<p>The present thesis concerns aspects of the interaction ofmatter in gas, liquid and solid phases, with electromagneticradiation, ranging from the optical to the X-ray region. Overthe last decade the availability of ultrashort strong laserpulses as well as of high power synchrotron sources of tunableX-ray radiation has stimulated a rapid development of newexperimental techniques which makes it possible to analysedifferent physical, chemical and biological processes inunprecedented detail. All of this urges a concomitantdevelopment of adequate theoretical language and methodscombined with simulation techniques.</p><p>The first part of the thesis addresses nonlinear propagationof strong optical pulses. This study is motivated by thebreakthrough in synthesis of novel organic materials possessingprespecified nonlinear optical properties and which has led toa multitude of potential applications such as, for example, 3Dimaging and data storage, optical limiting and photodynamiccancer therapy. In order to clarify the underlying physics, astrict solution has been derived of the density matrixequations of a material aiming at an explicit treatment of itsnonlinear polarization without addressing a conventional Taylorexpansion over field amplitudes. Such a formalism is developedfor many-level molecules, allowing to solve the coupledMaxwell's and density matrix equations for the propagation of afew interacting laser pulses through a nonlinear molecularmedium. The theory presented is capable to account formulti-photon processes of an arbitrary order and for differentsaturation effects. The theory is applied to simulations oftwo- and three-photon absorption as well as to upconvertedstimulated emission of organic molecules in solvents.</p><p>The second part of the thesis is devoted to resonant X-rayRaman scattering from free molecules, solutions and polymerfilms. The temporal analysis of the spectral profiles isperformed using the technique of scattering duration whichallows to select physical processes with different time scales.The slowing-down/speeding-up of the scattering by frequencydetuning provides insight in the formation of the differentparts of the scattering profile like atomic and molecularbands, resonant and vertical scattering channels, anomalousenhancement of the Stokes doubling effect. The lifetimevibrational interference (LVI), playing a crucial role inresonant scattering, is found to strongly influence thedispersion of the Auger resonances of polymers in agreementwith experiment. An almost complete quenching of the scatteringcross section by LVI is observed for the N₂molecule. It is found that the interferenceelimination of the scattering amplitude gives valuableinformation on molecular geometry. The electron Doppler effectis minutely studied making use of a wave packet technique. Thesimulations show an "interference burning" of a narrow hole onthe top of the Doppler broadened profile of the Auger spectraof molecular oxygen. For the SF₆molecule the Auger Doppler effect is found to besensitive to the detuning due to the scattering anisotropy. Inall of these studies the temporal language was foundconstructive and enormously helpful for understanding theunderlying physical processes. Most theoretical predictionsmade have been verified by experiments.</p>

Photodynamic therapy (PDT) is an alternative treatment of cancer requiring the use of chromophore molecules (photosensitizers), which can induce cell death after light excitation. Gold nanoparticles (AuNP), exhibiting localized Surface Plasmon Resonance, can enhance the photophysical response of chromophores located in their vicinity, and thus improve their therapeutic action. Moreover, the use of highly localized two-photon chromophores (photosensitizers and fluorophores), capable to undergo a localized excitation by light in the Near InfraRed region, should increase the penetration depth into tissues, thus improve the treatment efficiency (by PDT) and the imaging (by fluorescence microscopy) of cancer tissues.In this work, we describe the elaboration of water-soluble hybrid nano-objects for PDT and fluorescence bioimaging applications, composed of two-photon chromophore-polymer conjugates grafted onto gold nanoparticles. In order to obtain these nano-objects we follow a multistep strategy: i) the synthesis of a well-defined water-soluble chromophore-polymer conjugates; ii) the end-group oriented grafting of chromophore-polymer conjugates onto 20 nm AuNP. The coupling of hydrophobic two-photon chromophores on linear water-soluble copolymer chains (poly(N-acryloylmorpholine-co-N-acryloxysuccinimide)), obtained by controlled/living RAFT polymerization, resulted in well-defined water-soluble chromophore-polymer conjugates, with different polymer lengths (2 000 g.mol-1 < Mn < 37 000 g.mol-1) and architectures (random or block), and a controlled number of chromophores per chain (varying between 1 and 21). Their grafting onto 20 nm AuNP gave water-soluble hybrid nano-objects with high grafting densities (~0.5 chains/nm²). The role of the polymer chain being to tune the distance between chromophores and AuNP surface, we have evidenced the increase in the polymer corona thickness of grafted AuNP (estimated by TEM) with the increasing polymer Mn, corroborating with the corresponding distance-dependent fluorescence properties of those. Finally, the in cellulo biological properties of two-photon chromophore-polymer conjugates, before and after grafting onto AuNP, have been investigated, highlighting their potential for two-photon bioimaging and PDT applications.

