Dissertations / Theses on the topic 'Circularly Polarized Luminescence (CPL)'

Iridium complexes with a chiral metal center and chiral carbons, Λ/Δ-(dfppy)₂Ir(chty-R) and Λ/Δ-(dfppy)2Ir(chty-S), were synthesized and characterized. These isomers have the same steadystate photophysical properties, and obvious offsets in ECD spectra highlight both the chiral sources. Each enantiomeric couple shows mirror-image CPL bands with a dissymmetry factor in the order of 10ˉ³.

Des ligands binaphtyle dérivés contenant des groupes donneurs P"=" O ont été utilisés pour la synthèse rationnelle de composés de coordination à propriétés multiples avec des unités M〖(hfac)〗_3. L'oxyde chiral de bisphosphine L a agi comme un ligand chélate donnant des espèces racémiques monomères de formule [〖{Ln(hfac)_3 L}〗_3] (Ln= Eu,Dy and Yb). Ces complexes ont été caractérisés structurellement et leurs propriétés physiques ont été étudiées à l'état solide. Le composé [〖{Eu(hfac)_3 L}〗_3] présentait une luminescence centrée sur le métal. Différemment, le ligand L n'a pas sensibilisé l'émission de luminescence pour [〖{Dy(hfac)_3 L}〗_3]. Cependant, ce dernier affichait un comportement SMM induit par l’application d’un champ magnétique. Le complexe [〖{Yb(hfac)_3 L}〗_3] était un exemple de field-induced SMM chiral et luminescent. Pour les espèces à base de Dy(III)- et Yb(III)-, l'aimantation s'est relâchée via un processus Raman similaire sous l'effet d'un champ magnétique externe. Tous ces composés sont sublimés lorsqu'ils sont chauffés à pression réduite. Ensuite, la chimie de coordination des ligands bisphosphates énantiopurs dérivés du binaphtyle (S)/(R)-L^n (n=1,3) and (S,S,S)/(R,R,R)-L^n (n=2,4) a été étudié. La réaction de ces ligands avec des quantités équimolaires des précurseurs métalliques [M(hfac)_3 (H_2 O)_2] (M=Y,Eu,Dy and Yb) a donné des polymères de coordination monodimensionnel et énantiopurs. Avec les ligands (S)/(R)-L^n (n=1,3), deux espèces polymorphes différentes pourraient être cristallisées en changeant les conditions de réaction et la nature de l'ion métallique. composés à base d’ion Dy(III) ont manifesté un comportement field-induced SMM et une émission de luminescence. La corrélation magnéto-optique et les résultats des calculs ab initio sont présentés. Le complexe 〖[Dy(hfac)_3 {(S)-L^1}]〗_n a montré de contributions multiples de la relaxation d'aimantation malgré la présence d'un seul centre cristallographique de Dy(III). La solubilisation des polymères de coordination 〖[M(hfac)_3 {(S)/(R)-L^1}]〗_n a provoqué une réorganisation structurale en espèces monomères de formule [M(hfac)_3 {(S)/(R)-L^1}]. Ceci a été démontré par spectroscopie NMR et calculs DFT. De manière similaire à l'état solide, le complexe [Dy(hfac)_3 {(S)-L^1}] a présenté un comportement field-induced SMM à plusieurs contributions. Les processus régissant la relaxation d'aimantation de 〖[Dy(hfac)_3 {(S,S,S)-L^2}]〗_n et 〖[Dy〖(hfac)〗_3 {(S)-L^3 }]〗_n ont été étudiés plus en détail en appliquant une stratégie de dilution magnétique et d'enrichissement isotopique avec (_ ^163)Dy(III) (I=1⁄2) et (_ ^164)Dy(III) (I=0). Malgré la minimisation des interactions dipolaires et l'absence de spin nucléaire, une forte dépendance de l'aimantation par le champ a toujours été observée. Les ligands (S)/(R)-L^n (n=1,3) et (S,S,S)/(R,R,R)-L^n (n=2,4) ont sensibilisé efficacement le luminescence des espèces à base d'Eu(III). Leur nature énantiopure a favorisé l'émission de CPL à la fois en solution et à l'état solide. Enfin, le comportement SMM induit par le champ et l'émission de CPL ont été observés dans le même composé en utilisant des centres Yb(III). L'utilisation du ligand L^5 à base de TTF et des unités chirales Yb〖{(R)/(S)"-" facam}〗_3 a donné les dimères énantiopurs 〖[Yb〖{(R)/(S)"-" facam}〗_3 (L^5)]〗_2. Le fragment TTF conférait une activité redox. L'application d'un champ statique modéré a révélé une lente relaxation de l'aimantation. L'excitation directe des états ILCT de L^5 a sensibilisé la luminescence centrée sur le métal. De plus, des émissions NIR-CPL en solution et à l'état solide ont été détectées. Le complexe 〖[Yb〖{(R)/(S)"-" facam}〗_3 (L^5)]〗_2 était un SMM redox induit par champ chiral affichant une émission CPL. Avec les complexes à base d' Yb(III) coordonnés par les ligands (S)/(R)-L^n (n=1,3) et (S,S,S)/(R,R,R)-L^n (n=2,4), ce sont les premiers exemples d'émission NIR-CPL à l'état solide documentés pour les complexes moléculaires
Binaphthyl-derived ligands containing P"=" O donor groups were employed for the rational synthesis of multi-properties coordination compounds with M〖(hfac)〗_3 units. The chiral bisphosphine oxide L acted as a chelate ligand giving monomeric racemic species of formula [〖{Ln(hfac)_3 L}〗_3] (Ln= Eu,Dy and Yb). These complexes were structurally characterized and their physical properties were studied in solid state. The compound [〖{Eu(hfac)_3 L}〗_3] exhibited metal-centred luminescence. Conversely, the ligand L was not able to sensitise luminescence emission for [〖{Dy(hfac)_3 L}〗_3]. However, the latter displayed field-induced SMM behaviour. The complex [〖{Yb(hfac)_3 L}〗_3] was an example of a chiral luminescent field-induced SMM. For both Dy(III)- and Yb(III)-based species, the magnetization relaxed via a similar Raman process under the effect of an external magnetic field. All these compounds sublimated when heated at reduced pressure. Subsequently, the coordination chemistry of the enantiopure binaphthyl-derived bisphosphate ligands (S)/(R)-L^n (n=1,3) and (S,S,S)/(R,R,R)-L^n (n=2,4) was studied. Reaction of these ligands with equimolar quantities of the metal precursors [M(hfac)_3 (H_2 O)_2] (M=Y,Eu,Dy and Yb) yielded enantiopure 1D-coordiantion polymers. With ligands (S)/(R)-L^n (n=1,3), two different polymorphic species could be crystallised by changing reaction conditions and nature of the metal ion. The Dy(III)-based compounds manifested