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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
641

Síntese, propriedades espectrais e comportamento fotoquímico dos complexos diimínicos de ferro / Synthesis, spectral properties and photochemical behavior of iron diimine complexes

Marco Aurelio De Paoli 15 November 1974 (has links)
A fim de estudar as propriedades dos complexos de ferro com ligantes diirnínicos, tais corno: espectro eletrônico, reatividade dos complexos com cianeto e comportamento fotoquímico, novos complexos (I)ferrosos com diiminas foram preparados e caracterizados. A oxidação, em solução de H2SO4 11 M, dos complexos ferrosos com diiminas produziu os seus análogos férricos. A reação de um dos complexos ferrosos (R e R\' = CH3) com o íon cianeto produziu dois ciano-complexos mistos, onde um destes apresenta um dos ligantes modificado. Obtiveram-se também complexos com 1igantes tridentados(II). (Ver no arquivo em PDF). A investigação dos espectros eletrônicos dos complexos diirnínicos de ferro(II) apresentou três tipos de bandas, resu1tantes de transições de transferência de elétrons interna dos 1igantes (TEIL), metal-1igante (TEML)e transições d-d. As bandas de TEIL ocorrem na região de energia acima de 34 kK As de TEML ocorrem na região de 17 a 24 kK, com evidências indicando que o formato da banda não se deve ao acoplamento vibracional. Observa-se somente uma banda atribuída à transição d-d em 28 kK, usando dados da literatura obtidos para os complexos análogos com dipy e phen foram calculados os valores de B e Dq. Os espectros dos complexos férricos análogos apresentam bandas atribuídas a transições de transferência de elétrons ligante-metal (TELM), na região de 23 a 32 kK, e TEIL, na região de 47 a 50 kK. Verifica-se uma correlação entre a soma das energias das bandas de TEML, dos complexos ferrosos, com as de TELM, dos complexos férricos, e as energias das bandas de TEIL. Para os complexos com ligantes tridentados a atribuição das bandas tornou-se mais difícil devido à complexidade dos espectros. Ocorrem bandas na região de 16 a 21 kK, atribuídas a transições de TEML, e na região de 25 a 51 kK, atribuídas a TEIL. O desdobramento das bandas de TEML sugere uma baixa simetria para estes complexos com ligantes tridentados. Os ciano-complexos mistos obtidos foram caracterizados por espectros de infravermelho e de ressonância magnética nuclear, além das análises de ferro e cianeto. Também foram estudados os seus espectros eletrônicos. As bandas de TEML, que ocorrem na região de 18 a 21 kK em solução aquosa, apresentam uma forte dependência da sua energia com o solvente. Observam-se ainda bandas, na região em tôrno de 50 kK, atribuídas a TEIL. Experiências fotoquímicas indicaram que os complexos diimínicos de ferro(II), preparados neste trabalho, são fotoreativos, quando irradiados com uma lâmpada de mercúrio a média pressão. Há evidências indicando que o mecanismo da decomposição fotoquimica ocorre via ligante. / In order to investigate the properties of iron diimine complexes, six new complexes (I) were synthesized and characterized. The spectral properties, reactivity towards cynanide ions and photochemical behavior of these complexes were studied. In the reaction of the complex with R and R\' = CH3 with the cyanide ion two mixed-cyano complexes were obtained. One of these presents a modified diimine ligand. By chemical oxidation of the ferrous complexes, at high acid concentration, it was possible to study some of the properties of the ferric complexes. Some complexes with tridentade diimine ligands(II) were also studied. (See in the PDF file). The electronic spectra of the ferrous diimine complexes presented three kinds of absorption bands. These bands resulted from transitions due to: internal ligand electron transfer (ILET), metal to ligand electron transfer (MLET) and ligand field (d-d transitions). The ILET bands occur above 34 kK. The MLET bands occur from 17 to 24 kK. Evidence is presented that the structure of the MLET band cannot be accounted for by a vibrational coupling. It was possible to observe a d-d transition at 28 kK. By using literature data for complexes with 2,2\'-bipyridine and phenantroline it was possible to calculate the values and Dq. The corresponding ferric complexes presented bands from 23 to 32 kK and ILET bands from 47 to 50 kK. A correlation is observed between the surn of the frequencies of the MLET bands, of the ferrous complexes, LMET bands, of the ferric complexes, and the frequencies of the ILET bands. In the case of the complexes with tridentade ligands the assignment of the bands is not simple, due to the complexity of the absorption electronic spectra. Possibly, the MLET bands occurs from 16 to 21 kK and the ILET bands from 25 to 51 kK. The splitting of the MLET bands suggests a lower simmetry than D3 for these complexes. The mixed-cyano complexes obtained were characterized by their infrared and nuclear magnetic ressonance spectra and analytical data on Fe and CN contents. The study of the electronic absorption spectra showed a MLET band, in the region from 18 to 21 kK in aqueous solution. ILET bands were observed around 50 kK. The position of the MLET bands showed a strong solvent-dependence. Prelirninary photochernical experirnents indicated that the ferrous diirnine cornplexes are photoreactive, when irradiated with a rnediurn pressure rnercury lamp. Evidence is presented that the rnechanisrn of the photodecornposition occurs via the ligands.
642

