Sökning: "Proton shift"

Visar resultat 1 - 5 av 34 avhandlingar innehållade orden Proton shift.

1. 1. Catalytic Methods to Convert Allylic Substrates through Hydride and Proton Shifts : Transition Metal-Catalyzed and Organocatalyzed Approaches

   Författare :Samuel Martinez-Erro; Belén Martín-Matute; Franziska Schoenebeck; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Allylic substrates; Iridium catalysis; Base catalysis; Method development; Isomerization; Hydride shift; Proton shift; Mechanistic studies; organisk kemi; Organic Chemistry;

   Sammanfattning : The present thesis describes the development of new catalytic protocols to transform allylic substrates into a wide variety of versatile carbonyl and vinyl organic compounds. All procedures that are described in this work have in common the existence of one or more hydrogen shifts as key steps in the mechanism of the reactions. LÄS MER

3. 2. Iron Carbonyl Clusters as Proton Reduction Catalysts

   Författare :Ahibur Rahaman; Kemisk fysik; []
   Nyckelord :iron-only hydrogenase; phosphine-substitution; electrocatalysis; proton reduction;

   Sammanfattning : Abstract – The mixed-valence triiron complexes [Fe3(CO)7-x(PPh3)x(µ-edt)2] (x = 0, 1, 2; edt = SCH2CH2S) and [Fe3(CO)5(κ2-diphosphine)(µ-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. In comparison to the diiron complex [Fe2(CO)6(µ-edt)], [Fe3(CO)7(µ-edt)2] catalyzes proton reduction at 0. LÄS MER

4. 3. Monitoring Proton Exchange and Triplet States with Fluorescence

   Författare :Tor Sandén; Jerker Widengren; Vogel Horst; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; fluorescence correlation spectroscopy; proton transfer; cytochrome c oxidase; transient state imaging; modulated excitation; Optics; Optik; Biochemistry; Biokemi;

   Sammanfattning : Fluorescent molecules commonly shift to transient dark states, induced bylight or triggered by chemical reactions. The transient dark states can beused as probes of the local environment surrounding the fluorescent molecules,and are therefore attractive for use in biomolecular applications. LÄS MER

5. 4. Biochemical Studies on a Plant Epoxide Hydrolase : Discovery of a Proton Entry and Exit Pathway and the Use of In vitro Evolution to Shift Enantioselectivity

   Författare :Ann Gurell; Mikael Widersten; Bengt Mannervik; Dick Janssen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; epoxide hydrolase; enantioselectivity; in vitro evolution; proton wire; epoxides; selectivity; CASTing; structure-function; Biochemistry; Biokemi; Biokemi; Biochemistry;

   Sammanfattning : The work leading to this thesis has provided additional information and novel knowledge concerning structure-function relationship in the potato epoxide hydrolase. Epoxide hydrolases are enzymes catalyzing the hydrolysis of epoxides to yield the corresponding vicinal diols. LÄS MER

7. 5. Mechanistic Studies on Proton-Coupled Electron Transfer from Tyrosine and Tryptophan Derivatives

   Författare :Astrid Nilsen-Moe; Leif Hammarström; Pia Ädelroth; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Proton-Coupled Electron Transfer; PCET; Tyrosine; Tryptophan; Amino Acid Radicals; Transient Absorption; Chemistry with specialization in Physical Chemistry; Kemi med inriktning mot fysikalisk kemi;

   Sammanfattning : Proton-coupled electron transfer (PCET) from tyrosine (Y) and tryptophan (W) is vital to many redox reactions in Nature where PCET between several Ys, or Ws, or between a mix of Ys and Ws can be used to transfer electrons, or protons, or both over large distances of several Å. Studying the PCET reaction mechanisms of Y and W is important for fundamental knowledge, and can help researchers that wish to mimic redox reactions in Nature. LÄS MER