19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 1944" Lisa M. Ponton. 12/19/2004. Report is also available in paper and microfiche from NTIS.

xxi, 199 p. ： ill. (some col.) / Mimicking the simplicity and efficiency of Nature in the synthesis and design of non-covalent receptors for ions in solution has piqued the interest of the chemical community since the mid 20th century. Until recently most of that focus has been on the binding, sensing, or remediation of inorganic cations instead of their anionic counterparts. With the realization of the role anions play in biological function or dysfunction, the development of selective probes for these highly solvated and elusive targets has become an important goal in the chemical and biological communities. Concurrently the optoelectronic properties of planar extended π-systems have been exploited in the development of novel light absorbing and emitting organics and carbon-rich materials with tunable optical outputs. While many of these compounds exhibit desirable sensor properties, their insolubility and non-specificity has hindered the inclusion of these materials in probes for biologically relevant substrates. This body of research seeks to combine our knowledge of supramolecular structure-function relationships with novel extended aromatic topologies to yield highly specific probes for anions in competitive media that exhibit discrete, tunable outputs upon interaction with their target substrates. Chapter I provides a brief overview of phenylacetylene topologies as they have been used in supramolecular assemblies and sensor design, with an emphasis on their use in anion-directed complexes. Chapter II focuses on our choice of specific arylethynylpyridine architectures upon which we can build a modular synthetic scheme to access working receptors. Chapter III encompasses the synthesis of urea and sulfonamide derivatives of phenylethynylpyridine and binding studies with these receptors and halide salts in organic media. Chapters IV and V focus upon the optoelectronic properties of these receptors, the tunability of their outputs and how we utilized their behavior in aqueous media to develop in vitro sensors for halides. This chapter concludes with recent results regarding their self-assembly on the micro-scale. This dissertation contains my previously published and co-authored work. / Committee in charge: Victoria DeRose, Chairperson; Michael Haley, Co-Advisor; Darren Haley, Co-Advisor; Shih-Yuan Liu, Member; David Schmidt, Outside Member

A arilação seletiva de compostos orgânicos confere-lhes propriedades com amplas aplicações: em compostos de atividade biológica, inibidora da protease do vírus HIV-1, e de interesse como agroquímicos ou na engenharia de materiais. Em razão disso, novos métodos e reagentes tem sido desenvolvidos com essa finalidade. Sabe-se que a N-arilação de várias aminas, catalisadas por paládio, com haletos de arila e triflatos é tida como ferramenta importante a disposição do químico sintético. Do mesmo modo, publicou-se que a N-arilação de certos -amino ácidos por haletos de arila, procede-se facilmente quando catalisada por CuI. Alternativamente, a literatura cita outros métodos eficientes usando ácidos borônicos, compostos arilbismuto e compostos organochumbo. Neste trabalho foi estudada a arilação seletiva de ânions ambidentados pelo sal de iodo polivalente cloreto de difenil iodônio, em diferentes condições de reação, visando a otimização da síntese: 1) reação térmica (agitação magnética), sem catalisador, e em diferentes solventes, ou mistura de solventes; 2) reação sonoquímica, sem catalisador e em diferentes soluções; 3) reação térmica e sonoquímica na presença de catalisador CuCl (10%). Sacarinato de sódio, acesulfame de potássio, e ftalimida potássica foram escolhidos como ânions ambidentados derivados de sulfoimidas e imidas a serem arilados. No caso de N-fenil sacarina a quemiosseletividade e o melhor rendimento são observados com acetonitrila/água (1:1, v/v), sob refluxo para formação do par iônico intermediário (ou o iodano correspondente), seguido por fusão térmica na ausência de solvente. O acesulfame potássico, por sua vez, forneceu seletivamente produtos