Orientadora: Profa. Dra. Karina Passalacqua Morelli Frin / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência & Tecnologia - Química, 2014. / Neste trabalho, foram estudadas as propriedades fotofisicas de alguns compostos de coordenacao de renio(I), fac-[Re(CO)3(NN)L]0/+1 (NN = 2,2f-bipiridina ou 2,2f-bipirimidina; L = Cloreto (Cl-), piridina (py), 2-aminometilpiridina (ampy) ou 2-fenilpiridina (phpy), e [Cl(CO)3Re(bpm)Re(CO)3Cl]. Os compostos sintetizados foram caracterizados quanto as suas propriedades na espectroscopia de ressonancia magnetica nuclear de 1H (1H RMN), absorcao e emissao na regiao do Ultravioleta- Visivel (UV-Vis) e espectroscopia na regiao do Infravermelho (IV). Os espectros eletronicos de absorcao na regiao de UV-Vis evidenciaram que os compostos sintetizados apresentaram altos valores na absortividade molar (na ordem de 104 L.mol-1.cm-1) e exibiram na regiao analisada transicoes intraligante (1IL¿Î¨¿Î*) do ligante polipiridinico e do ligante piridinico e transicoes de transferencia de carga metal-ligante (1MLCTRe¨NN). Para o composto binuclear de renio(I), [Cl(CO)3Re(bpm)Re(CO)3Cl], observou-se uma prolongamento da banda de absorcao, isto e, o composto absorve radiacao visivel ate aproximadamente 600 nm.. Os espectros de emissao dos compostos fac-[Re(CO)3(bpy)L]0/+1 (L = Cl, py, ampy ou phpy) apresentaram uma banda larga e nao estruturada, sendo que o estado excitado 3MLCTRe¨bpy e o responsavel pela emissao. O composto fac-[Re(CO)3(bpy)Cl] apresentou em diclorometano (CH2Cl2) uma emissao maxima em 612 nm e 0,005 de rendimento quantico, enquanto que os compostos fac-[Re(CO)3(bpy)L]+1 (py, ampy ou phpy) apresentaram a emissao em 548, 558, 526 nm e rendimento quantico de 0,216, 0,078, 0,254, respectivamente. Portanto, a substituicao do ligante cloro pelo ligante piridinico provoca um deslocamento hipsocromico da emissao e tambem a um aumento. no rendimento quantico, tendo em vista que o ligante cloro reduz a eficiencia do cruzamento intersistema. Os compostos fac-[Re(CO)3(bpm)Cl] e [Cl(CO)3Re(bpm)Re(CO)3Cl] apresentaram uma emissao relativamente baixa em diferentes solventes, na ordem de 10-4. Enquanto que o estado responsavel pela emissao do composto mononuclear e 3MLCTRe¨bpm, por outro lado quando ocorre a coordenacao com outro atomo de renio, [Cl(CO)3Re(bpm)Re(CO)3Cl], existe a desestabilizacao deste estado, tendo assim, o estado excitado 3ILbpm responsavel pela emissao. O estado excitado de mais baixa energia 3MLCT para os compostos fac-[Re(CO)3(bpm)Cl] e fac-[Re(CO)3(bpy)L]+, (L= py, ampy ou phpy) e os diferentes valores observados em meios rigidos confirmaram a sensibilidade do estado excitado a rigidez do meio, observou-se o efeito rigidocromico. Consequentemente, estes compostos podem ser utilizados no desenvolvimento de dispositivos moleculares. / In this work, it were studied the photophysical properties of some coordination compounds of rhenium(I), fac-[Re(CO)3(NN)L]0/+1 (NN = 2,2'- bipyridine, bpy, or 2,2'-bipyrimidine, bpm; L = chloride (Cl), pyridine (py), 2-aminomethylpyridine (ampy) or 2 -phenylpyridine (phpy), and [Cl(CO)3Re(bpm)Re(CO)3Cl]]. The synthesized compounds were characterized by nuclear magnetic resonance spectroscopy of 1H (1H NMR), absorption and emission in the Ultraviolet- Visible region (UV - VIS) and spectroscopy in infrared region (IR). The electronic absorption spectra in the UV-Vis region showed that the synthesized compounds presented high molar absorptivity (in the order of 104 L.mol-1.cm-1) and exhibited in the analyzed region intraligand transitions (1IL¿Î¨¿Î*) of the polypyridyl ligant and pyridine, as well as metal to ligand charge transfer transitions (1MLCTRe ¨ NN). For binuclear compound of rhenium(I), [Cl(CO)3Re(bpm)Re(CO)3Cl], there was a prolongation of the absorption band, i.e., the compound absorbs visible radiation up to approximately 600 nm.The emissions spectra of the compounds fac-[Re(CO)3(bpy)L]0/+1(L = Cl-, py, ampy or phpy) exhibited a broad and unstructured band assigned to the lowest lying excited state, 3MLCTRe ¨ bpy. The compound fac-[Re(CO)3(bpy)Cl] presented in dichloromethane (CH2Cl2) a maximum emission at 612 nm and quantum yield of 0.005, while the compounds fac-[Re(CO)3(bpy)L]+1 (py, ampy or phpy) presented the emission in 548, 558, 526 nm and quantum yield of 0.216, 0.078, 