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1
Cabell, Larry Allen. « Chemosensors and competition sensing assays / ». Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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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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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.
4
Fan, Li-juan. « Design, synthesis and photophysics of fluorescence "turn-on" conjugated polymer chemosensors ». Diss., Online access via UMI:, 2006.
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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/.
Texte intégralRésumé :
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.
7
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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Paul, Uchenna Prince. « Fluorescence Detectors for Proteins and Toxic Heavy Metals ». Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd416.pdf.
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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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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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Zhu, Jianfa. « Fluorescent chemosensor development based on multifunctional spirobenzopyrans ». HKBU Institutional Repository, 2011. https://repository.hkbu.edu.hk/etd_ra/1299.
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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.
Texte intégralRésumé :
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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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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PIERSANTI, LUCA. « Nuovi chemosensori ottici aventi un derivato benzossazolico come unità sensibile ». Doctoral thesis, Urbino, 2015. http://hdl.handle.net/11576/2628889.
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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.
Texte intégralRésumé :
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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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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Kaur, Amandeep. « Fluorescent tools for imaging oxidative stress in biology ». Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15063.
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Oxidative stress has been implicated in a myriad of pathological conditions, but measuring it and deciphering the underlying the mechanisms has been a long-standing challenge. Most of the existing redox probes are reaction-based and irreversible. In contrast, reversible redox probes with biologically-tuned redox potential can distinguish between transient and chronic elevations in oxidative capacity. In this work, a series of novel fluorescent redox probes based on flavins and nicotinamides have been developed and tested. The first redox-responsive probe, NpFR1, localises in the cytoplasm and exhibits robust reversibility of oxidation and reduction and a clear fluorescence increase upon oxidation. Based on these promising results, attention turned to developing analogues of NpFR1, with two main aims: to send the probe to the specific sub-cellular organelles, and to develop a ratiometric probe, in which a change in redox state was signalled by a change in colour rather than fluorescence intensity. To this end, six further probes were developed. A mitochondrially-localising derivative NpFR2 was developed by incorporating a lipophilic cationic tag. The design of the emission-ratiometric redox probe FCR1 whose fluorescence emission changes from blue to green upon oxidation, is based on the FRET process between coumarin donor and flavin acceptor. Furthermore, a set of excitation-ratiometric FRET probes FRR1 and FRR2 were developed, in which mitochondrial targeting was achieved by employing rhodamine B with inherent mitochondrial accumulation properties. Finally, nicotinamide-based redox probes NCR3 and NCR4 demonstrate the use of ICT as a strategy to attain ratiometric fluorescence properties. Following the successful utilisation of ratiometric and targeting strategies, the developed probes were applied in a variety of biological investigations, whether in cellulo, ex vivo or non-mammalian systems. The probes demonstrated excellent abilities to report on the differences in oxidative capacities under different conditions within each system. This work therefore demonstrates that reversible redox probes based on flavins and nicotinamides exhibit suitable properties for use as cellular redox probes. The developed probes can be modulated to give ratiometric output and targeted to specific sub-cellular compartments. These probes therefore exhibit potential to aid in deciphering the role of oxidative stress in pathogenesis and disease progression.
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Laughlin, Sarah R. « Arylboronic Acids With Strong Fluorescence Intensity Changes Upon Sugar Binding ». Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/chemistry_theses/46.
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Boronic acids play an important role in the design and synthesis of chemosensors for carbohydrates due to their ability to reversibly bind with diol-containing compounds. Along this line, the availability of boronic acids that change fluorescence upon sugar binding is critical to a successful sensor design effort. Here, two boronic acids that show strong fluorescent intensity changes upon sugar binding are reported: isoquinoline-7-boronic acid (7-IQBA) and phenoxathiin-4-boronic acid (4-POBA).
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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.
Texte intégralRésumé :
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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Lim, Soojin. « Fluorescent Indicators for Disease Biomarkers ». PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/262.
Texte intégralRésumé :
Xanthene dyes are common fluorophores which have been widely used as molecular probes. The xanthene fluorophores can be used as highly selective optical sensors to detect disease biomarkers. A new fluorogenic dye containing an alpha, beta-unsaturated aldehyde moiety exhibits selective fluorescent signal enhancement in the presence of cysteine or peptides containing N-terminal cysteine residues. The mechanism is based on synergistic covalent and supramolecular interactions. A unique rhodamine boronic acid indicator is used in an optimized data collection protocol for wavelength- and time-dependent selectivity of various saccharides and nucleosides. One indicator is thereby capable of selectively distinguishing structurally related analytes in mixtures. Moreover, the rhodamine-based boronic acid responds linearly to increasing riboside concentrations in urine samples, potentially enabling the screening for inborn purine metabolism disorders.
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Kurishita, Yasutaka. « Development of Molecular Tools for Analysis and Imaging of ATP and Other Biomolecules Based on Coordination Chemistry ». 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188614.
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Guliyev, Ruslan. « Rational Design Of Ratiometric Chemosensor Via Modulation Of Energy Donor Efficiency ». Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609889/index.pdf.
Texte intégralRésumé :
Rational design of fluorescent chemosensors is an active area of supramolecular chemistry, photochemistry and photophysics. Ratiometric chemosensors are even more important, as they have an internal system for selfcalibration.
In order to develop a new methodology for a ratiometric chemosensor design, we proposed coupling of energy transfer phenomenon to ion sensing.