Propriedades fotoquímicas e fotofísicas, e investigação teórica de um novo monômero-complexo de Ru(II)-bipiridina / Photochemistry and photophysics properties and teoric investigation of novel complex-monomer of the Ru(II)-bipyridine

Simone Delezuk Inglez 14 March 2008 (has links)
As sínteses, o cálculo do OM, as propriedades fotoquímicas e fotofísicas dos complexos cis-[Ru(bpy)2(L)x](PF6)2, onde a bpy é 2,2\'-bipiridina e L é 5,6-bis(3-amidopiridina)-7-oxanorborneno (3amdpy2oxaNBE, complexo 2) ou 3-aminopiridina (3amnpy; complexo 3) foram estudados. 3amdpy2oxaNBE é o novo ligante quelato 5,6-bis(3-amidopiridina)-7-oxanorborneno (1) e apresenta duas amidas piridinas substituídas -conectadas ao monômero oxanorborneno - que são originadas da reação da 3amnpy e do monômero 5,6-bis-carboxilato-7-oxanorborneno. Os complexos 2 e 3 exibem absorções na região de 350 nm e entre 420-500 nm, atribuídas a uma contribuição das transições MLCT (d&pi; &rarr;bpy and d&pi; &rarr;L; L = 3amdpy2oxaNBE ou 3amnpy). Fotólise do complexo 3 levou ao cis-[Ru(bpy)2(3amnpy)(solvente)]2+, enquanto o complexo 2 é inerte à fotossubstituíção. Os comprimentos de onda de irradiação (330 > 440 > 500 nm) e os solventes (DMF > CH3CN > CH2Cl2 ~ THF) influenciam na fotolabilidade do complexo 3. A formação de cis-[Ru(bpy)2(CH3CN)2]2+ foi observada por RMN de 1H quando o complexo 3 foi irradiado em 420 nm em CH3CN. A emissão do complexo 2, em 594 nm, é atribuída como uma emissão MLCT (Ru &rarr;bpy) e é caracterizada por um tempo de vida longo à temperatura ambiente (650 ns em CH3CN e 509 ns em H2O). A emissão é independente do &lambda;irr, mas é dependente da temperatura, i.e., aumenta quando a temperatura é abaixada. Considerando-se que o anel quelato de 1 contribui para a estabilidade do complexo 2 sob irradiação de luz contínua, a diferença nos fotoprocessos primários de 3 (perda da 3amnpy) e 2 (luminescência) pode ser explicada pela influência de L na energia da banda de CT Ru &rarr;bpy. Para 2, o estado excitado Ru &rarr;bpy é o de mais baixa energia e o complexo é luminescente e inerte à fotossubstituição. Para o complexo 3, é possível mover a banda de absorção de CT Ru &rarr;bpy para uma posição comparável à da banda de MC mais abaixo. A eficiência da fotossubstituição é muito pequena quando o estado de TC é mais baixo, e razoavelmente grande quando o estado MC é mais baixo na energia. Esses resultados são corroborados pelo cálculo de TDDFT, que mostra a transição MC em 328 nm (3,78 eV) para 3. Então, a modificação na substituição do grupo piridina levou a uma diferença crucial nos fotoprocessos primários entre os dois complexos. No complexo 2, a depopulação eletrônica da unidade e a população de um orbital da bpy* por meio da excitação são evidentes pela comparação com as propriedades fotofísicas com complexos relacionados com [Ru(bpy)3]2+. Além disso, uma redução de um ligante bpy no estado excitado MLCT é indicada pelo espectro resolvido no tempo em que mostrou características típicas da bpy.-. As propriedades fotocatalíticas de 2 são espectroscopicamente demonstradas pela supressão oxidativa usando-se os íons receptores de elétrons metilviologênio2+ ou [RuCl(NH3)5]+2.Também foi realizado um estudo cinético da reação de desacetilação assistida por ultra-som. Com base nos resultados de %GA das amostras de quitina e de quitosana, os quais foram obtidos por espectroscopia de RMN 1H, análise elementar e titulação condutimétrica, pôde ser observado que o uso de ultra-som favoreceu o processo de desacetilação. Além disso, os resultados do estudo cinético da reação assistida por ultra-som a 100°, 110° e 120°C indicaram que o domínio cinético da reação foi abreviado para tempos inferiores a 30 min e que o patamar de velocidade constante