Syntheses and characterization of alkylzirconium complexes containing two silanolato ligands with a bowl-shaped framework

The reaction of a bowl-type silanol with tetrabenzylzirconium yielded a dibenzylbis(silanolato)zirconium complex selectively, which is an intriguing species in connection to the chemistry of silica-supported ZrR4 olefin polymerization catalysts. Treatment of this neutral complex with B(C6F5)3 afforded the corresponding cationic monobenzyl complex, presenting the first example of a cationic zirconium complex containing a silanolato ligand. The structures of both complexes have been characterized by X-ray crystallography.