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Title: Theoretical study on OH{sup −} site and electronic spin state of oxygen-evolving complex in photosystem II at the dark S{sub 1} state

Possible protonation and electronic-spin states of oxygen-evolving complex (OEC) in photosystem II have been investigated by using QM(DFT-UB3LYP)/MM(Amber) calculation, in order to elucidate which OEC state satisfies the known experimental results at the dark stable state (S{sub 1}), i.e. OEC involves Mn{sub 4}(III{sub 2},IV{sub 4})-cluster and a S=0 state as the lowest energy electronic-spin state at S{sub 1}. The configuration of Mn oxidation numbers and the lowest energy spin state within the Mn{sub 4}-cluster depend on the protonation state of one oxo-anion bridging three Mn ions. When all water-ligands and oxo-bridges form H{sub 2}O and O{sup 2−}, respectively, the resulting OEC model involved Mn{sub 4}(III{sub 2},IV{sub 2})-cluster and one S=0 state as the lowest energy spin state. To rationalize the O{sup 2−}-bridge model at S{sub 1} state, a new H{sup +}-release scheme during the H{sub 2}O-splitting reaction is proposed.
Authors:
; ;  [1] ;  [2]
  1. RIKEN Research Cluster for Innovation, Nakamura Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
  2. Department of Biomolecular Engineering, Tokyo Institute of Technology, B-70, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)
Publication Date:
OSTI Identifier:
22261741
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1568; Journal Issue: 1; Conference: International workshop on solar-chemical energy storage (SolChES), Sendai (Japan), 23-28 Jul 2012; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; COMPLEXES; LIGANDS; MANGANESE IONS; OXIDATION; OXYGEN; SPIN