SPECTROSCOPIC EVIDENCE FOR THE FORMATION OF A BRIDGED LITHIUM DICYCLOPENTADIENYL LITHIATE COMPLEX

One- and two-dimensional NMR and DNMR studies including Li-6 NMR prove the formation of a ferrocene-bridged lithium bis(vinylcyclopentadienyl)lithiate complex 8 in THF solution. Two different dynamic processes could be detected: the exchange of the ate-bound lithium ion with the solvent-separated lithium species and the intramolecular rotation of the hydrocarbon decks, involving the cleavage of the ate complex in the transition state. From the activation parameters of both processes derived from NMR line shape simulation it is shown that the lithium ion exchange process should proceed without the loss of the chelate conformation.