In this study, we targeted energy transfer cassette type chemosensors, where the efficiency of transfer is modulated on the donor side, by metal ion binding which changes the spectral overlap. This work involves the synthesis of a number of EET systems with varying degrees of EET efficiency.
The results suggest that this strategy for ratiometric ion sensing is a promising one, enabling a modular approach in chemosensor design.
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Bantinaki, Eleni. « Characterisation of a novel chemosensory pathway underlying adaptive evolution in experimental populations of Pseudomonas fluorescens SBW25 ». Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393362.
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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.
Texte intégralRésumé :
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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Chiu, Sheng-Wen. « Spatiotemporal dynamics of cytoskeletal and chemosensory proteins in the bacterium Rhodobacter sphaeroides ». Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:d7d05b1a-07c5-4e26-9650-37bcfae2fade.
Texte intégralRésumé :
The discovery of the prokaryotic cytoskeleton has revolutionized our thinking about spatial organisation in prokaryotes. However, the roles different bacterial cytoskeletal proteins play in the localisations of diverse biomolecules are controversial. Bacterial chemotaxis depends on signalling through large protein clusters and each cell must inherit a cluster on cytokinesis. In Escherichia coli the membrane chemosensory clusters are polar and new static clusters form at pre-cytokinetic sites, ensuring positioning at new poles after cytokinesis and suggesting a role for the bacterial FtsZ and MreB cytoskeletons. Rhodobacter sphaeroides has both polar, membrane-associated and cytoplasmic, chromosome-associated chemosensory clusters. This study sought to investigate the roles of FtsZ and MreB in the partitioning of the two chemosensory clusters in R. sphaeroides. The relative positioning between the two chemosensory systems, FtsZ and MreB in R. sphaeroides cells during the cell cycle was monitored using fluorescence microscopy. FtsZ forms polar spots after cytokinesis, which redistribute to the midcell forming nodes from which gradients of FtsZ extend circumferentially to form the Z-ring. The proposed node-precursor model might represent a common mechanism for the formation of cytokinetic rings. The MreB cytoskeleton continuously reorganizes between patchy and filamentous structures, and colocalises with FtsZ at midcell. Membrane chemosensory proteins form individual dynamic unit-clusters with mature clusters containing about 1000 CheW3 proteins. These unit-clusters diffuse randomly within the membrane but have a higher propensity for curved regions like cell poles. Membrane clusters do not colocalise with FtsZ and MreB and appear excluded from the Z-ring vicinity. The bipolar localisation of membrane clusters is established after cell division via random diffusion and polar trapping of clusters. The cytoplasmic chemosensory clusters colocalise with FtsZ at midcell in new-born cells. Before cytokinesis one cluster moves to a daughter cell, followed by the second moving to the other cell. FtsZ and MreB do not participate in the positioning of cytoplasmic clusters. Therefore the two homologous chemosensory clusters use different mechanisms to ensure partitioning, and neither system utilizes FtsZ or MreB for positioning.
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Atilgan, Serdar. « A Sensitive And Selective Ratiometric Near Ir Fluorescent Probes For Zinc And Mercury Ions Based On The Distyryl-bodipy Fluorophore ». Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610842/index.pdf.
Texte intégralRésumé :
Near-IR dyes that absorb and emit in the red visible or near-IR region
have attracted great interest in the fields of medicinal chemistry and
biochemistry for the last few decades. This interest is due to the multiple
notes of metal ions in biological and enviromental processes. Therefore the
development of cation selective and sensitive sensors have been a hot
subject for many researchers. Consequently, fluorescence based sensors
are the most efficient and favorable ones among its counterparts in the field
of sensor research.
In this study, we have targeted to synthesize BODIPY based near-IR
dyes as a selective fluorophore for Zn (II) and Hg (II) cations. We have also
demonstrated that the versatile BODIPY fluorophore can be functionalized for
long wavelength emission on the 3 and 5 position of the BODIPY core with
multiple and distinct functional groups in a stepwise manner. Thus we are
able to link two BODIPY cores with a different absorption wavelengths to
each other first time with click chemistry strategy to generate a chemosensor
for Hg (II) cation.
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Octa-Smolin, Frescilia [Verfasser], et 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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Shi, Danxin. « Preliminary research toward the total synthesis of a novel crown ether that is a potential fluorescent chemosensor for potassium ion recognition ». Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/941374.
Texte intégralRésumé :
The purpose of this research was to synthesize a novel crown ether compound that has been designed to fluoresce with greatly enhanced intensities when in the presence of selected alkali metal cations. The novel crown ether compound (cryptand) 12,25-(1,5 - dimethyloxynaphtho)-1,4,7,10,14,17,20,23-octaoxacyclohexacosane (1) was synthesized through 6 steps. The general synthetic route for the preparation of cryptand 1 is given in the proposed synthetic procedure. Reaction of benzaldehyde (23) with glycerol (24) in the presence of concentrated sulfuric acid afforded cis and traps-1,3-O-benzylideneglycerol (25). Cis and trans-2-O-benzyl-1,3-O-benzylideneglycerol (27) was obtained when 1,3O-benzylideneglycerol (25) was treated with benzyl bromide (26) and sodium wire in benzene. Acid-hydrolysis of the 2-O-benzyl-1,3-O-benzylideneglycerol (27) in methanol gave 2-O-benzylglcerol (28). The key starting material is 12,25-bisbenzyloxy1,4,7,10,14,17,20,23-octaoxacyclohexacosane (31), which requires the formation of four carbon-oxygen bonds. 2-O-benzylglcerol (28) was reacted with triethyene glycol ditosylate and sodium hydride in dioxane. This treatment gave the product 12,25-bisbenzyloxy1,4,7,10,14,17,20,23-octaoxacyclohexacosane likely to be (31) along with the 1:1 and a 3:3 crown ether products. The compound likely to be (31) was treated with H2 and a Pd/Ccatalyst and the resulting compound was 12,25-dihydroxy-1,4,7,10,14,17,20,23Octaoxacyclohexacosane (2). Compound likely to be (2) was reacted with 1,5bis(bromomethy)naphthalene and potassium t-butoxide in tetrahydrofuran to give the final cryptand compound 1. The structures of the crown ethers, the products of this reaction, have not yet been unambiguously assigned.Department of Chemistry
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Lo, Presti Maria. « Optical detection of chemical species of environmental and biological relevance using molecular sensors and hybrid materials ». Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/172664.
