Social ångeststörning (SAD) är ett ångestsyndrom som orsakar stor funktionsnedsättning och försämrad livskvalitet. I föreliggande studie presenteras förklaringsmodeller till SAD med fokus på temperamentsforskning och reinforcement sensitivity theory (RST). Syftet var att genom explorativ faktoranalys identifiera latenta variabler i frågeformuläret ”Hur man var som barn” (HMVSB), som administrerats i en klinisk population (n= 100) och i en kontrollgrupp (n= 246). Faktoranalysen extraherade två faktorer som döptes till beteendeinhibering (BI) respektive beteendeaktivering (BA). Ett andra syfte var att jämföra den kliniska populationen med kontrollgruppen avseende de extraherade faktorerna. Resultaten visade att HMVSB uppvisade god intern konsistens och tillfredsställande instrumentell reliabilitet. Vissa signifikanta korrelationer mellan HMVSB och jämförda skattningsformulär vid SAD erhölls. Gruppjämförelserna visade att den kliniska gruppen var signifikant mer beteendeinhiberad och mer beteendeaktiverad som barn. En subgrupp med generaliserad SAD var både signifikant mer beteendeaktiverad och beteendeinhiberad som barn. Subgruppen med specifik SAD skilde sig ej signifikant från kontrollgruppen. Studien manar till att beakta temperamentala faktorer vid SAD där kombinationen hög BI och hög BA skulle kunna korrelera med allvarligare klinisk bild.

The solid-state mesoscopic solar cells (sMSCs) have been developed as a promising alternative technology to the conventional photovoltaics. However, the device performance suffers from the low hole-mobilities and the incomplete pore filling of the hole transport materials (HTMs) into the mesoporous electrodes. A variety of HTMs and different preparation methods have been studied to overcome these limitations. There are two types of sMSCs included in this doctoral thesis, namely solid-state dye-sensitized solar cells (sDSCs) and organometallic halide perovskite based solar cells. Two different types of HTMs, namely the small molecule organic HTM spiro-OMeTAD and the conjugated polymer HTM P3HT, were compared in sDSCs. The photo-induced absorption spectroscopy (PIA) spectra and spectroelectrochemical data suggested that the dye-dye hole conduction occurs in the absence of HTM and appears to be of significant importance to the contribution of hole transport. The PIA measurements and transient absorption spectroscopy (TAS) indicated that the oxidized dye was efficiently regenerated by a small molecule organic HTM TPAA due to its excellent pore filling. The conducting polymer P3HT was employed as a co-HTM to transfer the holes away from TPAA to prohibit the charge carrier recombination and to improve the hole transport. An alternative small molecule organic HTM, MeO-TPD, was found to outperform spiro-OMeTAD in sDSCs due to its more efficient pore filling and higher hole-mobility. Moreover, an initial light soaking treatment was observed to significantly improve the device performance due to a mechanism of Li+ ion migration towards the TiO2 surface. In order to overcome the infiltration difficulty of conducting polymer HTMs, a state-of-the-art method to perform in-situ photoelectrochemical polymerization (PEP) in an aqueous micellar solution of bis-EDOT monomer was developed as an environmental-friendly alternative pathway with scale-up potential for constructing efficient sDSCs with polymer HTMs. Three different types of HTMs, namely DEH, spiro-OMeTAD and P3HT, were used to investigate the influence of HTMs on the charge recombination in CH3NH3PbI3 perovskite based sMSCs. The photovoltage decay measurements indicate that the electron lifetime (τn) of these devices decreases by one order of magnitude in the sequence τspiro-OMeTAD > τP3HT > τDEH.

Univ., Diss.--Bonn, 1999.

