Department of Chemistry, Graduate School of Science and Engineering, Saitama University , Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan.
J Am Chem Soc. 2014 Sep 17;136(37):13059-64. doi: 10.1021/ja507330p. Epub 2014 Sep 3.
The neutral triple-decker ruthenocenes and anionic ruthenocene bearing a stannole dianion were successfully synthesized by the reactions of dilithiostannoles with [CpRuCl]4. This is the first example of a transition-metal complex bearing a group 14 metallole dianion with μ-η(5):η(5) coordination mode. These complexes were fully characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. In the complexes, each of the ruthenium atoms is coordinated by the stannole ring in an η(5)-fashion. The aromaticity of the stannole dianion moieties is retained judging from no C-C bond alternation in the stannole rings. CH/π interaction was found in the packing structure of the SiMe3 derivative, which leads to a well-ordered column-like structure. The oxidation wave of the triple-decker complex was observed at -0.43 V (vs ferrocene), which reveals that the triple-decker type heavy ruthenocene is oxidized more easily than the ferrocene. Comparison of the oxidation potential between the triple-decker complex and decamethylruthenocene (Cp2Ru, Cp* = η(5)-C5Me5) reveals that a stannole ligand functions as an electron-donating ligand much stronger than the conventional electron-rich Cp* ligand.
中性三层钌配合物和带锡烷二负离子的阴离子钌配合物通过二锂锡烷与[CpRuCl]4 的反应成功合成。这是首例具有μ-η(5):η(5)配位模式的 14 族金属茂二负离子的过渡金属配合物。这些配合物通过 NMR 光谱和单晶 X 射线衍射分析进行了充分的表征。在这些配合物中，每个钌原子都以η(5)方式与锡烷环配位。从锡烷环中没有 C-C 键交替可以判断出锡烷二负离子部分的芳香性得以保留。在 SiMe3 衍生物的堆积结构中发现了 CH/π 相互作用，这导致了有序的柱状结构。三重堆积配合物的氧化波在-0.43 V（相对于 ferrocene）处观察到，这表明三重堆积型重钌比 ferrocene 更容易被氧化。三重堆积配合物和十甲基钌（Cp2Ru，Cp*=η(5)-C5Me5）之间的氧化电位比较表明，锡烷配体的供电子能力比传统的富电子 Cp*配体强得多。