The interaction between light and organometallic chromophores has been investigated theoretically in a strive for fast optical filters. The main emphasis is on two-photon absorption and excited state absorption as illustrated in the Jablonski diagram. We stress the need for relativistic calculations and have developed methods to address this issue. Furthermore, we present how quantum chemical calculations can be combined with Maxwell's equations in order to simulate propagation of laser pulses through a materials doped with chromophores with high two-photon absorption cross sections. Finally, we also discuss how fast agile filters using spin-transition materials can be modeled in order to accomplish theoretical material design. / <p>Report code: LIU-TEK-LIC-2006:55. On the day of the defence date the status on article III was Manuscript, article IV was Accepted and article V was Submitted.</p>

Ce travail porte sur l'élaboration et la caractérisation de cellules solaires organiques à base de nouvelles classes de matériaux donneurs dérivés de petites molécules solubles. Une première phase de ce travail a été consacrée à l'étude des cellules de type hétérojonction volumique à base de poly(3-hexylthiophène) et d'un dérivé soluble du fullerène C60, le PCBM. Le nombre considérable de travaux déjà publiés sur ces dispositifs en ont fait un système modèle particulièrement approprié à l'étude des différents paramètres expérimentaux impliqués dans la fabrication de ce type de cellules et à leur optimisation. Les protocoles expérimentaux définis sur la base de ces études ont été ensuite appliquées à l'évaluation de deux nouvelles classes de donneurs moléculaires à base du dicétopyrrolopyrrole (DPP) et de dipyrrométhène de bore (BODIPY). Les travaux sur les donneurs dérivés du DPP ont porté sur la réalisation de différentes séries de cellules solaires à hétérojonction planaire et volumique et les résultats obtenus ont permis à la fois d'atteindre des performances intéressantes et de progresser dans la compréhension des relations structure-propriétés dans cette famille de donneurs moléculaires. La dernière partie de ce travail concerne la réalisation et l'étude de cellules solaires à partir d'une classe originale de donneurs moléculaires dérivés du BODIPY. La caractérisation des propriétés électroniques de différentes familles de bodipys ainsi que la fabrication et l'étude de plusieurs séries de cellules solaires ont conduit à des avancées importantes et des rendements parmi les plus élevés obtenus jusqu'à présent sur des BHJ moléculaires à base d'accepteur dérivé du C60 ont été obtenus. Par ailleurs ces travaux ont permis de mettre pour la première fois en évidence des effets coopératifs dans des BHJ moléculaires utilisant des donneurs multiples.

