5. We exploited innovative techniques of x-ray fluorescence microscopy by using a multimodal approach in order to achieve within the cells the spatial distribution of the concentration of magnesium and fundamental light elements for life. The combination of classical and innovative analytical techniques can shed new light in the comprehension of magnesium homeostasis.
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Sargenti, Azzurra <1986>. "Study of Magnesium Homeostasis and Intracellular Compartmentalization in Human Cells by Fluorescent Chemosensors and Synchrotron X-Ray Fluorescence." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7496/.
Full textAbstract:
In this study, we investigated the analytical capabilities of DCHQ5, a new fluorescent chemosensor, belonging to the family of diaza-crown-hydroxyquinolines, for the quantitative assessment of total intracellular magnesium content, and its biological applications. We performed a comparative study of DCHQ5 and DCHQ1, the latter being the mother probe of the series, which showed preliminary encouraging results comparable to atomic absorption spectroscopy. We demonstrated that DCHQ5 is able to accurately quantify the total amount of Mg in a very “small” cellular population, by using a simple spectrofluorimetric assay. Furthermore, DCHQ5 demonstrated to be a versatile tool for different applications: its higher intracellular retentions allow to perform cytofluorimetric assays and two-photon confocal microscopy on whole and viable cells; its photochemical characteristic make it excitable in both UV and visible spectra, and the presence of different lifetimes allow to perform fluorescence life time imaging of intracellular Mg.
DCHQ5 was also exploited for studying the involvement of magnesium in the commitment of human adipose-derived mesenchymal stem cells (hASCs) with a mixture of hyaluronic, butyric and retinoic acids (HBR). We found that in normal magnesium availability, hASCs precommitment is associated by an increase of total magnesium content during time and by a block in the G2/M phase of the cell cycle. Moreover, our results demonstrated that magnesium deprivation triggers multilineage enrichments of HBR-induced preconditioning of hASCs.
The second part of this research was aimed at comparing single cells elemental analysis performed with synchrotron-based fluorescence and cell population analysis carry out by DCHQ5. We exploited innovative techniques of x-ray fluorescence microscopy by using a multimodal approach in order to achieve within the cells the spatial distribution of the concentration of magnesium and fundamental light elements for life. The combination of classical and innovative analytical techniques can shed new light in the comprehension of magnesium homeostasis.
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Pedras, Bruno André Cunha de Vallêra Jacques. "Synthesis, characterization and applications of new schiff base fluorescent chemosensors for metal and DNA interactions: conventional and "green" approaches." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2011. http://hdl.handle.net/10362/9684.
Full textAbstract:
Dissertação apresentada para a obtenção do Grau de Doutor em Química Sustentável, especialidade de Química-Física Inorgânica, pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaThe work presented in this thesis, which has as its central subject the synthesis and applications of new fluorescent chemosensors and probes, can be divided in two major groups. The first one deals with Schiff base-derived fluorescent chemosensors, with application in the detection of metal cations, and the second group concerns the development of new Ru(II) polypyridyl luminescent molecular probes for DNA. Before the description and discussion of the performed work, a general introduction is presented in Chapter I, where emphasis is put on the applications of molecular fluorescence to chemical sensing, in order to obtain a better understanding of the photophysical processes that underlie molecular recognition. This connection is made by defining concepts and giving examples when necessary. A brief mention to the studied analytes and the instrumental methods used both in developing the chemosensors and in their applications is also made. In Chapter II, two new chemosensors possessing crown ether moieties linked through a Schiff base to a bithiophene group are presented. These systems were synthesized and fully characterized, and their application in the sensing of Ni(II), Pd(II), Hg(II) and Na(I) was tested by absorption and emission spectroscopies, and MALDI-TOF MS. Chapter III describes two new pincer-type ligands, in which a thiophene unit is linked through a Schiff base either to pyrene or naphthalene chromophores. Sensing applications for Ni(II) and Pd(II) were investigated by different techniques, and solid complexes with the aforementioned metals were also synthesized. A new tripodal ligand derived from indole and containing three Schiff base groups is introduced in Chapter IV, and its complexes with Zn(II), Cu(II), Ni(II), Hg(II) and Pd(II) are also described. Metal ion titrations of the free ligand with the respective metal salts have been performed, helped by DFT calculations, in order to investigate the role of the central tertiary amine in metal coordination. The search for new luminescent molecular probes to be used in DNA binding is the subject of Chapter V, in which a new family of six Ru(II) polypyridyl complexes is synthesized. The relation between their structure and the binding mode to DNA is studied by absorption and steady-state emission spectroscopies, as well as by timeresolved experiments.
Fundação para a Ciência e a Tecnologia - bolsa de doutoramento SFRH/BD/27786/2006
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Chamier, Jessica. "Photoelectrochemical detection of inorganic mercury in aqueous solutions." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5213.