field-induced SMM behaviour and luminescence emission. Magneto-optical correlation and results from ab initio calculations are presented. The complex 〖[Dy(hfac)_3 {(S)-L^1}]〗_n showed multiple contributions of the magnetization relaxation despite the presence of a single crystallographic Dy(III) centre. Solubilization of the coordination polymers 〖[M(hfac)_3 {(S)/(R)-L^1}]〗_n caused a structural reorganization to monomeric species of formula [M(hfac)_3 {(S)/(R)-L^1}]. This was demonstrated by NMR spectroscopy and DFT calculations. Similarly to the solid state, complex [Dy(hfac)_3 {(S)-L^1}] exhibited a multi-contribution field-induced SMM behaviour. The processes governing the magnetization relaxation of 〖[Dy(hfac)_3 {(S,S,S)-L^2}]〗_n and 〖[Dy〖(hfac)〗_3 {(S)-L^3 }]〗_n were further investigated by applying a strategy of magnetic dilution and isotopic enrichment with (_ ^163)Dy(III) (I=1⁄2) and (_ ^164)Dy(III) (I=0). Despite the minimisation of the dipolar interactions and the absence of nuclear spin, a strong field dependence of the magnetization was still observed. The ligands (S)/(R)-L^n (n=1,3) and (S,S,S)/(R,R,R)-L^n (n=2,4) efficiently sensitised the luminescence of the Eu(III)-based species. Their enantiopure nature promoted CPL emission in both solution and solid state. Finally, field-induced SMM behaviour and CPL emission were observed in the same compound by employing Yb(III) centres. The use of the functionalized TTF-based ligand L^5 and chiral Yb〖{(R)/(S)"-" facam}〗_3 units gave the enantiopure pair of dimers 〖[Yb〖{(R)/(S)"-" facam}〗_3 (L^5)]〗_2. The TTF fragment conferred redox activity. The application of a moderate static field revealed slow relaxation of the magnetization. Direct excitation of the ILCT states of L^5 sensitised the metal-centred luminescence. Moreover, both solution and solid state NIR-CPL emission were detected. The complex 〖[Yb〖{(R)/(S)"-" facam}〗_3 (L^5)]〗_2 was a redox chiral filed-induced SMM displaying CPL emission. Together with the Yb(III)-based complexes coordinated by the ligands (S)/(R)-L^n (n=1,3) and (S,S,S)/(R,R,R)-L^n (n=2,4), these are the first documented solid state NIR-CPL emissive examples for molecular complexes

Dans ce travail, nous nous sommes concentrés sur la création de nanostructures chirales optiquement actives en fabriquant des nanohélices de silice fluorescente afin d’obtenir des matériaux souple, nanométriques, optiquement actifs pour des applications en tant que matériaux nanophotoniques. Dans cette optique, des nanohélices de silice chirales ont été utilisées pour greffer et organiser des nanocristaux inorganiques fluorescents achiraux tels que des quantums dots, des chromophores, des molécules et des polymères fluorescents selon différentes approches. Ces hélices inorganiques ont été formées par procédé sol-gel en utilisant des auto-assemblages hélicoïdaux organiques de molécules amphiphiles (amphiphile gemini cationique, avec un contre-ion chiral le tartrate) en tant que modèles. Tout d'abord, la surface de la silice hélicoïdale a été fonctionnalisée par l’APTES afin de greffer des quantum dots inorganiques ZnS-AgInS2 possédant divers ligands. Dans la deuxième partie, le polymère de dérivé anthracénique fluorescent a été organisé par dépôt et adsorption à la surface de silice hélicoïdale. Afin d’étudier les propriétés chiroptiques, différentes caractérisations ont été réalisées telle que la spectroscopie du dichroïsme circulaire (CD) et celle de la luminescence circulairement polarisée (CPL).Le premier chapitre présente l’étude bibliographique sur différents systèmes d’auto-assemblage organiques chiraux et leurs propriétés chiroptiques. Les études sur la formation de systèmes auto-assemblés chiraux dans différentes conditions, leur morphologie structurale, les techniques de fabrication et leurs applications sont discutées suivies de l'utilisation de nanocristaux fluorescents, à savoir, les quantums dots (QD) et les polymères fluorescents achiraux sur lesquels les propriétés chiroptiques peuvent être obtenues et leurs applications dans les nanodispositifs optiques, les capteurs et la nano-photonique.Dans la première partie du deuxième chapitre, différentes techniques de caractérisation telles que le microscope électronique en transmission (TEM), le microscope électronique en transmission haute résolution (HRTEM), la microscopie confocale, la spectroscopie UV-Vis, celle de la fluorescence, du dichroïsme circulaire (CD) et de la luminescence circulairement polarisée (CPL) sont décrites. Dans la deuxième partie, la synthèse du gemini 16-2-16 ainsi que son mécanisme d'auto-assemblage, et sa transformation en réplica de silice par l'intermédiaire de la chimie sol-gel sont décrits. Ces nanohélices de silice sont fonctionnalisées par le 3-aminopropyltriéthoxysilane (APTES). Leur analyse est effectuée par analyse thermogravimétrique (TGA) et analyse élémentaire (EA).Dans le troisième chapitre, nous nous sommes concentrés sur la synthèse de QDs inorganiques ((ZnS)x-1(AgInS2)x) avec différentes compositions rapport molaire et leurs caractérisations par TEM, TGA, EA, spectroscopie infrarouge à transformée de Fourier (FTIR), mesures de potentiel zêta, spectroscopie d'absorption et d'émission. Quatre types de ligands ont été utilisés, par échange de ligand, pour recouvrir les QDs : sulfure d'ammonium (AS), acide 3-mercaptopropionique (MPA), l-cystéine (L-Cys) et l'oleylamine (OLA). Ces QDs sont greffés à la surface des hélices de silice modifiée par de l’amine suite à des interactions ioniques. Diverses techniques ont été utilisées pour confirmer leur greffage à la surface des hélices de silice, et les propriétés optiques ont été étudiées par spectroscopie d'absorption et d'émission. Après le greffage, différents résultats ont été observés selon le ligand utilisé : la caractérisation par TEM montre que les QDs sont greffés à la surface des hélices de silice. [...]