0.254, respectively. Therefore, the substitution of the chloride ligant by pyridine causes a hypsochromic shift in the emission, as well as an increase in the quantum yield, since the chloride ligant reduces the efficiency of intersystem crossing. The fac-[Re(CO)3(bpm)Cl] and [Cl(CO)3Re(bpm)Re(CO)3Cl] compounds presented a relatively low emission in CH3CN, in the order of 10-4. While the 3MLCTRe ¨ bpm was the responsible for the mononuclear emission, when the coordination to an another atom of rhenium occurred [Cl(CO)3Re(bpm)Re(CO)3Cl], this state was destabilized, and thus, the 3ILbpm excited state became the responsible to emission. The state excited of lower energy 3MLCT for compounds fac-[Re(CO)3(bpm)Cl], fac-[Re(CO)3(bpy)L]+ (L = py, ampy or phpy) and the different values observed in rigid media have confirmed the sensitivity of the excited state to the medium rigidity, due to the rigidochromic effect. Consequently, these compounds can be used in the development of molecular devices.

Ce projet s’inscrit dans le cadre d’une étude fondamentale liée à l'oxydation et la réduction de ces éléments sous irradiation γ et He²⁺. ⁺. Tout d'abord la technique d’électrochimie a été utilisée pour la réduction du Mn (VII) afin d'obtenir les meilleures conditions expérimentales. Car les expériences étant réalisées sous irradiation ainsi les radicaux carbonate qui sont produits par radiolyse jouent un rôle important dans les réactions. La cinétique de formation et la décroissance des radicaux carbonate dans les solutions de carbonate concentrées ont été étudiés par radiolyse pulsée β pico-seconde. Après la réduction du Mn (VII) et l'oxydation du Mn (II) dans une solution de carbonate ([CO₃²⁻] = 5 mol.l⁻¹) sont réalisées sous irradiation γ et He²⁺. Par des données obtenues pour H₂ produit, les spectres UV-Vis et structure finale, les mécanismes de la réaction sont discutés. Re (III) est oxydé facilement dans une solution de carbonate concentré sous irradiation (γ et He²⁺) mais Re (VII) ne peut être réduite à moins que l'addition de formiate afin d'empêcher la formation de radicaux carbonate. De la même façon, Tc (VII) ne peut être réduit dans les solutions concentrées de carbonate sous irradiation (γ et He²⁺) sans ajout de formiate. L'état d'oxydation du produit final de la réduction de Tc(VII) a été déterminée par spectroscopie XANES et est de + IV. En outre, la structure finale du produit final a été déterminée par spectroscopie EXAFS. Le mécanisme de la réaction, le rendement radiolytique de décroissance et la formation du Tc et l’effet de concentration du carbonate sur la produit final de la réduction du Tc(VII) sous irradiation sont discutés. / This project is one part of the fundamental study and deals with theoxidation/reduction reactions and speciation of technetium and its homologous manganese and rhenium in highly concentrated carbonate solutions under γ and He²⁺ irradiation. Firstly the electrochemistry experiment is carried out for the reduction of Mn(VII) in order to obtain the best experimental conditions. As the experiments are performed under irradiation, the carbonate radicals,which are produced by radiolysis, play an important role in the reactions. The formation and decay kinetics of the carbonate radicals in concentrated carbonate solutions were studied by electron picosecond pulse radiolysis. The reduction of Mn(VII) and the oxidation of Mn(II) experiments in carbonate solution ([CO₃²⁻] = 5 mol.l⁻¹) are carried out under γ and He²⁺ irradiation. By the obtained data from the produced H₂, UV-Vis spectra and the final structure determination, the mechanisms of the reaction are discussed. Re(III)is oxidized easily in concentrated carbonate solution under irradiation (γ and He²⁺) but Re(VII) cannot be reduced unless addition of formate in order to prevent carbonate radical formation. Also Tc(VII) cannot be reduced in concentrated carbonate solutions under irradiation (γ and He²⁺) without formate addition. The oxidation state of the final product of reduction of Tc(VII) was determined by XANES spectroscopy and is +IV. Moreover, the final structure of the product was determined by EXAFS spectroscopy. The mechanisms of reaction, decay and formation radiolytic yield of Tc and also the effect of concentration of carbonate on final product of reduction ofTc(VII) under irradiation are discussed.