Texte intégralRésumé :
[ES] La presente tesis doctoral titulada "Detección óptica de especies químicas de importancia ambiental y biológica utilizando sensores moleculares y materiales híbridos" se centra en el diseño, preparación, caracterización y evaluación de sensores químicos moleculares. El trabajo realizado se puede dividir en dos partes: (i) síntesis de sensores de cationes metálicos en disolución y (ii) síntesis y caracterización de nanopartículas híbridas orgánico-inorgánicas para el reconocimiento de especies químicas y biológicas.
En el primer capítulo se introduce el marco en el que se engloban los fundamentos teóricos de la química supramolecular en que se basan los estudios prácticos realizados durante la presente tesis doctoral. A continuación, en el capítulo dos, se presentan los objetivos generales de la tesis.
En el tercer capítulo se presenta un quimiodosímetro cromo-fluorogénico, capaz de detectar selectivamente cationes trivalentes entre cationes y aniones monovalentes y divalentes mediante una reacción de deshidratación en agua.
En el cuarto capítulo se presenta una unidad (BODIPY) conectada electrónicamente con un macrociclo dithia-dioxa-aza. Las soluciones de acetonitrilo y agua-acetonitrilo 95: 5 v / v de la sonda mostraron una banda ICT en la zona visible y son casi no emisivas. Cuando se utilizó acetonitrilo como disolvente, la adición de Hg (II) y cationes metálicos trivalentes indujo un cambio hipsocrómico de la banda de absorción y mejoras moderadas de la emisión. Se obtuvo una respuesta altamente selectiva al utilizar medios competitivos como agua-acetonitrilo 95:5 v/v. En este caso, sólo el Hg (II) indujo un cambio hipsocrómico de la banda de absorción y una mejora marcada de la emisión.
El quinto capítulo explora el desarrollo de sensores para berberina y amantadina. Dos moléculas de interés biológico por su uso como fármacos. Se han preparado tres sistemas de sensores basados en la aproximación de puertas moleculares. En concreto, sobre nanopartículas MCM-41 cargadas con rodamina B como unidad de señalización, se ha llevado a cabo la funcionalización con diversas aminas y el bloqueo de poros con cucurbituril CB7. Las aminas utilizadas son
ii
ciclohexilamina, bencilamina y amantadina. Los materiales obtenidos se han caracterizado por técnicas de difracción de rayos X y microscopía electrónica de transmisión confirmando la estructura mesoporosa de las nanopartículas. Los materiales preparados muestran una respuesta a la berberina y la adamantina, quitando el tapón y liberando el tinte fluorescente al medio. La respuesta de los materiales a las dos sustancias de interés (berberina y amantadina) depende de la estructura química de cada uno de los materiales en función de las constantes de afinidad entre el analito y CB7. Los resultados obtenidos abren el camino al uso de puertas moleculares como sensores de berberina y amantadina.[CA] La present tesi doctoral titulada "Detecció òptica d'espècies químiques d'importància ambiental i biològica utilitzant sensors moleculars i materials híbrids" se centra en el disseny, preparació, caracterització i avaluació de sensors químics moleculars. El treball realitzat es pot dividir en dues parts: (i) síntesi de sensors de cations metàl·lics en dissolució i (ii) síntesi i caracterització de nanopartícules híbrides orgànic-inorgànics per al reconeixement d'espècies químiques i biològiques. En el primer capítol s'introdueix el marc en el qual s'engloben els fonaments teòrics de la química supramolecular en què es basen els estudis pràctics realitzats durant la present tesi doctoral. A continuació, en el capítol dos, es presenten els objectius generals de la tesi. En el tercer capítol es presenta un quimiodosímetro crom-fluorogénic, capaç de detectar selectivament cations trivalents entre cations i anions monovalents i divalents mitjançant una reacció de deshidratació en aigua. En el quart capítol es presenta una unitat (BODIPY) connectada electrònicament amb un macrocicle dithia-dioxa-aza. Les solucions de acetonitril i aigua-acetonitril 95:5 v/v de la sonda van mostrar una banda ICT a la zona visible i són gairebé no emisivas. Quan es va utilitzar acetonitril com a dissolvent, l'addició de Hg (II) i cations metàl·lics trivalents va induir un canvi hipsocròmic de la banda d'absorció i millores moderades de l'emissió. Es va obtenir una resposta altament selectiva a l'utilitzar mitjans competitius com aigua-acetonitril 95:5 v/v. En aquest cas, només el Hg (II) va induir un canvi hipsocròmic de la banda d'absorció i una millora marcada de l'emissió. El cinquè capítol explora el desenvolupament de sensors per berberina i amantadina. Dues molècules d'interès biològic pel seu ús com a fàrmacs. S'han preparat tres sistemes de sensors basats en l'aproximació de portes moleculars. En concret, sobre nanopartícules MCM-41 carregades amb rodamina B com a unitat de senyalització, s'ha dut a terme la funcionalització amb diverses amines i el bloqueig de porus amb cucurbituril CB7. Les amines utilitzades són ciclohexilamina, bencilamina i amantadina. Els materials obtinguts s'han caracteritzat per tècniques iv de difracció de raigs X i microscòpia electrònica de transmissió confirmant l'estructura mesoporosa de les nanopartícules. Els materials preparats mostren una resposta a la berberina i la adamantina, llevant el tap i alliberant el tint fluorescent a l'mig. La resposta dels materials a les dues substàncies d'interès (berberina i amantadina) depèn de l'estructura química de cada un dels materials en funció de les constants d'afinitat entre l'anàlit i CB7. Els resultats obtinguts obren el camí a l'ús de portes moleculars com a sensors de berberina i amantadina.
