Novel Mononuclear Vanadium Complexes Having Pentalene Ligands η8‐ Bonded to a Single Metal Atom—A New Type of Coordination in Organometallic Chemistry

The pronounced folding of the η8-coordinated pentalene ligand along the bond between the two bridgehead carbon atoms is the most prominent structural feature of the vanadium complex 2. This compound and further 18e complexes of this type are readily prepared by the reaction of vanadocene monohalides 2 or their derivatives with dilithium pentalenediide. Although these mononuclear complexes are air-sensitive, they are thermally so stable that they can be sublimed in high vacuum at 80–100°C without decomposition.