Academic literature on the topic 'Lanthanide antenna complexes'

Chiral lanthanide complexes can be prepared by choosing the achiral antenna ligand and the chiral inducer independently. With this modular approach, complexes optimized for use in efficient CP-OLEDs may be obtained.

The replacement of the secondary amide linker that carries the sensitizing carbostyril antenna with a tertiary amide in luminescent Eu and Tb complexes dramatically increases the lanthanide emission quantum yields.

A fragmentation scheme has been used to describe the photophysical phenomena associated with the antenna effect in organometallic lanthanide complexes. The theoretical protocol allows justifying the sensitization pathways.

DFT-based methods have been exploited to look into the structural, vibrational and electronic properties of antenna ligands, all of them crucial points for a reliable design of customized luminescent lanthanide (Ln³⁺) complexes.

The coordination compounds of the trivalent lanthanide ions (Ln(III)) have unique photophysical properties. Ln(III) excitation is usually performed through a light-harvesting antenna. To enable Ln(III)-based emitters to reach their full potential, an understanding of how complex structure affects sensitization and quenching processes is necessary. Here, the role of the linker between the antenna and the metal binding fragment was studied. Four macrocyclic ligands carrying coumarin 2 or 4-methoxymethylcarbostyril sensitizing antennae linked to an octadentate macrocyclic ligand binding site were synthesized. Complexation with Ln(III) (Ln = La, Sm, Eu, Gd, Tb, Yb and Lu) yielded species with overall −1, 0, or +2 and +3-charge. Paramagnetic 1H NMR spectroscopy indicated subtle differences between the coumarin- and carbostyril-carrying Eu(III) and Yb(III) complexes. Cyclic voltammetry showed that the effect of the linker on the Eu(III)/Eu(II) apparent reduction potential was dependent on the electronic properties of the N-substituent. The Eu(III), Tb(III) and Sm(III) complexes were all luminescent. Coumarin-sensitized complexes were poorly emissive; photoinduced electron transfer was not a major quenching pathway in these species. These results show that seemingly similar emitters can undergo very different photophysical processes, and highlight the crucial role the linker can play.

The series of luminescent monomeric lanthanide thiazole complexes [LnCl3(thz)4]⋅0.5thz (Ln = Sm, Eu, Gd, Tb, Dy; thz=1,3-thiazole) has been synthesised and characterised by powder and singlecrystal X-ray diffraction, IR and photoluminescence spectroscopy, DTA/TG as well as elemental analysis. The colourless compounds exhibit photoluminescence in the visible region with varying quantum efficiencies up to QY = 48% for [TbCl3(thz)4]⋅0.5thz. Both, the lanthanide ions as well as the thiazole ligand contribute to the luminescence. Excitation can be achieved via intra-4 f transitions and by exciting the ligand, emission is observed mainly from the lanthanide ions again by 4 f transitions. Thiazole can transfer energy to the lanthanide ions, which further feeds the lanthanide emission by an efficient antenna effect even at room temperature. The lanthanide ions show pentagonalbipyramidal coordination by three chloride anions and four N atoms of 1,3-thiazole, which leads to a strong 5D0 →7F4 transition for europium. Significant differences arise as compared to thiophene complexes because no sulphur atom is involved in the metal coordination, as the thiazole ligand is solely coordinated via its nitrogen function.

