Doctor of Philosophy / Department of Chemistry / Kenneth J. Klabunde / Non-polar halogens (Cl2, Br2 and I2) and polar interhalogen molecules (ICl, IBr and ICl3) have been adsorbed on the surface of several high surface area materials, including three different nanosized metal oxides (NanoActive® (NA) Al2O3 Plus, NA-TiO2 and NA-CeO2). The prepared halogen and interhalogen adducts have been characterized in detail by thermogravimetric analysis (TGA), UV-Vis, Raman and X-ray photoelectron spectroscopies (XPS) and the results are discussed herein. The different metal oxides lead to varying strength of adsorption of the halogen/interhalogen in the prepared adducts and adsorption is stronger in the nanosized metal oxides as compared to their macrocrystalline available counterparts. Nanosized metal oxide halogen adducts possess high surface reactivities due to their unique surface morphologies. These adducts have been used as reactive materials against vegetative cells, such as Escherichia coli and Bacillus megaterium, as well as spores, including Bacillus subtilis and Bacillus anthracis (Δ Sterne strain). High biocidal activities against both Gram-positive and Gram-negative bacteria, as well as spores have been obtained. Bactericidal test procedures include a water suspension method and a dry membrane method and the results illustrate that good results are obtained using both procedures. Transmission electron micrographs have been used to illustrate the treated and untreated cells and spores, giving insight into the mechanism. It is proposed that the abrasive character of the particles, along with the oxidative power of the halogens/interhalogens as well as the electrostatic attraction between some of the metal oxides and the biological material are main reasons for the high biocidal activities. Three different bacteriophages (MS2, φX174 and PRD1) have also been studied and initial results indicate that there is big potential for the use of metal oxide halogen and interhalogen adducts for the destruction of viruses. Other potential uses for them also include halogenating agents in organic and inorganic synthesis as well as a safe way to store intact halogens.

Non-covalent interactions are fundamental to molecular recognition processes that underpin the structure and function of chemical and biological systems. Their study is often difficult due to the interplay of multiple interactions and solvent effects common in complex systems. Herein, chapter one provides some general background on the area before presenting a literature review of key, contemporary developments on the use of folding molecules for the quantification of non-covalent interactions. Chapter two investigates the magnitude and extent of energetic cooperativity in H-bond chains. Utilising supramolecular complexes and synthetic molecular torsion balances, direct measurements of energetic cooperativity are presented in an experimental system in which the geometry and number of H-bonds in a chain were systematically controlled. Strikingly, it was found that adding a second H-bond donor to form a chain can almost double the strength of the terminal H-bond, while further extension had very little effect. Computations provide insights into this strong, short-range cooperative effect in a range of H-bonding contexts. Chapters three and four build on the concepts and molecular models discussed in chapter two. Chapter three discusses the effects of interplay and competition between strong H-bond acceptors such as formyl groups and the weaker organofluorine H-bond acceptor. There has been some debate in recent literature about the latter’s ability to accept H-bonds, the work presented shows that although organofluorine is a weak H-bond acceptor, it can have a significant modulating effect on stronger interactions when in direct competition. Chapter four investigates deuterium isotope effects on conformational equilibria governed by non-covalent interactions. The results show that any deuterium isotope effect which exists is less than the margins of experimental error. Finally, chapter five discusses a molecular torsion balance designed to investigate halogen∙∙∙arene interactions. The interaction energies were investigated in a range of solvents and mixtures in order to dissect out the dispersive and solvophobic components of folding. Overall, these interactions were found to be weak. Nonetheless, a model was used to dissect trends in solvophobic and electronic contributions to the binding using multiple linear regression based upon the cohesive energy density and polarisabilities of the solvents.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 5 uppsatser.

Made available in DSpace on 2014-10-09T12:23:12Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:23Z (GMT). No. of bitstreams: 1 00925.pdf: 4094460 bytes, checksum: c96e7617422d9bd6a8d1b96f8a26ea5f (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Farmacia e Bioquimica, Universidade de Sao Paulo - FB/USP