Neste trabalho foi realizado o estudo do comportamento fotoquímico e fotofísico de complexos mononucleares de rênio do tipo fac-[Re(CO)3(N N)(L)]+(N N = 1,10-fenantrolina, phen, dipirido[3,2-a:2,3-c]fenazina, dppz, L= trans-1,2bis(4-piridil)etileno, trans-bpe, trans-4-estirilpiridina. trans-stpy) e dos complexos binucleares [(CO)3(phen)Re(trans-bpe)Re(phen)(CO)3]2+, [(CO)3(phen)Re(trans-bpe)Fe(CN5]2- e [(phen)(CO)3Re(trans-bpe)Os(terpy)(bpy)]3+. O enfoque principal deste trabalho é a investigação das propriedades fotoquímicas dos complexos fac-[ Re(CO)3(phen)(trans-bpe)]+, fac-[Re(CO)3(phen)(trans-stpy)]+ fac-[Re(CO)3(dppz)(trans-bpe)+ e [(CO)3(phen)Re(trans-bpe)Re(phen)(CO)3]2+. Observou-se que os compostos em solução de acetonitrila, sob irradiação a 313, 334 ou 365 nm, apresentam variação espectral com definição de pontos isosbésticos, resultante do processo de fotoisomerização trans&#8594;cis do ligante coordenado trans-piridil etileno. Os rendimentos quânticos, &#934;, da reação de fotoisomerização foram calculados com base no decaimento espectral das bandas de absorção das transições eletrônicas. Os valores médios determinados para a fotoisomeriação dos complexos em solução de CH3CN variam de 0,15 - 0,39 sob excitação a 313 nm e de 0,12 - 0,33 sob excitação a 365 nm. As reações de fotoisomerização foram monitoradas também por medidas de emissão e por RMN de 1H. Observou-se um aumento da intensidade de luminescência com o tempo de irradiação dos complexos, consistente com o estado emissivo 3MLCT d&#960;[(Re)&#8594;&#960;*(&#945;-diimina). Após irradiação, as reações de fotoisomerização dos complexos foram monitoradas por RMN de 1H. Os sinais de prótons do isômero trans tiveram um decréscimo gradual, enquanto que a intensidade dos sinais referentes aos prótons da espécie cis aumentaram. Os rendimentos quânticos para o processo de fotoisomerização dos complexos foram calculados através da integração das áreas dos sinais de prótons. Os valores obtidos foram maiores, pelo menos o dobro, que aqueles valores obtidos via espectroscopia UV-Vis. O comportamento fotoquímico dos complexos incorporados em polimetacrilato de metila, PMMA, foi também investigado. A fotólise cios complexos em filmes de PMMA conduz à variação espectral, de absorção e emissão, similar àquela observada em solução de acetonitrila, atribuícla ao processo de fotoisomerização trans &#8594; cis do ligante coordenado. Este estudo mostra que a fotoisomerização do ligante coordenado trans-piridil etileno pode ser promovida também em meio rígido. Essa característica. típica de um dispositivo molecular, pode ser convenientemente explorada no desenvolvimento de fotossensores. As medidas de TRIR mostram que o estado excitado de menor energia para o fac-[Re(CO)3(phen)(trans-bpe)+ é o 3&#960;&#960;*. Para o fac-[Re(CO)3(phen)(cis-bpe)]+ a ordem dos estados excitados aparecem invertidas com o 3MLCT <3&#960;&#960;*, evidenciado pela emissão do complexo cis à temperatura ambiente. Nas espécies binucleares, [(phen) Re(CO)3(trans-bpe)Os(terpy)(bpy)]3+ e [(CO)3(phen)Re(trans-bpe)Fe(CN)5]2-, a fotoisomerização trans &#8594; cis do ligante coordenado trans-bpe, característica da subunidade fac-[Re(CO)3(phen)(trans-bpe)]+, é inibida pela competição de transferência de energia intramolecular. Em meio rígido, em PMMA ou em EPA a 77 K, os máximos de emissão dos complexos fac-[Re(CO)3(phen)(cis-bpe)]+, fac-[Re(CO)3(phen)(cis-stpy)r e [(CO)3(phen)Re(cis-bpe)Re(phen)(CO)3]2+ sofrem um deslocamento hipsocrômico com o aumento da rigidez do meio. As mudanças nas propriedades emissivas, em termos de energia e tempo de vida do estado excitado, são discutidas baseadas no efeito rigidocrômico luminescente. O trabalho mostra uma forma interessante de fotos sensibilizar um substrato orgâmco