corresponde a uma desacetilação mais completa (GA< 20%) do que aquele atingido com o uso do método de desacetilação heterogênea (20% < %GA < 45%). Estas conclusões estão de acordo com as caracterizações por difração de raios X, as quais revelaram a progressiva destruição dos domínios cristalinos à medida que os produtos foram mais desacetilados. Dessa forma, a desacetilação assistida por irradiação de ultra-som de alta potência possibilitou, de um modo mais simples e rápido, a obtenção de quitosanas com características semelhantes às obtidas após o emprego do método FPT, sendo que este último é relatado na literatura como o método mais eficiente para produção de quitosanas extensivamente desacetiladas. É proposto que a irradiação de ultra-som de alta potência contribuiu para aumentar acentuadamente a área superficial das partículas de quitina, propiciando pleno acesso do hidróxido de sódio aos grupos acetamida do polímero e promovendo a sua desacetilação homogênea. / The synthesis, MO calculations, photochemical and photophysical properties of cis-[Ru(bpy)2(L)x](PF6)2 complexes where bpy is 2,2\'-bipyridine and L is 5,6-bis(3- amidopyridine)-7-oxanorbornene (3amdpy2oxaNBE; complex 2) or 3-aminopyridine (3amnpy; complex 3) were studied. 3amdpy2oxaNBE is the novel chelate-ligand (1) and presents two amide-substituted pyridines connected to a 7-oxanorbornene-monomer type that comes from a reaction of 3amnpy and 5,6-bis-carboxylate-7-oxanorbornene monomer. Complexes 2 and 3 exhibit absorptions near 350 nm and in the 420-500 nm region attributable to a contribution from MLCT transitions (d&pi; &rarr;bpy and d&pi; &rarr;L; L = 3amdpy2oxaNBE or 3amnpy). Photolysis of complex 3 leads to cis-[Ru(bpy)2(3amnpy)(solvent)]2+ while complex 2 is photosubstitution inert. The irradiation wavelength (330 > 440 > 500 nm) and solvent (DMF > CH3CN > CH2Cl2 ~ THF) influence the photolability of complex 3. Formation of cis- [Ru(bpy)2(CH3CN)2]2+ was observed by 1H-NMR when complex 3 was irradiated at 420 nm in CH3CN. The emission of complex 2, in 594 nm, assignable as an MLCT (Ru &rarr;bpy) emission is characterized by a long lifetime at room temperature (650 ns in CH3CN and 509 ns in H2O). It is independent of &lambda;irr, but it is temperature dependent, i.e., it increases as the temperature is lowered. Considering the chelate ring of 1 contributes to the stability of the complex 2 under continuous light irradiation, the difference in the primary photoprocesses of 3 (loss of 3Amnpy) and 2 (luminescence) can be explained by the influence of L in the Ru &rarr;bpy CT band energy. For 2, the Ru &rarr;bpy excited state is the lowest in energy and the complex is luminescent and photosubstitution inert. For complex 3, it is possible to move the Ru&rarr;bpy CT absorption band from a position comparable to the MC band system to one well below. The photosubstitution efficiency is very small when the CT state is lowest and reasonably large when the MC state is lowest in energy. These results are corroborated by TDDFT calculations which show the MC transitions at 328 nm (3.78 eV) for 3. Thus, the modification in the pyridine substitution groups leads to the crucial difference in the primary photoprocesses between the two complexes. In the complex 2 the electronic depopulation of the {Ru(bpy)2} unit and population of a bpy* orbital upon excitation are evident by comparing the photophysical properties with [Ru(bpy)3]2+ related complex. Moreover, a reduction of a bpy ligand in the MLCT excited state is indicated by time-resolved spectra that show features typical of bpy.-. The photocatalytic property of 2 is spectroscopically demonstrated by oxidative quenching using either methylviologen2+ or [RuCl(NH3)5]+2 electron-acceptor ions.
643

