Alkane Elimination Reactions between Transition Metal Hydrides and Rare-Earth Alkyls
type: CreativeWork
description: In the present work various transition metal hydrides were examined regarding their potential to form unsupported bonds towards rare-earth metals. Selected rare-earth alkyls were reacted with the metal hydrides in question. Motivated by previous results of the Kempe group in which the alkane elimination reaction of [Cp*RuH2]2 with [Cp2Y(CH2SiMe3)(thf)] yielded [H(Cp*Ru)2H2YCp2], it was assumed that the reaction of the formal dihydride [Cp*RuH2]2 with two equivalents of a rare-earth bis(alkyl) should lead to products with unsupported metal-metal bonds. [Cp*RuH2]2 was reacted with two equivalents of [Ln(CH2SiMe3)2(OC6H3tBu2-2,6)(thf)2] (Ln = Y, Lu). However the heteromultimetallic polyhydride complexes [(Cp*Ru)3(μ-H)4Ln(OC6H3tBu2-2,6)(μ- H)2RuCp*] (Ln = Y, Lu) were obtained. Regardless the stoichiometry (0.5-2.0 equiv [Cp*RuH2]2) the cluster compounds were obtained selectively. Solid state structures of both compounds could be established by XRD analyses. The isostructural compounds feature four Ln-Ru intramolecular distances of which one is significantly shorter than the three others. Six bridging hydride ligands are located between the metal centers. As the reaction of [Cp*RuH2]2 towards rare-earth alkyls forms polyhydride complexes further studies focused on transition metal monohydrides. Inspired by the use of Rp and Fp fragments (Fp = [CpFe(CO)2], Rp = [CpRu(CO)2]) in metal-metal bonding the reactivity of [HW(CO)3Cp] towards yttrium alkyls was examined. The relatively high acidity of the metal-hydrogen bond should allow alkane elimination reactions. Indeed, reactions of [HW(CO)3Cp] with yttrium alkyls proceeded rapidly with evolution of tetramethylsilane. However, isocarbonyl bridged products were isolated. Several bonding modes in RE-TM carbonyl complexes are possible, namely unsupported metal-metal bonds, isocarbonyl linkages and solvate separated ion-pairs. Which bonding mode is preferred mainly depends on the nucleophilicity of the transition metal, the carbo…
abstract: In the present work various transition metal hydrides were examined regarding their potential to form unsupported bonds towards rare-earth metals. Selected rare-earth alkyls were reacted with the metal hydrides in question. Motivated by previous results of the Kempe group in which the alkane elimination reaction of [Cp*RuH2]2 with [Cp2Y(CH2SiMe3)(thf)] yielded [H(Cp*Ru)2H2YCp2], it was assumed that the reaction of the formal dihydride [Cp*RuH2]2 with two equivalents of a rare-earth bis(alkyl) should lead to products with unsupported metal-metal bonds. [Cp*RuH2]2 was reacted with two equivalents of [Ln(CH2SiMe3)2(OC6H3tBu2-2,6)(thf)2] (Ln = Y, Lu). However the heteromultimetallic polyhydride complexes [(Cp*Ru)3(μ-H)4Ln(OC6H3tBu2-2,6)(μ- H)2RuCp*] (Ln = Y, Lu) were obtained. Regardless the stoichiometry (0.5-2.0 equiv [Cp*RuH2]2) the cluster compounds were obtained selectively. Solid state structures of both compounds could be established by XRD analyses. The isostructural compounds feature four Ln-Ru intramolecular distances of which one is significantly shorter than the three others. Six bridging hydride ligands are located between the metal centers. As the reaction of [Cp*RuH2]2 towards rare-earth alkyls forms polyhydride complexes further studies focused on transition metal monohydrides. Inspired by the use of Rp and Fp fragments (Fp = [CpFe(CO)2], Rp = [CpRu(CO)2]) in metal-metal bonding the reactivity of [HW(CO)3Cp] towards yttrium alkyls was examined. The relatively high acidity of the metal-hydrogen bond should allow alkane elimination reactions. Indeed, reactions of [HW(CO)3Cp] with yttrium alkyls proceeded rapidly with evolution of tetramethylsilane. However, isocarbonyl bridged products were isolated. Several bonding modes in RE-TM carbonyl complexes are possible, namely unsupported metal-metal bonds, isocarbonyl linkages and solvate separated ion-pairs. Which bonding mode is preferred mainly depends on the nucleophilicity of the transition metal, the carbo…
author: Sobaczynski, Adam
date published: 2014-07-02
date modified: 2026-07-27T18:49:36Z
provider: Universität Bayreuth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universität Bayreuth