Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Garching bei München, Germany.
Nat Chem. 2020 Dec;12(12):1131-1135. doi: 10.1038/s41557-020-00555-4. Epub 2020 Oct 19.
Transition-metal-carbonyl complexes are common organometallic reagents that feature metal-CO bonds. These complexes have proven to be powerful catalysts for various applications. By contrast, silicon-carbonyl complexes, organosilicon reagents poised to be eco-friendly alternatives for transition-metal carbonyls, have remained largely elusive. They have mostly been explored theoretically and/or through low-temperature matrix isolation studies, but their instability had typically precluded isolation under ambient conditions. Here we present the synthesis, isolation and full characterization of stable silyl-substituted silicon-carbonyl complexes, along with bonding analysis. Initial reactivity investigations showed examples of CO liberation, which could be induced either thermally or photochemically, as well as substitution and functionalization of the CO moiety. Importantly, the complexes exhibit strong Si-CO bonding, with CO→Si σ-donation and Si→CO π-backbonding, which is reminiscent of transition-metal carbonyls. This similarity between the abundant semi-metal silicon and rare transition metals may provide new opportunities for the development of silicon-based catalysis.
过渡金属羰基配合物是常见的有机金属试剂，具有金属-CO 键。这些配合物已被证明是各种应用的有效催化剂。相比之下，硅-羰基配合物，作为过渡金属羰基的环保替代品的有机硅试剂，在很大程度上仍然难以捉摸。它们主要是通过理论和/或低温基质隔离研究来探索的，但由于其不稳定性，通常无法在环境条件下进行分离。在这里，我们提出了稳定的取代硅基硅-羰基配合物的合成、分离和全表征，以及键分析。初步的反应性研究表明，CO 释放的例子可以通过热或光化学诱导，以及 CO 部分的取代和官能化。重要的是，这些配合物表现出强的 Si-CO 键，具有 CO→Si σ-供体和 Si→CO π-反馈，这类似于过渡金属羰基。丰富的半金属硅和稀有过渡金属之间的这种相似性可能为开发基于硅的催化提供新的机会。
