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

Abstract

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 CpFe ( CN ) 3 - anion is 16 cm −1 higher than that in the more electron-donating pentamethylcyclopentadienyl derivative.