Os corantes ciânicos com dois cromóforos possuem características espectrais e energéticas vantajosas para aplicação em Terapia Fotodinâmica (TFD) do câncer. Entretanto, sua fotoatividade contra neoplasias não foi ainda estudada nem in vivo nem in vitro. Nesta tese apresentamos os resultados dos estudos in vitro dos mecanismos da fotocitotoxicidade dos corantes ciânicos com dois cromóforos (BCD) com ângulos entre os cromóforos = 1800, 1500 e 900 contra células neoplásicas, com a finalidade de avaliar a potencialidade da aplicação dos BCD como fotossensibilizadores (FS) em TFD. Os estudos foram realizados em comparação com o fotossensibilizador Photogem®,que já está sendo aplicado em TFD. Foram estudados o efeito fototóxico, a distribuição intracelular do BCD e a contribuição de apoptose e necrose na morte celular induzida por ele. Além disso, foi realizada a busca da formulação farmacêutica adequada para aplicação tópica do BCD180. Nos estudos da fotocitotoxicidade foram utilizadas as células neoplásicas de melanoma murino B16F10, melanoma humano C8161, adenocarcinoma de colo retal humano HT29, leucemia T humano (Jurkat) e leucemia mielóde aguda humana Hl-60. A citotoxicidade foi estudada em função da dose da irradiação, da concentração do FS e do tempo de incubação das células com FS. Todos os compostos testados apresentaram baixa citotoxicidade no escuro, quando sob irradiação com luz visível (? > 600 nm) sua citotoxicidade aumentou consideravelmente. Observamos que para todos os tipos de células neoplásicas a fotocitotoxicidade dos BCD, depois de atingir seu máximo na variação do tempo de incubação, é igual ou ultrapassa a fotocitotoxicidade do Photogem® nas mesmas condições experimentais. O estudo comparativo do BCD180 e dos BCD150 e BCD90 mostrou que nas mesmas condições experimentais os dois últimos possuem fotocitotoxicidade maior do que o BCD180. O conjunto dos resultados obtidos mostra que os BCD? podem ser considerados promissores FS para TFD do câncer. Os estudos através de microscopia de fluorescência da distribuição intracelular do BCD180 e dos marcadores fluorescentes das mitocôndrias Mitotracker GreenTM e Rodamina 123 e do núcleo 4\',6-diamidino-2-phenylindole (DAPI) mostraram que o BCD180 se localiza preferencialmente na região das mitocôndrias. Os mecanismos da morte celular induzida pelo BCD180 foram analisados através do estudo da morfologia das células Jurkat, liberação da fosfatidilserina, liberação do citocromo c, ativação da caspase-3 e do efeito na citotoxicidade do BCD180 da proteína Bcl-2 (inibidor do citocromo c). A análise mostrou que a apoptose é a principal responsável pela morte celular induzida pelo BCD180 no escuro, enquanto que, sob irradiação luminosa, tanto a apoptose quando a necrose contribuem para a morte celular, e a contribuição da necrose aumenta com o aumento da concentração do BCD180 e do tempo de pós-irradiação. A apoptose ocorre, provavelmente, pela via intrínseca ou mitocondrial. Além disso, foram realizados os testes de permeação cutânea do BCD180 utilizando várias formulações farmacológicas e foi determinado que a mistura de 10% de monoleína em propilenoglicol possui melhores características entre todas as formulações testadas. / Cyanine dyes with two chromophores possess vantage spectral and energetic characteristics for application in Photodynamic Therapy (PDT) of cancer. At the same time, their photoactivity against neoplasias was not yet studied neither in vivo, nor in vitro. In this thesis, we present the results of in vitro studies of photocytotoxicity mechanisms of cyanine dyes with two chromophores (BCD) with angles = 180,150 and 90 between chromophores against neoplasic cells, with the objective to evaluate BCD potentiality to be applied as photosensitizers (PS) to Photodynamic Therapy (PDT). The studies were realized in comparison with photosensitizer Photogem®, which is already applied to PDT. The BCD? phototoxic effect, their intracellular distribution and contribution of the apoptosis and necrosis in the cell death induced by BCD were studied. Besides, the search of adequate pharmaceutical formulation for BCD180 topic application was realized. The neoplasic cell lines of melanoma B16F10 in mice, human melanoma C8161, human colon adenocarcinoma HT29, human T-cell leukemia (Jurkat) and human leukemia Hl-60, were used in the study of photocytotoxicity, which was studied as a function of irradiation dose, PS concentration and incubation time of cells with PS. All tested compounds demonstrated low cytotoxicity in the darkness, while under irradiation by visible light (? > 600 nm) their cytotoxicity considerably increased. It was observed that for all types of neoplasic cells BCD photocytotoxicity under the same experimental conditions is equal or exceeds that of Photogem® when reaches the maximum with the incubation time variation. The comparative study of BCD180 with