The subject of this thesis is the design and development of a unified set up for femtosecond transient absorption and ultrafast Raman loss spectroscopy and demonstrate its potential in capturing the ultrafast photophysical and photochemical processes with excellent time and frequency resolution. Ultrafast spectroscopy has been serving as a powerful tool for understanding the structural dynamical properties of molecules in the condensed and gas phase. The advent of ultrashort pulses with their high peak power enables the laser spectroscopic community to study molecular reaction dynamics and photophysics that happen at extremely short timescales, ranging from picosecond to femtosecond. These processes can be measured with extremely high time resolution, which helps to resolve the under-lying molecular process. But in order to understand the global mechanism of the underlying molecular processes, we have to resolve the nuclear dynamics with the proper frequency resolution. However, achieving both, time and frequency resolutions simultaneously is not possible according to the Heisenberg uncertainty principle. Later, this limitation was overcome by femtosecond stimulated Raman spectroscopy (FSRS), a third order non-linear Raman spectroscopy. In this thesis we introduced the ultrafast Raman loss spectroscopic (URLS) technique which is analogous to FSRS, offering the modern ultrafast community to resolve molecular processes with better signal-to-noise ratio along with proper time and frequency resolution. We demonstrate the experimental procedure including the single shot detection scheme to measure whitelight background, ground state Ra-man, transient absorption and transient Raman in shot-to-shot detection fashion. URLS has been applied to understand the excited state planarization dynamics of 1,4-bis(phenylethynyl)benzene (BPEB) in different solvents. In addition, excitation wavelength dependent conformational reorganization dynamics of different sub-sets of thermally activated ground state population of BPEB are also discussed. Using the same techniques along with femtosecond transient absorption, we demonstrate the ultrafast vibrational energy transfer and the role of coherent oscillations of low frequency vibrations on the solution phase photo-isomerization of trans-stilbene from an optically excited state. The effects of solvents on the coherent nuclear motion are also discussed in the context of reaction rates. 2

Use of metal based anticancer medication began with the clinical approval of cisplatin in 1978. Research led to the development of six platinum based drug candidates which are in use around the world. However there is a great need to develop better treatment strategies. The present work entitled “Cytotoxicity of Metal Based Anticancer Active Complexes and Their Targeted Delivery Using Nanoparticles” is an effort to prepare cytotoxic metal complexes based on platinum(IV) and copper(II) and deliver them selectively to cancer cells using a targeting ligand, biotin, with two different delivery vehicles, viz. PEGylated polyamidoamine dendrimer (PAMAM) and gold nanoparticles (AuNPs). Chapter 1 provides a brief introduction to cancer and its characteristic features, followed by a short description about different treatment modalities in clinical practice. An account of the development of anticancer drugs starting from purely organic drugs to the field of metal based anticancer drugs is discussed. An overview of the available targeting strategies are discussed with specific examples. The section ends with the scope of the present work. Platinum based anticancer drugs currently in use contain platinum in the +2 oxidation state. These drugs showed side effects and are often ineffective against resistant cells, especially in the latter stages of treatment. A recent focus of metal based anticancer drug research is the development of platinum(IV) systems which shows promise to have greater activity in cancer cells in a reducing environment. Reported platinum(IV) dual drugs contain the components of “cisplatin” or an analogue along with an active organic drug. But there are no known dual drugs based on platinum(IV) that would generate a cytotoxic metal complex along with cisplatin. In Chapter 2, a bimetallic dual drug (M4) (Figure 1), the first of its kind, with components of cisplatin and copper bis(thiosemicarbazone) has been prepared (Figure 1). The components and the bimetallic complex were characterized using several spectroscopic techniques. The dual drug M4 was found to be highly cytotoxic (IC50 1.3 M) against HeLa cells and was better than cisplatin (IC50 6.8 M). The bimetallic complex turned out to be better than the mixture (IC50 7.2 M) of individual drugs which indicated possible synergism of the released cisplatin and the copper bis(thiosemicarbazone) from the dual drug. Figure 1: Structure of the platinum(IV) and copper bis(thiosemicarbazone) complexes. A novel approach towards conjugation of platinum(IV) drugs to a carrier has been developed using a malonate moiety (Figure 2). The bis(butyric acid) complex, Pt(NH3)2(OCOC3H7)2Cl2 (M1), was taken as model complex to demonstrate the conjugation strategy. The complex M4 was also conjugated to the partially PEGylated 5th generation PAMAM dendrimers. Figure 2: Schematic representation of the platinum(IV) drug conjugated PAMAM dendrimer. The cytotoxicity of M4 was reduced to a small extent on conjugation to the dendrimer. In the presence of 5 mM sodium ascorbate as a reducing agent, sustained release (40 %) of the drug was shown to occur over a period of 48 h by the drug release study. The reduction in cytotoxicity of the dendrimer conjugates could be due to incomplete release of the active