Catalyseurs greffés sur support et libérés sous stimulus externe / Supported catalysts deliverable upon external stimulus

Gogolieva, Ganna 28 April 2014 (has links)
La catalyse organométallique est à l’origine des avancées les plus significatives au cours des dernières années puisqu’elle a permis de découvrir de nouvelles voies d’accès à des molécules complexes; elle a ainsi révolutionné le monde de la synthèse organique. Bien que de nombreuses réactions s’appuyant sur des complexes organométalliques aient été développées, les catalyseurs organométalliques présentent encore deux inconvénients majeurs : leur toxicité, associée la plupart du temps à la présence de métaux lourds, et leur coût lié à la présence à la fois d’un centre métallique et de ligands élaborés. Dès lors de nombreuses recherches ont été lancées dans le but de mettre au point des techniques permettant de séparer simplement le catalyseur métallique des produits formés et de le recycler. C’est dans ce coeclat_13ntexte que nous avons cherché à développer de nouveaux catalyseurs supportés pouvant être libérés pendant la réaction afin d’effectuer la catalyse en conditions homogènes et de nouveau greffés au support en fin de réaction afin de pouvoir séparer le catalyseur des produits de la réaction et le recycler ensuite via une nouvelle libération. Cette capacité de passage du catalyseur du support vers la solution et vice-versa est basée sur un complexe de coordination lié au support et appelé «agrafe contrôlable» dont la sphère de coordination peut être modulée via un stimulus externe : soit un complexe du ruthénium avec un stimulus photochimique, soit un complexe du cuivre avec un stimulus électrochimique, tels qu’exploités dans de nombreuses machines moléculaires. Les nanotubes de carbone sont choisis comme support, les ligands de type NHC sont choisis comme ligands de base du système catalytique et des complexes du cuivre ou du ruthénium portant des ligands de type bipyridine, phénantroline ou terpyridine constituent le cœur de l’agrafe contrôlable. Des complexes de palladium basés sur des ligands NHC fonctionnalisés ont été synthétisés en utilisant un motif triazole comme lien entre le centre catalytique et la fonctionnalité impliquée dans la récupération du catalyseur. Les tests catalytiques dans des réactions de Suzuki-Miyaura ont montré que les complexes étaient actifs sur une large gamme de substrats et à des charges catalytiques faibles (jusqu’à 50 ppm) et ce, quelle que soit la fonctionnalité ajoutée. Des complexes du ruthénium portant des ligands terpyridine, bipyridine ou phénantroline ont été synthétisés et caractérisés. Le concept du switch photochimique a été validé sur un système modèle : nous avons pu montrer que sous irradiation à l’aide d’une lampe à vapeur de mercure, le complexe [Ru(II)(terpyridine)(bipyridine)(PhCN)][(PF6)2] était capable de libérer le ligand benzonitrile et que la réaction inverse se produisait par chauffage du complexe [Ru(II)(terpyridine)(bipyridine)(H2O)][(PF6)2] en présence de benzonitrile. D’autre part, des complexes du cuivre portant des ligands de type bis-bipyridine et terpyridine ont été synthétisés et caractérisés. Le concept du switch électrochimique a été validé sur un système modèle : nous avons pu montrer par voltamétrie cyclique qu’en présence de terpyridine, le complexe [Cu(I)(bis-bipyridine)][BF4] pouvait s’oxyder et former un complexe de type [Cu(II)(bipyridine)(terpyridine)][(BF4)2] et que la réaction inverse se produisait par réduction. Ces travaux démontrent le caractère contrôlable des agrafes choisies via un stimulus électrochimique ou photochimique, sur des systèmes