Orientador: Fernando Aparecido Sigoli
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-26T22:25:31Z (GMT). No. of bitstreams: 1 Petiote_Lanousse_M.pdf: 4326996 bytes, checksum: a438622b7ca8e3a70bbbec5abf7dc735 (MD5) Previous issue date: 2015
Resumo: Esse trabalho reporta o estudo das propriedades fotoluminescentes de uma série de complexos dinucleares de lantanídeos trivalentes contendo os ligantes 2 tenoiltrifluoro-acetilacetonato (tta), óxido de [2 (difenilfosforil)etil]difenilfosfina (dppeo), e óxido de trifenilfosfina (tppo). Os complexos de formula geral [{Ln(tta)3(tppo)}2(µ-dppeo)] foram obtidos a partir do controle da estequiometria e da ordem de adição dos reagentes em reações envolvendo os ligantes fosfinóxidos e os complexos precursores [Ln(tta)3(H2O)2]. A caracterização foi realizada por análise elementar, espectroscopia vibracional na região do infravermelho, espectroscopia eletrônica na região do visível, ressonância magnética nuclear de 1H e de 31P e análise termogravimétrica. Para os complexos de európio(III), são apresentados cálculos semi-empíricos realizados baseando-se nas geometrias de coordenação do estado fundamental desses complexos usando o modelo SPARKLE/AM1. Os espectros de fotoluminescência exibem as bandas de emissão características dos íons lantanídeos utilizados confirmando a atuação do efeito antena nos mesmos. Os espectros de emissão dos complexos do íon Eu(III) apresentam elevados valores da razão assimétrica I(5D0?7F2)/ I(5D0?7F1) e de ?2 evidenciando a presença dos íons Eu(III) em ambientes químicos de baixa simetria e a atuação do acoplamento dinâmico. Os complexos de európio(III) mostram um aumento do tempo de vida de emissão e do rendimento quântico com a substituição das moléculas de água devido a diminuição das taxas de decaimentos não radiativos do nível emissor 5D0. A energia do nível tripleto do complexo [{Eu(tta)3(tppo)}2(?-dppeo)] determinada experimentalmente e calculada apresentam boa concordância. Os cálculos das taxas de transferência e retro-transferência de energia mostram que, no caso da transferência de energia dos ligantes para o íon Eu(III), as rotas mais eficientes são T?5D1 e T?5D0. As coordenadas de cromaticidade da Commission Internacionale d¿Éclairage (CIE) indicam que a luz vermelha emitida pelos complexos contendo íons Eu(III) apresenta alta pureza. Os complexos com emissões na região do infravermelho próximo apresentam tempos de vida de emissão 10 vezes menor do que os complexos de európio devido baixa eficiência do efeito antena e a desativação não radiativa dos níveis emissores dos íons Er(III) e Yb(III). Palavras-chave: Lantanídeos. Complexos dinucleares. Luminescência. Efeito Antena
Abstract: This work reports on photoluminescent properties of a series of lanthanide dinuclear complexes containing 2- thenoyltrifluoroacetylacetonate, [2 (diphenylphosphoryl)ethyl](diphenyl)phosphine oxide and triphenyl oxide as ligands. The complexes have the general formula [{Ln(tta)3(tppo)}2(µ-dppeo)] and were obtained by controlling the stereochemistry and reagents addition in reactions involving the phosphine oxide ligands and precursor complexes [Ln(tta)3(H2O)2] The characterization was carried out using elemental analysis, IR vibrational spectroscopy, UV-Vis electronic spectroscopy, 1H and 31P NMR and thermogravimetric analysis techniques. Semi-empirical calculations have been carried out using the fundamental geometries of europium(III) complexes optimized by the SPARKLE/AM1 model. The photoluminescence spectra under excitation in the ligand show the narrow bands characteristics of lanthanide ions used, confirming that the antenna effect is operating in all complexes. The emission spectra of Eu(III) complexes show high values of either asymmetric ratio I(5D0?7F2)/ I(5D0?7F1) and the intensity parameter ?2 indicating low-symmetry chemical environments occupied by Eu(III) ions and contribution of the dynamic coupling mechanism. The Eu(III) complexes show an increasing of the luminescence lifetime and the quantum yield as the water molecules have been substituted. This was attributed to a reduction of the non-radiative decay of the 5D0 level in complexes without water molecules in the coordination sphere of lanthanide trivalent ion. The experimental value of the triplet energy level for the complex [{Eu(tta)3(tppo)}2(?-dppeo)] is consistent with the calculated one. Calculations of the energy transfer rates in the europium complexes show that the most efficient routes are T?5D1 e T?5D0. The chromaticity coordinates indicate high purity for the red light emitted by the europium complexes. The complexes with emission in the near infrared region show emission life 10 times lower than the europium complex. This was attributed to different factors such as low relative efficiency of the antenna effect and the efficient non-radiative deactivation of emitting levels in Er (III) and Yb (III) mainly by C-H oscillators in the ligands. Keywords: Lanthanides, Dinuclear complexes, Luminescence, Antenna effect
Mestrado
Quimica Inorganica
Mestre em Química

