Bibliografías temáticas / Chromophores Push-Pull

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Literatura académica sobre el tema "Chromophores Push-Pull"

Autor: Grafiati
Publicado: 25 de mayo de 2024

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Artículos de revistas sobre el tema "Chromophores Push-Pull"

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Kato, Shin-ichiro y François Diederich. "Non-planar push–pull chromophores". Chemical Communications 46, n.º 12 (2010): 1994. http://dx.doi.org/10.1039/b926601a.

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Gupta, Vinod Kumar y Ram Adhar Singh. "An investigation on single crystal growth, structural, thermal and optical properties of a series of organic D–π–A push–pull materials". RSC Advances 5, n.º 48 (2015): 38591–600. http://dx.doi.org/10.1039/c5ra04907e.

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We present the large single crystal growth of a series of donor–π–acceptor (D–π–A) push–pull chromophores (1–4). The thermal, structural and optical properties of the synthesized chromophores were explored. These studies indicate the potential opto-electronic application of these push–pull chromophores.
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3

Eom, Taejun y Anzar Khan. "Push-pull azobenzene chromophores with negative halochromism". Dyes and Pigments 188 (abril de 2021): 109197. http://dx.doi.org/10.1016/j.dyepig.2021.109197.

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Coluccini, Carmine, Pierangelo Metrangolo, Marco Parachini, Dario Pasini, Giuseppe Resnati y Pierpaolo Righetti. "“Push-pull” supramolecular chromophores supported on cyclopolymers". Journal of Polymer Science Part A: Polymer Chemistry 46, n.º 15 (1 de agosto de 2008): 5202–13. http://dx.doi.org/10.1002/pola.22848.

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Kato, Shin-ichiro y Francois Diederich. "ChemInform Abstract: Non-Planar Push-Pull Chromophores". ChemInform 41, n.º 25 (22 de junio de 2010): no. http://dx.doi.org/10.1002/chin.201025206.

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Yamada, Michio. "Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes". Beilstein Journal of Organic Chemistry 20 (22 de enero de 2024): 125–54. http://dx.doi.org/10.3762/bjoc.20.13.

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Various push–pull chromophores can be synthesized in a single and atom-economical step through [2 + 2] cycloaddition–retroelectrocyclization (CA–RE) reactions involving diverse electron-rich alkynes and electron-deficient alkenes. In this review, a comprehensive investigation of the recent and noteworthy advancements in the research on push–pull chromophores prepared via the [2 + 2] CA–RE reaction is conducted. In particular, an overview of the physicochemical properties of the family of these compounds that have been investigated is provided to clarify their potential for future applications.
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Labrunie, Antoine, Pierre Josse, Sylvie Dabos-Seignon, Philippe Blanchard y Clément Cabanetos. "Pentaerythritol based push–pull tetramers for organic photovoltaics". Sustainable Energy & Fuels 1, n.º 9 (2017): 1921–27. http://dx.doi.org/10.1039/c7se00345e.

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We report herein the synthesis, characterization and preliminary evaluation of two simple tetramers based on the functionalization of a central pentaerythritol σ-linker with push–pull chromophores as molecular donor for organic photovoltaics.
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Lepetit, Christine, Pascal G. Lacroix, Viviane Peyrou, Catherine Saccavini y Remi Chauvin. "Hyperpolarizability of novel carbo-meric push-pull chromophores". Journal of Computational Methods in Sciences and Engineering 4, n.º 4 (22 de diciembre de 2004): 569–88. http://dx.doi.org/10.3233/jcm-2004-4404.

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Breiten, Benjamin, Ivan Biaggio y François Diederich. "Nonplanar Push–Pull Chromophores for Opto-Electronic Applications". CHIMIA International Journal for Chemistry 64, n.º 6 (30 de junio de 2010): 409–13. http://dx.doi.org/10.2533/chimia.2010.409.

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Abbotto, A., L. Beverina, R. Bozio, S. Bradamante, C. Ferrante, G. A. Pagani y R. Signorini. "Push-Pull Organic Chromophores for Frequency-Upconverted Lasing". Advanced Materials 12, n.º 24 (diciembre de 2000): 1963–67. http://dx.doi.org/10.1002/1521-4095(200012)12:24<1963::aid-adma1963>3.0.co;2-s.