modèles. L’obtention de complexes de palladium comportant un ligand NHC-triazole fonctionnalisé, leur bonne activité et la voie de synthèse mise au point valident notre stratégie de récupération et ouvrent de nombreuses perspectives en catalyse. / Transition metal catalysed reaction is the source of the most significant advances in recent years since it revealed new access routes to complex molecules and as such has revolutionized the way of designing organic syntheses. Although many reactions based on complexes of transition metals have been developed, «organometallic» catalysts have still two major drawbacks: their toxicity, mostly related to the presence of heavy metals, and their cost mainly induced by the presence of both a metal center and sophisticated ligands. Therefore much research has been undertaken in order to develop techniques allowing a simple separation of the metal catalyst from reaction products and the recycling of the former. It is in this context that we sought to develop new supported catalysts that can be released during the reaction to perform catalysis under homogeneous conditions and being grafted back to the support (boomerang catalyst) at the end of the reaction in order to separate the catalyst from the products and then use the catalyst again, homogeneously in a new solution of substrate, through a new release. This ability to shift the catalyst from the support to the solution and vice versa is based on a coordination complex bound to the support and called the «controllable tether» which coordination sphere can be modulated via an external stimulus. Two type of tethers have been explored; one involving a ruthenium complex requiring a photochemical stimulus, and another using a copper complex and an electrochemical stimulus, similar to systems used in molecular machineries. Carbon nanotubes have been selected as solid support and NHC type ligands have been chosen for the robustness of their complexes in catalysis. Complexes of palladium based on functionalized NHC ligands were synthesized using a triazole link between the catalytic center and the function involved in the recovery of the catalyst on the tether. Catalytic reactions of Suzuki - Miyaura showed that the complexes were active on a wide scope of substrates and at catalytic low loads (up to 50 ppm), and this, whatever the added recovery function is. Ruthenium complexes bearing ligands such as terpyridine, bipyridine or phenanthroline have been synthesized and characterized. The concept of photochemical switch has been validated on a model system for which we have shown that under irradiation with a mercury vapor lamp, the complex [Ru(II)(terpyridine)(bipyridine)(PhCN)][(PF6)2] was able to release its benzonitrile ligand and the reverse reaction occurs by heating the complex [Ru(II)(terpyridine)(bipyridine)(H2O)][(PF6)2] in the presence of benzonitrile . On the other hand, copper complexes bearing ligands of bis-bipyridine and terpyridine were synthesized and characterized. The concept of electrochemical switch has been validated on a model system for which we have shown by cyclic voltammetry in the presence of terpyridine that the complex [Cu(I)(bis-bipyridine)][BF4] could be oxidized and form a complex of the type [Cu(II)(bipyridine)(terpyridine)][(BF4)2]; the reverse reaction occuring upon reduction . This work demonstrates the controllability of the selected tethers via an electrochemical or photochemical stimulus on model systems. Obtaining functionalized palladium complexes with good activity through an efficient synthesis route validates our strategy of recovery and opens many opportunities in catalysis.
644

