Search:
Computing and Library Services - delivering an inspiring information environment

Halide Ligated Iron Porphines: A DFT+Uand UB3LYP Study

Panchmatia, Pooja M., Ali, Md. Ehesan, Sanyal, Biplab and Oppeneer, Peter M. (2010) Halide Ligated Iron Porphines: A DFT+Uand UB3LYP Study. The Journal of Physical Chemistry A, 114 (51). pp. 13381-13387. ISSN 1089-5639

Metadata only available from this repository.

Abstract

We apply the density functional theory + U (DFT+U) and unrestricted hybrid functional DFT-UB3LYP methods to study the electronic structure and magnetic properties of two prototypical iron porphines: iron(III) porphine chloride (FePCl) and difluoro iron(III−IV) porphine. Plain DFT within the generalized gradient approximation (GGA) implementation fails in describing the correct high-spin ground state of these porphine molecules, whereas DFT+U and UB3LYP provide an improved description. For a range of U values (4−8 eV), we compare the results of the DFT+U approach to those obtained previously with the hybrid functional (B3LYP) and with the CASPT2 approach. The DFT+U and UB3LYP methods successfully predict the molecular high spin (S = 5/2) ground state of FePCl, and also provide the nontrivial S = 3 high spin ground state for FePF2. For the latter six-coordinated Fe porphine, our DFT+U calculations show that the S = 2, S = 5/2, and S = 3 states are energetically very close together (differences of 30 meV). Nonetheless, S = 3 is obtained as the ground state of the whole molecule, in accordance with the spin expected from the electron count. Our DFT+U calculations show furthermore that the Fe 3d occupancy is similar for FePF2 and FePCl, i.e., DFT+U does not support Fe(IV) for FePF2, but rather an Fe(III) porphyrin π-cation radical species, with an Fe high spin SFe = 5/2, and an additional S = 1/2 stemming from spin density distributed over the porphine ring. This observation is also supported by our UB3LYP calculations.

Item Type: Article
Subjects: Q Science > QD Chemistry
Schools: School of Applied Sciences
Depositing User: Graham Stone
Date Deposited: 20 Feb 2012 14:22
Last Modified: 20 Feb 2012 14:22
URI: http://eprints.hud.ac.uk/id/eprint/12808

Item control for Repository Staff only:

View Item

University of Huddersfield, Queensgate, Huddersfield, HD1 3DH Copyright and Disclaimer All rights reserved ©