Structural, electronic and optical properties of Fe(III) complex with pyridine-2,6-dicarboxylic acid: A combined experimental and theoretical study

Fe‐DPA as Catalyst for Oxidation of Organic Contaminants: Evidence of Homogeneous Fenton Process

“…Several studies have elucidated the mechanism of the Fenton type reaction for a series of compounds,27–29 including iron‐based materials 30,31. These studies are in good agreement with our theoretical results and suggest that the chemical bond between oxygen and the iron atom in the Fe‐DPA complex is predominantly electrostatic, small variation along the dihedral C–N–N–C is favored with little energy cost, and the spin density is centered mainly on the central atom 26. Thus, a chemical bond between iron and hydroxyl peroxide is feasible.…”

“…To gain insight into the role of the Fe‐DPA complex applied as a homogeneous catalyst the first‐principles calculations at DFT level were employed in this study, with the specific objective to provide a fundamental mechanistic understanding of the Fento‐ like process. Recently, our group conducted experimental and theoretical studies on the optical and structural properties of Fe‐DPA complex 9,26. These studies have demonstrated that the physical and chemical properties presented by the Fe‐DPA complex is strongly influenced by variation in the dihedral angle.…”

“…Synthesis of Fe‐DPA Complex: The Fe‐DPA complex was synthesized according to our previous work 26. Briefly the Fe‐DPA complex was synthesized using ferric nitrate [Fe(NO 3 ) 3 · 6H 2 O, 0.6 mM} (Vetec) dissolved in a 120 mM solution of DPA (Fluka) at the molar proportion of 1:2 iron/DPA.…”

“…The Fourier transform Raman (FT‐Raman) spectra were collected with a RFS100 spectrophotometer (Bruker, Germany). The FT‐IR and FT‐Raman analyses showed bands that confirm the formation of the complex compared with the free ligand spectrum 26. Mass spectrometry with electrospray ionization (ESI‐MS) was employed using a LC/MS Trap (Agilent‐1100) model.…”

“…Harmonic vibrational frequencies and intensities were calculated at the same level of theory with the analytical evaluation of second derivatives of energy as a function of atomic coordinates and the calculated intensities were used to generate the theoretical spectra. This computational procedure has been used previously in similar systems with success 26,37–39…”