En raison de l’omniprésence des hétérocycles azotés et de leurs propriétés biologiques, une attention particulière est accordée au développement de méthodologie pour leur synthèse et leur fonctionnalisation. L’étude de la fonctionnalisation d’énamides constitue une thématique importante car ces motifs s’avèrent être des outils synthétiques polyvalents permettant d’accéder à des dérivés hétérocycliques complexes. Les réactions de couplage Pd-catalysées constituent une méthode de choix rapide et efficace pour la synthèse d'énamides, notamment à partir de phosphates d'énols issus de lactames, d’imides ou d’amides. Le premier chapitre de ce travail porte sur le couplage organopalladié C-P de phosphines boranes secondaires chirales ou achirales avec des phosphates d’énols. Ce couplage C-P original, réalisé dans des conditions douces, conduit aux énamido-phosphines boranes correspondantes et offre de nombreuses possibilités pour la constitution d’une librairie de phosphines originales. Parallèlement à ce travail, l’addition nucléophile d’anions phosphures sur divers ène-carbamates acycliques conduit à des acides alpha-aminés béta-phosphorés originaux, porteurs d’un carbone quaternaire en alpha de l’azote. Le deuxième chapitre de la thèse porte sur la préparation et la caractérisation de chromophores organiques originaux basés sur un noyau pyrazinique et qui sont susceptibles de présenter des propriétés de fluorescence. Ces composés sont conçus pour former des nouveaux systèmes sensibilisateurs de cations de lanthanides, et être utilisés comme sensibilisateurs organiques pour l'imagerie moléculaire dans le proche infrarouge
On account of the ubiquity of nitrogen heterocycles and their biological properties, the great attention is paid to developing methodologies of their synthesis and functionalization. For this purpose, the study of functionalization of enamides constitutes an important topic due to the utility of these motifs in the construction of complex heterocyclic derivatives. Palladium-catalyzed reactions of cross- coupling are rapid and efficient methods of choice for synthesis of enamides particularly starting from enol phosphates derived from lactams, imides or amides. The first chapter of the thesis evokes the original C-P coupling reaction of chiral and achiral secondary phosphine boranes with different enol phosphates in mild reaction conditions, leading to corresponding enamido-phosphine boranes. This methodology permits the construction of libraries of novels phosphines. Also, the reaction of nucleophilic addition of phosphide anions onto various enecarbamates acyclic was elaborated, giving an access to original beta-phosphino alpha-amino acids, bearing the quaternary carbon on alpha position to nitrogen. The second chapter is devoted to the preparation and characterization of organic chromophores based on the pyrazinic core, which are likely to exhibit the fluorescence properties. These compounds were designed to form new sensitizing systems for lanthanide cations and could be used as organic sensitizers for molecular imaging in near infrared