[EN] The present doctoral thesis entitled "Optical detection of chemical species of environmental and biological importance using molecular sensors and hybrid materials" focuses on the design, preparation, characterization and evaluation of molecular chemical sensors. The work carried out can be divided into two parts: (i) synthesis of metal cation sensors in solution and (ii) synthesis and characterization of hybrid organic-inorganic nanoparticles for the recognition of chemical and biological species. The first chapter introduces the framework that encompasses the theoretical foundations of supramolecular chemistry on which the practical studies carried out during this doctoral thesis are based. Next, in chapter two, the general objectives of the thesis are presented. In the third chapter, a chromium-fluorogenic chemodosimeter is presented, capable of selectively detecting trivalent cations by means of a dehydration reaction in water. The fourth chapter presents a new compound containing a BODIPY unit electronically connected with a dithia-dioxa-aza macrocycle. Acetonitrile and water-acetonitrile 95:5 v/v solutions of the probe showed an ICT band in the visible zone and were nearly non-emissive. When acetonitrile was used as a solvent, addition of Hg(II) and trivalent metal cations induced an hypsochromic shift of the absorption band and moderate emission enhancements. A highly selective response was obtained when using competitive media such as water- acetonitrile 95:5 v/v. In this case only Hg(II) induced a hypsochromic shift of the absorption band and a marked emission enhancement. The fifth chapter explores the development of sensors for berberine and amantadine; two molecules of biological interest due to their use as drugs. Three sensing systems based on a "molecular gate" approximation have been prepared. Specifically, MCM-41 nanoparticles were loaded with Rhodamine B as a signalling unit, functionalized with various amines and capped with cucurbituril CB7. The amines used are cyclohexylamine, benzylamine and amantadine., The materials obtained were characterized by X-ray diffraction techniques and transmission vi electron microscopy, confirming the mesoporous structure of the nanoparticles. The prepared materials showed a response to berberine and adamantine, which induced release of the fluorescent dye to the medium. The response of the materials to the two substances of interest (berberine and amantadine) depends on the chemical structure of the capping ensemble and it is a function of the affinity constants between the analyte and CB7. The results obtained open the way to the use of gated materials as berberine and amantadine probes.
We thank the Spanish Government (MAT2015-64139-C4-1-R) and Generalitat Valenciana (PROMETEOII/2014/047). M. L. P. thanks Generalitat Valenciana for her Grisolia fellowship. Thanks are also due to Fundação para a Ciência e Tecnologia (Portugal) for financial support to the Portuguese NMR network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETEQREN- EU for financial support to the research centre CQ/UM [PEst-C/ QUI/UI0686/2013 (FCOMP-01-0124-FEDER-037302)], and a post- doctoral grant to R. M. F. Batista (SFRH/BPD/79333/2011).
Lo Presti, M. (2021). Optical detection of chemical species of environmental and biological relevance using molecular sensors and hybrid materials [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/172664
TESIS
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Dubois, Fabien. « Etude des modifications des propriétés spectroscopiques de chemosenseurs fluorescents extrinsèques en présence de cadmium (II), de zinc (II) et de mercure (II) ». Doctoral thesis, Universite Libre de Bruxelles, 2002. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211410.
Texte intégral
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Cheng, Yunfeng. « Development of Boronic Acid Flurescent Reporters, Boronic Acid-Modified Thymidine Triphosphates for Sensor Design and Antagonists of Bacterial Quorum Sensing in Vibrio Harveyi ». Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/chemistry_diss/58.
Texte intégralRésumé :
Carbohydrates are known to play important roles in a large number of physiological and pathological processes. Conceivably, “binders” of carbohydrates of biological importance could be used as diagnostic and therapeutic agents. Currently, lectins are the major available tools in research for carbohydrate recognition. However, the available lectins often have cross-reactivity issues, along with the high costs and stability issues. Therefore, there is a critical need to develop alternatives (lectin mimics). In this regard, there have been very active efforts in developing different “binders”, such as small molecule lectinmimics and aptamers. Among all the small molecule lectinbmimics developments, boronic acid stands out as the most important building blocks of the sensors design for carbohydrates biomarkers due to its intrinsic binding affinities with diols. To address a fundamental question that whether boronic acid also binds to six-membered ring sugars, with very limited precedents, we provided a concrete experimental evidence of the binding. Specifically, a series of isoquinolinylboronic acids were found to have remarkably high binding affinities with fluorescence change upon binding to representative sugars. Most importantly, these isoquinolinylboronic aicds showed weak but very encouraging bindings with six-membered sugar model. All these promising results paves the way of using boronic acids, especially isoquinolinylboronic acid as building blocks for chemosensors design for biological carbohydrates biomarkers, which universally contain six-membered ring and liner diols.
