(η⁵‐Cyclopentadienyl)(η⁴‐tetrasila‐ and η⁴‐trisilagermacyclobutadiene)cobalt: Sandwich Complexes Featuring Heavy Cyclobutadiene Ligands

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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Vladimir Ya. Lee

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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Masaaki Ichinohe

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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Akira Sekiguchi

sekiguch@chem.tsukuba.ac.jp

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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Kazunori Takanashi

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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Vladimir Ya. Lee

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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Masaaki Ichinohe

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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Akira Sekiguchi

sekiguch@chem.tsukuba.ac.jp

Department of Chemistry, Graduated School of Pure and Applied Sciences, University of Tsukuba Tsukuba, Ibaraki 305‐8571, Japan, Fax: +81‐29‐853‐4314

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First published: 28 November 2007

https://doi.org/10.1002/ejic.200701046

Citations: 21

Abstract

(η⁵‐Cyclopentadienyl)(η⁴‐tetrasilacyclobutadiene)cobalt{[(η⁴‐R₄Si₄)CoCp], 2} and (η⁵‐cyclopentadienyl)(η⁴‐trisilagermacyclobutadiene)cobalt {[(η⁴‐R₄Si₃Ge)CoCp], 4} (R = SiMetBu₂) were synthesized by reaction of the dipotassium salts of tetrasilacyclobutadiene dianion K⁺₂·[R₄Si₄]^2– (1) and trisilagermacyclobutadiene dianion K⁺₂·[R₄Si₃Ge]^2– (3) with [CpCoI₂(PPh₃)]. Alternatively, 4 was prepared by the reaction of 3 with [Cp₂Co]⁺·[PF₆]^–. X‐ray crystallographic analysis of 2 confirmed its sandwich‐type structure, manifesting a nearly square‐planar Si₄ ring and diagnostic perhaptocoordination of both ligands, η⁴‐tetrasilacyclobutadiene and η⁵‐cyclopentadienyl, to the Co atom. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)