Ultrashort metal-metal distances and extreme bond orders

在第一个支助期间调查了三个方面。具有极高键序（键序b> 4）的稳定分子是最近才发现的。因此，现在有可能研究它们的反应性，通过这样做，我们能够更好地理解这些键。我们的贡献在全球Cr-Cr五键反应性研究领域处于领先地位。超短金属-金属距离最近，经过30年的沉寂，铬配合物具有正式的五重键，获得了金属-金属短距离的新记录。合理的配体设计是关键。我们的工作决定了这个领域的技术水平。在第一个支撑期，我们可以分离出一个金属-金属距离与最长的C-C键相似的化合物（分别为1.706和1.704 Å）。钼和钨的键序> 4钼和钨配合物更适合形成高（有效）键序。因此，我们的目标是将铬的化学性质转移到钼上，最终转移到钨上。与此同时，钼的技术水平由蔡氏集团决定。钨化合物是未知的。我们可以在支持的第一阶段找到获得这些化合物的途径。第二阶段的研究确定了以下目标：五重键反应性研究的定稿。初级活化产物反应性的研究许多底物（或元素）与Cr-Cr五键反应得到的产物本身就是相当活泼的有机金属化合物。建议进一步研究它们的反应性，特别是在催化反应中的反应性。具有五键或六键的钨配合物的键序为bbb40的钨配合物是第二期支持的对象。对不稳定的M2分子（M = Cr， Mo和W）的理论研究表明，Mo2和W2的有效键序为6。这些分子只能在惰性基质中分离。Cr2的特征是相关的s-轨道和d-轨道的尺寸不匹配。因此，只有弱结合的相互作用是部分可能的。它们导致了低效率的债券秩序。我们计划找到一种途径来获得具有五组（和/或六组）键的W配合物。具有异常高键序的钨化合物的反应性研究

Three aspects have been investigated during the first period of support.1. The reactivity of Cr-Cr quintuple bondsStable molecules that contain extremely high bond orders (bond orders > 4) were found only recently. Thus, it is now possible to investigate their reactivity and by doing so we are enabled to understand such bonds better. Our contributions dominate the state of the art in the field of Cr-Cr quintuple bond reactivity worldwide.2. Ultra-short metal-metal distancesRecently, after 30 years of silence new records in terms of short metal-metal distances were obtained with chromium complexes having a formal quintuple bond. Rational ligand design is the key. Work carried our by us determines the state of the art in that field. During the first period of support, we could isolate a compound with a metal-metal distance similar to that of the longest C-C bond (1.706 and 1.704 Å, respectively).3. Bond orders > 4 for molybdenum and tungstenMolybdenum and tungsten complexes are better suited to form high (effective) bond orders. Accordingly, we aimed for transferring the chromium chemistry towards molybdenum and eventually towards tungsten. The state of the art for molybdenum is meanwhile determined by the Tsai group. Tungsten compounds are unknown. We could find an access to such compounds in the first period of support.The following aims have been defined for the second period of researchA. Finalization of the quintuple bond reactivity studiesB. Investigation of the reactivity of the primary activation productsMany products obtained by reacting substrates (or elements) with Cr-Cr quintuple bonds are themselves rather reactive organometallic compounds. Their reactivity especially in catalytic reactions is proposed to be investigated.C. Tungsten complexes with quintuple or sixtuple bondsTungsten complexes having bond orders > 4 are subject of the second period of support. Theoretical work on the instable M2 molecules (M = Cr, Mo and W), species that could only be isolated in an inert matrix, gave effective bond orders of six for Mo2 and W2. Cr2 is characterized by a strong size mismatch of the relevant s- and d-orbitals. Thus, only weakly binding interactions are partially possible. They lead to a low effective bond order. We plan to find an access to W complexes having quintuple (and/or sixtuple) bonds.D. Investigations of the reactivity of tungsten compounds having unusual high bond orders