Search for dissertations about: "electron transfer and hydrogen bond"

Showing result 1 - 5 of 20 swedish dissertations containing the words electron transfer and hydrogen bond.

2. 1. Regulation of Proton Coupled Electron Transfer from Amino Acids in Artificial Model Systems: A Mechanistic Study

   Author : Martin Sjödin; Leif Hammarström; Jan Davidsson; G. Daniel Nocera; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; Proton Coupled Electron Transfer; Tyrosine; Tryptophan; Electron Transfer; Hydrogen bond; Photosystem II; Proton transfer; Radical protein; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

   Abstract : Amino acid radicals are key redox intermediates in several natural enzymes including Cytochrome c peroxidase, DNA photolyase, ribonucletide reductase, cytochrome c oxidase and photosystem II. Electron transfer from amino acids is often coupled to deprotonation and this thesis concerns the coupling of electron transfer from tyrosine and tryptophan to trisbipyridineruthenium(III) with deprotonation in model complexes. READ MORE

4. 2. Proton-Coupled Electron Transfer from Hydrogen-Bonded Phenols

   Author : Tania Irebo; Leif Hammarström; James M. Mayer; Uppsala universitet; []
   Keywords : 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; Fysikalisk kemi; Physical Chemistry;

   Abstract : 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. READ MORE

5. 3. Trapping Tyrosine Z : Exploring the Relay between Photochemistry and Water Oxidation in Photosystem II

   Author : Johannes Sjöholm; Stenbjörn Styring; Fikret Mamedov; A. William Rutherford; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Photosystem II; Tyrosine Z; EPR; proton-coupled electron transfer; hydrogen bond; pH;

   Abstract : Photosystem II is unique! It remains the only enzyme that can oxidize water using light as energy input. Water oxidation in photosystem II is catalyzed by the CaMn4 cluster. The electrons extracted from the CaMn4 cluster are transferred to P680+ via the tyrosine residue D1-Tyr161 (YZ). READ MORE

6. 4. Intramolecular electron transfer in DNA and ruthenium(II) systems

   Author : Johan Olofsson; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; solvent relaxation; light switch effect; dppz; electron transfer and hydrogen bond;

   Abstract : When ruthenium(II) complexes with heteroaromatic ligands absorb light, an electron is pushed from the metal ion out into one of the ligands, a process called metal-to-ligand-charge-transfer (MLCT). The resulting excited state can be used to initiate further electron transfer processes, or it can decay relatively slow back into the ground state with the emission of light. READ MORE

7. 5. Hydrogen Bonded Phenols as Models for Redox-Active Tyrosines in Enzymes

   Author : Josefin Utas; Björn Åkermark; Helena Grennberg; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; electron transfer; photosystem II; radicals; imidazole; hydrogen bonding; Organic chemistry; Organisk kemi;

   Abstract : This thesis deals with the impact of hydrogen bonding on the properties of phenols. The possibility for tyrosine to form hydrogen bonds to other amino acids has been found to be important for its function as an electron transfer mediator in a number of important redox enzymes. READ MORE