Full textAbstract:
Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Due to the adverse human health effects associated with mercury (Hg) toxicity, an innovative method for inorganic mercury (Hg2+) determination in aqueous solutions was investigated. The method of Hg2+ determination involved the use of a Hg2+ selective chemosensor immobilised onto an indium tin oxide (ITO) coated electrode in a photoelectrochemical cell. Upon light activation and in the presence of Hg2+ the fluorescent chemosensor absorbed a photon, and charge separation would occur according to the nature of the semiconductive material coated onto the ITO substrate. The charge separators and semiconductors investigated were an n-type carrier TiO2, polyaniline (PANI) and copolymers of polyaniline and 2-bromoaniline (P[A-co-2- BrA]s) with different monomer ratios. The polymer and copolymer coated ITO working electrodes used in the Hg2+ sensitive photoelectrochemical cell were electrochemically evaluated. The results demonstrated that the ITO coated with PANI had superior conductive and semiconductive properties compared to ITO coated with P[A-co-2-BrA]s. The ITO glass substrates were coated with TiO2, PANI or P[A-co-2-BrA]s, followed by the fluorescent chemosensor, a rhodamine 6G derivative (RS). The electrodes were subsequently photoelectrochemically evaluated in a photoelectrochemical cell in the presence of Hg2+. The PANI-RS coated electrode behaved as a photocathode in the presence of Hg2+ under illumination. The PANI-RS photoresponse increased with increasing Hg2+ concentration in the range 10 to 150 μg L-1, with a limit of detection of 6 μg L-1. ITO coated with TiO2 (ITO/TiO2) followed by a composite of PANI and RS had a linear photoanodic response in the Hg2+ concentration range of 10 to 200 μg L-1 and a limit of detection of 5 μg L-1. ITO and ITO/TiO2 coated with the P[A-co-2-BrA]s and RS had considerably lower photoresponses towards Hg2+ in aqueous solutions compared to PANI-RS. The photoresponses decreased with increasing 2-bromoaniline content. The PANI and P[A-co-2-BrA]s coated ITO and ITO/TiO2 electrodes were then also coated with another rhodamine 6G derivative with a thiolactone moiety (RT). The PANI coated electrode yielded a photocathodic response in the Hg2+ concentration range 0.2 to 5 μg L-1. ITO coated with TiO2 had no photoresponse towards Hg2+ due to repulsive forces between TiO2 and the RT molecules. The photoresponses of the working photoelectrodes towards Hg2+ were further evaluated in a custom photoelectrochemical Hg2+ detector. The photoresponses of PANI-RS and PANI-RT gave qualitative results for the presence of Hg2+ in aqueous solutions in concentrations as low as 2 μg L-1.
AFRIKAANSE OPSOMMING: Weens die negatiewe gesondheids aspekte toegeskryf aan Hg2+ vergiftiging is ‘n nuwe innoveerende metode van Hg2+ deteksie in wateroplossings ondersoek. Die voorgestelde metode van Hg2+ deteksie behels die gebruik van ‘n Hg2+ selektiewe chemosensor geimmobiliseer op ITO elektrodes in ‘n fotoelektrochemiese sel. Met lig aktivering en in die teenwoordigheid van Hg2+, absorbeer die fluoreseerende chemosensor ‘n foton, gevolg deur lading skeiding, soos bepaal deur die aard van die halfgeleidende material wat op die ITO platjies bedek is. Die halfgeleiers wat ondersoek was, was TiO2, PANI en ko-polimere van PANI met 2-bromoanilien. Die polimeer en kopolimeer bedekte ITO werkende elektrodes wat in die Hg2+ sensitiewe fotoelektrochemiese sel gebruik is, is elektrochemies geevalueer. Daaruit is gevind dat ITO bedek met PANI superieure geleier en halfgeleier eienskappe het in vergelyking met die ITO wat bedek is met P[A-co-2-BrA] kopolimere. Die ITO glas plaatjies is bedek met TiO2, PANI en die P[A-co-2-BrA] kopolimere gevolg deur die fluoresseerende chemosensor, RS. Die elektrodes is onderskeidelik fotoelektrochemies getoets in ‘n fotoelektrochemiese sel in die teenwoordigheid van Hg2+. Die PANI-RS elektrode het soos ‘n fotokatode opgetree in die teewoordigheid van Hg2+ onder beligting. Die foto-reaksie van die PANI-RS elektrode teeonoor Hg2+ het liniêr toegeneem van 10 μg L-1 tot 150 μg.L-1 met ‘n limiet van deteksie op 6 μg L-1. ITO/TiO2 wat bedek is met ‘n samestelling van PANI en RS het ‘n fotoanodiese reaksie gehad teenoor Hg2+ in die liniêre reeks van 10 tot 200 μg L-1 met ‘n deteksie limiet van 5 μg L-1. ITO en ITO/TiO2 bedek met die P[A-co-2-BrA] kopolimere het heelwat laer fotoreaksies getoon teenoor Hg2+ in waterige oplossings Die fotoreaksie het afgeneem met toeneemende 2-bromoanilien inhoud van die kopolimeer. Die PANI en P[A-co-2-BrA] kopolimere bedekte ITO en ITO/TiO2 elektrodes is verder bedek met ‘n tweede rhodamine 6G afgeleide, RT. Die ITO/PANI bedek met RT het weer ‘n fotokatodiese reaksie gehad teenoor Hg2+ in die konsentrasie interval 0.2 tot 5 μg L-1. Die ITO/TiO2 elektrode bedek met die PANI-RT samestelling het geen fotoreaksie gehad teenoor Hg2+ weens afstotende kragte tussen die TiO2 and RT molekules. Die fotoreaksies van die verskeie werkende elektrodes teenoor Hg2+ is verder getoets in ‘n tuisgemaakte fotoelektrochemiese Hg2+ detektor. Die fotoreaksies van die PANIRS en PANI-RT samestellings op ITO het kwalitatiewe resultate gelewer vir die teenwoordigheid van Hg2+ in waterige oplossings in konsentrasies tot so laag soos 2 μg L-1.