BCD150 and BCD90 demonstrated that under the same experimental conditions two latter compounds possess photocytotoxicity exceeding that of BCD180. A set of the results obtained demonstrates that BCD can be considered as promising PS for PDT of cancer. The study of intracellular distribution of BCD180, and of mitochondria and nucleus fluorescence selective probes Mitotracker GreenTM, Rhodamine 123 and 4\',6-diamidino-2-phenylindole (DAPI) show that BCD180 is mostly localized in the region of mitochondria. The mechanisms of the cell death induced by BCD180 were analyzed in the study of Jurkat cells morphology, phosphatidyl serine and cytochrome c liberation, caspase-3 activation, and by protein Bcl-2 (cytochrome c inhibitor) effect on BCD180 cytotoxicity. The analysis demonstrated that apoptosis is the main responsible for the cell death induced by BCD180 in darkness, while under light irradiation both apoptosis and necrosis contribute to the cell death, and necrosis contribution increases with BCD180 concentration and post-irradiation time.The apoptosis is probably realized by an intrinsic or mitochondrial way. Besides, the tests of BCD180 cutaneum permeation were realized using various pharmacological formulations. It was determined that among all formulations tested, the mixture of 10% of monoleine in propylene glycol possesses the best characteristics.

Triarylborane Functionalized Dicyanovinyl and Acetylacetone Based Molecular Platforms: Building Blocks for Multiple Anion Sensors and Efficient Phosphorescence Emitters The main objective of this thesis is to design a simple strategy for triarylborane based multiple anion sensors and development of triarylborane incorporated phosphorescent metal complexes. The thesis consists of eight chapters and the contents of each chapter are given below. Chapter 1 This chapter gives a general introduction to recent advances relevant to the theme of the thesis. A review of the fundamental characteristics of triarylboranes and their applications in various fields such as chemical sensors and optoelectronics is presented. Advances in boron chemistry in the areas such as anion sensors, solid state emissive and phosphorescence materials are discussed in detail. The scope of the thesis is outlined at the end of the chapter. Chapter 2 The second chapter deals with the general experimental techniques and synthetic procedures followed in this thesis. Chapter 3 This chapter deals with a rational design strategy for differential identification of fluoride and cyanide ions using TAB based sensors. In general, most of the triarylboranes give similar optical responses towards fluoride and cyanide ions as they follow similar sensing mechanism. In order to circumvent this problem, two TAB-DCV conjugates (1 and 2) are designed and synthesised. The DCV unit is highly specific for cyanide ion owing to the presence of electrophilic carbon center. Probes 1 and 2 differ in steric crowding around the boron center. The less crowded boron center in 1 binds with fluoride as well as with cyanide ions giving similar optical response (luminescence is quenched in presence of F¯ and CN¯). In the case of 2, selectivity of boron center towards fluoride is tuned by increasing the steric crowding around the boron unit. The dicyanovinyl unit acts as selective sensing site for cyanide ions. As a result, 2 gives different fluorogenic response towards the anions F¯ and CN¯ which were considered as interfering anions in TAB based sensor chemistry. Thus, a modular design principle is developed for differential identification of fluoride and cyanide ions using TAB. Chapter 4 In this chapter, detailed photophysical studies of TAB-amine-DCV conjugates and colorimetric discrimination of fluoride and cyanide ions are discussed. Presence of amine based donor between the two electron deficient sites enhances the electronic conjugation in 3−5. Since there are two different acceptor sites with a common donor, two distinct charge transfer transition bands are observed in the visible region of electromagnetic spectrum. The absorption and emission spectra of these compounds show pronounced sensitivity to solvent polarity, signifying large excited state dipolmonents. Anion binding studies confirms that these compounds are highly selective towards fluoride and cyanide ions. Fluoride ions selectively interact with boron center and block the corresponding charge transfer transition thereby leading to a distinct colour change which is observable by naked eye. On the other hand, cyanide interacts with boron as well as DCV unit and blocks both the charge transfer transitions which results in disappearance of colour. Hence, compounds 4 and 5 exhibit different colorimetric signals for fluoride and cyanide ions. Since the absorption bands of 3 do not fall in the visible region, it does not show any colorimetric response towards the aforementioned