Ferric-Thiolate Bond Dissociation Studied with Electronic Structure Calculations.
The stability and reactivity of iron-sulfur clusters are fundamental properties for the biological function of these prosthetic groups. Here, we investigate the ferric-thiolate bond dissociation of model iron-sulfur tetrahedral complexes with high-level ab initio multiconfigurational electronic structure calculations. We find that the reaction mechanism is homolytic with a spin-crossing from the sextet state in the reactant to quartet state in the product. We also compare several density functionals and semiempirical configuration interaction with the high-level ab initio results to find an accurate but computationally more efficient method to describe the reaction. The functionals M06 and those based on the OPTX exchange functional show the best performance and may reasonably describe the various electron correlation effects involved in ferric-thiolate bond dissociation.
Department of Biochemistry, Instituto de Química, Universidade de São Paulo , Av. Prof. Lineu Prestes 748, 05508-900, São Paulo, SP Brazil.
Guilherme Menegon
GM
Arantes
Institut de Biologie Structurale (IBS), CEA/CNRS/Université Joseph Fourier , 71 Avenue des Martyrs, CS 10090, 38044 Grenoble Cedex 9, France.
Martin J
MJ
Field
D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008962:Models, Theoretical; D015394:Molecular Structure; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013816:Thermodynamics
D005290:Ferric Compounds; D007506:Iron-Sulfur Proteins; D013438:Sulfhydryl Compounds