Ultrashort metal-metal distances and extreme bond orders

超短金属-金属距离和极端键阶

基本信息

批准号：
172225015
负责人：
Professor Dr. Rhett Kempe
金额：
--
依托单位：
Arbeitsgruppe Anorganische Chemie II
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/172225015?language=en
关键词：
Ultrashort metal distances extreme bond

项目摘要

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

在第一阶段的支持期间，我们研究了三个方面： 1. Cr-Cr五重键的反应性含有极高键级（键级> 4）的稳定分子是最近才发现的，因此，现在可以研究它们的反应性。通过这样做，我们能够更好地理解这种键。我们的贡献主导了全球 Cr-Cr 五元键反应领域的最新技术。2. 最近，30 年后。经过多年的沉寂，我们在具有正式五重键的铬配合物方面取得了新的记录，我们所做的工作决定了该领域的最新技术。的载体，我们可以分离出金属-金属距离类似于最长 C-C 键的化合物（分别为 1.706 和 1.704 Å）。 3. 钼和的键阶 > 4。钨钼和钨络合物更适合形成高（有效）键序。因此，我们的目标是将铬化学转移到钼，并最终转向钨。同时，蔡组确定了钼的最新技术。我们可以在第一阶段的支持中找到此类化合物。已为第二阶段的研究确定了以下目标A。五重键反应性研究B. 初级活化产物的反应性研究许多通过底物（或元素）与Cr-Cr五重键反应获得的产物本身是相当反应性的有机金属化合物，特别是在催化反应中。具有五重或六重键的钨配合物键级大于 4 的钨配合物是第二阶段支持的主题，即不稳定的 M2 分子。 (M = Cr、Mo 和 W) 是只能在惰性基质中分离的物质，Mo2 和 Cr2 的有效键级为 6，其特点是相关 s 和 d 轨道的尺寸严重不匹配。因此，只有弱结合相互作用是部分可能的。我们计划找到具有五重（和/或六重）键的W复合物的途径。具有异常高键级的钨化合物