usando o fato de que a coordenação estende a absorção do ligante a uma região de comprimento de onda maior e promove a fotoisomerização assistida por complexos metálicos em energias menores. / In this work the photochemical and photophysical behavior of rhenium complexes fac-[Re(CO3( N N )(L\')]+N N = 1,10 phenanthroline, phen; dipirido[3,2-a:2\',3\'-c]phenazine, dppz; L\'= trans-1,2bis(4-pyridyl)ethylene, trans-bpe; trans-4-styrylpyridine, trans-stpy) and binuclear complexes [(CO)3(phen)Re(trans-bpe)Re(phen)(CO)3]2+, [(CO)3(phen)Re(trans-bpe)Fe(CN)5]2+ and [(phen)(CO)3Re(trans-bpe)Os(terpy)(bpy)]3+ were investigated. The main focus of the work is the investigation of photochemical behavior of fac-[Re(CO)3(phen)(trans-bpe)+, fac-[Re(CO)3(phen)(trans-stpy)+, fac-[Re(CO)3(dppz)(trans-bpe)]+ and [(CO)3(phen)Re(trans-bpe)Re(phen)(CO)3]2+ in acetonitrile solution. Photolyses of rhenium completes at 313. 334 or 365 nm led to spectral changes with clear and well defined isosbestic points. These spectral changes are due to the trans &#8594; cis isomerization process of the coordinated pyridyl-ethenyl ligand. Quantum yields, &#934;, for isomerization processes were calculated based on the absorption spectral changes. The average values for the isomerization reactions of the complexes in CH3CN solution are 0.15 - 0.39 at 313 nm excitation and 0.12 - 0.33 at 365 nm excitation. The photoisomerization reactions were also followed by emission and 1H NMR measurements. An increasing luminescence was observed after complexes irradiation which is consistent with an emitting 3MLCT state, d&#960;(Re)&#8594;&#960;*(&#945;.-diimine). Upon irradiation, the photoisomerization reactions for complexes were monitored by 1H NMR spectroscopy. The proton signals of the trans isomer were found to decrease gradually while the cis isomer signals gradually built up in intensity. Quantum yields for the isomerization process were calculated by integratian of the proton signals. The values abtained in this way were higher, twice at least, than those obtained by UV-Vis electronic spectroscopy. The photochemical behavior of the complexes incorporated in poly(methyl methacrilate), PMMA, was also investigated. Photolyses of the complexes in PMMA films lead to UV-Visible and emission changes similar to those observed in solution, due to the trans &#8594; cis isomerization of the coordinated ligand. Therefore the photoisomerization is occurring even in rigid media. This feature, typical for molecular devices, can be conveniently exploited, such as for photosensors. TRIR measurements showed that the lowest lying excited state is a bpe-based 3&#960;&#960;* for the fac-[Re(CO)3(phen)(trans-bpe)]+ complex. For fac-[Re(CO)3(phen)(cis-bpe)]+ the ordering of low-lying states appears to be reversed with 3MLCT < 3&#960;&#960;*, evidenced by emission of the cis complex at room temperature. In the binuclear species. [(phen)Re(CO)3(trans-bpe )Os(terpy)(bpy)]3+ and [(CO)3(phen)Re(trans-bpe)Fe(CN)5]2-, the trans &#8594; cis photoisomerization of the coordinated trans-bpe ligand. characteristic of the Re(CO)3(phen)(trans-bpe)+ subunit, is inhibited by competitive intramolecular energy transfer. In a rigid medium, such as PMMA or EPA at 77 K, the emission maxima of fac-[Re(CO)3(phen)(cis-bpe)+, fac-[Re(CO)3(phen)(cis-stpy)+ and [(CO)3(phen)Re(cis-bpe)Re(phen)(CO)3]2+ complexes exhibit hypsochromic shifts as the medium rigidity increases. Changes in emission properties (energy and lifetime of excited states) are discussed based on the luminescent rigidochromic effect. This work presents an interesting approach to photosensitization of an organic substrate by using the red-shifted absorption of the complex to achieve the photoassisted isomerization by irradiation in the low energy region.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