The present work concerns the synthesis, the characterization and the study of the light-activated properties (photodegradation, persistent luminescence, sensing) of different inorganic materials and molecular systems. In the first part, the realization of bismuth-based bifunctional materials for the adsorption and photodegradation of organic dyes is presented. Novel procedures for the synthesis of bismuth oxychlorides (BiOCl, Bi24O31Cl10, Bi12O17Cl2) and subcarbonate nanostructures are discussed. By modulating the synthesis parameters (temperature, pH and surfactant) and by means of different treatments (thermal and UV irradiation), a tuning of the chemical composition and consequently of the crystalline phase, morphology and optical properties was obtained. This was reflected in different absorbent properties and photo-degradation activity towards two model dyes: methyl orange and rhodamine B. The most promising nanostructures, based on (BiO)2CO3, are able to adsorb both dyes, from 50 up to 95 %, within 20 minutes. Further, under irradiation with visible light they are able to degrade the dye remained in solution. The second part concerns the study of chromium doped zinc gallate (ZnGa2O4:Cr3+) nanostructures. This material displays interesting emission properties in the red-NIR region (600-900 nm) and, especially, persistent luminescence. Adopting a sol-gel procedure and post-synthesis treatments in the range 500-1000 °C, thin films endowed with homogeneous composition, structure and thickness were obtained. These systems were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and optical spectroscopy (absorption and emission). A modulation of the emission properties was observed in a wide temperature range from -190 up to 250 °C, evidencing the possibility to employ these materials for the development of temperature sensors. Advanced synchrotron radiation techniques as X-Ray Absorption Spectroscopy (XAS) and X-Ray Excited Optical Luminescence (XEOL) were adopted to get site-specific information and to correlate short-range order to luminescent properties. Lastly, inorganic materials are also employed as substrates and/or hosting matrices for functional molecules. Besides the development of the inorganic system, the study of the molecular unit itself in terms of thermodynamic and kinetic stability, topology, functionality and reactivity is crucial. In this framework, the third part of the thesis describes the study of two lanthanide luminescent antenna complexes characterized by a macrocyclic ligand (1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, DO3A) for dysprosium and an acyclic (1,4,7-triazaheptane-1,1,7,7-tetraacetic acid, DTTA) one for europium. The behavior of the couple in aqueous solution was studied in presence of dipicolinic acid (pyridine-2,6-dicarboxylic acid, DPA). In particular, it was investigated the effect of a strongly coordinating agent like DPA on their emission properties and the possibility to develop a ratiometric sensor for small molecules like DPA. To this aim, the dysprosium complex was employed as reference and the europium one as probe for the recognition of DPA which is known as a biomarker for bacterial spores. The modulation of the emission properties (band profile and relative intensity) revealed an interaction between probe complex and dipicolinic acid. NMR and mass spectrometry measurements evidenced that a ligand exchange reaction occurred, with the formation of [EuDPA2]-. This indicates that macrocyclic ligands endowed with a preformed cavity hosting the metal ion insure a better stability over acyclic ligands having the same number and typology of coordination sites. These findings provide crucial information for the future development of solid state sensors, realized by grafting suitable complexes on appropriate solid matrices.
