Impact of solvent models and van der Waals corrections on DFT geometric and 57Fe Mössbauer parameters of trans-[FeCl2(iPrOH)4]

• DFT structural investigation of trans-[FeCl2(iPrOH)4].
• DFT calculations of Mössbauer parameters: isomer shift (δ) and quadrupole splitting (ΔEQ).
• Study of influence of van der Waals and solvation corrections to calculated parameters.
• B3LYP/Wachters/6–311G(d)/COSMO + VDW found as a suitable model for calculation of δ ΔEQ.

Geometric parameters of an iron(II) octahedral complex trans-[FeCl2(iPrOH)4] (Nunes et al., 2004), showing the Cl2O4 donor set (iPrOH = propan-2-ol), were investigated by a series of quantum-chemical calculations based on density functional theory (DFT), with the aim to quantify the influence of geometry and various corrections on the accuracy of the calculated 57Fe Mössbauer parameters, i.e. isomer shift, δ, and quadrupole splitting, ΔEQ. The B3LYP hybrid functional was used in combination with the Polarized Continuum Model (PCM), Conduktor-like screening model (COSMO) and van der Waals (VDW) corrections, involving the Wachters original full-electron, 6–311G(d) and TZVP basis sets. On the basis of the obtained data analysis it may be concluded that the overall good agreement between the experimental and theoretical results has been found for calculations performed at the B3LYP/Wachters/6–311G(d)/COSMO + VDW level of theory, showing the mean errors 0.0164 Å and 0.0315 Å for Fe–O and Fe–Cl bond lengths, respectively, 2.85° for the axial Cl–Fe–Cl and O–Fe–O angles, and absolute errors 0.09 mm s−1 for δ and 0.07 mm s−1 for ΔEQ.

Structural and Mössbauer parameters of trans-[FeCl2(iPrOH)4] were investigated using DFT calculations. The B3LYP/Wachters/6–311G(d)/COSMO + VDW approach was found as a suitable model for calculation of δ and ΔEQ.Figure optionsDownload as PowerPoint slide