Molecular [Yb(TM)2] Intermetalloids (TM = Ru, Re)
Molecular [Yb(TM)2] Intermetalloids (TM = Ru, Re)
复制标题
DOI：
10.1002/chem.201001310
复制
发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Kempe, Rhett
中科院分区：
文献类型：
--
作者：
Doering, Christian;Dietel, Anna-Maria;Kempe, Rhett
金属-金属键合激发了科学家们的许多灵感[1]，最近很多这种魅力和兴趣都转移到了无支撑的金属-金属键上。[2-4]无支撑RESTANTM键（RE =稀土，TM =过渡金属）是罕见的[5 - 7]，对于RESTANTM键合的一般理解特别重要。RESIDETM键合决定了相应金属间化合物的性质/特性，其中许多在我们的日常生活中发挥着重要作用。RESIDENTM金属间化合物用于高性能永磁体[8，9]、储氢材料[10]和汽车电池。[11]此外，RESENTTM键是强极性的[6，12]，并且含有具有显著不同电子性质的金属原子（或簇亚基）的混合金属实体提供了满足化学挑战的潜力，例如更高聚集体系的合理设计。[13]预期的反应性行为的结果从金属-金属键极性的引入。它类似于有机化学中采用的合成策略，其中复杂官能化烃的合理设计可以基于特定引入的键极性;例如，亲核或亲电反应中心的产生，用于区域或甚至立体选择性地形成或裂解C13C键。[14]它可以让我们合成，在一个可控的方式，单分散的聚集体的大小增加从简单的纳米复合物和小集群的纳米材料，甚至散装金属，以获得特定的访问丰富的物理化学效应沿着这条道路。[Yb（TM）2]类金属间化合物[15]分子的晶体结构和电子结构，其中二价镱显示出两个无支撑的键与两个钌原子或两个钌原子。低价镧系元素的配位化合物中的REESTTM键与海岸小组的名字有关，[16]他们合成了YbIII-Fe配位聚合物。受这项开创性工作的启发，我们决定使用镱（II）离子作为RE“伙伴”。除了在一般情况下形成无支撑RESTARTM键方面的复杂性之外，[17]必须解决镧系元素的低氧化态的不稳定性。为了避免从二价稀土原子到过渡金属的单电子转移，我们选择[CpRu（CO）2] nH3作为TM "伙伴"。Ru的氧化态为零，不太可能被进一步还原。
Metal–metal bonding has inspired scientists for many dec-ACHTUNGTRENNUNGades [1] and a lot of this fascination and interest has recently shifted towards unsupported metal–metal linkages.[2–4] Unsupported REÀTM bonds (RE= rare earth, TM= transition metal) are rare [5–7] and especially important with regard to the general understanding of REÀTM bonding. REÀTM bonding determines, for instance, the nature/characteristics of the corresponding intermetallic compounds of which many play an important role in our daily life. REÀTM intermetallic compounds are in high-performance permanent magnets,[8, 9] hydrogen-storage materials [10] and car batteries.[11] Furthermore, REÀTM bonds are strongly polar [6, 12] and mixed-metal entities containing metal atoms (or cluster subunits) with significantly different electronic properties offer the potential to meet chemical challenges like the rational design of higher aggregated systems.[13] The expected reactivity behaviour results from the introduction of metal–metal bond polarity. It is similar to synthetic strategies employed in organic chemistry, in which rational design of complicated functionalised hydrocarbons can be based on specifically introduced bond polarities; for example, the generation of nucleophilic or electrophilic centres of reactivity for the regio-or even stereoselective formation or cleavage of CÀC bonds.[14] It may allow us to synthesise, in a controlled fashion, monodisperse aggregates of increasing size starting from simple bimetallic complexes and small clusters to nanosized materials and even bulk metals in order to get specific access to the plenitude of physicochemical effects along this path.We report here on the synthesis, the crystal structure and the electronic structure of molecular [Yb (TM) 2] intermetalloids [15] in which divalent ytterbium displays two unsupported bonds with either two rhenium or two ruthenium atoms. REÀTM bonding in coordination compounds of low valent lanthanoids is connected with the name of the Shore group,[16] who synthesised YbIIÀFe coordination polymers. Inspired by this pioneering work we decided to use an ytterbium (II) ion as the RE “partner”. In addition to the complications one has in terms of forming unsupported REÀTM bonds in general,[17] the instability of the low oxidation state of the lanthanoid has to be addressed. In order to avoid single-electron transfer from the divalent RE atom to the transition metal we chose [CpRu (CO) 2] À as the TM “partner”. The oxidation state of Ru is zero and it is unlikely to be further reduced.