title: First-principle computation of zero-field splittings: application to a high valent Fe(IV)-oxo model of nonheme iron proteins.
abstract: We report the computational implementation of a combined spin-density-functional theory and perturbation theory (SDFT-PT) methodology for the accurate calculation of zero-field splittings (ZFS) in complexes of the most diverse nature including metal centers in proteins. We have applied the SDFT-PT methodology to study the cation of the recently synthesized complex [Fe(IV)(O)-(TMC)(NCCH(3))](OTf)(2), [J. Rohde et al., Science 299, 1037 (2003)] which is an important structural and functional analog of high-valent intermediates in catalytic cycles of nonheme iron enzymes. The calculated value (D(Theory)=28.67 cm(-1)) is in excellent agreement with the unusually large ZFS reported by experiment (D(Exp)=29+/-3 cm(-1)). The principal component D(zz) of the ZFS tensor is oriented along the Fe(IV)=oxo bond indicating that the oxo ligand dominates the electronic structure of the complex.
authors.affiliation: Department of Physics, Purdue University, West Lafayette, IN 47907-2036, USA.
authors.forename: Fredy
authors.initials: F
authors.lastname: Aquino
authors.forename: Jorge H
authors.initials: JH
authors.lastname: Rodriguez
mesh_terms: D002384:Catalysis; D002412:Cations; D003198:Computer Simulation; D007501:Iron / Q000737:chemistry*; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D019159:Nonheme Iron Proteins / Q000737:chemistry*; D025341:Principal Component Analysis; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D015203:Reproducibility of Results; D012984:Software
chemical_list: D002412:Cations; D019159:Nonheme Iron Proteins; D007501:Iron