Sökning: "hydrogen bonds"

Visar resultat 1 - 5 av 155 avhandlingar innehållade orden hydrogen bonds.

  1. 1. Proton-Coupled Electron Transfer from Hydrogen-Bonded Phenols

    Författare :Tania Irebo; Leif Hammarström; James M. Mayer; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Proton-coupled electron transfer; phenol oxidation; hydrogen bonds; artificial photosynthesis; promoting vibrations; proton transfer; laser flash-quench; transient absorption.; Physical chemistry; Fysikalisk kemi; Physical Chemistry; Fysikalisk kemi;

    Sammanfattning : Proton-coupled electron transfer (PCET) is one of the elementary reactions occurring in many chemical and biological systems, such as photosystem II where the oxidation of tyrosine (TyrZ) is coupled to deprotonation of the phenolic proton. This reaction is here modelled by the oxidation of a phenol covalently linked to a Ru(bpy)32+-moitey, which is photo-oxidized by a laser flash-quench method. LÄS MER

  2. 2. Ruthenium-Catalyzed Hydrogen Transfer Reactions : Mechanistic Studies and Chemoenzymatic Dynamic Kinetic Resolutions

    Författare :Madeleine Warner; Jan-Erling Bäckvall; Andreas Pfaltz; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Hydrogen transfer; ruthenium catalysis; kinetic resolution; dynamic kinetic resolution; racemization; asymmetric synthesis; Organic Chemistry; organisk kemi;

    Sammanfattning : The main focus of this thesis lies on transition metal-catalyzed hydrogen transfer reactions. In the first part of the thesis, the mechanism for racemization of sec-alcohols with a ruthenium complex, Ru(CO)2Cl(η5-C5Ph5) was studied. LÄS MER

  3. 3. Local Structure of Hydrogen-Bonded Liquids

    Författare :Matteo Cavalleri; Lars G.M. Pettersson; John Tse; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; hydrogen-bond; water; ice; density functional theory; DFT; core-level spectroscopies; x-ray absorption; Physical chemistry; Fysikalisk kemi;

    Sammanfattning : Ordinary yet unique, water is the substance on which life is based. Water seems, at first sight, to be a very simple molecule, consisting of two hydrogen atoms attached to one oxygen. LÄS MER

  4. 4. Hydrogen Bonding in Liquid Alcohols

    Författare :Per Sillrén; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; Hydrogen Bonded Liquids; Physics of liquids; Diffraction; Monte Carlo Simulation; Alcohols; Neutron Scattering; EPSR;

    Sammanfattning : Hydrogen bonded (H-bonded) materials, such as water, alcohols, sugars, and even DNA, are extremely important for biology, as well as chemical industry. Alcohols are used as solvents in paints, in perfumes, as cleaners, anti-freezers, or as an alternative to petrol in combustion engines. LÄS MER

  5. 5. Catalytic Water Production from First-Principles Calculations

    Författare :Gustav Karlberg; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; platinum; Monte Carlo; first-principles; hydroxyl; transition metals; density functional theory DFT ; Metropolis; oxygen; water; water production reaction; hydrogen;

    Sammanfattning : The main subject of this thesis is the catalytic water production reaction on metal surfaces. This reaction is of great current interest due to its importance in fuel cells, a clean and efficient way to convert chemical energy into electrical. LÄS MER