N -aryloxide-amidinate group 4 metal complexes.

A N -aryloxide-amidine ligand (H 3 L), integrating phenoxide (PhO - ) and amidine ligands through methylene linkers, has been synthesized from 2-(aminomethyl)-6-( tert -butyl)phenol in two steps. Upon reacting the deprotonated H 3 L ligand with group 4 metal chloride M IV Cl 4 , a corresponding (LM IV -Cl) 2 dimer could be obtained. The coordination modes exhibit variation depending on the radius of the metal ions. In the case of (LTi IV -Cl) 2 , the two ArO - arms from the same ligand bond to two different Ti(IV) centers, while in the case of (LZr IV /Hf IV -Cl) 2 , both ArO - arms coordinate with the same metal center. Moreover, the two C-N bonds in the amidinate moiety are localized in (LTi IV -Cl) 2 , whereas they delocalize in (LZr IV -Cl) 2 . Notably, (LHf IV -Cl) 2 could further react with one equivalent of HfCl 4 , yielding the binuclear metal azide in the presence of KN 3 and LiCl, where the coordination mode of the amidinate moiety changed from the bidentate chelating type to the bimetallic bridging coordination.