de N- ou O-fenilação, de acordo com as seguintes condições estabelecidas: 1) produto de fenilação por via térmica ou sonoquímica em etanol; 2) produto de O-fenilação, por via térmica ou sonoquímica em acetonitrila. A ftalimida potássica, na ausência de catalisador, é arilada em baixos rendimentos. A melhor condição de síntese é encontrada com acetonitrila e CuCl (10%), sendo 92% o rendimento por via sonoquímica e 78% por via térmica. A seletividade verificada foi analisada em termos das interações dos ânions ambidentados e dos solventes em questão. / The arylation of organic compounds gives place to a wide number of applications: concerning to their biological properties as HIV-1, protease inhibitor, as well as synthetic intermediates in pharmaceuticals, agrochemical and polymer chemistry. New methodologies and reagents have been developed as consequence of this. It is already known that N-arylation of several amines, catalyzed by palladium, with aryl halides and trifflates is a valuable tool to various reported organic synthesis. In the same way, it has been published that the N-arylation of certain -amino acids by aryl halides, proceeds smoothly when catalized by CuI. Alternatively, the literature reports other efficient methods using boranic acids, arylbismuth and organolead compounds. In the present work, it was studied the selective arylation of ambident anions by hypervalent iodine salts (chloride of diphenyl iodonium), in a different set of conditions, seeking the synthesis optimizations: 1) thermal reactions (silent mode, magnetic stirring), without catalyst, and, in different solvents or mixture of then; 2) sonochemical reactions, without catalyst, and in a different solvent composition; 3) thermal and sonochemical reactions carried out in the presence of (10%) CuCl as the catalyst. Sodium saccharinate, acessulfame K and potassium phthalimide were chosen as the ambident anions (derived from sulfonimides and imide functional groups) to be studied. In the N-phenyl saccharin case the chemioselectivity was achieved along the best yields when water/acetonitrila (1:1, v/v) solvent was employed in the step to form the ion pair (or the 3-iodane, intermediate), followed by the thermal fusion in the absence of solvent. The acessulfame K, for its turn, supplied selectively products of N- and O-arylation under the following established conditions: 1) N-phenylation in etanol through thermal and sonochemical approach; 2) O-phenylation product, in acetonitrila, by thermal and sonochemical method. Finally, arylation of potassium phthalimide with diaryliodonium is sluggish and gives low yields without catalyst. The best protocol to this synthesis was found with the solvent acetonitrile and (10%) CuCl catalyst addition, being 92% the yield of sonochemical reaction and 78% of the thermal one. The selectivity achieving was analyzed in accord with the solution interaction between the ambident anion and the solvent molecules.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-04-27T15:35:04Z No. of bitstreams: 1 Dissertação de Mestrado do curso de Geoquímica - Lívia 03-2010.pdf: 1379701 bytes, checksum: 122a8209347f09650bfb44e6c9ac14c4 (MD5) / Made available in DSpace on 2017-04-27T15:35:04Z (GMT). No. of bitstreams: 1 Dissertação de Mestrado do curso de Geoquímica - Lívia 03-2010.pdf: 1379701 bytes, checksum: 122a8209347f09650bfb44e6c9ac14c4 (MD5) / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geociências- Geoquímica Ambiental. Niterói, RJ / A análise de efluentes hipersalinos ainda é um problema analítico a ser resolvido. Atualmente, tem ocorrido um grande aumento da demanda para caracterização de águas de alta salinidade, tendo em vista que esta é um dos maiores descartes da indústria de petróleo. Devido a isto, técnicas analíticas para sua caracterização têm sido desenvolvidas amplamente e entre elas temos a cromatografia de íons, onde diferentes tipos de ânions são quantificados. Contudo, para que seja possível o uso desta técnica, é imprescindível que haja a retirada do cloreto dessas matrizes hipersalinas. Essa separação prévia pode ser realizada através do emprego de cartuchos comercializados, porém de custo elevado. Sendo assim, têm sido