drug. Unfortunately, no enhanced activity was observed with the additional targeting ligand, biotin. The drug uptake study revealed that the dendrimer conjugates were successful in entering cancer cells. There was no preferential uptake with biotin conjugated dendrimers which explained the similar cytotoxicity of dendrimer conjugates with and without biotin. Different delivery vehicles showed varied efficiency in delivering the pay load (drugs) to the cancer site. In this connection, PEGylated gold nanoparticles have shown good promise as a drug delivery vehicle. In Chapter 3, M1 and M4 are both conjugated to malonate functionalized PEGylated gold nanoparticles (30 nm). Biotin was also attached to the AuNPs for targeting HeLa cells. Figure 3: Schematic representation of the platinum(IV) drug and biotin conjugated AuNPs. The AuNPs were highly stable in water without agglomeration. There was no shift in the Surface Plasmon Resonance (SPR) band after conjugation of the drug molecules and targeting ligands. TEM images and DLS measurements showed there was no change in particle size. Drug conjugated AuNPs were also very stable in high salt concentrations as well as over a large range of pH. AuNPs with M1 were found to be less cytotoxic than the parent drug. Biotinylated AuNPs with M1 were more potent than non-biotinylated nanoparticles and increased cytotoxicity (35 %) was observed with biotin conjugation. Surprisingly, the enhanced activity of biotinylated AuNPs could not be correlated to the drug uptake study. The cytotoxicity of the bimetallic dual drug containing AuNPs were about 10-fold less and no increased activity was observed with the biotinylated conjugates. The reduced activity of AuNPs with the bimetallic drug was due to incomplete release from the AuNPs (20 % release after 48 h). But the release kinetics was very slow and sustained which might increase in vivo activity. The unexpected lower activity of biotinylated conjugates with copper bis(thiosemicarbazone) was suggestive of interference between bis(thiosemicarbazone) complex and the biotin receptor resulting in reduced drug uptake. Copper bis(thiosemicarbazone) complexes hold very good promise as a class of non-platinum anticancer drug candidates. However, they lack selectivity towards malignant cells. Recently, CuATSM has shown hypoxia selectivity and very good cytotoxicity resulting in 64CuATSM being used in advanced stages of clinical trials for imaging hypoxic cells. In Chapter 4, a copper bis(thiosemicarbazone) complex analogous to Cu(ATSM) with a redox active cleavable disulfide linker and a terminal carboxylic acid group (CuATSM-SS-COOH) was synthesised and characterised spectroscopically. The complex was highly cytotoxic and has an IC50 value (6.9 M) similar to that of cisplatin against HeLa cells. The complex was conjugated to PEGylated gold nanoparticles by amide coupling between the acid group from the drug molecule and the amine on the AuNPs (20 nm) for smart drug delivery. The gold nanoparticles were decorated with biotin for targeted delivery to the HeLa cells. Figure 4: Schematic representation of the CuATSM-SS-COOH and biotin decorated AuNPs. The CuATSM-SS-COOH was insoluble in water but conjugation to PEGylated gold nanoparticles made it water soluble. The drug molecules and biotin conjugated AuNPs were highly stable which was confirmed by TEM and DLS measurements. Similar to the study described in the previous chapter, these AuNPs were also stable in a wide range of pH and salt concentrations. In vitro glutathione (GSH) triggered release study demonstrated substantial release of the cytotoxic agent from the AuNPs (60 %) over a period of 48 h. In vitro cell viability study with HeLa cells showed reduced cytotoxicity (IC50 15 M) of AuNPs with and without biotin containing drug conjugates relative to the parent copper complex (IC50 6.9 M). The reduction of the cytotoxicity correlated well with the released amount of the active drug from the nanoconjugates over the same time period. In vivo studies demonstrated the effectiveness of these nanoparticle carriers as suitable vehicles as they exhibited nearly four-fold reduction of tumor volume without significant loss in body weight. Moreover, the biotin targeted nanoparticle showed significant (p < 0.5) reduction in tumor volume compared to the non-targeted gold nanoparticles. Thus, this smart linking strategy Can be extended to other cytotoxic complexes that suffer from non-specificity, low aqueous solubility and toxicity. Multinuclear anticancer active complexes do not act in the same way as that of their corresponding mononuclear analogues. In the case of multinuclear platinum complexes, the activity not only depends on the active moiety but also on the spacer length between the moieties. In Chapter 5, a series of multinuclear copper bis(thiosemicarbazone) complexes were prepared and characterised using different techniques. Figure 5: General structures of binuclear copper bis(thiosemicarbazone) complexes. All the complexes showed redox activity and have a very high negative reduction potential, i.e. these compounds would not be easily reduced in the biological medium and would remain as copper(II) species. As the concentration of the reducing agents are more within cancer cells, once these complexes are inside cells they would be reduced to Cu(I). These compounds were shown to be highly lipophilic from the large log P values. Unfortunately, these binuclear complexes were less active than similar mononuclear complexes. One possible reason for the reduced cytotoxicity of these complexes could be adherence of the complexes to the cell membrane due to the high lipophilicity of these complexes. Out of five different methylene spacers between two bis(thiosemicrarbazone) moieties, the complex with a three carbon spacer was shown to be the most active against HeLa cells. The complexes with five and six methylene spacers turn out to be noncytotoxic. Further experiments are necessary to reveal the mechanism of action in these complexes. In summary, bimetallic complexes can be very active and may be a way of overcoming drug resistance in platinum based therapy. A dual drug can be delivered using a malonate moiety and a disulfide linker. Gold nanoparticles are good delivery vehicles for these dual drugs and show great potential for improvement and translation to the next stage. (For figures pl refer the abstract pdf file)

