Redox-Dependent Metal-Metal Bonding in Trinuclear Metal Chains: Probing the Transition from Covalent Bonding to Exchange Coupling.
Redox-Dependent Metal-Metal Bonding in Trinuclear Metal Chains: Probing the Transition from Covalent Bonding to Exchange Coupling.
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DOI：
10.1002/chem.201704727
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发表时间：
2018-04
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影响因子：
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通讯作者：
Mohammed Obies;N. Perkins;V. Arcisauskaite;G. Heath;A. Edwards;J. McGrady
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文献类型：
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作者：
Mohammed Obies;N. Perkins;V. Arcisauskaite;G. Heath;A. Edwards;J. McGrady
本文报道了两种新的阳离子三金属链[（PEt 3）3RuCl 3 M 'Cl 3Ru（PEt 3）3 ]1+（M'= Rh和Ir）的合成和物理性质。这些是同构与以前报道的17-电子全钌类似物，但取代d5 RuIII离子在中心位置与d 6 RhIII /IrIII的金属-金属相互作用的性质有显着的影响。所有这三种材料的特征在于电化学在18-，17-和16-电子水平。X射线晶体学和光谱电化学，辅以DFT和CASPT 2水平的电子结构分析，表明虽然存在的RuIII离子在链的中心允许多中心共价键合的发展，一个封闭的壳RhIII /IrIII离子推动系统的交换耦合极限，其中外部Ru中心只有弱相互作用。这三个同构化合物的家庭揭示了金属成分的变化如何对靠近局域/离域边界的系统的物理性质产生微妙的影响。
The synthesis and physical properties of two new cationic tri-metallic chains, [(PEt3 )3 RuCl3 M'Cl3 Ru(PEt3 )3 ]1+ , M'=Rh and Ir are reported. These are isostructural with a previously reported 17-electron all-ruthenium analogue, but replacing a d5 RuIII ion in the central position with d6 RhIII /IrIII has a significant impact on the nature of the metal-metal interactions. All three materials have been characterized electrochemically at the 18-, 17- and 16-electron levels. X-ray crystallography and spectroelectrochemistry, complemented by electronic structure analysis at the DFT and CASPT2 levels, indicate that whilst the presence of a RuIII ion in the center of the chain allows multi-center covalent bonding to develop, a closed-shell RhIII /IrIII ion pushes the system towards the exchange-coupled limit, where the outer Ru centers are only weakly interacting. This family of three isostructural compounds reveals how changes in metal composition can have subtle effects on physical properties of systems that lie close to the localized/delocalized borderline.