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Octa-Smolin, Frescilia [Verfasser], and Jochen [Akademischer Betreuer] Niemeyer. "1,1‘-Binaphthyl Based Bis- and Tris-Phosphoric Acids : Syntheses and Application as Fluorescent Chemosensors / Frescilia Octa-Smolin ; Betreuer: Jochen Niemeyer." Duisburg, 2018. http://d-nb.info/117454385X/34.
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Oliveri, Ivan Pietro. "Zinc(II) Schiff Base Complexes and their Aggregation/Deaggregation Properties: Versatile and Multifunctional Materials as Chemosensors and Building Blocks for New Supramolecular Architectures." Doctoral thesis, Università di Catania, 2013. http://hdl.handle.net/10761/1292.
Full textAbstract:
In this PhD thesis the synthesis, characterization, and study of the aggregation/deaggregation properties of a series of amphiphilic bis(salicylaldiminato)ZnII Schiff base complexes, involving different bridging diamino groups, and their applications as molecular probes, nonlinear optical (NLO) and vapochromic materials, as well as synthons for the formation of new fibrillar and branched supramolecular nanostructures, are reported.
Through detailed 1H NMR, DOSY NMR and optical spectroscopic studies, it is found that these species always form aggregates in solution of non-coordinating solvents. The degree of aggregation is related to the nature of the bridging diamine. In coordinating solvents or in the presence of coordinating species, a complete deaggregation of all complexes occurs because of the axial coordination to the ZnII ion, accompanied by considerable changes of the 1H NMR and optical absorption and fluorescence spectra. Moreover, an easy switch-on of the NLO response upon addition of a Lewis base, such a pyridine, with formation of a 1:1 adduct, or 1,2-bis-(4-pyridyl)ethane, with formation of a 2:1 adduct, is observed. As the amount of the coordinating species for the complete deaggregation of the complexes is dependent of the Lewis character of the ZnII ion, an order of the Lewis acidic character can be established for the aggregate species in non-coordinating solvents. The effect of the alkyl chain length seems to play a minor role in the aggregation properties, since 1H NMR data, optical absorption and fluorescence spectra remain almost unaltered upon changing the chain lengths. The complexes having benzene ring bridge form fibrillar nanostructures whose width is influenced by the degree of interdigitation of side alkyl chains.
The Lewis acid properties of the complexes having 2,3-diaminomaleonitrile bridge, with respect a series of primary, secondary and tertiary aliphatic amines, and several alkaloids, are also investigated. Through the analysis of fluorescence titrations, it is found that the binding interaction, the selectivity and the sensitivity of these complexes are strongly influenced by the steric characteristics of the nitrogen based donors and then by their Lewis basicity, leading to high selectivity, in the micromolar range, and sensitivity for pyridine-based, cinchona alkaloids, primary and alicyclic amines. A distinct selectivity is also observed along the series of secondary or tertiary amines, paralleling the increasing steric hindrance at the nitrogen atom. Moreover, these complexes have been also involved as reference Lewis acids, to build up a reliable Lewis basicity scale in dichloromethane for amines and various common solvents whose trend is influenced by the steric hindrance of both the Lewis bases and the reference Lewis acid. The these complexes have also investigated as vapochromic materials, able to change their colour upon exposure to volatile Lewis bases, allowing their application as chemosensors for volatile Lewis bases in the solid state.
Finally, new branched nanostructures have been achieved for a ZnII Schiff base complex having an alkyl ammonium bromide in the alkyl side chains. Unlike to studies on the aforementioned amphiphilic complexes, in this case the control of the supramolecular architecture is governed by intermolecular Zn---Br interactions.
34
Akdeniz, Ali. "Sensing of Enantiomeric Excess in Chiral Carboxylates." Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1465223828.