Evaluating aerodynamic noise from aircraft engines is a design stage process, so that it conform to regulations at airports. Aerodynamic noise is also a principal source of structural vibration and internal noise in short/vertical take off and landing and rocket launches. Acoustic loads may be critical for the proper functioning of electronic and mechanical components. It is imperative to have tools with capability to predict noise generation from turbulent flows. Understanding the mechanism of noise generation is essential in identifying methods for noise reduction. Lighthill (1952) and Lighthill (1954) provided the first explanation for the mechanism of aerodynamic noise generation and a procedure to estimate the radiated sound field. Many such procedures, known as acoustic analogies are used for estimating the radiated sound field in terms of the turbulent fluid flow properties. In these methods, the governing equations of the fluid flow are rearranged into two parts, the acoustic sources and the propagation terms. The noise source terms and propagation terms are different in different approaches. A good description of the turbulent flow field and the noise sources is required to understand the mechanism of noise generation. Computational aeroacoustics (CAA) tools are used to calculate the radiated far field noise. The inputs to the CAA tools are results from CFD simulations which provide details of the turbulent flow field and noise sources. Reynolds-Averaged Navier Stokes (RANS) solutions can be used as inputs to CAA tools which require only time-averaged mean quantities. The output of such tools will also be mean quantities. While complete unsteady turbulent flow details can be obtained from Direct Numerical Simulation (DNS), the computation is limited to low or moderate Reynolds number flows. Large eddy simulations (LES) provide accurate description for the dynamics of a range of large scales. Most of the kinetic energy in a turbulent flow is accounted by the large-scale structures. It is also the large-scale structures which accounts for the maximum contribution towards the radiated sound field. The results from LES can be used as an input to a suitable CAA tool to calculate the sound field. Numerical prediction of turbulent flow field, the acoustic sources and the radiated sound field is at the focus of this study. LES based on explicit filtering method is used for the simulations. The method uses a low-pass compact filter to account for the sub-grid scale effects. A one-parameter fourth-order compact filter scheme from Lele (1992) is used for this purpose. LES has been carried out for four different flow situations: (i) round jet (ii) plane jet (iii) impinging round jet and (iv) impinging plane jet. LES has been used to calculate the unsteady flow evolution of these cases and the Lighthill’s acoustic sources. A compact difference scheme proposed by Hixon & Turkel (1998) which involves only bi-diagonal matrices are used for evaluating spatial derivatives. The scheme provides similar spectral resolution as standard tridiagonal compact schemes for the first spatial derivatives. The scheme is computationally less intensive as it involves only bi-diagonal matrices. Also, the scheme employs only a two-point stencil. To calculate the radiated sound field, the Helmholtz equation is solved using the Green’s function approach, in the form of the Kirchhoff-Helmholtz integral. The integral is performed over a surface which is present entirely in the linear region and covers the volume where acoustic sources are present. The time series data of pressure and the normal component of the pressure gradient on the surface are obtained from the CFD results. The Fourier transforms of the time series of pressure and pressure gradient are then calculated and are used as input for the Kirchhoff-Helmholtz integral. The flow evolution for free jets is characterised by the growth of the instability waves in the shear layer which then rolls up into large vortices. These large vortical structures then break down into smaller ones in a cascade which are convected downstream with the flow. The rms values of the Lighthill’s acoustic sources showed that the sources are located mainly at regions immediately downstream of jet break down. This corresponds to the large scale structures at break down. The radiated sound field from free jets contains two components of noise from the large scales and from the small scales. The large structures are the dominant source for the radiated sound field. The contribution from the large structures is directional, mainly at small angles to the downstream direction. To account for the difference in jet core length, the far field SPL are calculated at points suitably shifted based on the jet core length. The peak value for the radiated sound field occurs between 30°and 35°as reported in literature. Convection of acoustic sources causes the radiated sound field to be altered due to Doppler effect. Lighthills sources along the shear layer were examined in