Anionic and zwitterionic metallocene complexes derived from novel boratocyclopentadienyl ligands

Abstract
Borate-substituted di- and tri-anionic cyclopentadienyi ligands [X3B–C5H4]2– and [X2B(C5H4)2]3–-(X = C6F5) give anionic group 4 metallocene complexes which provide a facile route to zwitterionic ‘single-component’ alkene polymerisation catalysts.