desenvolvidos estudos com trocadores iônicos onde são utilizados no tratamento de diferentes tipos de matriz de amostra. Para o tratamento de matrizes salinas, estudos com trocadores catiônicos tratados com prata, como Amberlite IR 120 e Dowex W50, foram realizados mostrando-se eficientes na remoção do íon cloreto. Amostras de diferentes salinidades foram eluídas através de mini colunas preenchidas com estas resinas tratadas com prata. Entretanto, o seu uso leva à coluna íons de prata que também são retirados de forma eficaz do meio, através de mini colunas preenchidas com resinas na forma de hidrogênio, de modo que a coluna analítica não seja afetada. Análises comparativas com cartuchos comerciais de retenção de cloreto e prata foram realizadas, comprovando a eficiência do método. Testes para a retenção dos analitos foram realizados e mostraram que a primeira alíquota de 0,5 mL retém boa parte dos ânions de trabalho tanto nas resinas de estudo quanto nos cartuchos comerciais / ABSTRACT The analysis of hypersaline wastewater is still an analytical problem to be solved. Currently, there has been an increased demand for characterization of high salinity water, considering that this is one of the largest discharges of oil industry. Because of this, analytical methods for their characterization have been developed extensively, and among them we have the ion chromatography, where different types of anions are quantified. However, it is possible to use this technique, it is crucial that the withdrawal of these matrices hypersaline chloride. This separation can be accomplished in advance through the use of cartridges sold, however costly. Thus, studies have been developed with ion exchangers which are used to treat different types of sample matrix. For the treatment of salt matrices studies with cationic exchangers treated with silver, such as Amberlite IR 120 and Dowex W50 were performed showing to be efficient in the removal of chloride ion. Samples of different salinities were eluted through mini columns filled with these resins treated with silver. However, its use leads to a column of silver ions that are also effectively removed the medium, using mini columns filled with resins in the form of hydrogen, so that the analytical column is not affected. Comparisons with commercial cartridges retention of chloride and silver were performed, proving the efficiency of the method. Tests for retention of the analytes were performed and showed that the first rate of L retains much of the work of anions in both resins in the study as 0.5 μL commercial cartridges

Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work reports the study of the molecular structure influence of ionic liquid (IL) derived from 1,8-bis(3-methylimidazolium-1-yl)octane in the aggregates formation in a solution ethanol in water (4,75%) and in ethanol (95%). Was varied the anions (Br-, NO3-, BF4-, SCN- e NTf2-) of IL and the aggregation behavior was investigated by various methods, such as differential scanning calorimetry (DSC), conductivity, surface tension, fluorescence and dynamic light scattering (DLS). In the ethanol in water solution (4,75%), the critical aggregation concentration values (cac) (114 to 205 mM), free energy of aggregation (ΔG°a) ( 15 to 18 kJ/mol) and ionization degree (α) (0,37 a 0,44) for the IL with Br-, NO3-, BF4-, SCN- significantly decreased with the increase of anion hydrophobicity. In ethanol, the cac values (165 to 500 mM) and ΔG°a ( 9 to 11 kJ/mol) also decreased with the increase of anion size and hydrophobicity. The free energy adsorption data (ΔG°ads) (-35 to -39 kJ/mol) demonstrated that the ILs, in general, have a good surfactant activity and this property improve with the decrease in the hydrophobic characteristics of anions. In general, in the solvents used in this study, the hydrodynamic radius (Rh) of aggregates ranged between 200 and 500 nm for all the ILs. The critical packing parameter was determined using data from the X-Ray (of IL 4) and surface tension, and showed that aggregates are micelar. The cac data was obtained by the techniques of conductivity, fluorescence and surface tension. Where, was observed that increasing the anion hydrophobicity