In this work, we focused on the creation of optically active chiral nanostructures by fabricating fluorescent silica nanohelices in order to obtain optically active nanoscale soft materials for applications as nanophotonics materials. For this purpose, silica chiral nanohelices were used for grafting and organizing achiral fluorescent inorganic nanocrystals, dyes, molecules, and fluorescent polymers through different approaches. These inorganic helices were formed via sol-gel method using organic helical self–assemblies of surfactant molecules (achiral and cationic gemini surfactant, with chiral counterion, tartrate) as templates. First, the surface of helical silica was functionalized by APTES in order to graft inorganic quantum dots ZnS-AgInS2 with different capping ligands. In the second part, fluorescent anthracene derivative polymer was organized via deposition and absorption on the surface of helical silica. To investigate the chiroptical properties, circular dichroism and circularly polarised luminescence characterization were performed.In the first chapter, the bibliographic study on different chiral organic self-assembling systems and their chiroptical properties are shown. The studies on the formation of chiral self-assembled systems in different conditions, structural morphology, fabrication techniques and their applications are discussed followed by the use of fluorescent nanocrystals, i.e., quantum dots (QDs) and achiral fluorescent polymers on which chiroptical properties can be obtained and their applications in optical nanodevices, sensors, and nano-photonics.In the first part of the second chapter, different characterisation techniques such as transmission electron microscope (TEM) , high resolution transmission electron microscope (HRTEM), and confocal microscopy, UV-Vis spectroscopy and fluorescence spectroscopies, as well as circular dichroism (CD) and circularly polarised luminescence (CPL) spectroscopies are described. In the second part, the synthesis of Gemini 16-2-16 as well as their self-assemblies mechanism, and their transformation to silica replica via sol-gel chemistry are described. These silica nanohelices are functionalized by 3-aminopropyltriethoxysilane (APTES). Their analysis is performed by Thermogravimetric analysis (TGA) and elementary analysis (EA).In the third Chapter, we focused on the synthesis of inorganic ((ZnS)x-1(AgInS2)x) QDs with different compositions molar ratio and its characterizations by TEM, TGA, EA, Fourier-transform infrared spectroscopy (FTIR), zeta potential measurements, absorption, and emission spectroscopy. Four types of ligands were used to cap the QDs via phase ligand exchange as follows: ammonium sulphide (AS), 3-mercaptopropionic acid (MPA), l-cysteine (L-Cys) and the fourth one is oleylamine (OLA). These QDs are grafted on the surface of amine-modified silica helices through ionic interaction. Various techniques were used to show the grafting of QDs on the surface of silica helix, and their optical properties were studied using absorption and emission spectroscopy. After grafting, in each case of ligands, different results were observed as follows: The TEM characterization shows that QDs are grafted on the surface of silica helices. In the case of AS-capped QDs, the helical morphology of silica helices after grafting is destroyed; therefore the further ananlysis was not possible. While, in the cases of QDs with three other ligands MPA, OLA and L-cys, dense and homogeneous grafting of the QDs were observed by TEM and the helical morphology was preserved after their grafting. The HRTEM images were taken on the MPA-QDs@silica helices and energy-dispersive x-ray (EDX) analysis was performed in STEM mode, confirming the QDs elements present on the silica surfaces. [...]

A series of studies has been undertaken to facilitate the identification and development of chiral lanthanide complexes that are able to report on changes in their local environment through modulation of the circular polarization of their emission. Reports of such systems remain relatively rare in the literature, notwithstanding the prevalence and importance of chirality in biological systems. The work described herein is separated into five chapters, the first of which comprises a discussion of relevant background information, along with a comprehensive review of responsive lanthanide-based CPL probes reported to date. A classification of these probes is built up, which informs the content of the following three chapters. Chapter 2 describes work undertaken in the pursuit of a novel lanthanide-based system for use as a CPL probe for the detection of proteins. The synthesis of an enantiopure lanthanide complex was undertaken and characterisation of this system carried out with reference to a structurally related racemic complex. A series of comparative investigations designed to probe the relative protein binding capability of these complexes was subsequently performed, which revealed that the observation of induced CPL from racemic lanthanide systems may be brought about by a change in complex constitution. This is the first example of such an effect from a well-defined racemic lanthanide complex in solution. Chapter 3 goes on to detail studies undertaken to demonstrate the utility of this racemic lanthanide system as a probe for chiral detection. Chapter 4 describes investigations carried out in an attempt to identify new systems exhibiting chiral quenching effects in solution. Initially, two pairs of enantiomeric electron-rich quenching species were assessed for their ability to quench the emission from an enantiopure DOTA-derived lanthanide complex differentially. Subsequently, investigations were focussed on examining the quenching of emission from novel enantiopure lanthanide complexes based on a 1,4,7-triazacyclononane framework, using cobalt complexes as the quenching species. Finally, Chapter 5 contains experimental procedures for each compound synthesised, as well as general experimental procedures.

