Physik Department E20, Technische Universität München, James-Franck-Str., 85748, Garching, Germany.
Ecole Normale Supérieure, PSL Research University, Département de Chimie, CNRS UMR, 8640 PASTEUR, 75005, Paris, France.
Angew Chem Int Ed Engl. 2016 May 4;55(19):5754-9. doi: 10.1002/anie.201600567. Epub 2016 Apr 5.
Organocobalt complexes represent a versatile tool in organic synthesis as they are important intermediates in Pauson-Khand, Friedel-Crafts, and Nicholas reactions. Herein, a single-molecule-level investigation addressing the formation of an organocobalt complex at a solid-vacuum interface is reported. Deposition of 4,4'-(ethyne-1,2-diyl)dibenzonitrile and Co atoms on the Ag(111) surface followed by annealing resulted in genuine complexes in which single Co atoms laterally coordinated to two carbonitrile groups undergo organometallic bonding with the internal alkyne moiety of adjacent molecules. Alternative complexation scenarios involving fragmentation of the precursor were ruled out by complementary X-ray photoelectron spectroscopy. According to density functional theory analysis, the complexation with the alkyne moiety follows the Dewar-Chatt-Duncanson model for a two-electron-donor ligand where an alkyne-to-Co donation occurs together with a strong metal-to-alkyne back-donation.
有机钴配合物是有机合成中的一种多功能工具，因为它们是 Pauson-Khand、Friedel-Crafts 和 Nicholas 反应中的重要中间体。本文报道了在固-真空界面上形成有机钴配合物的单分子水平研究。将 4,4'-(乙炔-1,2-二基)二苯甲腈和 Co 原子沉积在 Ag(111)表面上，然后进行退火，得到真正的配合物，其中单个 Co 原子横向配位到两个腈基团上，并与相邻分子的内部炔基部分发生有机金属键合。通过补充的 X 射线光电子能谱排除了涉及前体断裂的替代配合物场景。根据密度泛函理论分析，与炔基部分的配合遵循 Dewar-Chatt-Duncanson 模型，对于双电子供体配体，发生炔基到 Co 的供体以及强的金属到炔基的反向供体。