Molecularly doped organic electroluminescent diodes

Kwong, Chin Fai 01 January 2000 (has links)
No description available.
645

Photodissociation Dynamics Of Mixed Halogenated Alkyl And Aryl Halides

Senapati, Dulal 07 1900 (has links) (PDF)
No description available.
646

Exploring the Chemistry of Re(I): Physical and Theoretical Investigations

Bulsink, Philip January 2015 (has links)
The development of Rhenium I photocatalysts has been pursued since Lehn first showed the excellent performance of the ReI bipyridine tricarbonyl catalyst. Since then, devel- opment has modified the organic ligand to demonstrate continued or improved activity with other α-diimine bidentate geometries. Geometry has been limited to bidentate motifs, with fac-(CO)3 and axial halides. This work will demonstrate the synthesis, characterization, and testing of a new terdentate, κ3(L3)−Re1(CO)2X (X = Cl, Br, CN, OTf) family of compounds for CO2 reduction, as well as computational investigations into the mechanism of the reduction of CO2 to CO and other species. Development of computational aides will be described as well.
647

Solution and solid state photochemistry of some bridgehead substituted dibenzobarrelene diesters : x-ray crystallography of starting materials and photoproducts

Pokkuluri, Phani Raj January 1990 (has links)
The solid state and solution phase photochemistry of three bridgehead-substituted dibenzobarrelene-11,12-diesters and a 2,3-naphthobarrelene diester derivative were investigated. These compounds were expected to undergo the di-π-methane rearrangement via their triplet excited states, and a rearrangement to a cyclooctatetraene (COT) derivative via their singlet excited states. All compounds investigated underwent smooth photoreactions in the solid state to produce the same products as observed in the corresponding solution phase photolyses. One exception to this was a bridgehead dimethyl- substituted dibenzobarrelene diester. In this case an unusual photo-product which was characterized as a dibenzopentalene derivative, was obtained in the solid state along with lesser amounts of the normal-solution products. The mechanism proposed for the formation of this product involves a 1,4-biradical intermediate which undergoes a novel double 1,2-ester migration. It was recognized that this biradical intermediate could also undergo fragmentation to produce a cyclooctatetraene (COT) derivative which differs in its symmetry from that of the COT expected based on the mechanism proposed by H. E. Zimmerman for similar transformations observed in the cases of benzo- and naphthobarrelenes. Thus, there are two structures possible for the COT formed which cannot be distinguished based on their spectral properties. For this reason, single crystal X-ray diffraction analysis of the COTs formed in each case was performed. Of the four COT structures determined by X-ray crystallography, three COTs had structures that were consistent with the fragmentation mechanism, while one had a structure consistent with the Zimmerman mechanism. In light of the possible unusual photorearrangements observed, it was thought desirable to establish the molecular structures of all photo-products obtained. To this end, crystal and molecular structures of 11 photoproducts were determined. Also, in an attempt to establish structure-reactivity relationships, crystal and molecular structures of four starting materials were determined. A bridgehead chloromethyl-substituted dibenzobarrelene diester was also found to produce dibenzopenatalene-like photoproducts in the solid state or in chloroform solution; these photoproducts were also characterized based mainly on X-ray crystallography. These results add to the generality of the unusual photobehavior of some dibenzobarrelene derivatives. In the solution phase photolysis of a bridgehead dichloro-substituted dibenzobarrelene diester, a novel cyclic peroxide product was obtained. This was rationalized as being derived from photolysis of the primary di-π-methane photoproduct followed by trapping of the resulting 1,3-biradical by traces of molecular oxygen present in the reaction mixture. Thus, in the present study it was found that bridgehead substituted dibenzobarrelene derivatives undergo di-π-methane rearrangement via their T₁ states as expected, but that their S₁ states may undergo unusual rearrangements to produce cyclooctatetraene derivatives with unexpected structures, and dibenzopentalene derivatives in some cases. / Science, Faculty of / Chemistry, Department of / Graduate
648