La polarisation de la lumière, bien que connue depuis fort longtemps, pourrait être plus exploitée. Cependant, de plus en plus d’entreprises de pointe dans les domaines de la sécurité et la transmission d’information commencent à l’utiliser. Une raison de la sous-exploitation actuelle de la polarisation vient des méthodes de polarisation, qui ont une transmission de la lumière limitée (généralement jusqu’à 45%). Afin d’outrepasser cette limite physique, un moyen est d’utiliser des matériaux fluorescents émettant une lumière polarisée. Cependant, la synthèse et la purification de tels matériaux sont compliquées et obtenir les deux énantiomères n’est pas toujours possible. Ce travail se concentre sur une nouvelle méthode de synthèse, plus simple, utilisant des nano-structures hybrides ou inorganiques hélicoïdale, et des luminophores organiques pouvant interagir ensemble. L’agrégation chirale des chromophores autour des structures formera ainsi des nano-objets fluorescents chiraux. Le premier chapitre explique comment la chiralité est aujourd’hui présente dans tous les domaines et à toutes les échelles, des molécules aux objets du quotidien. Nous y étudierons également l’induction de la chiralité à différentes échelles. Le second aspect de ce travail, l’interaction lumière-matière, sera également mis en avant, aussi bien concernant l’absorption que l’émission lumineuse, mais aussi en quoi l’assemblage des molécules peut affecter ces propriétés. Nous nous pencherons également sur les cas très particuliers du dichroïsme circulaire et de la luminescence circulairement polarisée. Pour finir, nous verrons quels sont les matériaux actuels existant pour obtenir ces propriétés et quels sont leurs inconvénients. Afin d’outrepasser ces défauts, nous avons choisi d’utiliser deux systèmes. Le premier, constitué de nano-hélices organiques dans une coque de silice a pour avantage d’utiliser à la fois une induction de chiralité par assemblage des chromophores organiques, mais aussi une seconde induction de la chiralité à l’échelle moléculaire. L’inconvénient étant que ce système n’est pas très robuste à un changement d’environnement. Pour résoudre cet inconvénient, nous n’avons conservé, dans un second temps, que la coque de silice afin de l’utiliser comme patron pour supporter le greffage covalent de luminophores à sa surface. Dans le second chapitre, la méthode de synthèse des nano-structures sera présentée. De même le choix des différents luminophores utilisés dans ces travaux sera justifié, et leur voie de synthèse, expliquée. Enfin, les différentes méthodes de caractérisation seront détaillées. Le troisième chapitre portera sur les résultats obtenus lors de l’intégration de chromophores non-chiraux dans les hélices hybrides, ou leur de greffage sur les structures inorganiques. Nous y verrons l’importance à la fois de l’assemblage intermoléculaire, mais aussi de l’interaction avec un environnement chiral, pour l’induction de chiralité dans le but d’obtenir dichroïsme circulaire et luminescence circulairement polarisée. Les différents chromophores utilisés y sont présentés et comparés permettant la mise en évidence des principaux facteurs aidant à l’induction de chiralité pour chaque type de structure. Enfin, un dernier chapitre s’intéressera à des systèmes plus complexes utilisant des molécules présentant en solution des propriétés chiro-optiques, ou ayant la capacité de s’agréger en nano-structures ayant de telles propriétés, et ce afin de savoir si leurs propriétés sont ajustables grâce à l’utilisation des hélices hybrides pour leur imposer une agrégation spécifique. Une dernière approche a également été étudiée, en synthétisant des quantum-dots carbonés fluorescents à partir des nano-structures hybrides. Ces quantum-dots, s’ils conservent la forme de la structure initiale, pourraient posséder un dichroïsme circulaire et une luminescence circulairement polarisée sans besoin de les complexer avec une molécule chirale
The polarization of light, despite being known since long time, is recently at the center of renewed interest. More and more high technology companies in the fields of safety and information transmission are starting to exploit this property. One bottleneck for their use comes from the limitation in the light transmission of current methods of polarization (typically up to 45%). In order to overpass this physical limitation, one possible approach would be to use fluorescent materials emitting polarized light. However, the synthesis and purification of such materials is complex and obtaining both enantiomers is not always possible. The current work focus on a new synthetic pathway, possibly simpler and more versatile, using chiral hybrid or inorganic nano-helices and organic fluorophores interacting together. The aggregation of chromophores around the template will form chiral fluorescent nano-objects. The first chapter explains how chirality is present in many fields and at every scale, from molecules to daily objects. We will discuss the way of inducting or transferring chirality. The second facet of this work, light-matter interactions, will also be explained, concerning both absorption and emission of light, but also on how molecular assembly can affect these properties. We will study into detail the very particular case of circular dichroism and circularly polarized luminescence. Finally, we will see the existing systems that are used to obtain these properties and the drawback of these materials. In this work, we chose to use two systems. The first, constituted of organic nano-helices in a silica shell, has the advantage of using the organic template confined in chiral nano-space to induce chirality to the organic chromophores in interaction with them molecularly, but also through aggregation due to the confinement. The disadvantage being that this system is not robust toward environmental changes. The alternative approach is to use the silica shell as an inorganic template for the covalent grafting of fluorophores onto its surface. In the second chapter, the method for the synthesis of nano-structures is described, along with an explanation on the choice and synthesis of the chromophores used in this study. Finally, the characterization processes used are detailed. The third chapter will focus on the results we obtained when integrating achiral chromophores into hybrid helices or by grafting then onto the silica surface. We will see the importance of the intermolecular assembly and of the interaction with a chiral environment to obtain circular dichroism and circularly polarized luminescence through chiral induction. Various fluorophores are presented and compared allowing the understanding of the key parameters for chirality induction of each type of structure.In the last chapter, more complex systems are studied using molecules presenting chiroptical properties in solution state or having the ability to form self-assemblies showing such properties. The objective will be to tune the chiroptical properties of these chromophores, by the use of hybrid helices to force a specific organization. The last part will focus on the synthesis of fluorescent carbon based quantum dots using hybrid structures. These quantum dots, can retain the shape of the original structure and show circular dichroism or circularly polarized luminescence without needing to form a complex with an external source of molecular chirality

