Institut für Chemie, Technische Universität Berlin , Straße des 17. Juni 135, 10623 Berlin, Germany.
Institute of Theoretical Chemistry, Jilin University , Changchun 130023, People's Republic of China.
J Am Chem Soc. 2017 May 3;139(17):6169-6176. doi: 10.1021/jacs.7b01255. Epub 2017 Apr 19.
The potential of carbonyl rhenium complexes in activating and coupling carbon dioxide and methane has been explored by using a combination of gas-phase experiments (FT-ICR mass spectrometry) and high-level quantum chemical calculations. While the complexes [Re(CO)] (x = 0, 1, 3) are thermally unreactive toward CO, [Re(CO)] abstracts one oxygen atom from this substrate spontaneously at ambient conditions. Based on C and O labeling experiments, the newly generated CO ligand is preferentially eliminated, and two mechanistic scenarios are considered to account for this unexpected finding. The oxo complex [ORe(CO)] reacts further with CH to produce the dihydridomethylene complex [ORe(CO)(CH)(H)]. However, coupling of the CO and CH ligands to form CH═C═O does not take place. Further, the complexes [Re(CO)(CH)] (x = 1, 2), generated in the thermal reaction of [Re(CO)] (x = 1, 2) with CH, are inert toward CO. Mechanistic insight on the origin of this remarkable reactivity pattern has been derived from detailed quantum chemical calculations.
羰基铼配合物在激活和偶联二氧化碳和甲烷方面的潜力已通过气相实验（FT-ICR 质谱）和高精度量子化学计算相结合的方法进行了探索。尽管配合物 [Re(CO)]（x = 0、1、3）对 CO 是热不反应的，但[Re(CO)]在环境条件下会自发地从该底物中夺取一个氧原子。基于 C 和 O 标记实验，新生成的 CO 配体被优先消除，并且考虑了两种机理情景来解释这一意外发现。氧代配合物 [ORe(CO)] 进一步与 CH 反应生成二氢亚甲基配合物 [ORe(CO)(CH)(H)]。然而，CO 和 CH 配体的偶联形成 CH═C═O 并未发生。此外，在 [Re(CO)]（x = 1、2）与 CH 的热反应中生成的配合物 [Re(CO)(CH)]（x = 1、2）对 CO 是惰性的。从详细的量子化学计算中得出了对这种显著反应性模式起源的机理见解。
