Yttrium Amidopyridinate Complexes: Synthesis and Characterization of New Y-Alkyl and Y-Hydrido Derivatives

Aryl- 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 ?-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.