C5Me4(CH2)3(OCH2CH2)3OMe: a tentacle-bearing cyclopentadienyl ligand and its use in complex chemistry

Abstract

The reaction of 2,3,4,5-tetramethylcyclopent-2-enone with the Grignard reagent MeO(CH₂CH₂O)₃(CH₂)₃MgCl 3 affords, after acidic workup, the novel cyclopentadiene HC₅Me₄(CH₂)₃(OCH₂CH₂)₃OMe 4, which allows the synthesis of cyclopentadienyl metal complexes that owing to the tentacle function show unusually high solubilities in solvents of all polarities; two such complexes are the ferrocene [Fe{C₅Me₄(CH₂)₃(OCH₂CH₂)₃OMe}₂]6 and the cobalt carbonyl [Co(CO)₂{C₅Me₄(CH₂)₃(OCH₂CH₂)₃OMe}]7.