Sökning: "rotation barrier"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden rotation barrier.

  1. 1. Internal rotation in molecules : a nuclear magnetic resonance relaxation study

    Författare :Anders Ericsson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : In order to study the internal rotation of methyl-type groups in molecules, the carbon-13 nuclear magnetic resonance (NMR) spin-lattice relaxation times (T1) and nuclear Overhauser enhancement factors (n) are measured for some terpenes (borneol, camphor, isopinocampheol and α-pinene), for octafluorotoluene and for 1-methylnaphtalene. In addition, deuterium NMR T1 data are presented for 1-methylnaphtalene-d10. LÄS MER

  3. 2. Flexibility – a tool for chirality control in asymmetric catalysis

    Författare :Raivis Zalubovskis; Christina Moberg; Alexandre Alexakis; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; flexibility; symmetry; dissymmetry; asymmetric catalysis; chiral ligands; pseudo-C2; pseudo-CS; conformational study; rotation barrier; pyrrolidines; phospholanes; azepines; phosphepines; supramolecular; hydrogenation; allylic alkylation; silaboration; palladium; rhodium; nickel; platinum; iridium.; Organic chemistry; Organisk kemi;

    Sammanfattning : This thesis deals with the design and synthesis of ligands for asymmetric catalysis: palladium catalyzed allylic alkylations, and rho-dium and iridium catalyzed hydrogenations of olefins. Chirally flexible phosphepine ligands based on biphenyl were synthesized and their properties were studied. LÄS MER

  4. 3. Self-adaptable catalysts : Importance of flexibility and applications in asymmetric catalysis

    Författare :Ester Fjellander; Christina Moberg; Jay Siegel; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; adaptable; flexible; semi-flexible; symmetry; conformational study; mechanistic study; rotation barrier; VT NMR; asymmetric catalysis; ligand design; allylic alkylation; hydrogenation; azepines; dioxaphosphepines; phosphepines; amines; phosphines; phosphoramidites; phosphinites; palladium; rhodium; Organic chemistry; Organisk kemi;

    Sammanfattning : The topic of this thesis is the design and synthesis of biaryl-based self adaptableligands for asymmetric metal catalysis. The results discussed in papers I-III are covered, together with some unpublished results concerning substrate-adaptable catalysts. A general survey of self-adaptable catalysts is presented first. LÄS MER

  5. 4. Microwave determination of conformation and barrier to internal rotation in the gas phase of some smaller organic molecules

    Författare :Hasse Karlsson; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : .... LÄS MER

  7. 5. Global Turbulent EquiPartition (TEP) in Tokamak Plasma

    Författare :Igor A. Ivonin; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; turbulent plasma; TEP; scaling laws; transport barrier; tokamak; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Space and Plasma Physics; rymd- och plasmafysik;

    Sammanfattning : We studied analytically and numerically the establishment of global turbulent equipartition (TEP) of magnetised electrons in a tokamak plasma. This allows us to investigate self-consistently the inhomogeneous distributions of the plasma density, the electron and the ion temperatures, the generation of radial electric field and the poloidal and the toroidal rotation in the turbulent tokamak plasma. LÄS MER