Il presente lavoro di tesi riguarda la sintesi, la caratterizzazione e lo studio delle proprietà attivate dalla luce (fotodegradazione, luminescenza persistente, sensing) di diversi materiali inorganici e di sistemi molecolari. Nella prima parte, viene presentato lo studio di materiali bifunzionali a base di bismuto per l’adsorbimento e la fotodegradazione di coloranti organici. Vengono discusse nuove procedure per la sintesi di nanostrutture di ossicloruri (BiOCl, Bi24O31Cl10, Bi12O17Cl2) e subcarbonato di bismuto. Modulando i parametri di sintesi (temperatura, pH, surfattante) ed utilizzando diversi trattamenti (termici e irraggiamento UV) sul materiale ottenuto, è stato possibile indurre una variazione della composizione chimica e conseguentemente della fase cristallina, della morfologia e delle proprietà ottiche. Ciò ha determinato proprietà adsorbenti e attività di fotodegradazione diverse nei confronti di due coloranti modello: metilarancio e rodamina B. Le nanostrutture più promettenti, a base (BiO)2CO3, sono in grado di adsorbire entrambi i coloranti, tra il 50 e il 95 %, nell’arco di 20 minuti. Inoltre, sotto irraggiamento con luce visibile sono in grado di foto-degradare il colorante rimanente in soluzione. La seconda parte riguarda lo studio di nanostrutture di gallato di zinco drogato con cromo (ZnGa2O4:Cr3+). Questo materiale è caratterizzato da interessanti proprietà di emissione nella regione del rosso-vicino infrarosso (600-900 nm) e, in particolare, da luminescenza persistente. Mediante tecnica sol-gel e trattamenti termici compresi tra 500 e 1000 °C, sono stati preparati film sottili omogenei in termini di composizione, struttura e spessore. Essi sono stati caratterizzati mediante diffrazione a raggi X (XRD), spettroscopia fotoelettronica a raggi X (XPS), microscopia a scansione elettronica (SEM) e spettroscopia ottica (assorbimento ed emissione). In un intervallo di temperature compreso tra i -190°C e i 250 °C, si è osservata una modulazione delle proprietà di emissione, indicando la possibilità di utilizzare in futuro questi materiali per lo sviluppo di sensori di temperatura. Per ottenere informazioni sito-specifiche e correlare le proprietà di luminescenza a quelle strutturali a corto raggio sono state impiegate tecniche avanzate di luce di sincrotrone quali X-Ray Absorption Spectroscopy (XAS) e X-Ray Excited Optical Luminescence (XEOL). I materiali inorganici possono inoltre essere impiegati come substrati o matrici per ospitare molecole funzionali. Accanto allo sviluppo del sistema inorganico, è fondamentale uno studio preliminare del sistema molecolare stesso, in termini di stabilità cinetica e termodinamica, topologia, funzionalità e reattività. In questo contesto, la terza parte del presente lavoro descrive lo studio di due complessi antenna lantanoidei luminescenti caratterizzati da un legante macrociclico (1,4,7,10-tetraazaciclododecano-1,4,7-acido triacetico, DO3A) per il disprosio ed uno aciclico (1,4,7-triazaeptano-1,1,7,7-acido tetraacetico, DTTA) per l’europio. Il comportamento della coppia in soluzione acquosa è stato studiato in presenza di acido dipicolinico (DPA). In particolare, è stato considerato l’effetto di un agente fortemente coordinante come il DPA sulle loro proprietà di emissione e la possibilità di sviluppare un sensore raziometrico per piccole molecole come il DPA. A questo scopo, il complesso di disprosio è stato utilizzato come riferimento e quello di europio come sonda per il riconoscimento di DPA che è un noto biomarker di spore batteriche. La variazione delle proprietà di emissione (forma ed intensità delle bande) ha messo in luce la presenza di interazioni tra il complesso sonda e l’acido dipicolinico. Con l’ausilio della risonanza magnetica nucleare (NMR) e con la spettrometria di massa è stato evidenziato l’instaurarsi di una reazione di scambio di leganti, con la formazione di [EuDPA2]-. Ciò indica che leganti macrociclici, dotati di una cavità preformata in grado di ospitare lo ione metallico, assicurano una maggior stabilità rispetto a leganti aciclici caratterizzati dallo stesso numero e tipologia di siti di coordinazione.

