The Effects of Redox-Inactive Metal Ions on the Activation of Dioxygen: Isolation and Characterization of a Heterobimetallic Complex Containing a MnIII–(μ-OH)–CaII Core
摘要:
Rate enhancements for the reduction of dioxygen by a Mn-II complex were observed in the presence of redox-inactive group 2 metal ions. The rate changes were correlated with an increase in the Lewis acidity of the group 2 metal ions. These studies led to the isolation of heterobimetallic complexes containing Mn-III-(mu-OH)-M-II cores (M-II = Ca-II, Ba-II) in which the hydroxo oxygen atom is derived from O-2. This type of core structure has relevance to the oxygen-evolving complex within photosystem II.
Synthesis, structure and reactivity of Fe<sup>II/III</sup>–NH<sub>3</sub> complexes bearing a tripodal sulfonamido ligand
作者:Nathaniel S. Sickerman、Sonja M. Peterson、Joseph W. Ziller、A. S. Borovik
DOI:10.1039/c3cc48804g
日期:——
Complexes [MnMST(NH3)]n−3 (Mn = FeII, FeIII, GaIII) were prepared and each contains a intramolecular hydrogen bonding network involving the ammonia ligand.
Terminal NiII−OH/−OH2 complexes in trigonal bipyramidal geometries derived from H2O
作者:Nathanael Lau、Yohei Sano、Joseph W. Ziller、A.S. Borovik
DOI:10.1016/j.poly.2016.11.015
日期:2017.3
The preparation and characterization of two NiII complexes are described, a terminal NiII-OH complex with the tripodal ligand tris[(N)-tertbutylureaylato)-N-ethyl)]aminato ([H3buea]3-) and a terminal Ni II-OH2 complex with the tripodal ligand N,N',N″-[2,2',2″-nitrilotris(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzenesulfonamido) ([MST]3-). For both complexes, the source of the -OH and -OH2 ligand is
Effects of coordination sphere on unusually large zero field splitting and slow magnetic relaxation in trigonally symmetric molecules
作者:Kelsey A. Schulte、Kuduva R. Vignesh、Kim R. Dunbar
DOI:10.1039/c8sc02820f
日期:——
Geometric control in mononuclear complexes has come to the forefront in the field of molecular magnets due to its profound effects on relaxation pathways and blocking temperature in singlemoleculemagnets (SMMs). Herein we report the synthesis and magnetic characterization of six trigonally symmetric, divalent Fe, Co, and Ni molecules, with the rigid geometry enforced via the use of the tris-anionic
单核配合物的几何控制因其对单分子磁体(SMM)的弛豫路径和阻断温度的深远影响而成为分子磁体领域的前沿。在此,我们报告了六个三角对称二价 Fe、Co 和 Ni 分子的合成和磁性表征,通过使用三阴离子四齿配体 MST ( N , N ', N ''-[ 2,2',2''-次氮基三-(乙烷-2,1-二基)]三(2,4,6-三甲基苯磺酰胺))。通过实验和计算对三角单锥体配合物(Me 4 N)[M(MST)]和三角双锥体配合物(Me 4 N)[M(MST)(OH 2 )]之间的转化效果进行了系统研究。研究发现,由于第一激发态极低,(Me 4 N)[Ni(MST)]表现出非常大的、接近记录的零场分裂参数( D )值-434 cm -1 。三角单锥体钴和铁配合物在外加磁场下表现出缓慢的磁弛豫,分别产生 45 K 和 63.9 K 的势垒。三角单锥体复合物的开放轴位点中单个水分子的配位对D值以及缓慢松弛产
Preparation and structural properties of InIII–OH complexes
作者:Nathaniel S. Sickerman、Renée M. Henry、Joseph W. Ziller、A.S. Borovik
DOI:10.1016/j.poly.2012.07.098
日期:2013.7
Abstract The use of the tripodal ligands tris[(N′-tert-butylureaylato)-N-ethyl]aminato ([H3buea]3−) and the sulfonamide-based N,N′,N″-[2,2′,2″-nitrilotris(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzene-sulfonamidato) ([MST]3−) has led to the synthesis of two structurally distinct In(III)–OH complexes. The first example of a five-coordinate indium(III) complex with a terminal hydroxide ligand, K[InIIIH3buea(OH)]
Heterobimetallic complexes with M<sup>III</sup>-(μ-OH)-M<sup>II</sup>cores (M<sup>III</sup>= Fe, Mn, Ga; M<sup>II</sup>= Ca, Sr, and Ba): structural, kinetic, and redox properties
作者:Young Jun Park、Sarah A. Cook、Nathaniel S. Sickerman、Yohei Sano、Joseph W. Ziller、A. S. Borovik
DOI:10.1039/c2sc21400h
日期:——
The effects of redox-inactive metal ions on dioxygen activation were explored using a new FeII complex containing a tripodal ligand with 3 sulfonamido groups. This iron complex exhibited a faster initial rate for the reduction of O2 than its MnII analog. Increases in initial rates were also observed in the presence of group 2 metal ions for both the FeII and MnII complexes, which followed the trend NMe4+ < BaII < CaII = SrII. These studies led to the isolation of heterobimetallic complexes containing FeIII-(μ-OH)-MII cores (MII = Ca, Sr, and Ba) and one with a [SrII(OH)MnIII]+ motif. The analogous [CaII(OH)GaIII]+ complex was also prepared and its solid state molecular structure is nearly identical to that of the [CaII(OH)FeIII]+ system. Nuclear magnetic resonance studies indicated that the diamagnetic [CaII(OH)GaIII]+ complex retained its structure in solution. Electrochemical measurements on the heterobimetallic systems revealed similar one-electron reduction potentials for the [CaII(OH)FeIII]+ and [SrII(OH)FeIII]+ complexes, which were more positive than the potential observed for [BaII(OH)FeIII]+. Similar results were obtained for the heterobimetallic MnII complexes. These findings suggest that Lewis acidity is not the only factor to consider when evaluating the effects of group 2 ions on redox processes, including those within the oxygen-evolving complex of Photosystem II.