the form of (x, t) plots and phase velocity pattern in (ω, k) plots to analyse for their convective speeds. These revealed that there is no unique convective speeds for the acoustic sources. The median convective velocity Uc of the acoustic sources in the shear layer is proportional to the jet velocity Uj at the center of the nozzle as Uc ≈ 0.6Uj. Simulations of the round jet at Mach number 0.9 were used for validating the LES approach. Five different cases of the round jet were used to understand the effect of Reynolds number and inflow perturbation on the flow, acoustic sources and the radiated sound field. Simulations were carried out for an Euler and LES at Reynolds number 3600 and 88000 at two different inflow perturbations. The LES results for the mean flow field, turbulence profiles and SPL directivity were compared with DNS of Freund (2001) and experimental data available in literature. The LES results showed that an increase in inflow forcing and higher Reynolds number caused the jet core length to reduce. The turbulent energy spectra showed that the energy content in smaller scale is higher for higher Reynolds number. LES of plane jets were carried out for two different cases, one with a co-flow and one without co-flow. LES of plane jets were carried out to understand the effect of co-flow on the sound field. The plane jets were of Mach number 0.5 and Reynolds number of 3000 based on center-line velocity excess at the nozzle. This is similar to the DNS by Stanley et al. (2002). It was identified that the co-flow leads to a reduction in turbulence levels. This was also corroborated by the turbulent energy spectrum plots. The far field radiation for the case without co-flow is higher over all angles. The contribution from the low frequencies is directional, mainly towards the downstream direction. The range of dominant convective velocities of the acoustic sources were different along shear layers and center-line. The plane jet results were also used to bring out a qualitative comparison of flow and the radiation characteristics with round jets. For the round jet, the center-line velocity decays linearly with the stream-wise distance. In the plane jet case, it is the square of the center-line velocity excess which decays linearly with the stream-wise distance. The turbulence levels at any section scales with the center-line stream-wise velocity. The decay of turbulence level is slower for the plane jet and hence the acoustic sources are present for longer distance along the downstream direction. Subsonic impinging jets are composed of four regions, the jet core, the fully developed jet, the impingement zone and the wall jet. The presence of the second region (fully developed free jet) depends on the distance of the wall from the nozzle and the length of the jet core. In impinging jets, reflection from the wall and the wall jet are additional sources of noise compared to the free jets. The results are analysed for the contribution of the different regions of the flow towards the radiated sound field. LES simulations of impinging round jets and impinging plane jet were carried out for this purpose. In addition, the results have been compared with equivalent free jets. The directivity plots showed that the SPL levels are significantly higher for the impinging jets at all angles. For free jets, a typical time scale for the acoustic sources is the ratio of the nozzle size to the jet velocity. This is ro/Uj for round jets and h/Uj for plane jets. For impinging jets, the non-dimensionlised rms of Lighthill’s source indicates that the time scale for acoustic sources is the ratio of the height of the nozzle from the wall to the jet velocity be L/Uj. LES of impinging round jets was carried out for two cases with different inflow perturbations. The jets were at Reynolds number of 88000 and Mach number of 0.9, same as the free jet cases. The impingement wall was at a distance L = 24ro from the nozzle exit. For impinging round jets, the SPL levels are found to be higher than the equivalent free jets. From the SPL levels and radiated noise spectra it was shown that the contribution from the large scale structures and its reflection from the wall is directional and at small angles to the wall normal. The difference in the range of angles where the radiation from the large scale structures were observed shows the significance of refraction of sound waves inside the flow. The rms values of the Lighthill’s sources indicate two dominant regions for the sources, just downstream of jet breakdown and in the impingement zone. The LES of impinging plane jet was done for a jet of Mach number 0.5 and Reynolds number of 6000. The impingement wall was at a distance L = 10h from the nozzle exit. The radiated sound field appears to emanate from this impingement zone. The directivity and the spectrum plots of the far field SPL indicate that there is no preferred direction of radiation from the impingement zone. The Lighthill’s sources are concentrated mainly in the impingement zone. The rms values of the sources indicate that the peak values occur in the impingement zone. The results from the different flow situations demonstrates the capability of LES with explicit filtering method in predicting the turbulent flow and radiated noise field. The method is robust and has been successfully used for moderate Reynolds number and an Euler simulation. An important feature is that LES can be used to identify acoustic sources and its convective speeds. It has been shown that the Lighthill source calculations, the calculated sound field and the observed radiation patterns agree well. An explanation for these based on the different turbulent flow structures has also been provided.

