Half-Open Ferrocenes and Ruthenocenes Containing an Edge-Bridged Open Indenyl Ligand

Potassium 1,1-dimethyl-1,2-dihydronaphthalenide, K­(eboInd) (1), was synthesized in three steps from 4,4-dimethyl-1-tetralone and used for the synthesis of half-open metallocenes containing an edge-bridged open indenyl ligand (eboInd). Successive treatment of [(THF)­FeI2] with Li­(C5Me5) and 1 at low temperatures afforded [(η5-C5Me5)­Fe­(η5-eboInd)] (2), whereas [(η5-C5Me5)­Ru­(η5-eboInd)] (3) was synthesized by reaction of 1 with [(C5Me5)­RuCl]4. Both compounds reacted with CO and 2,6-dimethylphenyl isocyanide (CN-o-Xy) to form [(η5-C5Me5)­M­(η3-eboInd)­L] (4: M = Fe, L = CO; 5: M = Ru, L = CO; 6: M = Fe, L = CN-o-Xy; 7: M = Ru, L = CN-o-Xy), in which the eboInd ligand has undergone an η5-to-η3 hapticity conversion. In contrast, the N-heterocyclic carbene 1,3,4,5-tetramethylimidazolin-2-ylidene (IMe) only reacted with the ruthenocene derivative 3 to give [(η5-C5Me5)­Ru­(η3-eboInd)­(IMe)] (8). The molecular structures of 2–7 were determined by X-ray diffraction analysis. None of the iron–ruthenium pairs are isotypic.