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Tesis sobre el tema "Chromophores Push-Pull"

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Winterfeld, Kim Alisa [Verfasser], Dirk M. [Akademischer Betreuer] Guldi y Dirk M. [Gutachter] Guldi. "Electronic Interplay between Porphyrinoids and Push-Pull Chromophores / Kim Alisa Winterfeld ; Gutachter: Dirk M. Guldi ; Betreuer: Dirk M. Guldi". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2020. http://d-nb.info/1213979234/34.

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Hebbar, Nordine. "Synthèse de chromophores ONL à base de pyrazine et de systèmes hexatriéniques : applications potentielles en optique non linéraire (ONL)". Rouen, 2008. http://www.theses.fr/2008ROUES060.

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Cette thèse décrit la synthèse de nouveaux chromophores susceptibles de présenter des propriétés optiques non linéaires. En utilisant des voies de synthèse originales alliant des réactions de métallation et couplage croisé, nous avons préparé de nombreux dérivés comportant un cycle π-déficitaire (chloropyrazine) substitué par un ou deux systèmes polyéniques porteurs de groupements électro-attracteurs ou donneurs. Ces composés de structures linéaires de type push-pull, permettent un transfert électronique entre le cycle pyrazinique pauvre en électrons et les groupements donneurs d’électrons, l’enchaînement triénique assurant le transfert électronique par une extension de la conjugaison. L’influence de la nature du système insaturé a également été testée en remplaçant un enchaînement triénique par une triple liaison. Des composés comportant un cœur 2,2¢-bipyrazine (susceptible d’induire des complexations de métaux) substitué par des enchaînements hexatriéniques ont été synthétisés, des structures symétriques et dissymétriques ont pu ainsi être obtenues
This thesis work describes the synthesis of new linear chromophores with potential applications in non linear optic. Various original synthetic ways using metalation and cross-coupling reactions allowed to access to numerous compounds with a π-deficient ring (chloropyrazine) substituted with one or two conjugated polyenic chains bearing donor- or withdrawing electron groups. These linear compounds with a push-pull character have a conjugated backbone allowing an important internal electronic charge transfer between the π-deficient pyrazine ring and the electron-donors groups through the hexatrienic chains. The influence of the nature of the multiple bond on the conjugation has been studied by replacement of a double bond by an alkyne linkage. New compounds with a 2,2¢-bipyrazine core, able to induce metal coordination, have been also synthesized. Symmetrical or dissymmetrical structures have been obtained by substitution of the 5 and 5¢ positions by identical or different conjugated polyenic chains
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Guerboukha, Mohamed-Amine. "Etude de l'auto-assemblage et des propriétés électroniques de monocouches moléculaires sur germanium". Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0020.

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Dans le domaine de la microélectronique, en raison de la mobilité intrinsèque élevée de ses porteurs de charge, le Ge apparaît comme un matériau alternatif prometteur pour remplacer le Si dans la prochaine génération de transistors à haute mobilité et à haute fréquence. Cependant, contrairement au dioxyde de silicium, l’oxyde de germanium n’est ni stable ni de bonne qualité. Ainsi la préparation de couches interfaciales permettant de passiver le Ge est nécessaire mais reste à ce jour encore problématique. Une voie prometteuse consiste à utiliser des SAM avec une constante diélectrique élevée. Au cours de ce travail nous nous sommes attachés à réaliser et caractériser de nouvelles SAMs à base d’organothiols greffés sur Ge, présentant une application potentielle comme isolants de grille. Nous avons utilisé des chaînes alkyles et des chromophores push-pull originaux. Nous avons adapté et mis au point la technique de désoxydation/greffage et montré qu’elle donne de meilleurs résultats que le traitement acide généralement utilisé. Cette méthode nous a en effet permis d’obtenir des surfaces de Ge fonctionnalisé moins rugueuses avec des SAMs bien organisées. Les analyses par XPS et FTIR démontrent l’élimination de l’oxyde du Ge. Nous avons mesuré les caractéristiques I-V des différentes SAMs à l'aide de contacts E-GaIn. Avec les PP, nous avons pu diminuer le courant d’un facteur 105 comparé au Ge, et 104 par rapport à l’alkyle. L’analyse statistique des caractéristiques électriques a été menée par spectroscopie de tension de transition, et corrélée avec niveaux moléculaires par IPES pour les niveaux inoccupés, la détermination des niveaux occupés par XPS, et calculs DFT
In the field of microelectronics, due to its high intrinsic carrier mobility, germanium (Ge) is emerging as a promising alternative material to replace silicon in the next generation of high-mobility and high-frequency transistors. However, unlike silicon dioxide, Ge oxide is neither stable nor of good quality. Thus, the preparation of interfacial layers to passivate and isolate Ge is necessary but still problematic. A promising approach is the use of SAMs with a high dielectric constant. In this perspective, during this work we have focused on the preparation and characterization of new SAMs based on organothiols grafted on Ge, exhibiting potential application as grid insulators. We have used hydro- and fluoro-carbonated alkyl chains, and novel bithiophene-based non-charged push-pull chromophores (PP) specially synthesized with the motivation to prepare layers with high dielectric constants by the presence of dipoles. We have adapted and developed the deoxidation/grafting technique in hydro-alcoholic solution and shown that it provides better results than the acid treatment. Indeed, such method has allowed us to obtain less rough functionalized Ge surfaces. XPS and FTIR analyses demonstrate the removal of oxide. We have measured I-V characteristics of the various SAMs using E-GaIn contacts. PP SAMs have allowed to decrease the current by a factor of 105 compared to Ge and of 104 compared to a twelve carbon atoms alkyl SAM. Statistical analyses of the electrical characteristics have been performed using TVS, and correlated with molecular levels, using IPES for probing the unoccupied levels, determination of the valence band occupied levels by XPS, and DFT calculations
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Novoa, Serrano Néstor-Alonso. "Complexes asymétriques de NiII et CuII à ligands base de Schiff tridentates ONO, précurseurs de nouveaux adduits dipolaires push-pull : étude de leurs propriétés optiques non linéaires du second ordre (ONL-2)". Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S018/document.