of dicationic ILs structure favored the formation of aggregates, while less hydrophobic anions improved the surfactant properties of the IL structures. / Este trabalho relata o estudo da influência da estrutura molecular de líquidos iônicos (LI) dicatiônicos, derivados do cátion 1,8-bis(3-metilimidazolil-1-íneo)-octano, na formação de agregados em uma solução etanol em água (4,75%) e em etanol (95%). Variaram-se os ânions (Br-, NO3-, BF4-, SCN- e NTf2-) dos LI e o comportamento de agregação foi investigado através das técnicas de calorimetria exploratória diferencial (DSC), condutividade, tensão superficial, fluorescência e espalhamento de luz dinâmico (DLS). Na solução etanol em água (4,75%), os valores de concentração de agregação crítica (cac) (114 a 205 mM), energia livre de agregação (ΔG°a) ( 15 a 18 kJ/mol) e grau de ionização do contra-íon (α) (0,37 a 0,44) para os LI contendo os ânions Br-, NO3-, BF4-, SCN- diminuíram significativamente com o aumento da hidrofobicidade do ânion. Em etanol, os dados de cac (165 a 500 mM), ΔG°a ( 9 a 11 kJ/mol) para os LI com os ânions Br-, SCN- e NTf2- também diminuíram com o aumento do volume e hidrofobicidade dos ânions. Dados de energia livre de adsorção (ΔG°ads) (-35 a -39 kJ/mol) demonstraram que os LI dicatiônicos, de forma geral, possuem boa atividade tensoativa e esta propriedade aumenta com a diminuição das características hidrofóbicas dos ânions. Em geral, nos solventes utilizados no estudo, o raio hidrodinâmico (Rh) dos agregados variou entre 200 e 500 nm para todos os LI. Valores de parâmetro de empacotamento crítico (Pc) determinados a partir de dados de raios-X e tensão superficial indicaram que os agregados formados são micelares. Os dados de cac obtidos por condutividade, fluorescência e tensão superficial apresentaram-se de forma concordante. Observou-se que o aumento da hidrofobicidade da estrutura do ânion do LI dicatiônico favoreceu a formação dos agregados, enquanto que ânions menos hidrofóbicos melhoraram as propriedades tensoativas das estruturas dos LI.

Ce manuscrit décrit d'une part la synthèse et la fonctionnalisation de dérivés de types azacalix[4]arènes et d'autre part l'élaboration d'une nouvelle voie de synthèse des ligands benzoquinonediimines.La première partie, consacrée aux azacalix[4]arènes, détaille les différents procédés utilisés pour fonctionnaliser des azacalix[4]arènes après leur macrocyclisation. L'introduction de groupes amides a généré des récepteurs d'anions qui présentent une sélectivité non usuelle pour les ions chlorures. Les complexes hotes-invités formés reposent sur des intercations supramoléculaires et constituent l'une des principales thématiques de ce manuscrit.La seconde part du manuscrit porté sur une nouvelle voie de synthèse des ligands benzoquinonediimines qui reposent sur la transamination du 1,2,4,5-tétraaminobenzène en présence d'un excès d'amine primaire. La simplicité de cette procédure permet d'obtenir une grande variété de benzoquinondiimines diversement substiuées. L'impact de cette substiution est illusté via l'étude de nouveaux complexes bimétalliques contenant un ligand benzoquinonediimine pontant. / The first pat of this manuscrit deals with the synthetis and fonctionalization of azacalix[4]arnes derivatives while the second part describes a new syntetic access of benzoquinonediimines ligands.In the first part, differents approaches were used to introduce fonctional groups on the peripheral positions of alrealdy formed azacalix[4]arenes. the introduction of hydrogen donor groups such as amides groups generated azacalix[4]arnes based anions receptor that preferentially bind chloride anions. These host-guest complexes are built on supramolecular interations and are one of the main topic of this manuscrit.In the second part, a new synthetic procedure of benzoquinonediimines is described and studied. The simple and efficient one-pot reaction involves a transamination between 1,2,4,5-tetraaminobenzene and primary amine and allows to prepare a large range of N-substituted benzoquinonediimines derivatives. The impact of the N-substitution is enlightened through the study on bimetallic complexes containing a bridging benzoquinonediimine unit.