Aptamer provides another alternative way for sensors development for carbohydrates biomarkers as lectin mimics. Compared to lectins, they are normally cheaper and more stable. However, there is much less options. Another challenging area for aptamer-based lectin mimics development is the difficulty to differentiate changes in glycosylation patterns of a glycoprotein, which affect the function of a glycoprotein and thus recognized as biomarkers. To address this major challenge, our group first demonstrated that the incorporation of a boronic acid into DNA would allow for the aptamer selection process to gravitate towards the glycosylation site. To examine the generality of boronic acid incorporation, increase the structural diversity, and broaden the application of boronic acid-modified DNA, a series of B-TTP analogues with simplified structures were designed, synthesized, and successfully incorporated into DNA. A simple route was also developed using 1,7-octadiyne as a linker for both Sonogashira coupling with thymidine and CuAAC tethering of a boronic acid moiety. This paves the way for the preparation of a large number of B-TTPs with different structural features for aptamer selection or array analysis.
Finally, bacterial quorum sensing has received much attention in recent years because of its relevance to pathological events such as biofilm formation. As one of the very first groups that developed a series of antagonists for AI-2 mediated quorum sensing, we herein designed and synthesized a series of analogues based on the structures of two lead inhibitors identified through virtual screening. Besides, we also examined their inhibitory activities, twelve of which showed equal or better inhibitory activities compared with the lead inhibitors. The best compound showed an IC50 of about 6 mM in a whole cell assay using Vibrio harveyi as the model organism. This encouraging results and SAR discuss also paves the way for the finding of more potent compound through further structure optimization.
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OLIVARI, MARTINA. « Neutral receptors for anion recognition : synthesis, selectivity studies and transport properties ». Doctoral thesis, Università degli Studi di Cagliari, 2014. http://hdl.handle.net/11584/266429.
Texte intégralRésumé :
This thesis reports the synthesis and studies of a new series of compounds containing urea groups that can function as selective anion receptors and efficient anion transmembrane transporters.
Two new asymmetric ureidic receptors L1 (1-(1H-indol-7-yl)-3- (quinolin-2-yl)urea) and L2 (1-(quinolin-2-yl)-3-(quinolin-8-yl)urea), shown in Figure 1, have been synthesised and their affinity towards different anions tested in DMSO-d6. L1 adopts both in solution and in the solid state an (E,Z) conformation. A moderate affinity for acetate has been observed with L1 while no interaction has been observed with L2. The different behaviour has been ascribed to the presence/absence of the indole group. In the case of L1 the indole group causes the formation of a peculiar supramolecular architecture with two molecules of the receptor binding the anions in (E,Z) conformation via H-bonds. L2 also adopts an (E,Z) conformation in the solid state. However, the absence of the indole in L2 hampers the formation of the supramolecular assembly with the participation of anionic species. The results are discussed in Chapter 2.
In Chapter 3 a new family of bis-ureidic receptors (L3-L8) is reported (Figure 2). The binding properties of L3-L8 towards different anions (acetate, benzoate, glutarate, malonate, dihydrogen phosphate, hydrogen pyrophosphate, triphosphate, AMP and ADP) have been studied by means of 1H-NMR, UV-Vis and fluorescence spectroscopies and a remarkable affinity for HPpi3- has been observed in the case L5 (in DMSO- d6 and DMSO-d6/5% H2O) which also acts as fluorimetric chemosensor, even at naked eye, for this anion. Theoretical calculations helped us to explain the binding properties observed.
A series of bis-ureidic receptor L9-L14 (Figure 3) was prepared and the studies of their transmembrane anion transport activity and anion binding properties are described in Chapter 4. Vesicle anion transport assays using ion selective electrodes demonstrate that these compounds function as efficient mobile carriers that are able to transport chloride through lipid bilayer predominantly via anion exchange mechanism including Cl-/NO3- and Cl-/HCO3- antiport. Compound L14 was found to be the most active transporter of the series. As anion receptors, we observed that compounds L10 and L12 demonstrate strong 1:1 binding with TBA fluoride (Ka >104 M-1) and moderate 1:1 binding with TBA dihydrogenphosphate.
In Chapter 5, the anion transport efficiency of a series of trisureas L15-L20 (Figure 4) was investigated. The compounds showed a potent transmembrane anion transport activity. The mechanism of transport was extensively investigated using a combination ion selective electrode and fluorescence techniques. It was found that compounds L15-L20 mediate chloride transport via Cl-/NO3- and Cl-/HCO3- antiport and NaCl symport. The tris-urea L15 was found to be a remarkably potent anion carrier at low concentration.
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Hubble, Lee John. « Development of carbon nanotube-based gas and vapour sensors and supramolecular chemistry of carbon nano-materials ». University of Western Australia. Centre for Forensic Science, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0191.