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Les précurseurs de ligands base de Schiff électro-donneurs et électro-accepteurs R-ONOH₂ sont préparés par réaction de monocondensation entre les β-dicétones appropriées et respectivement le 1,2- et le 1,2-4-nitro-aminophénol. Ils existent exclusivement sous leurs formes tautomériques céto-énamine en solution et à l'état solide. Dans les complexes correspondants de NiII et de CuII, le métal adopte une géométrie plan carré et est coordiné par les atomes d'azote et d'oxygène du ligand dianionique tridentate et par l'azote du coligand pyridine. L'hyperpolarisabilité quadratique, déterminée par la technique DHL est très élevée. La substitution de la pyridine par la 4,4'-bipyridine conduit systématiquement aux complexes dimériques correspondants. Un composé similaire comportant l'espaceur bis(4-pyridyle)acétylène est formé après réaction de couplage croisé de Sonogashira. Cette même réaction de couplage croisé entre les blocs de construction électrodonneurs et électro-accepteur permettent de préparer le système «push-pull» D-π-A désiré. Les réponses ONL du second ordre des complexes contenant le ligand électro-actif methylène-pyrane peuvent être modulées par bi- (R = An) et tétra- (R = Fc) oxydation réversible avec formation/rupture d'une liaison C-C, constituant ainsi un nouvel exemple de commutateur ONL-2 réversible
Electron donating and electron withdrawing ligand precursors R-ONOH₂ were prepared by monocondensation reaction of the appropriate β-diketones and 1,2- and 1,2-4-nitro-aminophenol, respectively. They do exclusively exist as their enaminone tautomeric form both in solid-state and in solution phase. In their corresponding Schiff base complexes of NiII and CuII, the central metal is tetracoordinated in a square-planar environment. The coordination sphere is formed by the nitrogen and oxygen atoms of the dianionic tridentate ligand and the fourth coordination site is occupied by the nitrogen atom of the pyridine co-ligand. The derivative exhibited a high quadratic hyperpolarizability (β1.91) determined by the HLS technique. Substitution of 4,4’-bipyridine for pyridine invariably leads to the formation of the respective dimers [(R-ONO)MII(4,4’-bipy)MII(ONO-R)]. A similar compound having the bis(4-pyridyle)acetylene as spacer was formed upon cross-coupling Sonogashira reaction with ethynylpyridine chlorhydrate. The same cross-coupling reaction carried out between the electron releasing and electron withdrawing building blocks, respectively, allowed the preparation of the expected «push-pull» D-π-A system. The second-order NLO responses of compounds bearing a redox active methylenepyran ligand can be modulated upon reversible bi- (R = An) and tetra- (R = Fc) oxydation involving C-C bond formation/breaking reactions, thus forming a new class of NLO molecular switches
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Bhatambrekar, Nishant. "Realizing a fractional volt half-wave voltage in Mach-Zehnder modulators using a DC biased push-pull method and synthesis and characterization of indole based NLO chromophores for improving electro-optic activity /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/11606.