Dans le cadre de ma thèse, de nouveaux complexes de métaux de transitions (rhénium, iridium, cuivre, or) chiraux possédant des ligands NHC-hélicéniques ont été synthétisés et les propriétés chiroptiques et photophysiques ont été étudiées. Le premier sujet d’étude s’est focalisé sur l’étude de complexes de rhénium(I) cyclométallés par des ligands hélicéniques-NHC de type (N^C:) émettant de la phosphorescence circulairement polarisée. Une influence du design du ligand, des ligands ancillaires et de la géométrie des complexes sur les propriétés chiroptiques et photophysiques a été observée. Le deuxième projet a été consacré à l’étude de nouveaux complexes chiraux d’iridium cyclométallés possédant un ou plusieurs ligands N-[6]helicenyl-benzimidazolylidène. L’attention s’est ensuite portée sur des complexes possédant des ligands monodentes. Ainsi, dans le cadre d’un troisième projet, un complexe de cuivre portant un ligand NHC-hélicénique démontrant des propriétés de fluorescence circulairement polarisée a pu être obtenu avec succès. Enfin, des complexes chiraux d’or coordinés par des ligands hélicéniques-NHC ont été préparés. Pendant ce projet, les propriétés électroniques (sigma-donatrice et pi-acceptrice) d’un carbène hélicénique ont été quantifiées
My PhD work was dedicated to the synthesis and the study of novel chiral transition metal complexes (rhenium, iridium, copper, gold) bearing NHC-helicenes ligands and to the study of their chiroptical and photophysical properties. The first subject focused on the preparation and the study of CP-phosphorescent complexes of cyclometalated rhenium(I) complexes bearing NHC-helicenic (N^C:) ligands. The influence of the ligand design, ancillary ligands and geometry of the complexes on the chiroptical and photophysical properties has been highlighted. In the second project, we have prepared novel chiral cyclometalated iridium complexes bearing one or multiple N-[6]helicenyl- benzimidazolylidene ligands.Then, the attention has been focused on monodentate complexes. Thus, in the third project, a chiral copper complex bearing a helicenic-NHC ligand which emits circularly polarized fluorescence was successfully obtained. Finally, chiral monodentate helicenic-NHC gold(I) complexes have been prepared. During this project, the electronic properties (sigma-donating et pi-accepting) of a helicenic-NHC were investigated

Les dispositifs d’affichage prennent de plus en plus d’importance dans notre monde connecté. Dans un souci d’économie d’énergie, de protection de l’environnement et d’optimisation des performances des écrans, la technologie OLED (pour Organic Light Emitting Diodes) se présente comme l’une des plus prometteuse. Toutefois, pour une utilisation courante et efficace au sein de dispositifs d’affichage, les molécules émettrices composant les OLEDs doivent posséder deux propriétés : elles doivent émettre de la fluorescence retardée (TADF pour Thermally Activated Delayed Fluorescence) et de la lumière circulairement polarisée (CPL pour Circularly Polarized Luminescence). La première permet de convertir, théoriquement, la totalité de l’énergie électrique en lumière alors que la seconde retransmet l’entièreté de l’intensité lumineuse en passant à travers des filtres composant l’écran sans atténuation. Aujourd’hui, peu de molécules entièrement organique présentent ces caractéristiques et ce domaine d’étude n’en est qu’à ses prémices.Cette thèse se porte sur plusieurs aspects de cette thématique. Elle se développe en quatre parties : une étude structure-propriétés ayant pour but de corréler l’efficacité de plusieurs designs moléculaires avec les propriétés de fluorescence retardée et d’émission de lumière circulairement polarisée ; l’observation de l’influence de la diastéréoisomérie sur la TADF et la CPL ; la synthèse et la caractérisation de molécules présentant des caractéristiques de « switch-chiroptiques » ; et l’étude de l’influence du nombre de groupements chiraux sur un même type de synthon moléculaire
Display devices are more and more involved in our connected world. In a prospect of energy saving, protection of the environment and optimization of display performances, the Organic Light Emitting Diode (OLED) technology appears as one of the most promising alternative. However, widespread and efficient display devices require organic emitting molecules merging both Thermally Activated Delayed Fluorescence (TADF) and Circularly Polarized Luminescence (CPL). TADF enables to convert, theoretically, the whole electric energy into light, whereas CPL relays light intensity through screen’s filters without attenuation. Nowadays, organic molecules combining TADF and CPL properties remain rare.The aim of this work is to develop new molecules with both properties. Four main projects have been carried out to fulfill this purpose and are described herein: the first one consists in a structure-properties relationship in order to give guidelines for molecular design merging TADF and CPL; then the influence of diastereoisomerism on the emission of circularly polarized luminescence and delayed fluorescence is described; following this, the synthesis and characterization of molecules displaying “chiroptical-switch” have been performed; finally, the impact of the number of chiral units and of the geometry on a single molecule is outlined

