title: First-Principles Study on Structural and Chemical Asymmetry of a Biomimetic Water-Splitting Dimanganese Complex.
abstract: Density-functional theory calculations are carried out for a biomimetic dimanganese complex, [H2O(terpy)Mn(III)(μ-O)2Mn(IV)(terpy)OH2](3+)(1, terpy = 2,2':6',2″-terpyridine), which is a structural model for the oxygen evolving center of photosystem II. Theoretical investigations aim at elucidating the asymmetry features in the geometric and electronic structures of complex 1, as well as their influences on the chemical functions of the two manganese centers, in the presence of water solvent. With the insight gained from the first-principles calculations, we study the oxidation state of complex 1 in the acetate buffer solution. Both the thermodynamic and kinetic aspects are explored in detail, and the structural and chemical asymmetry of the two manganese centers is fully considered. It is found that the larger steric repulsion associated with the Mn(IV) center plays a decisive role, which leads to the predominant acetate coordination at the Mn(III) ion. This thus resolves the existing controversy on the preferential acetate binding to complex 1.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China , Hefei, Anhui 230026, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian, Liaoning 116023, China.
authors.forename: Xiangsong
authors.initials: X
authors.lastname: Lin
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China , Hefei, Anhui 230026, China.|Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Institute of Applied Physics, Guizhou Normal College , Guiyang, Guizhou 550018, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zheng