Aminopyridinato-Ligand-Stabilized Lanthanoid Complexes: Synthesis, Reactivity, Ethylene and Isoprene Polymerization
type: CreativeWork
description: The aim of the present thesis was the synthesis and complete characterization of aminopyridinato-ligand-stabilized complexes of the lanthanoids. The lanthanoid complexes were synthesized by amine or alkane elimination. The thus obtained compounds were investigated in regard to their properties as precatalysts for the polymerization of ethylene or isoprene und their ability to form hydrido complexes or cations. Previous investigations carried out in our group have shown that aminopyridinate-stabilized organoyttrium cations exhibit very high activity in the polymerization of ethylene in the presence of aluminium alkyl compounds. This work showed that the thereby used precursor [Ap*Y(CH2SiMe3)2(thf)] can selectively react with phenylsilane or hydrogen to a novel trinuclear lanthanoid alkyl hydrido cluster. The corresponding lutetium derivative reacts analogous to the yttrium compound. The lanthanoid alkyl hydrido clusters were characterized by X-ray structure analyses, and the presence of the hydrid ligands were clearly proved by 1H NMR spectroscopy. Dialkyl complexes, stabilized by aminopyridinato ligands, react with anilinium borate to yield organolanthanoid cations after alkane elimination. They were isolated and characterized as thf adducts. The dibenzyl complexes of scandium and erbium were characterized by single crystal structure analyses. The dialkyl complexes of scandium are selective and active catalysts for the 3,4-selective polymerization of isoprene after activation with borates. We could even obtain isotactically enriched 3,4-polyisoprene through appropriate choice of the polymerization conditions (cocatalyst, polymerization temperature). The aminopyridinate-stabilized diamide of scandium can polymerize isoprene in the presence of anilinium borate and trialkylaluminium compounds, to obtain a polymer with a high cis-1,4-content. The dialkyl compounds of yttrium, erbium and lutetium are also suitable precatalysts for the initiation of the polymerization of …
abstract: The aim of the present thesis was the synthesis and complete characterization of aminopyridinato-ligand-stabilized complexes of the lanthanoids. The lanthanoid complexes were synthesized by amine or alkane elimination. The thus obtained compounds were investigated in regard to their properties as precatalysts for the polymerization of ethylene or isoprene und their ability to form hydrido complexes or cations. Previous investigations carried out in our group have shown that aminopyridinate-stabilized organoyttrium cations exhibit very high activity in the polymerization of ethylene in the presence of aluminium alkyl compounds. This work showed that the thereby used precursor [Ap*Y(CH2SiMe3)2(thf)] can selectively react with phenylsilane or hydrogen to a novel trinuclear lanthanoid alkyl hydrido cluster. The corresponding lutetium derivative reacts analogous to the yttrium compound. The lanthanoid alkyl hydrido clusters were characterized by X-ray structure analyses, and the presence of the hydrid ligands were clearly proved by 1H NMR spectroscopy. Dialkyl complexes, stabilized by aminopyridinato ligands, react with anilinium borate to yield organolanthanoid cations after alkane elimination. They were isolated and characterized as thf adducts. The dibenzyl complexes of scandium and erbium were characterized by single crystal structure analyses. The dialkyl complexes of scandium are selective and active catalysts for the 3,4-selective polymerization of isoprene after activation with borates. We could even obtain isotactically enriched 3,4-polyisoprene through appropriate choice of the polymerization conditions (cocatalyst, polymerization temperature). The aminopyridinate-stabilized diamide of scandium can polymerize isoprene in the presence of anilinium borate and trialkylaluminium compounds, to obtain a polymer with a high cis-1,4-content. The dialkyl compounds of yttrium, erbium and lutetium are also suitable precatalysts for the initiation of the polymerization of …
author: Döring, Christian
date published: 2009-10-28
date modified: 2026-07-27T18:49:16Z
provider: Universität Bayreuth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universität Bayreuth