Les récepteurs moléculaires synthétiques sont au cœur de la chimie supramoléculaire. Ils procurent un apport théorique important en reconnaissance moléculaire et peuvent trouver des applications en nanoscience, science séparative, biologie, médecine, catalyse, chimie analytique, science des matériaux ou industrie alimentaire. Dans le cadre de la reconnaissance moléculaire, les calix[6]arènes sont des candidats de choix car ils possèdent des arguments structuraux uniques et une cavité hydrophobe de taille propice à l’inclusion de petites molécules organiques. De plus, de nombreuses méthodes ont été mises au point pour les modifier chimiquement. Ainsi, dans ce travail, nous nous sommes intéressés à la complexation d’anions, de paires/triades d’ions de contact (anion et ammonium(s) associé(s)) ou de cations métalliques et de molécules neutres. Ces complexations sont classiquement mises en évidence par spectroscopie de résonance magnétique nucléaire (RMN). Toutefois, cette méthode souffre d’un manque de sensibilité, et nous nous sommes donc proposé de développer une nouvelle génération de calix[6]arènes portant des fluorophores, ce qui permettait la détection d’analytes présents en faible concentration dans le milieu par des méthodes spectrophotométriques. A notre connaissance, seuls de rares exemples de calix[6]arènes porteurs de fluorophores ont été décrits pour la détection de paires/triades d’ions de contact ou de cations métalliques et de molécules neutres. Notre démarche est donc tout à fait originale dans le sens où la cavité du récepteur est exploitée, au contraire de la plupart des exemples décrits dans la littérature qui n’utilisent que des sites de complexation extra-cavité.<p><p>Deux types de récepteurs ont été étudiés :les calix[6]trisurées qui sont capables de complexer des anions et des paires d’ions et les calix[6]trisimidazoles qui peuvent coordiner un ion métallique et une molécule neutre. En ce qui concerne le fluorophore, nous nous sommes particulièrement intéressés au pyrène, connu pour son aptitude à former des excimères, facilement détectables par fluorimétrie. Ainsi, le calix[6]trispyrénylurée, portant un site de reconnaissance pour anions au niveau de son petit col, a été synthétisé avec succès. La haute flexibilité de la structure associée à la taille importante des groupes pyrène du récepteur ont conduit à des problèmes de stœchiométrie pour la complexation de la plupart des anions dans le CDCl3 et dans un mélange CDCl3/CD3CN. Toutefois, l’anion sulfate est le seul à être reconnu en stœchiométrie 1:1 par ce récepteur avec une constante d’association élevée, déterminée avec précision par fluorimétrie. Ce récepteur est même sélectif pour le sulfate dans le DMSO. Un problème de sélectivité du mode de reconnaissance, lié à la flexibilité du récepteur et à l’encombrement des groupes pyrène, a été observé avec des paires d’ions de type RNH3+X- (X-=anion). Toutefois, de manière remarquable, la complexation de triades d’ions de type ammoniumTBASO4 (ammonium = PrNH3+, HexNH3+, DodNH3+, TMA+, pyrrolidinium) a pu être observée au sein du récepteur avec une sélectivité assurée par la cavité du calixarène, ceci par spectroscopie de RMN ainsi que par des méthodes spectrophotométriques. Un mécanisme d’adaptation induite de la structure du récepteur a en outre été observé au cours de la complexation de ces ammoniums de tailles différentes. Trois récepteurs calix[6]trisimidazoles portant des fluorophores de type pyrène, dansyle ou dérivé du benzothiazole au niveau du grand col ont également été obtenus. La complexation de cations métalliques tels que Zn2+, Cd2+, Co2+, Mg2+, Cu+ ou Cu2+ a pu être détectée par fluorimétrie, méthode qui a également permis de déterminer les constantes d’association de ces complexes, ce qui n’était pas possible par spectroscopie RMN. Le complexe zincique du récepteur trisimidazole trispyrényle a pour sa part permis d’inclure des amines primaires linéaires (PrNH2, DodNH2) ainsi qu’un dérivé de la dopamine, composé d’importance biologique, au sein de la cavité avec une haute sélectivité assurée par un effet cavitaire du calixarène. En outre, la complexation de ces espèces a pu être mise en évidence par fluorimétrie avec une grande sensibilité via une modification du rapport IM/IE du fluorophore en présence de l’amine d’intérêt endo-complexée. La fonctionnalisation sélective d’un invité ditopique complexé dans la cavité du récepteur a également pu être réalisée. Enfin, l’utilisation de multiples méthodes d’analyse (RMN, UV-Vis, fluorimétrie, ITC) pour mettre en évidence les phénomènes de complexation a permis de montrer leur complémentarité et de mettre en lumière certaines de leurs limites.<p><p>Tous ces travaux prometteurs permettent de valider le concept de détection d’espèces neutres ou chargées par des calix[6]arènes porteurs de fluorophores via des méthodes spectrophotométriques avec une haute sélectivité assurée par la cavité du calix[6]arène.