anions. The anion sensing mechanisms are established by 1H, and 19F NMR studies. Chapter 5 This chapter presents a systematic study of the effect of length of π-electronic conjugation on the optical properties and anion sensing abilities of a series of TAB-oligothiophene-DCV conjugates (6−8). Their absorption as well as emission bands undergo redshift upon increasing the number of thiophene units between TAB and DCV units as the π-electronic conjugation in 6−8 is greatly dependent on the number of thiophene units. Their fluorescence emission is highly sensitive to solvent polarity. In the case of 6, the emission band undergoes a redshift with reduced intensity. In the case of 7 the emission band undergoes a redshift but the intensity is not affected by solvent polarity. In the case of 8, the emission band undergoes redshift with enhanced intensity in polar solvents. Interestingly, 7 and 8 show solvent viscosity dependent fluorescence. Structural reorganisation is restricted in viscous medium and results in enhanced emission for 7 and 8. Further, these compounds exhibit selective response towards the fluoride and cyanide ions with different colorimetric responses. Test strips made up of probes 7 and 8 have potential application in identifying fluoride and cyanide ions in aqueous medium. Chapter 6 This chapter describes synthesis and optical characterisation of triarylborane incorporated acetylacetone (acacH) ligands (9, 10) and their borondifluoride complexes (11, 12). AcacH ligands and BF2 complexes show solvent dependent emission phenomena due to the involvement of charge transfer transition. Their optical properties are highly dependent on molecular conformations. Complex with duryl spacer (12) exhibits more red shifted emission in polar solvents due to the enhanced charge transfer transition facilitated by twisted rigid geometry. In presence of fluoride and cyanide ions, the borondifluoride complexes are not stable. The anions concomitantly interact with tricoordinate boron as well as acac-BF2 unit to give rise to complex pattern of photoluminescence spectral changes during the titration experiment. The binding pathway and the possible species involved are established with the help of 1H, 19F and 11B NMR spectral studies in presence of the anions. Complexes 11 and 12 act as selective chemodosimetric sensors for fluoride and cyanide ions. Chapter 7 In this chapter, the synthesis and optical characterisations of triarylborane conjugated cyclometalated platinum complexes are discussed. A series of square planar platinum complexes are synthesised with different cyclometalating ligands. Complexes (13−18) exhibit a range of luminescence from green to red in solution as well as in the solid state. Their emission intensities are highly sensitive towards atmospheric oxygen suggesting that they originate from a triplet excited state. A maximum of 85% quantum yield is observed for complex 15 in solution state while complex 14 showed a maximum of 58% quantum yield in solid state. Complexes with rigid molecular conformation (14, 16 and 18) showed higher luminescence quantum yield than those having phenyl spacer (13, 15 and 17). The sterically encumbered boryl (-BMes2) group significantly reduces π-π stacking between the square planar entities. Thus, complexes 13−18 show bright luminescence in solid state compared to model complexes without boryl group. The effect of Lewis acidic boron center on luminescence behaviour is explored by fluoride binding studies. Chapter 8 This chapter is divided into two parts. Part-I describes the synthesis and optical characterisation of triarylborane conjugated cyclometalated iridium complexes (19−24). They are brightly luminescent in solution state with high sensitivity towards atmospheric oxygen. Complex 20 shows a highest quantum yield of 91%. Interestingly, under ambient atmospheric conditions, they exhibit a rare type of dual emission. Life time data suggest that the lower energy emission band originates from cyclometalated iridium based triplet excited state while higher energy emission band originates from boryl ased singlet excited state. Fluoride binding at the boron site results in luminescence quenching; evidently, tri-coordinate boron has a major contribution to the luminescence features of these iridium complexes. Part-II deals with synthesis of triarylborane conjugated pyrazole ligand (25) and its binuclear iridium complexes (26−28) in which two iridium centers are bridged by hydroxo as well as pyrazolato ligands. These binuclear iridium complexes exhibit higher luminescence quantum yield than TAB-acac-Iridium complexes (mononuclear complexes; part I). Binding of fluoride ions at the boron center has a minor impact on their luminescence nature. High sensitivity of their luminescence towards atmospheric oxygen indicates the involvement of triplet excited state in their emission process.