Texte intégralRésumé :
[Truncated abstract] The scientific endeavours described within this thesis attempt to create novel solutions to current scientific, commercial and industrial downfalls, and contribute to the advancement of technologies in these areas. This has been achieved through the application of theoretical and experimental principles, entrenched in the domains of chemistry and physics, which have been harnessed to assist in the transformation from nanoscience to nanotechnology. These solutions range from unique supramolecular systems capable of selective-diameter enrichment of single-walled carbon nanotubes (SWCNTs), to the fabrication of low-cost, potentially remote deployable carbon nanotube-based gas and vapour sensors, and expand right through to the development of water-soluble fluoroionophoric sensors and manipulations of a molecular form of carbon in constructing all-carbon nano-architectures. For the advancement and successful integration of carbon nanotubes (CNTs) into commercial processes, the advent of scalable separation protocols based on their electronic properties is required. SWCNTs have been successfully solubilised using water-soluble p-phosphonated calix[n]arenes (n = 4, 6, 8) and 'extended arm' upper rim functionalised (benzyl, phenyl) p-sulfonated calix[8]arenes. Selective SWCNT diameter solubilisation has been demonstrated and subsequent preferential enrichment of SWCNTs with semiconducting or metallic electronic properties has been achieved. In addition, semiconducting nanotube-enriched supernatants (liquid) have been utilised to fabricate on/off field effect transistors (FET). These water-soluble supramolecular systems can be incorporated into post-growth purification protocols, with direct implications in areas such as carbon nano-electronics and device fabrication. In the current global environment there is a heightened level of public and governmental disquiet due to the reality of impending terrorist attacks. This is compounded by the inherent ease of manufacture and effectiveness of specific chemical warfare agents (CWAs) used in small-scale terrorist operations. ... Additional all-carbon structures are described with the formation of rings of helical SWCNT bundles through post-growth SWCNT modifications, and a variety of fibrous all-carbon structures, most notably novel square-geometry carbon nano-fibres (CNFs), through catalytic-chemical vapour deposition (C-CVD) synthesis strategies. The current requirement for entirely water-soluble fluorescent sensors is routinely documented in the literature. The autofluorescence properties of p-phenyl-sulfonated calix[8]arene are characterised and this water-soluble cavitand is surveyed as a metal cation sensor candidate. This particular system was found to exhibit a change in fluorescence response when exposed to divalent metal cations, and interactions with [UO2]2+, Pb2+, Co2+, and Cu2+ ions are discussed in detail. The system is characterised through a variety of analytical techniques to yield sensor calibration data, degradation characteristics, pH sensitivity and suitability as a 'small molecule' drug-carrier.
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Santos, Figueroa Luis Enrique. « New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest ». Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/43216.
Texte intégralRésumé :
El presente proyecto de investigación está enfocado al desarrollo de sensores químicos fluoro-cromogénicos, para la detección y determinación de especies químicas de interés biológico, industrial y medioambiental de forma selectiva y con alta sensibilidad.
En forma general, se busca el diseñar nuevos sistemas sensores basados en compuestos (receptores) formados por dos unidades: una unidad coordinante que interacciona con el anión a determinar y una unidad generadora de señal que alerta del reconocimiento molecular efectuado.
Durante este estudio se están preparando diversas moléculas receptoras funcionalizandas con grupos modificadores de estructura para evaluar su influencia sobre las capacidades de detección y selectividad como receptores de especies específicas en diferentes condiciones y medios.
Las diferentes aproximaciones en prueba implican a su vez el diseño y síntesis molecular, así como el análisis de las diferentes señales ópticas producidas en el reconocimiento, con el fin de diseñar sistemas de alta eficacia y eficiencia, y con posibilidades reales de aplicación.Santos Figueroa, LE. (2014). New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43216
TESIS
Premiado
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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.
Texte intégralRésumé :
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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BARTOLI, FRANCESCO. « SYNTHESIS OF NEW POLYAMINE RECEPTORS AND THEIR METAL COMPLEXES AS FLUORESCENCE CHEMOSENSORS FOR ANIONS ». Doctoral thesis, 2015. http://hdl.handle.net/2158/1054958.
Texte intégralRésumé :
This project will be devoted to design and synthesis of new fluorescence molecular
sensors (chemosensors) for anions in aqueous solution. The targeted species will be
inorganic anions of environmental importance, such as halides, phosphates, nitrates,
arsenate, etc., or biological substrates having anionic or easy ionizable functions,
such as aliphatic and aromatic carboxylic acids, nucleosides and nucleotides. In this
respect, we will synthesize new fluorescent polyamine systems, whose protonated
forms can be able to bind anions in water, as well as their metal complexes. Both
polyammonium and metal based receptors will be tested as selective binding and
signaling agents for anionic substrates; this aim is reached when the coordination of
the guest changes the fluorescence emission properties of the chemosensor.
Selective binding can be achieved by synthesizing receptors containing suitably
constructed cleft or cavities to host the anion, in order to maximize the receptoranion
interaction.
In the course of the development of new metal-based chemosensors for anions, we
have in particular investigated the fluorescence emission properties of Zn(II)
complexes, whose ability to adapt its coordination environment to bind exogenous
substrates is well known. This has lead to the synthesis and characterization of
selective fluorescence chemosensors for the recognition of the ion Zn(II). This goal
may be also of relevance. Zinc(II) is in fact an essential trace element in all forms of
life. Despite its crucial importance in the basic functions maintenance such as
proliferation and cell growth, the knowledge of the biological mechanisms
involving Zn(II) at a cellular and sub-cellular level are not completely clarified and
Zn(II) chemosensors may represent new efficient tools for the analysis of its role in
biological processes.
