Yttrium‐Amidopyridinate Complexes: Synthesis and Characterization of Yttrium‐Alkyl and Yttrium‐Hydrido Derivatives
摘要:
AbstractAryl‐ or heteroaryl‐substituted aminopyridine ligands (N2HAr) react with an equimolar amount of [Y(CH2SiMe3)3(thf)2] to give yttrium(III)‐monoalkyl complexes. The process involves the deprotonation of N2HAr by a yttrium alkyl followed by a rapid and quantitative intramolecular sp2‐CH bond activation of the aryl or heteroaryl pyridine substituents. As a result, new Y complexes distinguished by rare examples of CH bond activations have been isolated and completely characterized. Selective σ‐bond metathesis reactions take place on the residual Y–alkyl bonds upon treatment with PhSiH3. Unusual binuclear metallacyclic yttrium(III)‐hydrido complexes have been obtained and characterized by NMR spectroscopy and X‐ray diffraction analysis.
Selective Oligomerization of Ethylene to Linear α-Olefins by Tetrahedral Cobalt(II) Complexes with 6-(Organyl)-2-(imino)pyridyl Ligands: Influence of the Heteroatom in the Organyl Group on the Catalytic Activity
The oligomerization of ethylene to alpha-olefins has been obtained by MAO activation of tetrahedral Co-II complexes of iminopyridines substituted in the 6-position of the pyridine ring by thiophen-2-yl, furan-2-yl, or phenyl groups. An intriguing heteroatom effect has been noticed on both activity and selectivity, together with a change in the Co-II spin state upon activation of the dichloride precursors with MAO.