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Reactions of Group 4 Metallocene Complexes with Mono- and Diphenylacetonitrile: Formation of Unusual Four- and Six-Membered Metallacycles

Authors

  • Lisanne Becker,

    1. Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176
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  • Dr. Vladimir V. Burlakov,

    1. Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176
    2. A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov St. 28, 119991, Moscow (Russia)
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  • Dr. Perdita Arndt,

    1. Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176
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  • Dr. Anke Spannenberg,

    1. Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176
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  • Dr. Wolfgang Baumann,

    1. Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176
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  • Dr. Haijun Jiao,

    1. Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176
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  • Prof. Dr. Uwe Rosenthal

    Corresponding author
    1. Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176
    • Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-51176

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Abstract

Reactions of Group 4 metallocene alkyne complexes [Cp′2M(η2-Me3SiC2SiMe3)] (1: M=Zr, Cp′=Cp*=η5-pentamethylcyclopentadienyl; 2 a: M=Ti, Cp′=Cp*, and 2 b: M=Ti, Cp′2=rac-(ebthi)=rac-1,2-ethylene-1,1′-bis(η5-tetrahydroindenyl)) with diphenylacetonitrile (Ph2CHCN) and of the seven-membered zirconacyclocumulene 3 with phenylacetonitrile (PhCH2CN) were investigated. Different compounds were obtained depending on the metal, the cyclopentadienyl ligand and the reaction temperature. In the first step, Ph2CHCN coordinated to 1 to form [Cp*2Zr(η2-Me3SiC2SiMe3)(NCCHPh2)] (4). Higher temperatures led to elimination of the alkyne, coordination of a second Ph2CHCN and transformation of the nitriles to a keteniminate and an imine ligand in [Cp*2Zr(NC2Ph2)(NCHCHPh2)] (5). The conversion of 4 to 5 was monitored by using 1H NMR spectroscopy. The analogue titanocene complex 2 a eliminated the alkyne first, which led directly to [Cp*2Ti(NC2Ph2)2] (6) with two keteniminate ligands. In contrast, the reaction of 2 b with diphenylacetonitrile involved a formal coupling of the nitriles to obtain the unusual four-membered titanacycle 7. An unexpected six-membered fused zirconaheterocycle (8) resulted from the reaction of 3 with PhCH2CN. The molecular structures of complexes 4, 5, 6, 7 and 8 were determined by X-ray crystallography.

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