Mercury-Sensitized Photochemical Reactions of Isopropyl Alcohol

Armstrong, Andrew Thurman 05 1900 (has links)
This thesis describes the reactions of mercury-sensitized isopropyl alcohol when bombarded with 2537 Angstrom radiation.
649

Synthèse et étude de systèmes mutlichromophoriques à base de Bodipy / Synthesis and studies of new multichromophoric systems based on Bodipy

Galangau, Olivier 07 December 2011 (has links)
Les travaux présentés dans ce manuscrit portent sur la synthèse et l’étude des propriétés spectroscopiques de systèmes multichromophoriques à base de Bodipy, fluorophore choisi pour ses propriétés émissives remarquables (&#61541-&#61472-et élevés, ) et pour son aptitude à donner et accepter les électrons. Notre objectif est de contrôler sa luminescence par association à un ou plusieurs chromophores de nature variée et répondant à des stimuli déterminés. L’exposé est divisé en quatre chapitres, dont le premier rappelle les méthodes de synthèse et de fonctionnalisation du noyau et détaille leur influence sur les propriétés de fluorescence. Le second chapitre présente le contrôle des propriétés d’émission intrinsèques par extension de conjugaison, au moyen d’une nouvelle réaction de type Knœvenagel. Les résultats spectroscopiques y sont notamment étudiés par modélisation quantique (DFT). Ensuite, nous démontrons qu’il est possible de contrôler la fluorescence par désagrégation de fluorophores greffés, en milieu aqueux par ajout de surfactant et par chélation d’anions. Le troisième chapitre est consacré à la modulation de la fluorescence par changement de l’état « rédox » du partenaire (électrofluorochromisme). A cet effet, deux chromophores ont été employés : la s-tétrazine et le ferrocène. Enfin, nous terminons notre étude par un quatrième chapitre qui aborde la photomodulation des propriétés émissives du Bodipy par couplage à diverses entités photochromes : les azobenzènes, les aniles et les photochromes à cyclisation péricyclique. Nous y détaillons les difficultés synthétiques rencontrées au cours de notre étude. / This work deals with the synthesis and the study of multichromophoric systems, based on Bodipy which is known for its oustanding emission properties (high &#61541- and values, ) and for both, its donating and withdrawing electronic characteristics. Our goal is to couple the fluorophore to other(s) chromophore(s) sensitive to a specific stimulus, to modulate the Bodipy’s emission. The first part, a bibliographic report, focuses on the various ways to functionalize the Bodipy core and discusses their influence on its spectroscopic properties. The second section aims at describing, first, the emission shift by extension of the core conjugation via a new Knœvenagel type reaction. DFT calculations will support experimental facts. It also focuses on external modulation factors such as disaggregation of Bodipy in aqueous media and anion chelation. The third chapter is fully devoted to the possibility of controlling the fluorescence properties by modification of the counter-chromophore “redox” state (so called electrofluorochromism). To that, two chromophores are used: the s-tetrazine and the ferrocene. Final section gathers the preliminary results of coupling reaction of photochromic species with Bodipy, in order to photocommutate its photophysics properties. Synthetic issues are largely discussed so as to highlight some general synthetic pathways that one needs to follow to succeed.
650

Chemistry on Flapping Fluorophores That Bridges Photochemistry and Polymer Mechanochemistry / 光化学とポリマーメカノケミストリーを繋ぐ羽ばたく蛍光団の化学

Kotani, Ryota 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第23025号 / 理博第4702号 / 新制||理||1674(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)准教授 齊藤 尚平, 教授 依光 英樹, 教授 時任 宣博 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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