New approaches to nitrogen ligands bearing electron withdrawing groups and their role in coordination chemistry.

摘要

The search for non-cyclopentadienide-type catalyst systems continues, driven by industry's desire to obtain even greater control over polymer properties and extend the family of products to include new monomer combinations. At the forefront of this search are two ligand types, diketimines and their oxygen-substituted analogs, the aminoenones. We have recently found an efficient and clean synthetic pathway, developed in conjunction with the Los Alamos National Laboratory, to these ligand types, utilizing novel aluminum chemistry. A variety of dimeric alkylaminoalanes, with the general formula, [Me2AIN(H)Ar_f] ₂, that feature aryl groups with varying degrees of fluorination, are presented. A non-fluorinated pyridine derivative that resulted in a novel pentasubstituted aluminum species is also discussed.{09}The use of these new aminoalane reagents for the transformation of the ketone functionality to the imine functionality was very successful, and in most instances, led to a higher yield of a cleaner product, than with the traditional methodology. Finally, the coordination capability of this class of ligand was studied by the reactions with both early and late transition metals, as well as the main group metal aluminum. Simple adducts of titanium, vanadium, chromium, and platinum were prepared, as well as complexes of titanium, zirconium, and aluminum.