Les complexes luminescents d'ions lanthanides(III), de par leurs caractéristiques spectroscopiques, sont des alternatives intéressantes aux fluorophores organiques usuels pour des applications dans le domaine de la bioanalyse et de l'imagerie cellulaire. Les propriétés photophysiques de ces types de complexes sont notamment exploitées en tant que donneur de FRET en temps résolu permettant d'améliorer la sensibilité et la spécificité de la détection. Des développements récents ont aussi permis d'obtenir des sondes luminescentes pour le pH physiologique, pour divers analytes endogènes ou pour des compartiments cellulaires. Dans ce cadre, l'enjeu est d'obtenir des luminophores plus brillants pour une détection plus performante. Pour ceci, nous avons souhaité, par deux approches, apporter des modifications à une plateforme nonacoordinante pyridinophane présentant trois antennes pyridine et possédant trois bras acétate. D'une part, les bras complexants ont été diversifiés soit par d'autres motifs monodentes, soit par des motifs potentiellement bidentes, de manière à protéger l'ion lanthanide de la coordination de toute molécule d'eau qui limiterait l'efficacité de luminescence. La mesure des propriétés photophysiques des complexes d'europium ou de terbium a montré que l'introduction d'un bras coordinant phosphonate permettait de diminuer le degré d'hydratation des complexes, et que, par ailleurs, l'introduction d'un bras coordinant picolinate, portant la coordinance du ligand à 10, conduisait à des complexes exempts d'eau. D'autre part, il a été envisagé de modifier les chromophores pyridine de manière à rapprocher la longueur d'onde du maximum d'absorption de la fenêtre de transparence des milieux biologiques, et à augmenter le coefficient d'absorption molaire de l'édifice. Sur la base de travaux précédents, le motif chlorine a été choisi, synthétisé, et fonctionnalisé en vue de son couplage à un des noyaux pyridine du macrocycle pyridinophane
Lanthanide luminescent complexes are, through their spectroscopic properties, interesting alternatives to organic fluorophores for bioanalyses or cell imaging. Their photophysical properties are in particular used as time-resolved FRET donors that can improve the detection sensitivity and specificity. Recent developments afforded luminescent probes for physiological pH, several endogenous ions or for cell compartments. In this context, developing brighter luminophores is a major stake for a more efficient detection. Following this goal, we envisioned two approaches in order to modify a nonacoordinated pyridinophane platform bearing three pyridine antennae and three acetate pendant arms. First, the pendant arms have been modified, either by other monodentate moieties or by potentially bidentate moieties, in order to shield the lanthanide ion from any water molecule that could limit the luminescence efficiency. Europium or terbium complexes photophysical measurements showed that the introduction of a phosphonate coordinating arm decreased the number of coordinated water molecules, and that the introduction of a picolinate arm, leading to a decacoordinated ligand, afforded a water-free complex. Second, the pyridine chromophores were targeted both in order to bring the maximum absorption wavelength closer to the biological tissue transparency window and to increase the absorption coefficient of the structure. According to previous results (Borbas group), a chlorin antenna has been chosen, synthesized, and functionalized in order to couple this antenna to the pyridinophane macrocycle

