Designing and characterization of Fe(III) complexes of oxydiacetate containing α-diimine as auxiliary ligand: 57Fe-Mössbauer and cyclic voltammetric studies

•The present work describes synthesis and characterization of three Fe(III) complexes.•The complexes are characterized by spectral, thermal and cyclic voltammetric techniques.•57Fe-Mössbauer spectra ascertained a distorted octahedral geometry of the complexes.•The electrochemical redox properties of the complexes (1) and (2) have been studied.

The newly prepared complexes with stoichiometries [Fe(oda)(phen)Cl] (1), [Fe(oda)(4-picNO)(H2O)Cl)] (2) and [Fe2(oda)2(H2O)2Cl2] (3) [H2oda = oxydiacetic acid, phen = 1,10′-phenantroline and 4-picNO = 4-picoline-N-oxide] were synthesized under varying experimental conditions. The complexes were characterized by spectral (IR, FAB-MS and Mössbauer), electrochemical and thermal studies. 57Fe-Mössbauer spectral data for complexes exhibit a quadrupole splitting confirming the presence of iron nuclei in asymmetric environment. The relevant parameters like isomer shift (δ), quadruple splitting (ΔEQ), line widths and peak height ratio (HWh/HWl) are consistent with high spin state of Fe(III) centre with the presence of Kramer’s double degeneracy in distorted octahedral environment. The electrochemical studies indicate existence of quasi-reversible redox couples (FeII/III) in solution.

Graphical abstractThree complexes of iron containing oxydiacetic acid as primary ligand have been synthesized and characterized by FTIR, FAB-MS, UV–Visible and 57Fe-Mössbauer spectral, thermal and electrochemical studies.Figure optionsDownload full-size imageDownload as PowerPoint slide