Sökning: "carbonyl cluster"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden carbonyl cluster.

  1. 1. Cluster-Based Catalysts for Asymmetric Synthesis

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

    Sammanfattning : 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. LÄS MER

  3. 2. Coordination of Phosphine-Thioether Ligands to Low-valent Metal Centers

    Författare :Roger Persson; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; polynuclear metal complexes; fluxional behavior; cluster; thioether; phosphine; crystal structure; sulfur; triosmium;

    Sammanfattning : The reactivity of the phosphine-thioether ligands bis(2-diphenylphosphino) ethylthio)ethane (PSSP), bis(2-(diphenylphosphino) ethyl)sulfane (PSP), PPh2CH2CH2SMe (PS), PPh2(o-C6H4SMe (PortoS), and PPh(o-C6H4SMe)2 (PSS) towards low-valent carbonyl clusters has been studied. In all structurally characterized clusters, the ligand donor atoms are terminally coordinated. LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  5. 4. Studies of second coordination sphere effects and metal variations on [FeFe]-hydrogenase mimics

    Författare :Holly J. Redman; Gustav Berggren; Pickett Chris; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; hydrogenases; synthesis; inorganic chemistry; molecular biomimetics; spectroscopy; FTIR; cyclic voltammetry; catalysis; Chemistry with specialization in Molecular Biomimetics; Kemi med inriktning mot molekylär biomimetik;

    Sammanfattning : Mitigation of climate change motivates researchers to explore hydrogen as a potential energy carrier. Unfortunately, widespread use of hydrogen as an energy carrier is limited by numerous challenges in its production, including high energy consumption; high economic cost; current reliance on rare metals such as platinum. LÄS MER

  7. 5. New Catalytic Systems for Light-driven Hydrogen Evolution

    Författare :Chuanshuai Li; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; photocatalysis; hydrogen evolution; semiconductor; molecular catalyst; charge transfer; mechanism;

    Sammanfattning : Solar-driven reduction of water to produce hydrogen is one of the most promising ways to develop sustainable cleanenergy for the future. The challenge in photocatalytic hydrogen evolution research is to design inexpensive catalystsand construct efficient hydrogen production systems. LÄS MER