title: Development of parameter sets for semi-empirical MO calculations of transition metal systems: iron parameters for iron-sulfur proteins.
abstract: A semi-empirical parameter set for iron has been developed which is appropriate for the study of iron-sulfur proteins having a single iron atom, by fitting to density-functional theory (DFT) calculations obtained for a series of small models of iron-containing proteins. These parameters are obtained using a modified BFGS optimisation procedure previously used to obtain semi-empirical parameters for the main group elements. The modifications to this procedure for obtaining parameters for transition metal atoms are outlined. In addition to modifications to the semi-empirical core repulsion function, which yield significant improvements in the calculation of molecular structures, compared to the standard core repulsion function, are outlined. The reported parameters are then tested on a set of model complexes containing a variety of ligands and show good agreement with both DFT and experimental data for these species.
authors.affiliation: School of Chemistry, University of Manchester, Manchester M13 9PL, UK.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: McNamara
authors.forename: Mahesh
authors.initials: M
authors.lastname: Sundararajan
authors.forename: Ian H
authors.initials: IH
authors.lastname: Hillier
mesh_terms: D000465:Algorithms; D019295:Computational Biology; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D008956:Models, Chemical; D012416:Rubredoxins / Q000737:chemistry; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D007506:Iron-Sulfur Proteins; D012416:Rubredoxins; D028561:Transition Elements; D007501:Iron