La chiralité est une propriété essentielle des molécules naturelles, intervenant dans de nombreux mécanismes biologiques du vivant. Elle peut être caractérisée grâce à l’activité chiroptique des molécules chirales, à travers le dichroïsme circulaire, le pouvoir rotatoire, la dispersion rotatoire optique ou encore la luminescence polarisée circulairement. Les molécules biaryles et hélicéniques possèdent des propriétés chiroptiques intenses et sont des molécules de choix pour leurs applications dans de nombreux domaines, de la catalyse à l’optoélectronique.Les travaux réalisés au cours de cette thèse traitent de la synthèse de nouvelles molécules biaryles et hélicénoïdes et de l’étude de leurs propriétés spectroscopiques en interaction avec leur environnement. Dans un premier temps, nous avons effectué la synthèse de différentes familles de molécules à géométrie hélicoïdale possédant des systèmes aromatiques étendus. Afin de cibler des applications biologiques, nous avons également mis au point leur hydrosolubilisation par introduction de chaînes PEG. Dans un deuxième temps, nous nous sommes consacrés à l’étude de leurs propriétés spectroscopiques et en particulier chiroptiques en fonction de leur structure et de la dépendance de ces propriétés en présence de protons, de métaux ou d’acide désoxyribonucléique (ADN). Au cours de cette étude, une réaction photochimique inattendue a permis d’obtenir un produit photogénéré inédit présentant des interactions sélectives avec des ADN G-quadruplexes. Enfin, afin d’exploiter la modularité contrôlée des propriétés chiroptiques, nous avons travaillé sur un projet de conception de nouvelles molécules chirales pouvant détecter sélectivement les sucres en modifiant le squelette de ces molécules avec des acides boroniques
Chirality is an essential property of natural molecules, involved in many living biological mechanisms. It can be characterized by the chiroptical activity of chiral molecules, through circular dichroism, rotatory power, optical rotatory dispersion or circularly polarized luminescence. Biaryl and helicenic molecules are known for their intense chiroptical properties and they can be used for their applications in many fields, going from catalysis to optoelectronics.The research carried out during this thesis deals with the synthesis of new biaryl and helicenoid molecules and the study of their spectroscopic properties in interaction with their environment. First, different families of helicoidal molecules with extended aromatic systems have been synthesized. In order to target biological applications, their hydrosolubilization was achieved by the addition of PEG chain. Then, we focused on their spectroscopic and especially chiroptical properties and their modulation according to their structures, their interaction with protons, metals or deoxyribonucleix acid (DNA). During these studies, we experienced an unexpected photochemical reaction, which lead to a new photogenerated product revealing selective interactions with DNA G-quadruplexes. Finally, in order to exploit the controlled modularity of chiroptical properties, new chiral molecules that selectively detecting sugars by with boronic acids have been designed

Des morphologies contrôlées de nanocristaux de semi-conducteurs II – VI traditionnels à base de cadmium (NCs) sont présentées. Différentes morphologies peuvent être obtenues en utilisant le processus d'extraction et de purification à la tri-n-octylphosphine (TOP), tels que les nanodots, les nanofleurs, les têtards, les bâtonnets (dot-in-rods) et les tétrapodes. Les objets appelés CdSe/CdS (DRs) ont été spécifiquement choisis pour la poursuite de l'étude sur la chiralité et la photodéposition en raison de leur chiralité potentielle induite par le ligand et de leurs performances catalytiques. Le mécanisme de transmission chirale induite par un ligand a été étudié par un procédé top-down de gravure de domaine sélectif. Les résultats ont montré que lors de la comparaison des signaux de chiralité d'une nanoparticule individuelle, la couche de coquille avait un impact négatif sur la chiralité du premier pic d'exciton, mais une corrélation positive sur la chiralité d'absorption de la coquille. Nous présentons pour la première fois les signaux de luminescence à polarisation circulaire (CPL) de chiralité induite dans des nanoplaquettes deCdSe / CdS (NPL) synthétisées par une approche en une étape. La chiralité des nanocristaux semi-conducteurs de morphologies différentes induite par le ligand est étudiée plus en détail, et les activités de dichroïsme circulaire (CD) et de CPL observées sont étroitement associées aux caractères géométriques des nanostructures tels que l'épaisseur de la coque et le rapport d'aspect des NR CdSe/CdS . Enfin, le mécanisme de croissance par photodéposition induite par laser de nanocristaux d'or sur des bâtonnets préformés de CdSe/CdS (DRs) est abordé. Les nanoparticules HNPs Au-CdSe/CdS sont obtenues en utilisant une lumière laser bleue. Les effets du capteur de trous pour la synthèse des HNPs à pointe unique sont étudiés en profondeur pour la première fois. De plus, d'autres paramètres sont également étudiés, tels que l'intensité d'irradiation, le temps de dépôt, le rapport Au / DRs, etc. Nos résultats sont en bon accord avec un modèle développé pour la croissance d'un seul nanocristal Au en surface du DR
Controlled morphologies of traditional cadmium-based II–VI semiconductor nanocrystals (NCs) are presented. Different morphologies can be achieved by using the tri-n-octylphosphine (TOP) extraction and purification process, such as nanodots, nanoflowers, tadpoles, dot-in-rods and tetrapods. CdSe/CdS dot-in-rods (DRs) were specifically chosen for the further study on chirality and photodeposition due to its potential ligand-induced chirality and catalytic performances. The mechanism of ligand-induced chiral transmission was studied by the top-down selective domain etching process. The results showed that when comparing the chirality signals of an individual nanoparticle, the shell layer had a negative correlation with the first exciton peak chirality, but positive correlation with the shell absorption chirality. We present the induced chirality circularly polarized luminescence (CPL) signals in CdSe/CdS nanoplates (NPLs) synthesized by a one-pot approach for the first time. The ligand induced chirality of semiconductor nanocrystals with different morphologies are further studied, and the observed circular dichroism (CD) and CPL activities are closely associated to the geometrical characters of the nanostructures such as the shell thickness and the aspect ratio of the CdSe/CdS Tadpoles. Finally, the laser-induced photodeposition growth mechanism of gold nanocrystals onto preformed CdSe@CdS dot-in-rods (DRs) is presented. The hybrid NPs (HNPs) Au-CdSe/CdS are achieved by using a blue-laser light. The effects of the hole scavenger for the synthesis of single-tipped HNPs are studied deeply for the first time. Additionally, other parameters are also studied, such as the irradiation intensity, the deposition time, the Au/DRs ratio and so on. Our results compare quite well with a model developed for the growth of single Au nanocrystal