This thesis investigated the emission and transport of very short–lived halogens (VSLS) over the tropics. VSLS are described as organic halogen gases with lifetimes of less than 6 months. In areas of rapid convective transport they reach the upper troposphere and lower stratosphere where they contribute to total bromine loading (~20 pptv) in the stratosphere that is a cause of ozone (O3) depletion. This thesis investigated speed of transport in the tropics using model age of air (Chapter 3), the strength of VSLS source regions in tropical troposphere (Chapter 4), and quantification of their monthly emission fluxes (Chapter 5). The two most abundant VSLS bromoform (CHBr3) and CH2Br2 were focussed on. A new model age of air calculation was used to describe transport of ocean emissions in the tropical latitudes. Age of air describes how long an air mass has been out of contact with the emission source region. The two most rapid convection regions of the Indian Ocean (InO) and Western Pacific (WPa) showed age of air in the tropical tropopause layer (TTL) to be 25 days. This is similar to the lifetime of CHBr3 (24 days). Using age of air estimated from simulations covering 1989–2013, it was shown how strong El Niño events can increase the age of air over the WPa by 5–7 days in the mid–troposphere, and up to 12 days in the TTL. This increase in age was due to a change in the Walker Circulation, weakening convection in the WPa and increasing convection over the CPa. Over this period, it was shown that age decreases in the tropical circulation system (the Hadley Cell). Decreasing age results from increasing convection, and more rapid transport of VSLS to the upper troposphere, lower stratosphere (UTLS). To study regional emission sources over the WPa, a tagged CHBr3 and CH2Br2 model was developed. It is the first study to quantify how open and coastal emissions contribute separately to the vertical profiles of CHBr3 and CH2Br2 in the WPa. Variability over the WPa is dominated by an open oceanic emission source, with enhanced coastal emissions influencing concentrations in the upper troposphere. Estimations of 3.14 pptv of CHBr3 and CH2Br2 contribution to TTL Bry were in agreement with recent observational studies (3.27 pptv, Navarro et al. (2015)) over the same region. Comparison with aircraft observations showed that the model has a positive bias and this is attributed to over estimation of model emissions. Ground–based observations were used in an inverse model to estimate surface emissions of CHBr3. This method has not been previously used to estimate CHBr3 emissions. The monthly a posteriori emissions had seasonal cycles in the northern and southern hemisphere coastal emissions, and reductions over tropical open oceans. A posteriori emissions were put in to the model and the predicted volume mixing ratios were able to reproduce ground stations observations over the mid–latitude and tropical stations, important for convective transport of VSLS. The model still showed a bias when compared to CAST and CONTRAST aircraft observations over the Western Pacific, but the mean model minus observed residual was reduced by around 0.3 pptv and 0.1 pptv for respective CAST and CONTRAST campaigns from the a priori emissions.

Specially prepared 2-arylquinolin-4(1H)-ones and their 2-aryl-1-methyl-4-quinolone derivatives were converted in high yield and purity to the corresponding C-3 brominated products using pyridinium tribromide in acetic acid at room temperature. The 2-arylquinolin-4(1H)-ones were reacted with iodine and Na2CO3 mixture in THF at room temperature to produce the 3-iodo-2-arylquinolin-4(1H)-one derivatives. The latter were, in turn, N-methylated using NaH-MeI mixture in dry THF to afford the corresponding 2-aryl-3-iodo-1-methyl-4-quinolone derivatives. The 3-iodo-2-arylquinolin-4(1H)-one and 2-aryl-3-iodo-1-methyl-4-quinolones were converted to 2,3-diarylquinolin-4(1H)-one and 2,3-diaryl-1-methyl-4-quinolones following Suzuki cross-coupling reaction method, respectively. The 2-aryl-3-bromoquinolin-4(1H)-ones, on the other hand, were converted to 2-aryl-3-bromo-4-chloroquinoline derivatives using phosphorus oxychloride under reflux. The 2-aryl-3-bromo-4-chloroquinoline were then transformed to the corresponding 2-aryl-3-bromo-4-N-(4'-chloroaryl)-4-aminoquinolines derivatives using 4-chloroaniline in ethanol under reflux. The products synthesized in this investigation were characterised using a combination of 1H NMR, 13C NMR, IR and mass spectroscopic techniques. / Chemistry / Chemistry / MSC (CHEMISTRY) / MSC (Chemistry)

Made available in DSpace on 2014-10-09T12:29:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:04Z (GMT). No. of bitstreams: 1 01290.pdf: 840073 bytes, checksum: 58828cfcb75bc5ca0a2529d61706549b (MD5) / Tese (Doutoramento) / IEA/T / Instituto de Biociencias, Universidade de Sao Paulo - IB/USP

Made available in DSpace on 2014-10-09T12:30:28Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:35Z (GMT). No. of bitstreams: 1 00822.pdf: 1477974 bytes, checksum: 5fab683e00fb93c844b67abbe1a837d9 (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo - CF/USP

Made available in DSpace on 2014-10-09T12:23:56Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:47Z (GMT). No. of bitstreams: 1 01284.pdf: 4352198 bytes, checksum: f153ada9e8c083a925fdcac3eedb0d46 (MD5) / Tese (Docencia) / IEA/T / Faculdade de Medicina, Universidade de Sao Paulo - FM/USP

Made available in DSpace on 2014-10-09T12:23:12Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:23Z (GMT). No. of bitstreams: 1 00925.pdf: 4094460 bytes, checksum: c96e7617422d9bd6a8d1b96f8a26ea5f (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Farmacia e Bioquimica, Universidade de Sao Paulo - FB/USP