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Finkelmeier, Nils. "Synthesis and Fluorescence Properties of Anthracene Derivatives and their Metal Complexes." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://hdl.handle.net/11858/00-1735-0000-0023-994A-7.
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Agostini, Alessandro. "Supramolecular and heterosupramolecar chemistry in controlled release and molecular recognition processes." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/29397.
Full textAbstract:
La presente tesis doctoral titulada ¿Supramolecular and heterosupramolecular chemistry in controlled release and molecular recognition
processes¿ está centrada en los dos aspectos principales de la química
supramolecular que han experimentado un gran auge en los últimos años:
el reconocimiento molecular y los procesos de liberación controlada.
En particular la primera parte de la tesis se focaliza en el diseño y
síntesis de moléculas orgánicas que pueden ser empleados cómo sensores
para especies aniónicas y neutras. El paradigma seleccionado para los
procesos de reconocimiento molecular fue la aproximación del dosimetro
químico. Esta aproximación presenta ventajas con respecto a los otros dos
métodos de determinación de aniones (desplazamiento y unidad coordinanteunidad indicadora), cómo, por ejemplo, la posibilidad de determinar los
analitos en disolución acuosa. Así se sintetizaron dos sensores selectivos,
uno para el anión fluoruro (F-) y el otro para glutatión (GSH). El sensor
selectivo para la determinación de F- está basado en un colorante azoico
funcionalizado, en su ¿OH fenólico, cómo silileter. Esta molécula presenta
una banda de absroción muy intensa centrada a 350 nm que, después de la
adición de F-
, sufre un efecto hipocrómico significativo y un
desplazamiento batocromico ligero (de ca. 10 nm), mientras aparece una
nueva banda a 470 nm, determinando un cambio de incoloro a amarillorojo. Para obtener un sensor selectivo para GSH se sintetizó una sonda
químico basado en una sal de 2,6-difenilpirilio. Sucesivamente se preparó
una disolución de este compuesto en agua/CTAB, que se caracterizaba por
un intenso color azul. En este caso, la adición de GSH produce una
disminución significativa de la banda del visible, acompañada por la
consecuente decoloración. Además la adicón de GSH induce la aparición de Resumen
vi
una intensa banda de emisión centrada a 485 nm (después de la irradiación
a 350 nm).
La segunda parte de esta tesis doctoral se basa en el diseño y síntesis de
nuevos sistemas híbridos orgánicos-inorgánicos para procesos de liberación
controlada en ambiente celular. Estos materiales híbridos se componen en
general, de dos unidades: una matriz inorgánica mesoporosa de base
silícea, capaz de almacenar moléculas orgánicas (colorantes, farmacos...) y
un compuesto orgánico anclado covalentemente a la superficie externa del
soporte inorgánico mesoporoso, que actúa cómo puerta molecular. La
aplicación de un estímulo externo puede modificar la conformación de la
puerta molecular permitiendo o bien impidiendo la difusión de la carga
almacenada en los mesoporos hacía el exterior (disolución o citoplasma). El
primer sistema sintetizado y estudiado se compone de una matriz
inorgánica mesoporosa (MCM-41), cargada con el colorante Ru(bipy)3
2+ y
funcionalizada en la superficie con un oligoetilen glicol mediante un grupo
ester. La adición de la enzima esterasa determinaba la hidrólisis del grupo
ester y la consecuente reducción del tamaño de la puerta molecular,
acompañada por la liberación del colorante previamente cargado. Otro
sistema de liberación preparado consiste en el uso de la misma matriz
MCM-41 nanoscópica y el mismo colorante Ru(bipy)3
2+, pero se
funcionalizó la superficie con una puerta molecular fotolabil. La irradiación
en el maximo de absorción de la puerta molecular inducía la
fotodegradación de la misma y la consecuente liberación del colorante. Un
tercer ejemplo de sistema de liberación consiste en una puerta molecular
caracterizada por la presencia de dos grupos funcionales hidrolizables con
enzimas diferentes: grupos urea y amida. vii
El material final, caracterizado por la presencia del mismo esqueleto
inorgánico, y cargado con Ru(bipy)3
2+, era capaz de liberar selectivamente
cantidades distintas de colorante, dependiendo del enzima empleado. Así
se podían conseguir dos tipos de perfiles de liberación: uno muy rápido y
poco intenso y otro más lento pero mucho mas intenso. Finalmente se
sintetizó un material híbrido siempre basado en la misma matriz de MCM-
41, cargado con rodamina-B y funcionalizado en la superficie con
galactooligosacáridos. Con este material se podía conseguir una liberación
controlada del colorante selectivamente en células senescentes, debido a
que estas sobreexpresan el enzima ß-galactosidasa que es capaz de
hidrolizar los galactooligosacáridos.Agostini, A. (2013). Supramolecular and heterosupramolecar chemistry in controlled release and molecular recognition processes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/29397
TESIS
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Palacios, Manuel A. "Materials and Strategies in Optical Chemical Sensing." Bowling Green State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1225902887.