L’exposition prénatale à différents agents toxiques est généralement étudiée en considérant le placenta comme une barrière entre la mère et le fœtus ; nous le considérons en tant qu’organe cible des agents toxiques. Pour ce faire, nous avons sélectionné un modèle cellulaire de trophoblastes adapté aux études toxicologiques. En clinique, des pathologies de la grossesse sont associées à des modifications de la sécrétion de l’hormone placentaire lactogène hPL et de l’hormone gonadotrope chorionique hCG. Nos travaux in vitro ont permis de faire le lien entre une exposition à des micropolluants (le mono(2-ethylhexyl) phtalate, un perturbateur endocrinien, et le benzo(a)pyrene, un carcinogène) et ces observations cliniques. Les biomarqueurs de sécrétion hormonale (hPL et hCG hyperglycosylée) et de dégénérescence (activation du purinorécepteur P2X7) que nous avons identifiés permettent de détecter l’exposition et le risque suite à une exposition à des polluants. / Prenatal exposure to pollutants is commonly evaluated using placenta as a barrier between mother and fetus. Here, we consider placenta as a target organ for toxic agents. To achieve this, we selected a trophoblastic cell model, which is adapted to toxicological studies. In clinical studies, pregnancy pathologies are associated to changes in human placental lactogen (hPL) and human chorionic gonadotropin (hCG) secretions. Our in vitro work links exposure to micropollutants (mono(2-ethylhexyl)phthalate, an endocrine disruptor, and benzo(a)pyrene, a carcinogen) and clinical observations. We identified biomarkers of hormonal secretion (hPL and hyperglycosylated hCG) and degeneration (P2X7 receptor activation), which enable the evaluation of exposure and risk attached to exposure to pollutants.

Catalytic amination reactions are a powerful tool in organic synthesis. They aim to introduce nitrogen atom to alkane, alkene or thioether moieties, giving rise to amine products that have various medical and industrial applications. The Lebel group has developed catalytic amination reactions in the presence of rhodium dimers using N-sulfonyloxycarbamates as nitrene precursors. In the presence of a base, N-sulfonyloxycarbamates presumably afforded rhodium nitrenes which underwent C-H insertions, C=C additions or reactions with the sulfur atom of thioethers resulting in acyclic and cyclic carbamates, aziridines and sulfilimines respectively. In addition, good diastereoselectivities were observed in the presence of a chiral N-sulfonyloxycarbamate reagent and a chiral rhodium dimer for all three reactions. In this dissertation, we are interested in the mechanistic aspects of these amination reactions. Given the absence of experimental proofs of in-situ generated rhodium nitrene species, playing the role of the amination agent, nor of its precomplex, the rhodium nitrenoid, the different amination reactions mechanisms remain uncertain. Our approach is based on the scan of the potential energy surfaces of different mechanistic paths, for each of the amination reactions, well established on the experimental level, by resorting to the Functional Theory of Density (DFT). The Ernzerhof research group is expert on the development of exchange-correlation functionals, therefore relevant strict criteria have been considered when choosing and validating the theoretical model used during the mechanistic studies. The correlation exchange functional developed by Perdew-Burke-Ernzerhof (PBE) was established as the best to study reactions involving rhodium dimers where the electronic correlation is strong. We studied the formation and reactivity of rhodium nitrene species considering their two lower energy spin states. Singlet rhodium nitrenes appeared to be the most reactive intermediates for the C-H amination reaction. In addition, singlet rhodium nitrenes were shown responsible for the formation of secondary products such as carbonyls and primary carbamates derived from the corresponding N-mesyloxycarbamates. In sharp contrast, in the aziridination reaction, both singlet and