Abstract In the presente work the complexes Na3[Fe(CN)5(NC(CH2)nCN)] (n = 1 = malononitrile and n= 2 = succinonitrile) have been isolated and characterized by cyclic voltammetry, Uv-vis and FTIR spectroscopies. A metal to ligand charge-transfer transition was observed only for Na3[Fe(CN)5(NCCH2CN)] complexe (316 nm, 3,57×103 L mol-1cm-1). The succinonitrile complex of pentacyanoferrate(II) exhibits a band maximum at 370 nm, which was assigned to ligand field transition. The half wave potentials, E1/2, for [Fe(CN)5(C3H2N2)]3-/2-, [Fe(CN)5(C4H4N2)]3-/2- and [Fe(CN)5H2O]3-/2- were measured as 341, 350 and 126 ± 5 mV (vs ECS), respectively. That is, in comparison with Fe(CN)5H2O]-3, MN and SN, stabilize the Fe(II) ion by 215 and 224 mV, respectively.
Keywords Malononitrile, succiononitrile, pentacionoferrate, voltammetry, electron transfer.