title: High-spin and low-spin iron(II) complexes with facially-coordinated borohydride ligands.
abstract: Rare examples of monometallic high-spin and low-spin L3Fe(H3BH) complexes have been characterized, where the two L3 ligands are [TpPh2] and [PhBP3] ([TpPh2] = [HB(3,5-Ph2pz)3]- and [PhBP3] = [PhB(CH2PPh2)3]-). The structures are reported wherein the borohydride ligand is facially coordinated to the iron center in each complex. Density functional methods have been employed to explain the bonding in these unusual iron(II) centers. Despite the differences in spin states, short Fe-B distances are observed in both complexes and there is significant theoretical evidence to support a substantial bonding interaction between the iron and boron nuclei. In light of this interaction, we suggest that these complexes can be described as (L3)Fe(eta4-H3BH) complexes.
authors.affiliation: Department of Chemistry, Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Mehn
authors.forename: Steven D
authors.initials: SD
authors.lastname: Brown
authors.forename: Tapan K
authors.initials: TK
authors.lastname: Paine
authors.forename: William W
authors.initials: WW
authors.lastname: Brennessel
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Cramer
authors.forename: Jonas C
authors.initials: JC
authors.lastname: Peters
authors.forename: Lawrence
authors.initials: L
authors.lastname: Que
mesh_terms: D001894:Borohydrides / Q000737:chemistry*; D002384:Catalysis; D005296:Ferrous Compounds / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry; D008024:Ligands; D015394:Molecular Structure; D009591:Nitrogenase / Q000737:chemistry
chemical_list: D001894:Borohydrides; D005296:Ferrous Compounds; D008024:Ligands; D006864:Hydrogenase; D009591:Nitrogenase