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ZARTIT, RANIA. "Synthesis of new macrocyclic and macropolycyclic systems for metal ion recognition. Sintesi di nuovi sistemi macrociclici e polimacrociclici per il riconoscimento di cationi metallici." Doctoral thesis, 2015. http://hdl.handle.net/2158/1043014.
Full textAbstract:
The objective of the research is the realization of receptors able to bind selectively and reveal the metal ions of environmental or biological interest through variations quantifiable of their fluorescence emission. For this purpose we have made some chemosensors of fluorescence containing one or more polyamine units as coordination sites for metal ions and we started the study of their coordinative properties. In this thesis they have been achieved several chemosensors of fluorescence, that are capable of recognizing the ion zinc in the solution, in cells and tissues, where most of these chemosensores are capable of coordinating just with zinc(II). So, this thesis is targeted towards the synthesis and characterization of five fluorescent chemosensors to evaluate their luminescent properties in the presence of bipositive ions of the transition metals and post-transition metals, also for the selective recognition of zinc(II). L’obbiettivo della ricerca è la realizzazione di recettori in grado di legare selettivamente e rivelare ioni metallici di interesse ambientale o biologico attraverso variazioni quantificabili della loro emissione di fluorescenza. A tale scopo, abbiamo sintetizzato alcuni chemosensori di fluorescenza contenenti una o più unità poliamminiche come siti di coordinazione per ioni metalli e ne abbiamo iniziato lo studio delle loro proprietà coordinative. In questo progetto di tesi sono stati realizzati diversi chemosensori di fluorescenza capaci di riconoscere lo ione zinco(II) sia in soluzione che in cellule e tessuti, in cui la maggior parte di questi chemosensori sono capaci di coordinare un solo ione zinco(II). Quindi, questa tesi è rivolta verso la sintesi e la caratterizzazione di cinque chemosensori fluorescenti per valutare le loro proprietà luminescenti in presenza d
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Huang, Jyun-Jie, and 黃俊傑. "Xanthenedione Derivatives as Chemosensors." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/62pdcb.
Full textAbstract:
碩士靜宜大學
應用化學系
107
Arylbisarylbis(1,3-dioxocyclohexyl)methanes derivatives 1–14 were prepared by starting materials of benzaldehydes and 1,3-cyclohexanedione in ethanol at room temperature. 9-Aryl-1,8-dioxo-octahydroxanthenes derivatives 15–30 were synthesized by one-pot reaction with catalyst TsOH at reflux in cosolvents of 1:2 ethylene glycol/water. By using 2-pyridinecarboxaldehyde as the starting material and TsOH, 9-pyridin-2-yl-1,8-dioxo-octahydroxanthenes 27 and 30 were achieved in ethanol at reflux while indolizine derivatives 33 and 34 were obtained in water. Arylbis(1,3-dioxocyclohexyl)methanes and indolizine derivatives could detect mercury ion and anions acetate, fluoride, cyanide, benzoate and phosphate.
40
Hu, Sheng-Qi, and 胡勝琪. "Coumarin Carbohydrazide Derivatives as Chemosensors." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/hmsm7g.
Full textAbstract:
碩士靜宜大學
應用化學系
107
In this thesis, a series of coumarin carbohydrazine derivatives were prepared via different substituted aromatic aldehydes to evaluate the effects of sensing anions and cations. Due to the spatial configuration of the aromatic ring and nitrogen of the coumarin carbohydrazine derivatives, there exist the possibility to chelate the divalent copper ion. The results demonstrated that the treatment of copper ion with compounds 4d and 4i resulted in a color change from colorless to yellow. As can be seen in the absorption spectra, a new absorption peak appears at 410 nm. For compound 4e, the corresponding new absorption peak was at 400 nm. It is known that coumarin is electrophic and might undergo nucleophic addition reaction with cyanide anion. Our results showed that this series of coumarin carbohydrazine derivative is easily nucleophilically added by cyanide ions. In the absorption spectra, the absorption peak of the coumarin ring at 300 nm was disappeared with adding cyanide anions. This results were futher supported by the NMR titration experiment of cyanide ions with compound 4a and 4i. On the other hand, fluoride ion only acted as a base with coumarin carbohydrazine derivatives 4a and 4i. The fluoride ion formed a hydrogen bond with the NH of the acylhydrazone, and leading to. a blue shift in the absorption of the coumarin ring at 300 nm in the absorption spectra.
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Wang, Tzu-Hao, and 王子豪. "Synthesis and Application of Cu2+ Chemosensors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/99727510451462160678.
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Zamora, Olivares Diana Paulina. "Differential sensing of kinases." Thesis, 2014. http://hdl.handle.net/2152/30454.
Full textAbstract:
During the last decade, organic and supramolecular chemistry in combination with analytical and fluorescent-based sensing methods have led to the development of chemical biology tools to study protein phosphorylation in vitro. However, further challenges remain present to develop better chemical approaches that can allow us to understand the activation/inhibition of specific kinase pathways.