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Oehlke, Alexander. "Chromophore Arylboronsäureester und ihr Komplexbildungsverhalten gegenüber Lewis-Basen". Doctoral thesis, Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-63088.

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Die vorliegende Arbeit hat die Synthese und Charakterisierung von chromophoren Arylboronsäureestern mit besonderem Augenmerk auf einer breiten strukturellen Variation zum Inhalt. An dieser Verbindungsklasse wird die Wechselwirkung mit Lewis-Basen tiefgehend untersucht. Die Koordination von Lewis-Basen am Bor-Atom führt zu einer Beeinflussung der elektronischen Eigenschaften des borbasierten Substituenten, wobei der Charakter eines direkt am Bor-Atom gebundenen pi-Elektronensystems von pull zu push-pull geschaltet werden kann. In der vorliegenden Arbeit wird beschrieben, wie geometrische und elektronische Strukturmerkmale von boronsäureesterfunktionalisierten Chromophoren durch die Lewis-Säure-Base-Wechselwirkung am Bor-Atom beeinflusst werden. Die Veränderung von molekularen Eigenschaften wird mit Hilfe der UV/vis-Absorptions- und Fluoreszenzspektroskopie, 1H- und 11B-NMR-Spektroskopie sowie mit röntgendiffraktometrischen Methoden untersucht. Die experimentellen Daten werden durch quantenchemische Berechnungen auf DFT-Niveau unterstützt.
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Vergote, Thomas. "Synthèse de générateurs de photoacides activables par absorption biphotonique pour la microfabrication à trois dimensions". Thesis, Mulhouse, 2014. http://www.theses.fr/2014MULH7514.

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Depuis les années 60, la génération d’acide fort de Brönsted par un processus photoinduit à un photon est utilisée dans des nombreux domaines de recherche de plus en plus nombreux. Cependant, de tels acides peuvent-être facilement obtenus par voie biphotonique ce qui présente de nombreux avantages comme par exemple : une meilleure réactivité via une excitation direct du photoacide, l’utilisation possible d’une atmosphère non contrôlée, l’utilisation de microlasers à impulsions sub-nanosecondes peu couteux, mais aussi l’augmentation de la résolution spatiale des micro-objets 3D fabriqués. La génération d’acide se fait généralement par transfert d’électron entre un sensibilisateur et un générateur de photoacide (PAG). Une approche prometteuse consiste à associer, sur une même molécule, un PAG et un chromophore actif à deux photons. Il a donc semblé intéressant de développer de nouveaux PAG capables, par excitation biphotonique, d’amorcer directement la photopolymérisation. Nous avons choisi de préparer des systèmes capto-datifs stilbéniques, de nature neutre ou ionique. Aussi, une série de PAG neutres substitués par des groupements diphénylamino- donneur et iminosulfonates -cyanés accepteurs a été synthétisée. Nous avons également commencé, mais non achevé, la synthèse de PAG neutres portant des groupements iminosulfonates -trifluorométhylés. Puis, nous avons cherché à synthétiser des PAG ioniques substitués soit par un groupement éthoxy soit par un groupement diphénylamino soit par un groupement julolidine. Néanmoins, la dernière étape de la synthèse est pour l’instant un verrou synthétique
Since the 60’s, the generation of strong Brönsted acids by a one-proton photoinduced process has been used in more and more research areas. Recently, it has been shown, that such acids are easily obtained by a two-photon process. This offers many advantages such as: i) a better reactivity owing to a direct excitation of the photoacid, ii) the possible use of a non-controlled atmosphere, iii) the use of inexpensive microlasers with sub-nanosecond impulsions, iv) the increase of spatial resolution in 3D microfabrication. The acid generation generally proceeds through a photo-induced electro transfer from an excited sensitizer to the photoacid generator (PAG). A promising approach should be the introduction on a single molecule of both a PAG and a two-photon active chromophore moiety. In this context, we have developed new PAGs able to initiate photopolymerisation through a two-photon activation process. The syntheses were focused on stilbenic push-pull systems having either a neutral or an ionic nature. A series of neutral PAGs bearing a diphenylamino donor group and an α-cyano iminosulfonate acceptor moiety has been synthesized. The preparation of neutral PAGs bearing iminosulfonate α-trifluoromethylated groups were not yet completed. The syntheses of ionic PAGs substituted by an ethoxy group, a diphenylamino group or a julolidine one, could not be completed either
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Challa, Jagannadha Reddy. "Electronic and Vibrational Dynamics of Heme Model Compounds-An Ultrafast Spectroscopic Study". Case Western Reserve University School of Graduate Studies / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=case1181323422.

