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Iron(IV) Porphyrin Difluoride Does Not Exist: Implications for DFT Calculations on Heme Protein Reaction Pathways.
- Source :
-
Journal of chemical theory and computation [J Chem Theory Comput] 2005 Jul; Vol. 1 (4), pp. 597-600. - Publication Year :
- 2005
-
Abstract
- DFT (B3LYP as well as a number of common exchange-correlation functionals) predicts a low-spin Fe(IV) ground state for Fe(P)F2 (P = porphyrinato), whereas electrochemical evidence has apparently indicated an Fe(III) porphyrin π-cation radical formulation for such a species. Ab initio CASPT2 calculations favor a high-spin porphyrin π-cation radical as the ground state by a significant energetic margin, thus dramatically overturning the DFT results. In contrast, both DFT and CASPT2 calculations correctly indicate a true Mn(IV) ground state for Mn(P)F2. The remarkable failure of DFT to correctly predict the metal- versus ligand-oxidized nature of Fe(P)F2 may have significant ramifications for the theoretical modeling of heme protein reaction pathways where until now the performance of DFT has raised little concern.
Details
- Language :
- English
- ISSN :
- 1549-9618
- Volume :
- 1
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Journal of chemical theory and computation
- Publication Type :
- Academic Journal
- Accession number :
- 26641680
- Full Text :
- https://doi.org/10.1021/ct050086s