Search for dissertations about: "osmium"

Showing result 1 - 5 of 26 swedish dissertations containing the word osmium.

  2. 1. Advances in Stellar Astrophysics from Laboratory Spectroscopy

    Author : Stefan Ivarsson; Atomfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; iridium; osmium; uranium; oscillator strengths; Spectroscopy; term analysis; line profiles; line structure; astrophysics; Sun; Chi Lupi; 17 Comae A; chemically peculiar; praseodymium; stars; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:2004:Ivarsson;

    Abstract : Investigation of astrophysical plasmas, such as stellar atmospheres, require both knowledge of atomic structure and data. We present laboratory instruments, techniques and tools for acquisition of the data required to derive important atomic parameters such as, wavelengths, oscillator strengths and line profiles. READ MORE

  4. 2. Homogeneous and Heterogeneous Cluster-Based Catalysts for Asymmetric Reactions

    Author : Ahmed Fawzy; Kemisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Asymmetric synthesis; hydrogenation; ruthenium; osmium; rhenium; phosphine ligands; chirality.;

    Abstract : Synthesis and characterization of new transition metal carbonyl clusters has been undertaken, and evaluation of the new clusters to act as catalysts/catalysts precursor in asymmetric reactions has been carried out. The catalytic hydrogenation of tiglic acid under relatively mild conditions, using diastereomeric clusters of the general formula [(µ-H)2Ru3(µ3-S)(CO)7(µ-1,2-L)] (L= chiral diphosphine of the ferrocene-based Walphos and Josiphos families) as catalysts, reveal different catalytic behavior in terms of conversion and enantioselectivity. READ MORE

  5. 3. Cluster-Based Catalysts for Asymmetric Synthesis

    Author : Viktor Moberg; Kemisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Metallorganisk kemi; Organometallic chemistry; Oorganisk kemi; Inorganic chemistry; Kemi; Chemistry; hydride; cobalt; osmium; ruthenium; cyclocarbonylation; Pauson-Khand; carbonyl cluster; asymmetric hydrogenation;

    Abstract : In this work, the synthesis and characterisation of new low-valence transition metal carbonyl clusters, and an investigation into their viability to act as catalysts/catalyst precursors in asymmetric synthesis, are described. Carbonyl clusters based on ruthenium and osmium have been tested as (pre)catalysts for asymmetric hydrogenation of alpha-unsaturated carboxylic acids, and cobalt carbonyl clusters have been used as (pre)catalysts in (asymmetric) Pauson-Khand synthesis. READ MORE

  6. 4. Life of Excitons in Artificial Photosynthetic Antennas

    Author : Johan Andersson; Kemisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Zn-porphyrin; Osmium; Ruthenium; Polypyridine; Inter Ligand Energy Transfer; Inter System Crossing; Excited state dynamics; Transition metal complexes; Photosynthetic Antennas; Solar energy conversion; Artificial photosynthesis; Physical chemistry; Fysikalisk kemi; Transient Absorption Anisotropy.; Reaction Center; Dendrimer; Energy Transfer;

    Abstract : Due to the predicted energy crisis when fossil fuels will be exhausted it is important to search for alternative energy sources. Utilizing sunlight via artificial photosynthesis is an interesting possibility. READ MORE

  7. 5. Molecular oxygen and hydrogen peroxide as mild oxidants in catalytic oxidations : Applications to palladium and osmium catalysis

    Author : Katarina Bergstad; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Chemistry; Kemi; organisk kemi; Organic Chemistry;

    Abstract : In this thesis the use of molecular oxygen and hydrogen peroxide as mild oxidants in transition metal-catalyzed oxidations of organic substrates is discussed. The thesis is divided into three parts.In the first part the use of heteropolyacids as robust oxygen-activating agents for aerobic reoxidation of zerovalent palladium is described. READ MORE