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Massin, Julien. "Ingénierie moléculaire pour l'imagerie par microscopie non-linéaire : synthèse et propriétés de nouvelles sondes". Thesis, Lyon, École normale supérieure, 2011. http://www.theses.fr/2011ENSL0701.

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L’objectif de cette thèse est l’élaboration de sondes organiques pour la microscopie optique non-linéaire par fluorescence excitée à deux photons (F2P) et génération de seconde harmonique (GSH). Dans une première partie, cette thèse décrit la synthèse de sondes pour l’imagerie de potentiels de membrane par GSH, comportant un ou plusieurs motifs sucres ainsi que leurs caractérisations spectroscopiques. Les premiers essais en imagerie biologique ont permis de démontrer une bonne affinité des sondes sucres pour la membrane cellulaire et un signal de GSH sur cellule neuronale a pu être observé sur une période de temps allant jusqu'à près de trois heures. La seconde approche a consisté à synthétiser et étudier des chromophores possédant des propriétés de fluorescence à l’état solide pour des applications dans la synthèse de nanoparticules fluorescentes pour l’imagerie biologique. 18 des 21 composés synthétisés ont pu être cristallisés et leur structure résolue par diffraction des rayons X et les propriétés spectroscopique en solution et à l’état solide ont été réalisées. Cette étude a permis de montrer que l’arrangement des molécules les unes par rapport aux autres avait une grande influence sur la fluorescence à l’état solide et donc que les substituants avaient une grande importance. Enfin, cette partie se termine sur les premiers essais effectués pour synthétiser des nanoparticules fluorescentes
The objective of this thesis is the design of new organic probes for nonlinear optical microscopy by two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). In the first part, we describe the synthesis of probes for voltage sensitive imaging by SHG, bearing one or more sugar units and their spectroscopic characterization. The first biological imaging tests have shown good affinity of the probes to the cell membrane and the SHG signal of neuronal cell was observed over a period of nearly three hours. The second part comprises the synthesis and the study of chromophores with solid state fluorescence properties for use in fluorescent nanoparticles for biological imaging. 18 of the 21 compounds synthesized have been crystallized, their crystal structures determined by X-ray diffraction and their spectroscopic properties studied in solution and in the solid state. These studies showed that the arrangement of molecules relative to each had a great influence on the solid state fluorescence and therefore that the substitution was very important. The chapter ends with the first tests of fluorescent nanoparticles synthesis
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Tripathy, Madhusmita. "Donor-π-acceptor based push-pull organic chromophores: chemosensing applications through modulation in intramolecular charge transfer". Thesis, 2021. http://ethesis.nitrkl.ac.in/10279/1/2021_PhD_MTripathy_514CY3005_Donor.pdf.

