title: Electronic structure of ferric heme nitrosyl complexes with thiolate coordination.
abstract: The effect of trans thiolate ligation on the coordinated nitric oxide in ferric heme nitrosyl complexes as a function of the thiolate donor strength, induced by variation of NH-S(thiolate) hydrogen bonds, is explored. Density functional theory (DFT) calculations (BP86/TZVP) are used to define the electronic structures of corresponding six-coordinate ferric [Fe(P)(SR)(NO)] complexes. In contrast to N-donor-coordinated ferric heme nitrosyls, an additional Fe-N(O) sigma interaction that is mediated by the dz2/dxz orbital of Fe and a sigma*-type orbital of NO is observed in the corresponding complexes with S-donor ligands. Experimentally, this is reflected by lower nu(N-O) and nu(Fe-N) stretching frequencies and a bent Fe-N-O moiety in the thiolate-bound case.
authors.affiliation: Department of Chemistry, The University of Michigan, 930 N. University, Ann Arbor, Michigan 48109-1055, USA.
authors.forename: Florian
authors.initials: F
authors.lastname: Paulat
authors.forename: Nicolai
authors.initials: N
authors.lastname: Lehnert
mesh_terms: D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry*; D006418:Heme / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D015394:Molecular Structure; D009603:Nitroso Compounds / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D008024:Ligands; D009603:Nitroso Compounds; D013438:Sulfhydryl Compounds; D006418:Heme