Preparation and Properties of an MnIV-Hydroxide Complex: Proton and Electron Transfer at a Mononuclear Manganese Site and its Relationship to the Oxygen Evolving Complex within Photosystem II.
Preparation and Properties of an MnIV-Hydroxide Complex: Proton and Electron Transfer at a Mononuclear Manganese Site and its Relationship to the Oxygen Evolving Complex within Photosystem II.
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MnIV-氢氧化物络合物的制备和性质：单核锰位点的质子和电子转移及其与光系统 II 内放氧络合物的关系。
DOI：
10.1039/c4sc00453a
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发表时间：
2014
期刊：
影响因子：
8.4
通讯作者：
Borovik,AS
中科院分区：
文献类型：
--
作者：
Taguchi,Taketo;Stone,KariL;Gupta,Rupal;Kaiser-Lassalle,Benedikt;Yano,Junko;Hendrich,MichaelP;Borovik,AS
光合水氧化催化Mn 4 O 5Ca簇与一个前所未有的安排，其中一个单一的锰中心是绑定到一个扭曲的Mn 3 O 4Ca立方烷样结构的金属离子。几种机理建议描述了独特的锰中心作为水结合的位点，随后形成高价Mn-氧代中心，其与M-OH单元（M = Mn或CaII）反应形成O-O键。低价Mn-OHn（n = 1，2）转化为Mn-氧代物种需要单个锰位点能够适应几种氧化态，因为水配体被去质子化。为了研究这些过程，一个新的单体MnIV-OH复合物的制备和表征。MnIV-OH复合物完成了一系列充分表征的Mn-OH和Mn-氧代复合物，其含有相同的初级和次级配位球;因此，这项工作表明，单个配体可以支持单核Mn复合物跨越四个不同的氧化态（II至V）与氧代和羟基配体，衍生自水。此外，我们已经完成了一个热力学分析的基础上，这一系列的锰配合物，以预测形成的高价锰氧物种，我们证明了MnIV-OH物种的转换为MnV-氧配合物可能会发生通过逐步质子转移-电子转移机制。MnIVO-H键的大解离能（约95 kcal mol−1）降低了其他途径在生物学背景下起作用的可能性。此外，这些研究表明，Mn-OH和Mn-氧代络合物之间的反应导致非生产性的单电子过程，表明与OEC的初始O-O键形成不涉及Mn-OH单元。
Photosynthetic water oxidation is catalyzed by a Mn4O5Ca cluster with an unprecedented arrangement of metal ions in which a single manganese center is bonded to a distorted Mn3O4Ca cubane-like structure. Several mechanistic proposals describe the unique manganese center as a site for water binding and subsequent formation of a high valent Mn–oxo center that reacts with a M–OH unit (M = Mn or CaII) to form the O–O bond. The conversion of low valent Mn–OHn (n = 1, 2) to a Mn–oxo species requires that a single manganese site be able to accommodate several oxidation states as the water ligand is deprotonated. To study these processes, the preparation and characterization of a new monomeric MnIV–OH complex is described. The MnIV–OH complex completes a series of well characterized Mn–OH and Mn–oxo complexes containing the same primary and secondary coordination spheres; this work thus demonstrates that a single ligand can support mononuclear Mn complexes spanning four different oxidation states (II through V) with oxo and hydroxo ligands that are derived from water. Moreover, we have completed a thermodynamic analysis based on this series of manganese complexes to predict the formation of high valent Mn–oxo species; we demonstrated that the conversion of a MnIV–OH species to a MnV–oxo complex would likely occur via a stepwise proton transfer-electron transfer mechanism. The large dissociation energy for the MnIVO–H bond (∼95 kcal mol−1) diminished the likelihood that other pathways are operative within a biological context. Furthermore, these studies showed that reactions between Mn–OH and Mn–oxo complexes lead to non-productive, one-electron processes suggesting that initial O–O bond formation with the OEC does not involve an Mn–OH unit.
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影响因子：
32.5
作者：
Lassalle-Kaiser B;Hureau C;Pantazis DA;Pushkar Y;Guillot R;Yachandra VK;Yano J;Neese F;Anxolabéhère-Mallart E
通讯作者：
Anxolabéhère-Mallart E
光系统 II 的 O2 演化复合体的结构和机制模型
DOI：
--
发表时间：
1998
期刊：
影响因子：
--
作者：
V. Szalai;D. A. Stone;G. Brudvig
通讯作者：
G. Brudvig
1.9 Å 分辨率下释氧光系统 II 的晶体结构
影响因子：
64.8
作者：
Umena Y.;Kawakami K.;Shen J.-R.;Kamiya N.
通讯作者：
Kamiya N.
使用 87Sr ESEEM 光谱研究光系统 II 的放氧复合物的钙结合位点。
DOI：
10.1021/ja030614e
发表时间：
2004
期刊：
Journal of the American Chemical Society.
影响因子：
--
作者：
Kim,SunHee;Gregor,Wolfgang;Peloquin,JeffreyM;Brynda,Marcin;Britt,RDavid
通讯作者：
Britt,RDavid
影响因子：
21.8
作者：
Cook,SarahA;Borovik,AS
通讯作者：
Borovik,AS