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Sensing of various targeted analytes including cations, anions and neutral molecules both qualitatively and quantitatively has been receiving growing attention amongst scientist working in diverse areas viz. environmental science, chemical and biochemical science, agricultural science, food processing, medicinal chemistry, pharmacy and health sciences. Several small cations and anions are functionally connected to a wide range of bio-chemical processes within organisms and in the external environment. Further, some small ions are also highly toxic to organisms bringing biological malfunction when present above their permissible limit. Consequently, early detection of these analytes is advantageous and of great concern to the scientific community. Compared to classical methods for ion detection, chemosensors and especially optical chemosensors (including fluorescent and colourimetric chemosensors) demonstrate many advantages, such as easy and visual detection, high sensitivity, low background interference, and convenient applications in bio-imaging. Investigation of naked-eye colour change and change in UV-Vis absorption and fluorescence spectral behavior of chromogenic and fluorogenic receptors are the most versatile and simple means of analyzing molecular recognition. Among several chromogenic and fluorogenic chemosensors, compounds with Donor--Acceptor (D-π-A) push-pull molecular systems with inherent intramolecular charge transfer (ICT) character are gaining wide interest. The combination of a dipolar D--A signaling moiety with a polar ion recognition unit tends to increase the aqueous solubility of an organic chromophore, which is an essential property of a chemosensors for environmentally and biologically important ions. Presence of ICT may also possibly make them chromogenic and fluorogenic dual responsive chemosensors and provide diverse optical signals favorable for simultaneous detection of multiple analytes. Although a large number of studies on optical chemosensors are found in the literature, the efficacy of most of these sensors is inadequate because of factors such as complex synthetic procedures, strong interferences, feeble sensitivity and low aqueous solubility. Further challenges for chemosensors are to make the transition from research tools into practically useful portable systems for on-site real time qualitative and quantitative detection of required analyte. It is difficult to make predictions regarding selective interaction between the species of interest (analyte) and receptors in a particular medium when several interfering species are present. Multifaceted behaviour is often observed as a function of receptor structures, mode of binding, mechanism of optical response, medium composition, presence of interfering ions (if any). Therefore, comprehensive investigations are usually required to fully understand the sensing mechanism, to test the feasibility of a particular chemosensor for a specific analyte, and to utilize their potentials to fabricate efficient dual-responsive chromo-fluorogenic chemosensors for specific applications. Owing to the importance of D-π-A push-pull molecular systems to act both as chromogenic and fluorogenic dual-responsive chemosensors, and the fact that structurally different probes can unveil different aspects of receptor-analyte interactions in aqueous and semi-aqueous solvent systems, the present dissertation entitled “Donor--Acceptor Based Push-Pull Organic Chromophores: Chemosensing Applications through Modulation in Intramolecular Charge Transfer” aims at employing three different simple D-π-A push-pull dipolar chromophores, namely: (E)-4-(4-N,N-bis-(2-hydroxyethylthioethylamino)styryl)-1-methylpyridinium iodide (L1), 2-hydroxy-5-((4-nitrophenyl)diazenyl)benzaldehyde (L2), and N-((4-N,N-diethylamino)-2-hydroxybenzylidene) isonicotinohydrazide (L3) containing cyanine dye, azo dye and hydrazide Schiff base respectively as chromophores. These chromophores are proposed to transduce the event of molecular recognition of metal ions and anions to an readable optical signal. In this thesis attempt has been made to propose possible binding mode and mechanism of signal transduction based on experimental studies as well as theoretical calculations. The designed D-π-A chromophores are synthesized in good yields and purified by simple procedures. These chromophores are found to be either soluble in pure aqueous or water-rich aqueous-organic binary solvent mixtures and are appropriate for sensing within environmental and biological samples. These chromophores exhibit very intense ICT absorption bands in the visible region. Further, these molecules are found to be weakly fluorescent, assigned to photo electron transfer (PET) due to the presence of non-bonding electrons. However this property became an advantage, as it facilitated a turn-on fluorescence response upon binding to the metal centre; the mechanism of which is believed to be chelation enhanced fluorescence (CHEF) through inhibition of PET. Selective ion recognition by these chemosensors is monitored through investigation of naked-eye colour change and a change in UV-Vis absorption and fluorescence spectral behaviour. Styrylpyridinium (cyanine) dye based D-π-A chromophore (L1), which is attached to a NS2O2 binding unit in its donor site is found to exhibit Hg2+ selective turn-off colourimetric response from orange to colourless. This is accompanied by a turn-on fluorescence response along with a blue shift of emission peak ascribed to the arrest of ICT and PET, through the formation of a conformationally rigid stable 1:1 L1+Hg2+ adduct. Similar Hg2+ selective turn-off colourimetric sensing behaviour is also observed for azo dye based chemosensor (L2) ascribed to the arrest of ICT through the formation of a 1:1 L2-Hg2+ adduct. As expected from the structure of the hydrazide-Schiff base based chemosensor (L3), it demonstrated both cation and anion selective chemosensing behaviour. Out of several metal ions and anions tested, L3 showed a selective response to Al3+ and AsO2-. The obvious colour change of L3 in the presence of these analytes is primarily due to the modulation of ICT upon ion complexation. Conversely, a combined effect of PET, ICT, and excited state intramolecular proton transfer (ESIPT) modulation is proposed to be responsible for prominent fluorescence enhancement. Reversible selective molecular recognition events with turn-on or turn-off optical signal are used to construct different combinational molecular logic gates. The turn-on fluorescence responses of L1 and L3 in association with their appreciable cell membrane permeability are utilized for the intracellular detection of ions in living cells i.e. Hg2+ by using L1 and Al3+ and AsO2- by using L3. All the three chemosensors are successfully utilized to prepare disposable test paper strips, which can track the presence of targeted metal ions in aqueous media by simple naked-eye detection. This feature makes these test strips practical for the real time on-site detection of targeted analytes. Therefore, the D--A based organic chromophores with simple chemical architectures can be promising candidates for chemosensing applications. It is worth mentioning that chromogenic and fluorogenic dual responsive chemosensing in combination with multiple interplaying sensing mechanisms can provide diverse optical signals, favourable for the simultaneous detection of multiple analytes. A good understanding of the factors affecting the sensing mechanism, mode of binding in different type of receptors, and the mechanism of signal transduction can lead to the design of novel probe molecules. A proper choice of donor, acceptor and -bridge are expected to deliver targeted properties i.e. better selectivity, sensitivity, aqueous solubility, NIR emission properties for practical applications in areas of molecular chemosensors.
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Capítulos de libros sobre el tema "Chromophores Push-Pull"