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Chang, Wei-Chih, et 張惟智. « Polyethoxy Salicylideneimines as Fluorescence Chemosensors : Design, Synthesis and Sensing in Different Solvent Media ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/90208340860561831140.
Texte intégralRésumé :
碩士國立暨南國際大學
應用化學系
102
Two new fluorescence chemosensors, 1,4-Bis(2-(2-(2-(3,5-di-tert-butyl-salicyald-2-imine)phenoxy)ethoxy)ethoxy)ethoxy)benzene ( named as compound DT ) and 1,4-Bis(2-(2-(2-(3,5-dichloro-salicyald-2-imine)phenoxy)ethoxy)ethoxy)ethoxy)benzene ( named as compound DC ) hereafter, containing polyethoxy chain and salicyaldimine moiety has been designed and synthesized. The cation recognition abilities of DT and DC toward various cations ( Li+, Na+, K+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Ag+, Al3+, Cd2+, Co2+, Cr3+, Cu2+, Mn2+, Ni2+, Pb2+ and Zn2+ ) in different solvent media have been examined by UV-Vis and fluorescence spectroscopies. In methanol and 10 mM HEPES media, sensors DT and DC also showed ″Off-On″ fluorescence signaling behavior when interacted with Zn2+ ion. (I) Methanol as media: According to the competitive studies, in the DT-Zn system, Zn2+ ion would be replaced by Al3+, Cr3+, Cu2+ and Pb2+ ions while in the DC-Zn system, Zn2+ ion would be replaced by Co2+, Cr3+, Cu2+, Ni2+ and Pb2+ ions, as observations of absorption change in the UV-vis spectra and fluorescence quenching in the fluorescence spectra. Interestingly, when adding Ba2+ ion into the solution of DT-Zn system and adding Al3+ ion into the solution of DC-Zn system, the fluorescence intensity for both systems are enhanced, signifying noticeable co-operative effect and substitution effect, respectively. On the basis of titration and Job′s plot, sensors DT and DC bind with Zn2+ both in a 2:3 stoichiometry. (II) 10 mM HEPES as media: Sensors DT and DC recognize only the Zn2+ ion. No other metal ion can replace Zn2+ ion in the DT-Zn and DC-Zn complexes.
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Chen, Chun-Lin, et 陳群霖. « Colorimetric and Ratiometric Fluorescent Chemosensors for Anions ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/40360733737680328712.
Texte intégralRésumé :
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, et 劉浩敏. « Selective Turn-on Fluorescent Chemosensors for Zn2+ ». Thesis, 2012. http://ndltd.ncl.edu.tw/handle/83548961019625517788.
Texte intégralRésumé :
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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Huang, Tien-Peng, et 黃天鵬. « Syntheses of Novel Fluorescent Chemosensor： Bis-crown-distyryl naphthalene 6,7,8 and fluorescence changes after chelated with sodium、potassium ions ». Thesis, 2002. http://ndltd.ncl.edu.tw/handle/95999521608566585668.
Texte intégral
46
GUO, Chao-Ci, et 郭朝其. « The Synthesis of glycosidase inhibitors and fluorescent chemosensors derivatives ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/58171484089769612463.
Texte intégralRésumé :
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.
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Chen, Chan-Yu, et 陳瞻佑. « Cooperation Chromogenic and Fluorescent Chemosensors for Fluoride and Related Anion ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/46452122000099815432.
Texte intégralRésumé :
碩士國立中央大學
化學研究所
94
We have designed and synthesized two chromogenic and fluorescent chemosensors S1 and S2, which provide hydrazine and hyrdazone groups to form hydrogen bonding interactions with various anions. Through the variations of UV-Vis absorption and fluorescent spectra, the sensing mechanism of compounds S1 and S2 with a variety of anion including F-, Cl- , Br- , I- , CN- , OAc- , and H2PO4- are systematically investigated. According to the results of UV-Vis absorption changes and fluorescence quenching, the binding strength of chemosensors S1 and S2 to different anions can be depicted in the following order: F- > CN- > OAc- > H2PO4- > Cl- > Br-~I-. Due to the electron-withdrawing nature of hydroxyl groups in S1, the hydrogen bonding between hydrazine/hydrazone and anions is stronger compared to S2. Furthermore, Job plots revealed that both sensors S1 and S2 react with anions in a 1:1 stoichiometry. On the other hand, the characteristic band for the excimer could be found from the fluorescent spectra of S1 titrated with F- or CN- . On the basis of these evidences We propose the formation of a [2+2] associated dimer complex via hydrazine/hydrazone-anion hydrogen bonding and ��-�� stacking interaction. The Hill plots and Scatchard plots further confirmed that a [2+2] complex composed of sensor S1 and F- , or CN- formed under the positive coopreativity. In light of obtained information, we propose the stepwise formation mechanism for the interaction between sensor S1 and F- or CN-. Sensor S1 initially form a [2+1] complex with anion followed by a fast dimerization to form the [2+2] associated dimer complex. Moreover, in the case of F-, addition of excess F- could deprotonate the hydroxyl group and generate negative charged [2+2] dimer which disassemble into individual monomer due to the charge repulsion.