This Ph.D. thesis describes the versatility of metal complexes with tris(2-pyridylmethyl)amine (TPMA) based ligands to be used either as self-assembling molecular scaffolds with application on molecular recognition and chiroptical probing, or as active catalysts in atom transfer radical polymerization and hydrogen evolving catalysis reactions. Quantitative chirality determination is fundamental due to the broad effect that stereochemistry has in many different scientific fields. Within this subject, there is a strong urge to develop fast and effective methods to perform stereochemical analysis to couple with high throughput screening methods for production or analysis of biological samples. Chiroptical methods are able to provide the speed and accuracy that enantiomeric excess determination measurement needs. Within that scope, three molecular probes for amino acids have been developed allowing to perform enantiomeric determination and absolute configuration by measuring the induced circular dichroism (CD), vibrational circular dichroism (VDC) or circularly polarized luminescence (CPL). The reported systems were able to provide reliable information about the chirality of the studied analytes. In this dissertation the mechanistic investigation for the elucidation of the self-assembly process of TPMA with amino acids and metals is described. The complex equilibrium that yields the dimeric supramolecular architectures responsible for the chiroptical signals is exposed. The main factor that affects the final products of the reaction as well. Then the effects on the chiroptical response when changing the metal ions on the main structure are reported. Some impressive results were obtained by using Co (II) instead of Zn (II) on the VCD measurements. It was actually possible to enhance the signal intensity by two orders of magnitude. Furthermore, after modifying the initial ligand structure to add a quinolinic moiety in order to give fluorescent properties to the system, it was possible to obtain CPL bands. Moreover, the versatility of the studied ligands was assessed in other areas like catalysis. Eight novel copper complexes were synthesized and applied as active catalysts in atom transfer radical polymerization (ATRP). Hidroxyquinolinic based cobalt, nickel and iron complexes were evaluated as potential catalysts for hydrogen evolving reactions with positive results.
Questa tesi di dottorato descrive la versatilità dei complessi metallici con leganti tris(2-piridilmetil)amminici (TPMA) da utilizzare come scaffold molecolari autoassemblanti con applicazione sul riconoscimento molecolare e sonde chiroptiche, o come catalizzatori attivi nella polimerizzazione radicale a trasferimento atomico e reazioni di catalisi di sviluppo di idrogeno. La determinazione quantitativa della chiralità è fondamentale a causa dell'ampio effetto che la stereochimica ha in molti campi scientifici diversi. All'interno di quest’area, esiste una grande necessità di sviluppare metodi rapidi ed efficaci per eseguire analisi stereochimiche da abbinare a metodi di screening ad alto rendimento per la produzione o l'analisi di campioni biologici. I metodi chiropici sono in grado di fornire la velocità e la precisione necessarie per la determinazione dell’eccesso enantiomerico. Con questo obiettivo sono state sviluppate tre sonde molecolari per amminoacidi che consentono di eseguire la determinazione enantiomerica e la configurazione assoluta misurando il dicroismo circolare indotto (CD), il dicroismo circolare vibrazionale (VDC) o la luminescenza circolare polarizzata (CPL). I sistemi riportati sono stati in grado di fornire informazioni affidabili sulla chiralità degli analiti studiati. In questa dissertazione viene descritta l'indagine meccanicistica per la delucidazione del processo di auto-assemblaggio di TPMA con amminoacidi e metalli. Viene esposto il complesso equilibrio che produce le architetture supramolecolari dimeriche responsabili dei segnali chiropici. Il fattore principale che influisce anche sui prodotti finali della reazione. Quindi vengono riportati gli effetti sulla risposta chiropica al cambiare degli ioni metallici sulla struttura principale. Alcuni risultati significativi sono stati ottenuti utilizzando Co (II) invece di Zn (II) sulle misurazioni VCD. In realtà è stato possibile aumentare l'intensità del segnale di due ordini di grandezza. Inoltre, dopo aver modificare la struttura del legante iniziale per aggiungere un gruppo chinolinico al fine di conferire proprietà fluorescenti al sistema, è stato possibile ottenere le bande CPL. In aggiunta, la versatilità dei leganti studiati è stata valutata in altre aree come la catalisi. Otto nuovi complessi di rame sono stati sintetizzati e applicati come catalizzatori attivi nella polimerizzazione radicale a trasferimento atomico (ATRP). I complessi cobalto, nichel e ferro idrossichinolinici sono stati valutati come potenziali catalizzatori per reazioni di sviluppo di idrogeno con risultati positivi.

An improved understanding of the fluorescent excited states of chlorophyll in Photosystem II (PSII) is needed for several aspects of photosynthesis research. This thesis describes an investigation into these excited states, carried out using circularly polarised luminescence (CPL) spectroscopy. The CPL signal of photosynthetic proteins arises due to exciton interactions between chlorophyll molecules within the enzyme, in a similar manner to the better-known circular dichroism (CD) technique. Measurements were carried out at low temperature on purified preparations of the PSII core complex and two of its substituents, the proximal antenna proteins CP43 and CP47. Development of the low-temperature CPL measurement technique was a major part of the work. This was necessary to demonstrate that polarisation artifacts were small, and hence to ensure that circular polarisation was measureable with the required precision (within 1 part in 10^4). The utility of temperature-dependent CPL measurements in the range of 2– 120 K was demonstrated on the already well-characterised CP43 protein. The lowest-energy excited states of this protein have negative CPL, which matches their exciton CD as expected. This result does not require any change to prior assignments of the low-energy states of CP43. There are significant open questions regarding the lowest-energy excited state of the CP47 protein. Careful measurements on this protein reveal a positive CPL signal for this state (wavelength ≥690 nm), which also matches its CD spectrum. Using structure-based exciton calculations, it is proposed that the lowest state of CP47 is most likely located on Chlorophyll 612. This is a significant departure from the previous assignment of Chlorophyll 627. Measurements on intact PSII core complexes confirm that the same low-energy state is present in these complexes as in CP47, resulting in a new assignment for the well-known F695 fluorescence band. The new assignment is found to be consistent with many aspects of the published PSII literature.

