Boratabenzene Zirconium Complexes

Abstract

1-Substituted boratabenzenes (1) are six π-electron aromatic anions which can serve as surrogates for cyclopentadienyl in important organometallic compounds. The reaction of 1 with ZrCl₄ produces bis(boratabenzene) zirconium(IV) dichlorides 3, which when activated by excess methylaluminoxane react with ethylene to produce either high molecular weight polyethylene or smaller ethylene oligomers, depending upon the substituents at boron. The reaction of 3 with BuLi in the presence of PMe₃ affords the corresponding zirconium(II) complexes (4). The reaction of 4 with acetylene involves an unprecedented ring annulation to afford complexes which contain the novel ligand lOH-5-boratanaphthalene.

Keywords::

• Boron Heterocycles
• Zirconium Complexes
• Polymerization
• Agostic Interactions