48
Chou, Yu-Shan, et 周郁姍. « Synthesis and Fluorescence Chemosensory Properties of Conjugated Polyfluorenes Containing Diketopyrrolopyrrole Moieties ». Thesis, 2016. http://ndltd.ncl.edu.tw/handle/74218118865057352375.
Texte intégralRésumé :
碩士元智大學
化學工程與材料科學學系
104
This study describes the synthesis of conjugated polyfluorene (PF) and conjugated polymer (PFDPP) containing diketopyrrolopyrrole (DPP) groups in the main chain, through Suzuki coupling polymerization. The weight-average molecular weights of PF and PFDPP were 2.18 × 104 and 0.74 × 104 g/mol, with the corresponding polydispersity indices being 2.01 and 1. 47, respectively. PF and PFDPP exhibited the strong UV-vis absorption bands at 380 and 489 nm in the THF solution, respectively. The absorption band of PFDPP was red-shifted by approximately 109 nm relative to PF (380 nm). This red-shift was attributed to the electronic transitions in PFDPP that involved the migration of electron density from fluorene donor groups towards the DPP acceptor, resulting in the observed ICT interactions and bathochromic shifts. PF and PFDPP showed the strong emission bands at 416 nm and 547 nm in THF solution. Photoluminescence titrations demonstrated that PFDPP exhibited high sensitivity towards Fe3+ and F- ion, with Stern-Volmer constants (Ksvs) of 1.58 × 104 M-1 and 1.07 × 103 M-1, respectively. The detection limit (LOD) towards Fe3+ and F- ion was as low as 4.90 × 10-6 M and 1.34 × 10-5 M, respectively. PFDPP showed fluorescence quenching in the pH value of 7~13. The estimated HOMO and LUMO energy levels for PFDPP were –5.70 and –3.46 eV, respectively. These results demonstrated that PFDPP is a promising material for application of sensing cations, anions and pH values.
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Walkup, Grant Kingsley. « Fluorescent peptidyl chemosensors for the measurement of divalent metal cation concentrations ». Thesis, 1998. https://thesis.library.caltech.edu/7279/2/Walkup_kg_1998.pdf.
Texte intégralRésumé :
Studies toward the production of fluorescent chemosensors for trace divalent metal ions have been conducted, with emphasis placed on the attainment of sufficient analyte selectivity and sensitivity for the measurement of environmental or biomedical samples. One technique that has historically been applied for the design of selective metal ion sensors is to prepare biosensors, devices that exploit proteins for their unmatched specificity in the recognition of small molecules. Alternately, the construction of abiotic chemosensors has been favored by other researchers, but the synthetic simplicity and enhanced durability exhibited by these agents comes at the expense of analyte-detection selectivity. By applying a strategy that is a hybrid of these approaches, selective and sensitive chemosensors for divalent zinc, copper, and nickel have been prepared. These devices combine the advantageous aspects of biosensors within a peptidyl architecture that by virtue of its synthetic origin contains an expanded repertoire of amino acids for metal ion binding and signaling.
Fluorescent chemosensors for Zn(II) have been prepared that are based upon the zinc finger domains and enable the quantitation of sub-micromolar concentrations of that ion in the presence of many other divalent ions. In addition, other fluorosensors have been prepared that employ nonnatural alpha-amino acid derivatives that contain the bidentate metal binding functionality of oxine (8-hydroxyquinoline). These also enable the selective detection of sub-micromolar concentrations of Zn(II), but require only seven amino acid residues as opposed to the 25 present in the zinc finger-based sensors.
By exploiting the metal binding properties of the amino terminal Cu(II)- and Ni(II)-binding (ATCUN) motif of the serum albumins, sensors have been prepared which enable the selective determination of sub-micromolar concentrations of the Cu(II) ion, even in the presence of elevated concentrations of Ni(II). Sensors for Ni(II) that employ a fluorescence resonance energy transer (FRET) mechanism for analyte detection have also been prepared. In addition, studies have been performed to convert these solution based chemosensing reagents into solid phase-attached devices, in order to perform realtime measurements with regenerable sensing materials.
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Tsou, Chia-Chen, et 鄒佳臻. « N,N’-diphenylpyridine-2,6-dicarboxamide-based fluorescent chemosensors for sensing anions ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/62497002187402959260.
Texte intégralRésumé :
碩士國立中央大學
化學研究所
93
Two N,N’-diphenylpyridine-2,6-dicarboxamide-based fluorescent chemosensors M1 and M2 were designed and synthesized for sensing anions. The binding affinity of M1 and M2 toward various anions was investigated by UV-Vis and fluorescence spectroscopy. Several anions were surveyed in this research, including hydrogen phosphate, pyrophosphate, halides, cyanide, nitrate, hydrogen sulfate and acetate. Notably, both M1 and M2 are particularly sensitive to anions with tetrahedron geometry, i.e. pyrophosphate and hydrogen phosphate. In general, binding constants of these two anions are higher than other anions with different geometries. The 1:1 binding ratio of the chemosensor-anion complex was determined by Job-plot. A blueshift in fluorescence spectra of M1 and M2 were observed upon titration of with fluoride, pyrophosphate and hydrogen phosphate. It is believed that blueshift was induced by raising the LUMO with the formation of hydrogen bonds between the anions and amide hydrogens. In addition, M2 formed gel-like structure in certain solvents. Some tubular structures were constructed after solvent evaporation, which could be observed by microscopes. The study of the nature and properties of the gel is under progress.