title: Synthesis, structures, and electronic properties of triple- and double-decker ruthenocenes incorporated by a group 14 metallole dianion ligand.
abstract: The neutral triple-decker ruthenocenes and anionic ruthenocene bearing a stannole dianion were successfully synthesized by the reactions of dilithiostannoles with [Cp*RuCl]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 (Cp*2Ru, Cp* = η(5)-C5Me5) reveals that a stannole ligand functions as an electron-donating ligand much stronger than the conventional electron-rich Cp* ligand.
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Saitama University , Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kuwabara
authors.forename: Jing-Dong
authors.initials: JD
authors.lastname: Guo
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nagase
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sasamori
authors.forename: Norihiro
authors.initials: N
authors.lastname: Tokitoh
authors.forename: Masaichi
authors.initials: M
authors.lastname: Saito