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Barzoukas, Marguerite y Mireille Blanchard-Desce. "Molecular Engineering of Push-Pull Chromophores". En Advances in Multi-Photon Processes and Spectroscopy, 257–337. WORLD SCIENTIFIC, 2000. http://dx.doi.org/10.1142/9789812791955_0004.

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Actas de conferencias sobre el tema "Chromophores Push-Pull"

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Lee, Sebok, Taehyung Jang, Jonwon Im y Yoonsoo Pang. "Ultrafast Structural Changes of Push-pull Chromophores with the Intramolecular Charge Transfer in Excited State". En International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/up.2022.tu4a.62.

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Structural changes of push-pull chromophores with π-bridges of biphenyl and stilbene were investigated by femtosecond stimulated Raman spectroscopy, where vibrational couplings of skeletal vibrational modes are sensitive to the structural changes with intramolecular charge transfer.
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2

Rao, Varanasi P., King-Young Wong, Alex K. Y. Jen y Robert M. Mininni. "Optimization of second-order nonlinear optical properties of push-pull conjugated chromophores using heteroaromatics". En SPIE's 1993 International Symposium on Optics, Imaging, and Instrumentation, editado por Gustaaf R. Moehlmann. SPIE, 1993. http://dx.doi.org/10.1117/12.165253.

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Ahlheim, M., J. L. Brédas, M. Barzoukas, P. V. Bedworth, Y. Cai, C. Dehu, M. Blanchard-Desce et al. "Experimental and Theoretical Studies of Nonlinear Optical Chromophores". En Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.tud.1.

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We have described how the first hyperpolarizability, β, varies as a function of ground-state polarization and bond length alternation, BLA.1 Previously, our predictions of this relationship were derived by examining an prototypical push-pull polyene under the presence of static homogenous electric field.1 In order to develop a more realistic understanding of how real molecules behave in solution, we have now examined both p-nitroaniline and the push-pull polyene 1,1-dicyano-6-dibutylamino-hexatriene at the Hartree Fock ab initio level on the basis of an expanded Self Consistent Reaction-Field approach to simulate solvents with dielectric constants up to 37.5. The calculations were carried out using both spherical and elliptical cavities and taking into account multipole interactions up to 26 poles. Predictions were compared to Hyper-Rayleigh Scattering (HRS) results determined by Persoons et al. As had been shown earlier,2 the second-order NLO response of 1,1-dicyano-6-dibutylamino-hexatriene exhibits a peak as a function of solvent polarity, which was confirmed by the HRS measurements. Interestingly, we found that this peaked behavior of β as a function of solvent dielectric constant was predicted only when an elliptical cavity and the up to l = 6 pole contributions were taken into account, but was not observed when the calculations employed either an elliptical cavity and a dipole (l = 1) approximation, or a spherical cavity with up to l = 6 pole contributions. These results suggest that it is possible to model the geometric and electronic structure of polarizable molecules using a Self Consistent Reaction-Field approach, but it is necessary to build into the calculations mechanisms to account for the subtleties of the molecular charge distributions, not taken into account within a simple dipole approximation.
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Abbotto, Alessandro, Renato Bozio, Giovanna Brusatin, Antonio Facchetti, Massimo Guglielmi, Plinio Innocenzi, Moreno Meneghetti, Giorgio A. Pagani y Raffaella Signorini. "Novel hybrid organic-inorganic sol-gel materials based on highly efficient heterocyclic push-pull chromophores". En SPIE's International Symposium on Optical Science, Engineering, and Instrumentation, editado por Mario N. Armenise, Walter Pecorella, Liliane G. Hubert-Pfalzgraf y S. Iraj Najafi. SPIE, 1999. http://dx.doi.org/10.1117/12.366757.