To avoid the tedious process of developing individual highly selective receptors, the use of differential sensing techniques has been growing in the supramolecular chemistry field. This sensing protocol exploits the interactions between target analytes and a library of cross-reactive receptors to create a response pattern that is unique for individual analytes or different mixtures thereof. Using this approach, one obtains a distinct fingerprint of composite signals produced by the sensor elements allowing for discrimination of different kinases in vitro and in complex mixtures such as cell lysates.
The main emphasis of this work sought to expand the current optical-based detection systems of phosphorylated proteins to include a new pattern-based recognition method for a new class of protein kinases. To this end, the synthesis of chemosensors and peptide-based biosensors was pursued to detect and differentiate relevant mitogen-activated protein (MAP) kinases which represent targets of pharmaceutical interest. Further, this research included the quantitative detection of MAP kinases and corresponding inhibitors using a combination of pattern recognition approaches with new chemometric tools.text
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Chen, Chun-Lin, and 陳群霖. "Colorimetric and Ratiometric Fluorescent Chemosensors for Anions." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/40360733737680328712.
Full textAbstract:
碩士國立中正大學
化學所
94
We have designed and synthesized a series of chemosensors containing amide and pyrrole groups for anion recognition and sensing. The binding affinity between these chemosensors and various anions has been investigated to elucidate the influence of electronic effect generated by different functional groups such as terthiophene, dinitrobenzene, and diphenylquinoxaline in the structure of these chemosensors. According to the changes of UV-Vis and fluorescentce spectra on addition of anions, the chemosensors 1, 2 and 3 display strong binding ability to fluoride, pyrophosphate and cyanide. Moreover, the appearance of the ratiometric phenomenon upon interaction with anions further enhances the spectral differentiation for anion sensing. The reaction mechanism between chemosensor and anions is further investigated by the 1H-NMR titration experiments. Anions strongly intereacting with chemsensors and producing large changes during the titration in UV-Vis and fluorescent spectra usually result in deprotonation of the amide group while the weaker anions initially form hydrogen bonds with NHs on amides and pyrroles followed by deprotonation at higher anion concentration. The weakest anions, however, form only 2 or 4 hydrogen bonds with chemosensors during titration. Moreover, both sensors 2 and 3 are able to recognize cyanide under semi-aqueous environment. We proposed that the formation of covalent bonded cyanohydrin derivatives from cyanide addition to carbonyl center is responsible for the effectiveness of sensors 2 and 3 in semi-aqueous environment. The structures of the cyanide adducts have been confirmed by 1H-NMR and ESI mass spectra. On the other hand, sensor 1 could not form stable cyanide adduct under the competition with water due to the less electron-withdrawing nature of terthiophene. Based on the hydrogen bonding and deprotonation, chemosensors 1, 2 and 3 show very good recognition ability to F- and HP2O73- in polar organic solvents. Most importantly, we have demonstrated that chemosensors 2 and 3 exhibit outstanding selectivity and sensitivity to cyanide over other anions in the semi-aqueous solution, which renders them highy promising chemosensors for cyanide.
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Liu, Hao-Ming, and 劉浩敏. "Selective Turn-on Fluorescent Chemosensors for Zn2+." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/83548961019625517788.
Full textAbstract:
碩士國立交通大學
應用化學系碩博士班
100
In this thesis, three chemosensors DP1, DP2 and DP3 based on dipyrrins were designed for Zn2+ detection. DP1 produced significant fluorescence enhancement (20 fold) in the presence of Zn2+ ion, while the metal ions Ag+, Ca2+, Cd2+, Co2+,Cu2+, Fe2+,Fe3+, Hg2+, Mg2+, Mn2+, Ni2+ and Pb2+ produced only minor changes in fluorescence. After addition of more than one equivalent of Zn2+, the emission intensity reached a maximum, at which the quantum yield was 0.10. According to 1H NMR studies, addition of Zn2+ caused the disappearance of amine (NH) hydrogen signal. This observation indicates that Zn2+ binding with DP1 is mainly through one nitrogen atom at benzoimidazole moiety and two nitrogen atoms at the dipyrrin group. The binding ratio of DP1–Zn2+ complexes was determined as 1 : 1 according to Job plot. Using Benesi-Hildebrand plot, the binding constant of DP1–Zn2+ complexes was decided as 6.12 x 104 M-1. The detection limit of the DP1-Zn2+ was 0.236 μM. The quantum yield and the binding constant of the DP2-Zn2+ were 0.017 and 6.64*104 M-1, respectively. The detection limit was 0.325 μM of DP2 for binding Zn2+. The quantum yield and the binding constant of DP3–Zn2+ complexes were 0.026 and 1.47*105 M-1, respectively. The detection limit was 0.492 μM of DP3 for detecting Zn2+.
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林宛瑩. "Rhodamine – based chemosensors for Cu2+ and Fe3+." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/88688327860308284424.
