A Homoleptic Biradicaloid-Ligated Analogue of Ferrocene

In this communication, we report the synthesis, characterisation and electronic structure of a ferrocene analogue containing two biradicaloid ligands, representing the first homoleptic sandwich complex in this ligand class. In this quest, we found that the target compound was unattainable via routes involving Fe(0) or Fe(II) intermediates, and counterintuitively that the rare and much less-explored +1 oxidation state was crucial for the synthesis.