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Le premier projet de ce travail de doctorat a consisté à étudier l’activité catalytique de complexes à base de gallium(I), pour continuer à rechercher des alternatives aux catalyseurs à base de métaux nobles, plus communs, mais réputés coûteux et/ou toxiques. Le savoir-faire de l’équipe en catalyse par des complexes de gallium(III) a pu être réinvesti dans l’étude de ce bas degré d’oxydation du gallium, rarement étudié dans la littérature scientifique, dans l’espoir de détecter des réactivités et/ou sélectivités différentes d’avec des complexes de gallium(III). Ainsi, le complexe cationique bien défini de gallium(I) [Ga(PhF)2][Al(OC(CF3)3)4] a été employé dans une large gamme de réactions dans lesquelles les catalyseurs à base de gallium(III) avaient déjà fait leurs preuves, telles que l’hydroarylation d’arénynes, la réaction de Friedel-Crafts ou encore l’hydrogénation d’alcènes par transfert, pour laquelle une réactivité supérieure à celle des complexes usuellement utilisés au sein de l’équipe a été observée. Un analogue à base d’indium(I), [In(PhF)2][Al(OC(CF3)3)4], a également été étudié dans ces réactions, sans succès. En revanche, il s’est avéré efficace dans le cadre de réactions d’hydroamination d’aminoalcènes.En parallèle a été conduit un projet basé sur l’étude en tant qu’abstracteurs d’halogénures de complexes de divers métaux (argent, lithium, potassium, thallium(I)) comportant l’anion perfluoré, très volumineux et très faiblement coordinant [Al(OC(CF3)3)4]-. Dans le cadre de l’activation de pré-catalyseurs à base d’or(I), de gallium(III) ou d’indium(III) par abstraction d’halogénures, les sels d’argent sont les plus communément employés dans la littérature. Cependant, ces sels d’argents ne sont pas innocents en termes de réactivité. Par ailleurs, si les cations métalliques des sels employés en abstraction d’halogénures font l’objet d’un nombre raisonnable d’études dans la littérature, ce n’est pas autant le cas des anions qui leur sont associés : notre étude s’oriente selon ces deux problématiques. Il s’est avéré que les propriétés très faiblement coordinantes de l’anion [Al(OC(CF3)3)4]- ont mené à des réactivités et sélectivités différentes de celles obtenues avec l’emploi de sels plus usuels, AgSbF6 plus particulièrement, dans le cadre de réaction classiquement catalysées par l’or(I) ou le gallium(III) et déjà étudiées dans le premier projet de ce travail de thèse. Les complexes à base de gallium(I) et d’indium(I) impliqués dans le premier projet ont également été, succinctement, étudiés dans ce projet parallèle. / In the main project of this thesis work, the catalytic activity of gallium(I)-based complexes was explored. The aim was to keep on looking for alternatives to noble metals-based, more common catalysts, which have a reputation for being expensive and/or toxic. The know-how developed in the team on gallium(III)-based catalysis was reinvested into the study of this low oxidation degree of gallium, only scarcely studied in the literature. It was hoped to then detect different reactivity and/or selectivity than with gallium(III) complexes. Thus, the well-defined, cationic, gallium(I)-based complex [Ga(PhF)2][Al(OC(CF3)3)4] was used in a large array of reactions that were already successfully studied with gallium(III)-based catalysts, such as the hydroarylation of arenynes, the Friedel-Crafts reaction or the transfer hydrogenation of alkenes. In this later reaction in particular, the observed reactivity was superior to that achieved with the catalysts more commonly used in the team. An indium(I)-based analogue, [In(PhF)2][Al(OC(CF3)3)4], was also tested in these reactions, without any success. However, it was actually efficient in the context of aminoalkenes hydroamination reactions.The side-project of this work consisted in the study as halide abstractors of complexes, based on diverse metals (silver, lithium, potassium, thallium(I)) and containing the perfluorinated, very bulky and very weakly coordinating anion (WCA) [Al(OC(CF3)3)4]-. In the frame of the activation of gold(I), gallium(III) or even indium(III)-based pre-catalysts by halide abstraction, silver salts are the most frequently used. However, these silver salts are not non-innocent in terms of reactivity. Besides, if the cationic metal of the salts used in halide abstraction are the subject of a reasonable amount of studies in the literature, it is not the case of their anionic counterparts: we planned to address these two problematics with this project. It appeared that the very weakly coordinating properties of the anion [Al(OC(CF3)3)4]- in the context of the previously referred to reactions classically catalyzed by gold(I) or gallium(III)-based complexes led to different reactivity and selectivity than those achieved with the usual salts and in particular AgSbF6. The gallium(I) and indium(I)-based complexes involved into the main project were also briefly studied in this side-project.