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Bombenger, J. P., D. Gindre, L. Mager, J. P. Vola, C. Carré y A. Fort. "Fabrication of quasi phase matched structures for frequency conversion in photopolymers doped with push-pull chromophores". En Photonics Europe, editado por Paul L. Heremans, Michele Muccini y Eric A. Meulenkamp. SPIE, 2006. http://dx.doi.org/10.1117/12.663419.

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Meyers, Fabienne, Chin-Ti Chen, David Beljonne, Jean-Luc Brédas y Seth R. Marder. "Electronic and Nonlinear Optical Properties of Organic Molecules: Assessment of the Influence of the Molecular Structure". En Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.mc.3.

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In a previous work, using computational approaches, we analyzed how the polarizability, α, second-order polarizability, β, and third-order polarizability, γ, are controled by the ground state polarization [1-4]. To do so, we investigated the influence of an external, static electric field upon the nonlinear optical (NLO) properties, for a set of push-pull polyenes [1]. The calculated effect of the external electric field on the molecular structure and electronic properties of the chromophores is similar to that resulting from donor-acceptor substituents on a segment of the chromophore, or from changing the dielectric properties of the environment around the molecule, e.g., increasing the polarity of the solvent. The structure/properties relationships derived from that study are summarized in Figure 1, and have allowed us to propose chemical design prescriptions for the optimization of second- and third-order optical nonlinearities in organic molecules [3].
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7

Barzoukas, Marguerite y Mireille H. Blanchard-Desce. "Resonant and static cubic hyperpolarizabilities of push-pull dipolar and quadrupolar chromophores: toward enhanced two-photon absorption". En International Symposium on Optical Science and Technology, editado por Manfred Eich y Mark G. Kuzyk. SPIE, 2001. http://dx.doi.org/10.1117/12.449818.

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Fillaut, Jean-Luc, Jerome Luc y Bouchta Sahraoui. "Design of push-pull chromophores based on the incorporation of transition metal acetylides in the main π conjugated system". En 2007 ICTON Mediterranean Winter Conference. IEEE, 2007. http://dx.doi.org/10.1109/ictonmw.2007.4446926.

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Kim, O. K., A. Fort, M. Barzoukas y J. M. Lehn. "Nonlinear Optical Chromophores Containing Fused Terthiophene As A New Type of Electron Relay". En Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/otfa.1997.fa.3.

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Thiophene-based D-A molecules have been actively sought recently, exploiting interesting results indicating that the incorporation of a thiophene unit or the replacement of a phenylene moiety by thienylene in the relay of a D-A molecule enhanced the molecular hyperpolarizability (μβ(0)) significantly (1-3). Accordingly, it is expected that oligothiophenes give a larger contribution to the μβ(0) compared to oligophenylenes. As in the case of polyenes, the rigidification of thiophenes (by cyclization) has also been known to enhance charge-transfer in push-pull D-A molecules, as indicated by a bathochromic shift of absorption bands and a stronger solvatochromism compared to the flexible counterpart (4,5). A further indication for the effectiveness of fused thiophenes as relay is demonstrated by the fact that their absorption maxima increase linearly with the number of rings up to five (6). Aside from the electronic features, another merit of thiophenes is their inherent thermal stability from which thiophene-containing chromophores will benefit (2,3).
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10

Batista, Rosa M. F., Susana P. G. Costa, Michael Belsley y M. Manuela M. Raposo. "Synthesis and characterization of novel push-pull thiophene and thienylpyrrole derivatives functionalized with indanonedicyanovinyl acceptor moiety as efficient NLO-chromophores". En International Conference on Applications of Optics and Photonics, editado por Manuel F. Costa. SPIE, 2011. http://dx.doi.org/10.1117/12.892215.

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