Les nanoparticules d’or (AuNPs) intriguent tout particulièrement ces dernières années de par leurs propriétés fascinantes. Elles sont variables selon la forme et la taille des nanoparticules ce qui en fait des objets ouvrant des perspectives dans plusieurs domaines. L’or est d’autant plus intéressant qu’il a une grande flexibilité de ces bandes de résonance plasmon de surface, allant du visible au proche infrarouge (IR). Au cours de cette thèse, nous avons donc travaillé sur la synthèse d’AuNPs de tailles et de formes différentes pour pouvoir travailler à de nombreuses longueurs d’onde du visible à l’IR. Cette multitude de AuNPs nous a permis d’étudier l’effet de ces différentes résonances plasmons sur des chromophores afin d’essayer de comprendre les mécanismes de ces interactions. Le but final de ces travaux, outre l’amélioration de la compréhension de ces interactions, est la réalisation de matériaux monolithiques pour l’optique par une approche sol-gel permettant l’incorporation de molécules optiquement actives et de ces systèmes plasmoniques, qui donnent des propriétés intéressantes aux matériaux obtenus. Nous nous sommes intéressés plus précisément aux propriétés d’absorption non-linéaire, dans le but de réaliser des matériaux limiteurs optiques pour protéger des systèmes optiques contre des rayonnements intenses, comme les lasers. Ces systèmes ont commencé à être mis au point dans les thèses précédentes faites au laboratoire mais la compréhension amenée par ces travaux auront permis d’approfondir les interactions particules-chromophores et le rôle de la longueur d’onde de la résonance plasmon afin d’optimiser l’efficacité en limitation optique. / Gold nanoparticles (AuNPs) particularly intrigued over the last decades because of their fascinating properties. They vary according to the size and shape of nanoparticles making objects opening opportunities in many areas. Gold is especially interesting since it has a great flexibility of these resonance surface plasmon bands ranging from the visible to near infrared (IR).In this thesis, we worked on the synthesis of AuNPs of different sizes and shapes in order to be able to work in many wavelengths from visible to IR. This multitude of AuNPs enabled us to study the effect of these different plasmon resonances of chromophores in an effort to understand the mechanisms of these interactions. The ultimate goal of this work, in addition to improving the understanding of these interactions, is the realization of monolithic materials for optics by a sol-gel approach allowing the incorporation of optically active molecules and these plasmonic systems, which give interesting properties to the obtained materials. We focused specifically on nonlinear absorption properties, in order to produce optical limiting materials to protect optical systems against intense radiation, such as lasers.These systems began to be developed in previous PhD thesis made in our laboratory but the understanding brought by this work have helped deepen the particles-chromophore interactions and the role of the wavelength of the plasmon resonance in order to optimize efficiency in optical limiting.

No description available.

