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Alternative mechani...
Alternative mechanisms for O-2 release and O-O bond formation in the oxygen evolving complex of photosystem II
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- Li, Xichen (författare)
- Stockholms universitet,Institutionen för organisk kemi,Beijing Normal University, People's Republic of China
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- Siegbahn, Per E. M. (författare)
- Stockholms universitet,Institutionen för organisk kemi
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(creator_code:org_t)
- 2015
- 2015
- Engelska.
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Owner Societies 2015. - 1463-9076 .- 1463-9084. ; 17:18, s. 12168-12174
- Relaterad länk:
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https://urn.kb.se/re...
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visa fler...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- In a previous detailed study of all the steps of water oxidation in photosystem II, it was surprisingly found that O-2 release is as critical for the rate as O-O bond formation. A new mechanism for O-2 release has now been found, which can be described as an opening followed by a closing of the interior of the oxygen evolving complex. A transition state for peroxide rotation forming a superoxide radical, missed in the previous study, and a structural change around the outside manganese are two key steps in the new mechanism. However, O-2 release may still remain rate-limiting. Additionally, for the step forming the O-O bond, an alternative, experimentally suggested, mechanism was investigated. The new model calculations can rule out the precise use of that mechanism. However, a variant with a rotation of the ligands around the outer manganese by about 301 will give a low barrier, competitive with the old DFT mechanism. Both these mechanisms use an oxyl-oxo mechanism for O-O bond formation involving the same two manganese atoms and the central oxo group (O5).
Ämnesord
- NATURVETENSKAP -- Kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences (hsv//eng)
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
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- ref (ämneskategori)
- art (ämneskategori)
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