Il design e il controllo del processo di self-assembly di capsule a base di lantanidi è uno stimolante ambito di ricerca nello sviluppo della chimica supramolecolare. Allo stesso tempo, la possibilità di costruire architetture con specifiche proprietà strutturali e funzionali conferisce a questi sistemi un promettente futuro nel campo dei materiali funzionali luminescenti. A questo scopo, questa tesi riporta la progettazione, la sintesi e la caratterizzazione di nuove capsule metallorganiche a base di lantanidi (LOC). I sistemi sviluppati sono capsule dimeriche, classificate come elicati (M o P, chirali) o mesocati (achirali). La formula generale è [Ln2(L)4]2- dove il centro metallico è uno ione lantanoideo (Ln3+ = La3+, Eu3+, Tb3+, Gd3+) e i leganti L sono tre diversi bis-β-dichetoni. L'unità chelante, in grado di sensibilizzare l'emissione di Eu3+ e Tb3+, è la stessa per tutti e tre i leganti e corrisponde al benzoiltrifluoroacetone, mentre i diversi spacer centrali (gruppo carbammato, fenilico o metilenico) permettono di ottenere sistemi con diverse proprietà strutturali (dimensioni e forma). La formazione dei LOC, confermata da diverse tecniche di analisi (NMR, spettrometria di massa e XRD su cristallo singolo), evidenzia la presenza di: i) interazioni host-guest e ii) proprietà di chiralità supramolecolare, che, insieme alle peculiari caratteristiche di luminescenza degli ioni Ln3+, possono essere sfruttate sia per il sensing chimico (riconoscimento guest chirali) che per quello fisico (termometria di luminescenza). In primo luogo, viene presentato lo studio delle proprietà strutturali e l'applicazione dei LOC come sensori chirali. I sistemi sono stati studiati attraverso calcoli DFT per comprendere i fattori che governano la chiralità supramolecolare (flessibilità del legante, incapsulamento di un guest (chirale o meno) e dimensione del guest) e poi testati come sensori chimici. È interessante notare che i LOC, in presenza degli enantiomeri dell’α-metilcolina, mostrano sia dicroismo circolare che luminescenza circolarmente polarizzata indotta, confermando la loro efficacia nel riconoscimento del guest chirale. Prima di procedere con gli studi di termometria, è stata investigata, tramite ESI-MS, la cinetica dello scambio di ioni metallici tra capsule omometalliche. Infatti, poiché i termometri molecolari (TM) raziometrici vengono preparati miscelando [Eu2(L)4]2- e [Tb2(L)4]2- in diversi rapporti Eu3+/Tb3+, non si può escludere la formazione di capsule eterometalliche. Nella seconda parte vengono discussi due aspetti principali della termometria di luminescenza, ovvero lo sviluppo di: i) un modello in grado di prevedere e interpretare le proprietà termometriche dei TM e ii) nuovi termometri luminescenti basati su ioni Ln3+. Il modello predittivo permette di identificare e pesare i fenomeni coinvolti nella modulazione della luminescenza dell’europio, utilizzando parametri (sperimentali o calcolati) facilmente ottenibili. Ad oggi, sono stati inclusi con successo tre possibili canali di disattivazione: due termini competitivi relativi al metallo (back energy transfer metallo-legante e quenching multifononico), e un terzo termine relativo al legante per tenere conto del processo di disattivazione non-radiativa del tripletto. Infine, i LOC di Eu3+ e Tb3+, grazie alle loro proprietà di luminescenza, sono stati impiegati per sviluppare sia termometri luminescenti a singola emissione (Eu3+ e Tb3+) sia termometri raziometrici autocalibranti (misti, Eu3+/Tb3+), mostrando una buona sensibilità termica relativa (Sr massimo 3.2 – 5.5 %·K-1) e un ampio (oltre 150 K) intervallo di applicabilità (assunto come intervallo di temperatura in cui il valore di Sr è superiore a 1 %·K-1). Inoltre, la presenza di due emettitori (Tb3+, verde e Eu3+, rosso), le cui intensità di emissione dipendono dalla temperatura, apre la strada all'impiego di questi sistemi anche come sensori colorimetrici di temperatura.

Title: Theory and Applications of Optical Activity of Biomolecules Author: Monika Krupová Supervisor: prof. RNDr. Petr Bouř, DSc. Institutions: Faculty of Mathematics and Physics, Charles University, and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic Abstract: This thesis describes how we used several chiroptical spectroscopic methods to study chiral molecules: vibrational circular dichroism (VCD), circularly polarized luminescence (CPL) and magnetic circular dichroism (MCD). VCD and induced lanthanide CPL were used to study the structure of amyloid protein fibrils. We found out that VCD is very sensitive to their structure and supramolecular chirality. It could be used to distinguish between various polymorphic fibrils. On the other hand, induced lanthanide CPL provided information on the local structure. VCD was also used to study the hydration polymorphism of nucleoside crystals. Due to the crystal packing, the VCD signal was strong and specific for different types of crystals. Finally, electronic structure of hydrated Ln3+ ions was studied by MCD. Molecular dynamics simulations together with crystal field theory (CFT) and multistate complete active space calculations with second order perturbation correction (MS-CASPT2) were used to interpret the spectra. CFT...