The synthesis and characterization of iron cyanide building blocks: [K]2[CpFe(CN)3] and its pentamethylcyclopentadienyl (Cp*) analog

The synthesis of [K]2[CpFe(CN)3] (1) and its pentamethylcyclopentadienyl analog (2) has been described via the photolysis of the corresponding [K][CpFe(CO)(CN)2] salts in methanol in the presence of KCN. The structure of complex 1 has been characterized by means of X-ray crystallography, where the potassium ions are interacting with the N atoms of the cyanide ligands. As expected, the average ν CN stretching frequency in the View the MathML sourceCpFe(CN)3- anion is 16 cm−1 higher than that in the more electron-donating pentamethylcyclopentadienyl derivative.