Investigations in the 99mTc chemistry are stimulated by the search for new radiopharmaceuticals for nuclear medical applications. To understand the coordination mode of Tc with various complexing agents, macroscopic studies of technetium coordination chemistry are often performed using the low energy ß-emitting radionuclide 99Tc, which has a much longer half life (t1/2 = 2.12 x 105 years) than 99mTc, in the mg level. Investigations of Re coordination chemistry are done in conjunction with Tc studies because Re possesses chemical properties similar to those of Tc. For some chemical tasks, Re provides a non-radioactive alternative to work with Tc radioisotopes. In addition, 186Re and 188Re are of great interest to nuclear medicine as they possess nuclear properties favorable for use in therapeutic radiopharmaceuticals. Our investigations of Tc and Re coordination chemistry are toward this goal. A large series of technetium and rhenium complexes resulted from this studies have been characterized by X-ray crystal structure determinations. This survey covers the structural investigations performed by P.Leibnitz and G.Reck (BAM) from 1992 till now. It summarizes results obtained in the Rossendorf technetium group and is not intended to compete with the well-written reviews published so far.

During the attempts to carry out Suzuki coupling reactions, the σ-bonded Pd−Caryl benzochalcogenadiazolyl complexes trans-[ClPd(PPh3)2(C6H2BrN2E)] (E = S, Se) were isolated. The corresponding bromo derivatives were also synthesized on purpose to investigate their activity in Stille coupling reactions. A head-to-tail dimer trans- [{ClPd(PPh3)(μ-C6H2BrN2Se)}2] was synthesized from the thermolysis of trans- [ClPd(PPh3)2(C6H2BrN2Se)] in the presence of SeO2. The reduction potentials of the mononuclear and dinuclear complexes were measured by cyclic voltammetry (CV) and square wave voltammetry (SWV). 4,7-bis(2/4-pyridyl)benzochalcogenadiazole ligands were synthesized by Stille coupling reactions and the 1,5-bis(4-pyridyl)naphthalene ligand was prepared by a Suzuki coupling reaction. Reactions of the labile complex [BrRe(CO)4(NCMe)] with 4,7-bis(4- pyridyl)benzochalcogenadiazole ligands in a 2:1 ratio afforded self-assembled molecular rods [{ReBr(CO)4}2(μ-4,7-bis(4-pyridyl)benzochalcogenadiazoles)]. Palladium directed molecular squares [(enPd)(μ-4,7-bis(4-pyridyl)benzochalcogenadiazole)]4[PF6]8 were prepared by reactions of enPd(PF6)2 and 4,7-bis(4-pyridyl)benzochalco-genadiazoles in a 1:1 ratio. The optoelectronic properties of the ligands and the molecular rods were investigated by CV and SWV, and by luminescence spectroscopy. The optical properties of the square complexes were also studied by luminescence spectroscopy. / xvii, 152 leaves : ill. (some col.) ; 29 cm

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

Orientadora: Prof.ª Dr.ª Karina Passalacqua Morelli Frin / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2016. / Quatro compostos polipiridinicos de Re(I), fac-[Re(CO)3(ph2phen)(L)]+ (L = bpa, 4,4¡¦-bpy e, apy) e fac-[{(Ph2phen)(CO)3Re}2(bpa)]+2, foram sintetizados e purificados. Os complexos foram caracterizados por espectroscopia de 1H RMN, IR/ATR e UV-vis em MeCN a 298 K. Foi verificado intensa absortividade (4.104 Lmol-1cm-1) na regiao UVB (£fmax =292 nm) do espectro atribuida a transicao intraligante 1ILPh2phen, e a transicao de transferencia de carga do metal para o ligante 1MLCTRe ¿_ Ph2phen (1.104 Lmol-1cm-1) em aproximadamente £f ~350 nm. As propriedades fotofisicas produzem 3MLCT Re ¿_ Ph2phen que apresentam intensa luminescencia em £fem = 562 nm usando-se excitacao em comprimento de onda monocromatico de 375 nm possuindo rendimento quantico de emissao (¿Öem) da