Al and Zn phenoxy-amidine complexes for lactide ROP catalysis.

We report the synthesis of a new generation of phenoxy-amidine ligands based on an aryloxy moiety possessing an -linked trisubstituted amidine. The reaction of the phenol-amidine proligands with aluminum and zinc alkyls gave mono- or bis-ligated complexes depending on the metal/ligand ratio used. The solid-state structure of four proligands and thirteen Zn and Al complexes has been determined by X-Ray diffraction analysis.

Bis(salicylamidine) Ligands (FAlen): A Variant of Salen with "à la Carte" Denticity.

Ethylene- and phenylene-bridged bis(salicylamidine) ligands have been readily prepared from ethylene or phenylenediamine and iminium chloride derivatives generated from ,-dialkylsalicylamides. The former, in its diprotonated form (FAlenH), reacts with AlMe to afford a zwitterionic dimethyldiphenoxyaluminate complex with the FAlen ligand monoprotonated and in a bidentate κ, fashion. A phenylene-bridged proligand behaves differently, yielding a neutral methylaluminum complex bearing a κ,,-coordinated FAlen ligand.