triplet rhodium nitrene species acted as aminating agents in a process involving an intersystem spin crossover. To further rationalize the asymmetric induction of catalytic aziridination reactions, we have undertaken the calculation of the diastereoselectivity ratios in the presence of the chiral catalyst Rh2[(S)-nttl]4. An exhaustive study was performed and it revealed that the asymmetric induction was due to a reactive conformation of rhodium nitrene species in which the ligand adopts C4 symmetry. Up to now, no mechanistic study involving DFT calculations have been reported in the literature for the amination of thioethers, no matter what catalytic system is used. To study catalytic sulfimidation reactions, we calculated the different mechanistic paths of rhodium catalyzed thioanisole imidation with and without DMAP and bis(DMAP)CH2Cl2 additives. The study showed a 'classical' insertion mechanism of rhodium nitrene species into the thioether in absence of bis(DMAP)CH2Cl2. In the presence of the latter, the mechanism diverged to a thioether insertion/salt (bis(DMAP)CH2Cl-OMs) elimination reaction where the rhodium nitrenoid complex was, henceforth, the imidation reagent. / Les réactions d’amination catalytiques sont un outil très efficace en synthèse organique. Elles consistent à introduire un azote sur différents composés organiques, permettant de synthétiser des produits aminés qui peuvent être utilisés pour différentes applications médicales et industrielles. Le groupe de recherche du Pr Lebel a développé des réactions d’amination faisant appel aux dimères de rhodium comme catalyseurs et en utilisant les Nsulfonyloxycarbamates, comme précurseurs de nitrènes métalliques. En effet, en présence d’une base, les N-sulfonyloxycarbamates forment possiblement un intermédiaire de type nitrène de rhodium qui peuvent s’insérer dans un lien C-H, s’additionner sur un lien C=C ou réagir avec un atome de soufre d’un thioéther. On peut ainsi préparer des carbamates cycliques et acycliques, des aziridines et des sulfilimines respectivement. Dans le cas où les réactions d’amination sont catalysées par des dimères de rhodium chiraux, on obtient de bonnes diastéréosélectivités en présence d’un réactif N-sulfonyloxycarbamate chiral. Dans cette dissertation, nous nous sommes intéressés aux aspects mécanistiques de ces réactions d’amination. À défaut de preuves expérimentales solides pour prouver la génération in-situ des espèces nitrènes de rhodium, lesquelles sont les agents d’amination clés, ni de celle du pré-complexe, nitrénoïde de rhodium, des incertitudes subsistaient toujours concernant les mécanismes des différentes réactions d’amination. Notre approche se base sur l’étude des surfaces d’énergies potentielles de différents chemins mécanistiques possibles pour chacune des réactions d’amination, bien établie sur le plan expérimental, en faisant recours à la Théorie des Fonctionnelles de la Densité (DFT). Le groupe de recherche du Pr Ernzerhof est expert dans le développement des fonctionnelles d’échange-corrélation. Pour ce, des critères strictes et pertinents ont été pris en compte lors du choix et de la validation du modèle théorique utilisé dans ces études mécanistiques. La fonctionnelle d’échange corrélation développée par Perdew–Burke– Ernzerhof (PBE) s’est révélé être la meilleure pour décrire ces systèmes réactionnels faisant intervenir les dimères de rhodium dont la corrélation électronique est forte. À l’aide de cette fonctionnelle pure, nous avons étudié la formation et la réactivité des espèces nitrènes de rhodium en fonction de leurs deux états de spin de plus basse énergie. Les nitrènes de rhodium singulet se sont révélés être les intermédiaires les plus réactifs dans l`amination de liens C-H. De plus, les nitrènes de rhodium à l’état singulet sont responsables de la formation des produits secondaires tels que les carbonyles et les carbamates primaires dérivés des Nmésyloxycarbamates correspondants. Dans la réaction d’aziridination, les espèces nitrènes de rhodium à l’état singulet et triplet peuvent toutes