Cyclopentadienide Ligand Cp^C– Possessing Intrinsic Helical Chirality and Its Ferrocene Analogues

Abstract

The novel chiral cyclopentadiene-type ligand CpCH is accessible from dibenzosuberenone in a five-step sequence with overall yields of 64%. NMR spectroscopy as well as DFT calculations prove that the racemization of this compound is slow at room temperature. By deprotonation of CpCH and subsequent reaction with appropriate iron(II) precursors, the novel ferrocene derivatives (CpC)2Fe and (CpC)Fe(4Cp) are accessible in good yields. The latter could structurally be characterized by means of single-crystal X-ray crystallography. Mössbauer spectroscopy proves the ferrocene nature of (CpC)2Fe and (CpC)Fe(4Cp), and electrochemical investigations carried out with (CpC)Fe(4Cp) show that the compound is, as expected, more easily oxidized than ferrocene.