ordem de 0,036-0,360 e tempo de vida de emissao (£n) de £gs, sendo que a luminescencia observada varia em funcao do carater doador e aceptor de densidade eletronica do ligante (L) definindo a basicidade e acidez dos complexos em solucao. As propriedades fotofisicas em pol (metacrilato de metila) PMMA exibiram o efeito rigidocromico observado por meio do deslocamento hipsocromico da emissao sem alteracao na estrutura da banda 3MLCT Re Ph2phen. O estudo de supressao com hidroquinona (H2Q) em solucao desaerada de MeCN a 298 K demonstrou excelente correlacao entre intensidade de emissao (I) e tempo de vida de emissao (£n) dos complexos na metodologia de Stern-Volmer. Para os complexos fac-[R (CO)3(Ph2phen)(bpa)]+, fac-[Re(CO)3(Ph2phen)(4,4¡¦-bpy)]+ e fac-[{(Ph2phen)(CO)3Re}2(bpa)]2+ foram determinadas as constantes Ksv da ordem de 104 Lmol-1 com correspondentes constantes cineticas de supressao bimolecular kq 109 Lmol-1s-1 revelando forte supressao do estado excitado associado ao mecanismo dinamico de transferencia de eletron (ET) por meio de interacoes/empilhamento £k-£k* como sugestao de rota mais eficiente. Enquanto, para o complexo fac-[Re(CO)3(Ph2phen)(apy)]+ a constante Ksv obtida foi de 102 Lmol-1 e, kq 109 Lmol-1s-1, demostrando evidencias de um caminho alternativo para supressao desse composto com H2Q envolvendo um possivel mecanismo dinamico de supressao via transferencia protonica acoplada a transferencia de eletron (EPT) que e menos eficiente, assumindo-se a existencia de intrinseco pre-equilibrio acido-base desse complexo em solucao. / Four polypyridyl Re(I) compounds, fac-[Re(CO)3(ph2phen)(L)]+ (L = bpa, 4,4¡¦-bpy e, apy) and fac-[{(Ph2phen)(CO)3Re}2(bpa)]+2, were synthesized and purified. The complexes have been characterized by 1H NMR, IR/ATR and UV-vis spectroscopies in MeCN at 298 K. Verified intensity absorption (4.104 Lmol-1cm-1) in UVB spectral region (£fmax = 292 nm) assigned to the intraligand 1ILPh2phen transition, and the metal-to-ligand charge transfer 1MLCTRe ¿_ Ph2phen transitions (1.104 Lmol-1cm-1) in about £f ~350 nm. The photophysical properties produces 3MLCT Re ¿_ Ph2phen which account for stronger luminescence in £fem = 562 nm using monochromatic excitation 375 nm resulting in emission quantum yields (¿Öem) in the range of 0,036-0,360 and lifetimes (£n) of the order of £gs, wherein the luminescence observed as a function of the donor or acceptor of electron density of the ligand (L) defining the basicity and acidity of the complexes in solution. The photophysical properties in poly(methyl methacrylate) PMMA exhibited the rigidochromic effect observed by hypsochomic shifts in spectra with no change in the emission band structure 3MLCT Re ¿_ Ph2phen. The quencher studies by hydroquinone (H2Q) in degassed MeCN solution at 298 K demonstrated excellent correlation between emission intensity (I) and lifetime (£n) for the complexes using Stern-Volmer methodology. For fac-[Re(CO)3(Ph2phen)(bpa)]+, fac-[Re(CO)3(Ph2phen)(4,4¡¦-bpy)]+ and fac-[{(Ph2phen)(CO)3Re}2(bpa)]2+ complexes were determined Ksv constant in 104 Lmol-1 order, and the corresponding rate constant for the bimolecular excited state quenching kq 109 Lmol-1s-1 revealed stronger excited-state quenching associated with the dynamic mechanism of the electron transfer (ET) by £k-£k* stacked suggesting a more efficient pathway. While for the fac-[Re(CO)3(Ph2phen)(apy)]+ complex the Ksv obtained constant was 102 Lmol-1 and respective kq = 109 Lmol-1s-1 demonstrated the evidence of an alternate path for quenching that compound by H2Q involving a possible less efficient dynamic mechanism the electron-proton-transfer (EPT) assumed the intrinsic preequilibria acid-base that complexes in solution.

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