This thesis presents investigations into structural and photophysical properties of naphthalenetetracarboxylic diimide (NDI) functionalised calixarenes and their corresponding lanthanoid complexes. Six new calixarene ligands were synthesied and fully characterised. Upon complexation, europium (III), ytterbium(III) and neodynium(III) luminescence can be induced by energy transfer from the NDI of ligand and/or calixarene aromatic backbone. The reduction of neutral NDI to NDI radical anion was successful, and the NDI radical anion also sensitised ytterbium(III) luminescence.

La chimie des cinnamates ortho-fonctionnalisés est particulièrement riche et variée, comme en témoigne le nombre important de méthodologies de synthèse reposant sur leur utilisation comme substrats précurseurs d'hétérocycles d'intérêt biologique. En effet, suivant la nature du groupe fonctionnel et les conditions opératoires, des substrats à base cinnamique ont déjà été exploités avec succès pour la construction d'un large panel de squelettes hétérocycliques, allant de systèmes cycliques à cinq chaînons (benzofurane, indole, ...) à des cycles à six chaînons (coumarine, quinolin(on)e, ...). Dans ce contexte, ma thèse avait pour objectif principal d'apporter une contribution à cette chimie propre aux cinnamates ortho-fonctionnalisés. Le premier objectif de mon travail a porté sur le développement de nouvelles méthodes de synthèse hétérocyclique employant des cinnamates ortho-fonctionnalisés comme précurseurs. D'une part, une méthode de synthèse de coumarines et de quinolones 3-trifluorométhylées a été mise au point à partir de d'ortho-hydroxy- et d'ortho-aminocinnamates. Une étude mécanistique a également été conduite et a permis de mettre évidence la nature radicalaire de la réaction de trifluorométhylation concernée. D'autre part, nous avons évalué avec succès le potentiel synthétique d'ortho-azidocinnamates pour la construction photoinduite d'indoles et de quinoléines. Le second objectif de mon travail a concerné la conception, la synthèse et l'évaluation photophysique/photochimique de nouvelles sondes photoactivables luminescentes à base d'ions lanthanides. Dans ce cas, le motif cinnamique a été installé sur un complexe de lanthanide non luminescent afin de jouer le rôle d'antenne photoactivable. Après une première étude ayant permis de prouver le concept, toute une série de composés a été préparée afin d'établir des relations structures-propriétés, relations qui nous ont finalement permis d'optimiser la performance de cette nouvelle classe de sondes luminescentes photoactivables
The chemistry of ortho-functionalized cinnamates is particularly rich and varied, as evidenced by the large number of methods using them as building blocks for the synthesis of biologically-relevant heterocycles. In fact, depending on the nature of the functional group and the reaction conditions, various cinnamic-based substrates have already been successfully employed for the synthesis of a wide range of heterocyclic skeletons, ranging from five-membered ring systems (benzofuran, indole, ...) to six-membered rings (coumarin, quinolin(on)e, ...). In this context, the main goal of my thesis was to make a significant contribution to the chemistry peculiar to ortho-functionalized cinnamates. The first objective of my work dealt with the development of new methods for heterocyclic synthesis using ortho-functionalized cinnamates as building blocks. On one hand, a method for the regioselective synthesis of 3-trifluoromethylated coumarins and quinolones was elaborated starting from ortho-hydroxy- and ortho-aminocinnamates. The reaction mechanism of this trifluoromethylation reaction was further investigated and was found to involve radical participation. On the other hand, ortho-azidocinnamates proved suitable building blocks to achieve the construction of indoles and quinolines via a solvent-dependent photochemical process. The second objective of my work was devoted to the design, synthesis and photophysical/photochemical evaluation of new photoactivatable luminescent probes based on lanthanide ions. In this case, a non-luminescent lanthanide complex was equipped with a cinnamoyl residue in order to act as a photoactivatable sensitizer. A preliminary study allowed us to validate the concept "OFF/ON", and then a series of probes was prepared in order to establish relevant structure-property relationships, hence enabling the optimization of this novel class of photoactivatable luminescent probes

Ce travail de thèse visait la conception de marqueurs à base d'ions lanthanides pour le diagnosticprécoce de la maladie d'Alzheimer, à travers un transfert d'énergie avec des nanocristaux semi- conducteurs luminescents. Notre choix s'est porté sur des ligands polyaminophosphonatés de type pyridine-bis-pyrazolyl rendus réactifs vis-à-vis des biomolécules par la présence de groupements activés. Nous présentons la synthèse d'un ligand modèle incorporant seulement l'unité de photosensibilisation tridentate et des groupes phosphonatés. À partir de ce ligand, les complexes d'europium et de terbium synthétisés ont été caractérisés. Une grande stabilité et des propriétés de luminescence avantageuses ont été mises en évidence par nos études, notamment en ce qui concerne le complexe de terbium. Une méthode synthèse de ligands de ce type, fonctionnalisés par la présence de groupements réactifs a été développée et le marquage de biomolécules dont des marqueurs de la maladie d'Alzheimer a été réalisé avec succès. La synthèse d'un autre ligand phosphonaté associé de façon covalente à la biotine et l'utilisation de son complexe de terbium comme donneur d'énergie a permis de réaliser des expériences de transfert d'énergie avec divers accepteurs luminescents dont des nanocristaux semi-conducteurs.