les deux agir comme agents d'amination et les processus font intervenir un croisement intersystème de spin. Afin de rationaliser l’induction asymétrique des réactions d’aziridination catalytiques, nous avons entrepris le calcul des ratios de diastéréosélectivités en présence du catalyseur chiral Rh2[(S)-nttl]4. L’étude exhaustive de cette réaction a permis de déterminer que l’induction asymétrique provient d’une conformation réactive de l’espèce nitrène de rhodium de symétrie C4. Aucune étude mécanistique s’appuyant sur la chimie computationnelle n’a été rapportée dans la littérature pour la réaction d’amination de thioéthers et ce peu importe le système catalytique. Afin d’étudier les réactions de sulfimidation catalytiques, nous avons calculé les différents chemins mécanistiques de l’imidation du thioanisole catalysée par un complexe de rhodium avec et sans les additifs DMAP et bis(DMAP)CH2Cl2. L’étude montre que le mécanisme procède via une insertion ‘classique’ des espèces nitrènes de rhodium dans le thioéther en absence de bis(DMAP)CH2Cl2. En présence de ce dernier, le mécanisme diverge vers une réaction d’insertion du thioéther/élimination d’un sel (bis(DMAP)CH2Cl-OMs) où le complexe nitrénoïde de rhodium devient, désormais, l’agent d’imidation.

We present a theoretical and experimental study on the lowest electronically excited states in quasi-one-dimensional molecular crystals. The specific calculations and the experiments are performed for the model compounds MePTCDI (N-N'-dimethylperylene-3,4:9,10-dicarboximide) and TCDA(3,4:9,10-perylenetetracarboxylic dianhydride). The intermolecular interactions between nearest neighbors are quantum chemically analyzed on the basis of semi-empirical (ZINDO/S) Hartree-Fock calculations and a singly excited configuration interaction scheme. Supermolecular dimer states are projected onto a basis set of localized excitations. The nature of the lowest states is then completely explained as a superposition of molecular and low lying charge-transfer excitations. The CT excitations show a significant intrinsic transition dipole, which is oriented approximately parallel to the molecular planes and has a large component along the molecular M-axis. The exciton states in the one-dimensional stacks are described by a model Hamiltonian that includes interactions between three vibronic levels of the lowest molecular excitation and nearest-neighbor CT excitations. The three-dimensional crystal structure is considered by Frenkel exciton transfer between arbitrary molecules. This model is compared to polarized absorption spectra. With a small set of parameters, we can describe the key features of the absorption spectra, the polarization behavior, and the Davydov splitting. The variation of the polarization ratio for the various exciton states is analyzed as a direct qualitative proof for the mixing between Frenkel and charge-transfer excitons.

Untersuchungen über die Entstehung der einstigen Kirchsteige sind bisher kaum vorhanden. Ein interessantes Thema in Verbindung mit Kirchenentwicklung. Die Bedeutung dieser Straßen- und Wegeverläufe sind in den Erinnerungen der Menschen heute bereits vergessen, keiner denkt mehr über die Entstehungsgeschichte nach, warum die Straßen zumeist bewusst, auf kürzestem Weg, zu einer Kirche führten, die früher für die Bewohner eine große kulturelle, wirtschaftliche und sozialgeschichtliche Komponente besaßen. Unser heutiges, zumeist befestigtes Straßennetz beruht noch zu einem Großteil auf diesen lokalen, seit Jahrhunderten bestehenden Wegeverbindungen, die durchaus als historisches Erbe unserer Vorfahren anzusehen und zu erleben sind. Diese Wege spielten, besonders im Leben der Landbevölkerung, eine wichtige Rolle, wenn die Dörfer fernab der Kirchen lagen, in denen sie eingepfarrt waren. Der Lotzdorfer Kirchsteig wurde zum Ausgangspunkt der Recherchen, er ist teilweise durch historische Karten noch rekonstruierbar. Auf ihm gingen die Einwohner der Dörfer Lotzdorf und Liegau in vergangenen Zeiten zum Gottesdienst in die Radeberger Kirche.