Synthesis and Structure of the First [22]Metallocenophanes

The dark red Fe and colorless ZrCl2 complexes 2 are easily accessible from the doubly bridged biscyclopentadienes 1. The substantial torsion of the two eclipsing decks of the conformationally rigid ligand framework of 2 exposes the metal center and points to the potential of such complexes as catalysts for the stereoselective polymerization of alkenes.