(η5-Cyclopentadienyl)(η4-tetrasila- and η4-trisilagermacyclobutadiene)cobalt: Sandwich Complexes Featuring Heavy Cyclobutadiene Ligands (Eur. J. Inorg. Chem. 35/2007)

✍ Scribed by Kazunori Takanashi; Vladimir Ya. Lee; Masaaki Ichinohe; Akira Sekiguchi

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 514 KB
• Volume: 2007
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200790092

✦ Synopsis

Abstract

The cover picture shows two spotlights illuminating the structure of the first sandwich complex featuring an all‐heavy group 14 element‐consisting Si~4~‐cyclic ligand, namely, a derivative of (?^5^‐cyclopentadienyl)(η^4^‐tetrasilacyclobutadiene)cobalt [(η^4^‐R~4~Si~4~)CoCp] (R = SiMe__t__Bu~2~). The Me and __t__Bu groups on the Si substituents, as well as the H atoms on the Cp ring, are removed for simplicity. The title compound was smoothly prepared by a ligand exchange reaction between the tetrasilacyclobutadiene dianion salt K^+^~2~·[R~4~Si~4~]~2~ and [CpCoI~2~(PPh~3~)]. Systematic comparison of the complex [(η^4^‐R~4~Si~4~)CoCp] and its carbon analogue [η^4^‐(Me~3~Si)~4~C~4~]CoCp revealed important structural distinctions between the two complexes that result from the different ring sizes of the cyclobutadiene ligands η^4^‐R~4~E~4~ (R = SiMe__t__Bu~2~, E = Si vs. R = SiMe~3~, E = C). Details of the synthesis of the novel Co complex, as well as of its structural and electronic peculiarities, are discussed in the Short Communication by A. Sekiguchi et al. on p. 5471 ff.