title: Spin-state ordering in hydroxo-bridged diiron(III)bisporphyrin complexes.
abstract: We report the synthesis, structure, and spectroscopic characterization of 1,2-bis[μ-hydroxo iron(III) 5-(2,3,7,8,12,13,17,18-octaethylporphyrinyl)]ethane with PF6(–) and SbF6(–) counteranions. The two iron centers are nonequivalent with admixed intermediate spin state (S = 3/2 with a minor contribution of S = 5/2) on each metal both in the solid and in solution. The molecules are compared with previously known μ-hydroxo complexes with other counterions, such as I3(–), BF4(–), and ClO4(–), which demonstrates that the nature of the counterion can affect the spin-state ordering dramatically. To understand how the spin-state ordering is affected by external perturbations, we also have done a comprehensive computational study. The calculations show that subtle environmental perturbations affect the spin-state ordering and relative energies and are likely to be the root cause of the variation in spin-state ordering observed experimentally.
authors.affiliation: Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom.
authors.forename: Mala A
authors.initials: MA
authors.lastname: Sainna
authors.forename: Debangsu
authors.initials: D
authors.lastname: Sil
authors.forename: Dipankar
authors.initials: D
authors.lastname: Sahoo
authors.forename: Bodo
authors.initials: B
authors.lastname: Martin
authors.forename: Sankar Prasad
authors.initials: SP
authors.lastname: Rath
authors.forename: Peter
authors.initials: P
authors.lastname: Comba
authors.forename: Sam P
authors.initials: SP
authors.lastname: de Visser
mesh_terms: D001952:Bridged-Ring Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D005290:Ferric Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D008665:Metalloporphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory
chemical_list: D001952:Bridged-Ring Compounds; D005290:Ferric Compounds; D008665:Metalloporphyrins