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

摘要

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 Fe-57 Mossbauer parameters, i.e. isomer shift, delta, and quadrupole splitting, Delta E-Q. 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 angstrom and 0.0315 angstrom for Fe-O and Fe-Cl bond lengths, respectively, 2.85 degrees for the axial Cl-Fe-Cl and O-Fe-O angles, and absolute errors 0.09 mm s(-1) for delta and 0.07 mm s(-1) for Delta E-Q. (C) 2014 Elsevier B.V. All rights reserved.