MSc (Chemistry) / Department of Chemistry / Surface water is used for domestic and agricultural activities in Musina region and other surrounding areas. This is because of the shortage of potable water. As a result, the people living in the region and its surrounding areas are potentially exposed to hazardous contaminants that may be present in the surface water. It is therefore important to ascertain the quality of the surface water in the region. Surface water samples were collected from Mutale, Nwanedi, Tshipise and Nzhelele rivers. The samples were analysed for anions such as fluoride (F-), chloride (Cl-), nitrate (NO3-), phosphate (PO43-), sulphate (SO42-); cations such as aluminium (Al), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), sodium (Na) and trace metals such as lithium (Li), vanadium (V), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), molybdenum (Mo), cadmium (Cd), thallium (Tl) and lead (Pb) by using analytical techniques such as IC, ICP-OES and ICP-MS. The same samples were also investigated for other parameters such as pH, temperature, EC, TH, TDS, Na % and SAR. The WHO (2008), SANS 241 (2006) and Canadian guideline (2017) were used as a water quality guideline for drinking purposes. Higher concentrations of Li, V, Cr, Ni, Cu, Zn, Al, Ca, Mg, K and Na in river water were detected in rainy season, whereas higher concentrations of As, Mo, K and Fe were recorded in dry season. The concentration of F-, Cd, Tl and Pb showed low contamination level in river samples. The results demonstrated that Tshipise river water was contaminated with high concentration of parameters: TDS (1864.0.8-3372.8 mg L-1), EC (2960.3-5270 mS cm-1), F- (6.403-8.419 mg L-1), SO42- (289.657-326.598 mg L-1), Na (836.690-922.810 mg L-1) and As (10.017-11.267 μg L-1) and relative to the (WHO) water guidelines. Nwanedi river also showed higher values of EC (298.0-699.0) mS cm-1 and TDS (190.3-447.5) mg L-1. In this study, the results indicated that water from Tshipise and Nwanedi river is not suitable for human consumption based on the guidelines of drinking water. The results also indicated that the soil sample had abundance of Ca, Al, Mn and Fe with concentration ranging from 0.13-10595, 0.0084-4.16, 0.0455-1116.5, 2.4-287404 mg Kg-1 respectively. / NRF

In the present work, the results of the experimental study of reactions of ions with molecular hydrogen in the temperature range 15 - 300 K using a 22-pole ion trap apparatus are presented. The reaction of OD- with para-enriched hydrogen was studied using a combination of the 22-pole ion trap apparatus with a para-hydrogen generator. Also reactions of O- with H2, D2, and HD were studied. These reactions have a channel of water production and a channel of hydrogen or deuterium transfer. Another field of study was a sequence of reactions of oxygen hydride cations with H2 and D2 which leads to the production of H3O+ or its isotopic variant, specifically reactions OH+ with H2, H2O+ with H2, D2O+ with H2, and D2O+ with D2. This reaction chain can be followed by the electron recombination of H3O+ or its isotopologue, which has a channel of water production.