For inorganic semiconductors such as silicon, crystalline order leads to bands in the electronic structure which give rise to drastic differences with respect to disordered materials. Distinct band features lead to photo-effect, and the band structure can be tuned to optimize the performance of the photovoltaic (PV) device. An example is the presence of an indirect band gap. For organic semiconductors, such effects are typically precluded, since most organic materials employed are disordered, which hampers their characterization and theoretical analysis. The inspiration for this thesis came from the very first evidence of an indirect band gap exhibited by highly ordered and crystalline porphyrin-based surface-mounted metal-organic framework (PP-based SURMOF) material [J. Liu et al. Angew. Chem. Int. Ed. 2015, 54, 7441]. The presence of an indirect band gap should in principle result in suppressed charge recombination and efficient charge separations which would significantly enhance the PV device performance. However, the energy gain from the electronic band dispersion in the reported Pd-PP-Zn-SURMOF is far too low (≈5 meV) and results in a very low photocurrent generation (efficiency 0.2%), which is certainly not sufficient for the application. Another noticeable shortcoming is the weakly absorbing Q-bands of the employed PP chromophore (Pd-metal containing porphyrinoid, Pd-PP) in the visible region of the solar spectrum. Nevertheless, this novel research has highlighted the potential to improve the photophysical properties of PP-based SURMOFs by (i) introducing various functional groups or metal ions to the PP-core and (ii) controlling the PP-stacking behavior in layered materials. To overcome the posed shortcomings of the PP-MOF prototype PV material and to exploit the potential of PP-based SURMOFs, we have employed the following approach to increase the light absorption and the electronic band dispersion. Firstly, we proposed a computationally feasible simplified time-dependent approach to investigate the light absorption properties of PP derivatives or related PP-containing materials. Secondly, we predicted the light absorption properties of multi-functionalized PPs (i.e. tuning the weakly absorbing Q-bands), thus allowing us to identify different PP linkers with different light absorption properties, allowing to bridge the so-called green gap. Finally, we incorporated the most promising PP linkers for the construction of SURMOFs and applied state-of-the-art DFT methods in various approximations to optimize the PP-stacking behavior to achieve the desired photophysical properties. Besides PPs, we have extended our investigations to phthalocyanines (PCs) as alternative individual SURMOF building blocks, because they do not only exhibit structural robustness and stability but also possess enhanced absorption in the visible and the near IR spectral regions in comparison to PPs. Hence, the exploitation of PCs could enrich the library of SURMOFs with the desired optical quality.

Les chromophores classiques ne sont pas toujours efficaces en absorption à deux photons. Leur faible efficacité nécessite l'utilisation de fortes puissances laser et de grandes concentrations en colorants. Dans ce sens, la microscopie à deux photons in vivo requière le développement de nouvelles stratégies de marquage utilisant des chromophores spécialement dédiés à la microscopie à deux photons. Dans le cadre de collaborations avec des chimistes spécialisés dans la synthèse de molécules à forte section efficace d'absorption à deux photons, différents chromophores ont été synthétisés. Ces molécules organiques sont souvent hydrophobes et ne sont pas utilisables directement pour les applications en biologie. Le travail effectuer ici a consisté à encapsuler ces molécules dans des micelles de copolymères biocompatibles, les Pluronic. Les Pluronic sont des matériaux pouvant s'auto assembler en milieu aqueux sous forme de micelles et permettent de solubiliser des composés hydrophobes. Cette stratégie est déjà utilisé pour permettre de transporter différents composés hydrophobes dans les organismes vivants et a été utilisée ici pour transporter des chromophores ultrasensibles à deux photons dans le sang de manière à imager la vascularisation in vivo. / Classic fluorescent dyes are not necessary efficient in two-photon absorption. Their low two-photon absorption efficiency often requires high laser power and important dye concentrations. Therefore, new dyes and other administration strategies need to be developed specifically for intravital two-photon microscopy. In collaboration with chemists, specialized in the synthesis of molecules with a high two-photon absorption cross-section, different dyes have been synthesized. Most of these dyes are hydrophobic and not directly suitable for biological applications. The work presented in this thesis consisted of encapsulating hydrophobic molecules in biocompatible Pluronic block copolymers. In water, Pluronic unimers with hydrophobic and hydrophilic blocks self-assembled in hydrophilic micelles forming a hydrophobic core around the molecules. This strategy has been used already for the transport and delivery of different hydrophobic molecules in living organism. In the present study, this strategy has been transposed to transport ultra sensitive two-photon dyes in the blood plasma for deep vascular imaging in vivo.