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LEE, YU-HSUAN, and 李育軒. "Azine Derivatives as Chemosensors for Metal Ions." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/56405954963164618846.
Full textAbstract:
碩士靜宜大學
應用化學系
105
In this thesis, a series of azine derivatives were designed and synthesized as for metal ion chemosensors. UV-Vis spectra showed that 1,2-di(N,N-dimethylaminobenzylidene)hydrazine (3) in acetonitrile and dichloromethane had interactions with silver, chromium, ferrous, ferric, and copper ions. The interaction of azine 3 with ferric ions was most pronounced. Symmetric azine 7 and asymmetric azine 8 showed interactions with copper, cobalt, cadmium, nickel, lead, and zinc ions. At pH 8, both asymmetric azine 8 and symmetric azine 2, 2-hydroxyphenyl azine, exhibited weak orange fluorescence at high concentrations and weak green fluorescence at low concentrations. At the same condition, both symmetric azine 8 and symmetric azine 2 demonstrated strong AIEE phenomena, namely, no fluorescence in DMSO/water 9:1, weak green fluorescence in fluorescence in DMSO/water 1:1, and strong green fluorescence in DMSO/water 1:9.
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Huang, Ray-Yui, and 黃睿裕. "Cu(II) Chemosensors based on 1,4-Naphthoquinone." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/08144928734151463008.
Full textAbstract:
碩士國立交通大學
應用化學系所
97
In this thesis, four chemosensors, 2-Methyl-3-[(pyridin-2-ylmethyl)-amino] -1,4-naphthoquinone (1), 2-Methyl-3-(2-pyridin-2-yl-ethylamino)-1,4- naphthoquinone (2), 1-[(Pyridin-2-ylmethyl)-amino]-anthraquinone (3), and 1-(2-Pyridin-2-yl-ethylamino)-anthraquinone(4) were synthesized and evaluated for cation detection. In the binding study of 1 and 2 with transition metal ions, Cu2+ is the only ion caused maximum wavelength shifted from 460 nm (red) to 640 nm (blue). Job’s plot revealed that both sensors 1 and 2 reacted with Cu2+ in a 1:1 stoichiometry. Addition of Cu2+ caused great absorbance at pH > 6, indicating deprotonation of the secondary amine was required for Cu2+ binding. The maximum absorbance at 640 nm was observed between pH 7 and pH 7.4 which was the physiological pH in a cell. When pH > 8, the absorbance at 640 nm was lower than that in the pH range of 6-8 (likely due to the formation of CuLH-1OH). Furthermore, according to the results of solvent effect, the color change disappeared in a few minutes as solvent was changed to acetonitrile. In the binding study of 3 and 4 with transition metal ions, Cu2+ is the only ion caused maximum wavelength shifted from 490 nm (red) to 590 nm (blue). Job’s plot revealed that sensor 3 reacted with Cu2+ in more than one kind of stoichiometry. Job’s plot revealed that sensor 4 reacted with Cu2+ in a 1:1 stoichiometry. Furthermore, according to the results of solvent effect, the color change disappeared in a few minutes as solvent was changed to acetonitrile. Through the variation of UV-vis absorption and IR spectra, the sensing mechanism of 1, 2, 3, 4 with Cu2+ are investigated. As Cu2+ was added into the chemosensors, Cu2+ bound with C=O, secondary amine, pyridine and then let the hydrogen atom leave from secondary amine. Both the negative charge on secondary amine and Cu2+ influenced the resonance system of naphthoquinone. The energy gap was changed between π to π* and blue-shift was formed. From EPR spectrums, we know Cu(II) never changed to Cu(I) after it binding with chemosensors.
48
Luo, Chin-Ren, and 羅欽仁. "Salicylideneimine-Based Chemosensors : Design, Synthesis and Sensing." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/90156908783499782424.
Full textAbstract:
碩士國立暨南國際大學
應用化學系
100
Two new fluorescence sensors, namely receptors 3 and 6, incorporating polyether spacer and salicylideneimine moiety have been designed and synthesized. Receptor 3 showed “Off-On” fluorescence signaling behavior for Cd2+. Completing studies showed that the 3-Cd2+ adduct could be replaced by Cr3+, Cu2+, Al3+, Ag+, which would quench the fluorescence. On the basis of titration, Job’s plot and mass spectrum analysis, receptor 3 binds with Cd2+ in a 1:1 stoichiometry with the binding constant K = 5 × 104. Receptor 6 showed “Off-On” fluorescence signaling behavior for Zn2+. Uv-vis absorption sperctra show that a metal-to-ligand charge transfer (MLCT) band appeard. Upon the addition of Cu2+,Co2+and Zn2+into the solution of receptor 6. Completing studies showed that the 6-Zn2+ complex could be replaced by Cu2+ and Co2+ , which would quench the fluorescence signaling and shift the MLCT absorption. According to the titration, Job’s plot and mass spectra analyses, receptor 6 binds with Zn2+, Co2+ and Cu2+ all in a 1:1 stoichiometry. The binding constants (K) is 2 × 104, 3 × 104 and 5 × 104 for Zn2+, Co2+ and Cu2+ ions, respectively, which show an order of binding strength: Cu2+ > Co2+ > Zn2+. On the other hand, it is worth to note that when adding Mg2+ ions into the solution of 6-Zn and 6-Cd, unusual fluorescence enhancement along with blue shift occurred.
