Mimicking photosystem II reactions in artificial photosynthesis: Ru(II)-polypyridine photosensitisers linked to tyrosine and manganese electron donors
2000 (English)In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 58, no 03-feb, 57-69 p.Article in journal (Refereed) Published
The paper describes a project aiming at constructing functional mimics of the oxygen evolving complex in photosystem II, coupled to photoinduced charge separation. Biomimetic electron donors, manganese complexes and tyrosine, have been linked to a Ru(II)-polypyridine photosensitiser. Oxidation of the donors by intramolecular electron transfer from the photooxidised Ru(III) complex was demonstrated using optical flash photolysis and EPR experiments. A step-wise electron transfer Mn(III,III)-->tyrosine-->Ru(III) was demonstrated, in analogy to the reaction on the donor side of photosystem II. Electron transfer from the tyrosine to Ru(III) was coupled to tyrosine deprotonation. This resulted in a large reorganisation energy and thus a slow reaction rate, unless the tyrosine was hydrogen bonded or already deprotonated. A comparison with analogous reaction in photosystem II is made. Finally, light-induced oxidation of a manganese dimer linked to a Ru(II)-photosensitiser was observed. Preliminary results suggest the possibility of photooxidising manganese dimers in several steps, which is an important step towards water oxidation,
Place, publisher, year, edition, pages
2000. Vol. 58, no 03-feb, 57-69 p.
artificial photosynthesis, photosystem II, electron transfer, manganese, ruthenium, photochemistry, oxygen evolution, water-oxidation, complex, hydrogen, histidine-190, proton, model, side
IdentifiersURN: urn:nbn:se:kth:diva-19779ISI: 000087198800002OAI: oai:DiVA.org:kth-19779DiVA: diva2:338471
QC 201005252010-08-102010-08-10Bibliographically approved