Ethyl 5-ferrocenyl-1H-pyrazolecarboxylates: The synthesis and redox properties

Redox potentials of isomeric ethyl 5-ferrocenyl-1H-pyrazole-3-carboxylates 2 and ethyl 5-ferrocenyl-1H-pyrazole-4-carboxylates 4 were measured and their dependences on the acidity of the medium were determined. The structures of various conformers of neutral molecules and corresponding radical cations were calculated by the B3LYP/6-31G* method. The results of calculations for neutral molecules were confirmed by X-ray data.