49
Chen, Kuan-Hung, and 陳冠宏. "Design and Synthesis of Chemosensors to Detect Phospholipids." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/73451820000853468749.
Full textAbstract:
博士國立臺灣大學
化學研究所
96
Part 1: Detection of Phospholipids Base on Chemosensing Ensemble We have previously designed a fluorescence receptor for sensing of phosphate ions. This kind of receptor is established by incorporating four additional amido groups onto pyridine 2,6-biscarboxamide to provide a pseudo-tetrahedral cleft and multiple hydrogen bondings to hold phosphates in a 1:1 complexation stoichiometry. For sensing phospholipids, such as geranyl pyrophosphate (GPP), a modified receptor was synthesized by incorporation of long hydrocarbon chains to increase hydrophobic interaction with the lipid moiety of phospholipids, and two pyrene units were kept for the fluorescence readout. In this study, a chemosensing ensemble system was applied by using coumarin derivatives as the indicator. Upon photoirradiation at 340 nm, a fluorescence resonance energy transfer (FRET) would occur due to the interaction of the coumarin with the pyrene unit. Because of high binding affinity of the receptor with GPP, addition of GPP would cause displacement of the coumarin indicator. Once the coumarin indicator was extruded out of the receptor cleft, the FRET would be diminished. Thus, phospholipid is readily detected by this method, and the binding constant is determined by the fluorescence changes during the titration. Part 2: Synthesis of BPA–Zn Complex for Selective Binding with LysoPA. A bis(2-pyridylmethyl) amine–Zn complex [Ph–(BPA–Zn)2, 48] is designed to contain a rigid benzene unit and dinuclei of Zn2+ ions. On binding with a phosphate ion, each zinc ion is four-coordinated with BPA and one oxygen of phosphate. Because a Zn2+ ion can have coordination number of five, the residual vacant orbital on the Ph–BPA–Zn–phosphate is available to incorporate an additional ligand. Based on this concept, both Zn2+ ions of BPA–Zn can bind synergistically to the hydroxyl group and the phosphate moiety of lysophosphatidic acid (LysoPA). The binding constants for LysoPA and phosphatidic acid (PA) are determined in a chemosensing ensemble system using coumarin derivative as the indicator. As our anticipation, the binding of Ph–(BPA–Zn)2 receptor with LysoPA is about 4–fold stronger than that with PA. Part 3: Phospholipid-Induced Aggregation and Anthracene Excimer Formation: Application to sensing phospholipids. Receptor 60 displays an unusual and selective fluorescence response to LysoPA in aqueous buffer solutions through a concentration-dependent formation of aggregates and fluorescent anthracene excimers. The aggregation behavior relies on the hydrophobic aliphatic chains in LysoPA, and the excimer emission results from excitation of the ground-state pre-associated anthracene dimer or clusters. The aggregate formation is consistent with the broadening and red-shift of their absorption and excitation titration spectra. The elevation of absorption might reflect the formation of microcrystal-like aggregates in the buffer solution. The proposed fluroescence sensing mechanism can also account for the observed changes in the fluorescence decay time. The anthracene excimer vs monomer emission would allow a more favorable ratiometric detection of LysoPA. Furthermore, this method may be used to detect the activity of transglycosylase based on the selective binding of receptor 60 with pyrophosphate mono-ester over the corresponding di-ester. It may serve as a new tool for screening the inhibitors against formation of bacterial cell wall.
50
GUO, Chao-Ci, and 郭朝其. "The Synthesis of glycosidase inhibitors and fluorescent chemosensors derivatives." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/58171484089769612463.
Full textAbstract:
碩士國立彰化師範大學
化學系
96
We synthesized a series of N-alkylated aza-C-glycosides starting from the commercial D-ribose. Our strategy take advantage of a direct coupling reaction of alkylated amine with 5-OMs-ribose and further undergoes intramolecular hetero-Michael reaction under base condition. In addition, we also synthesized a novel cyclodextrin-like artifical receptor which is a 1,2,3-triazole compound through Huisgen 1,3-dipolar cycloadditions of alkynes to azides. This idea is based upon the assumption that a cyclic array of carbohydrate moieties, nitrogen atom and amino acid functional groups may lead to exquisite specificity of recognition and catalysis. If compound 9、10、11 with an appropriate appended chromophore would be a good candidate for cation probes because of their aza-crown structures which can be used as a cation recognition unit.