title: Magnetic resonance and structural investigations of (monooxooctaethylchlorinato)iron(III) chloride and its bis(imidazole) complex.
abstract: (Monooxooctaethylchlorinato)iron(III) chloride, (oxo-OEC)FeCl, 1, has been investigated by X-ray crystallography and by 1H NMR spectroscopy. Its bis(imidazole-d4) complex has been studied by multidimensional 1H NMR and EPR spectroscopies, and the results are compared to those for the bis(Im-d4) complex of (octaethylchlorinato)iron(III) chloride, (OEC)FeCl, 2. EPR and NMR results show that both [(oxo-OEC)Fe(Im-d4)2]Cl and [(OEC)Fe(Im-d4)2]Cl are low-spin Fe(III) complexes with (d(xy))2 (d(xz),d(yz))3 electronic ground states, both at 4.2 K (EPR spectra) and at ambient temperatures utilized for solution NMR studies. The pattern of chemical shifts of the pyrrole-CH2 and meso protons are similar, with the 8,17-carbons having the largest and the 12,13-carbons having the smallest spin densities in each case, except that [(OEC)Fe(Im-d4)2]Cl has a slightly wider range of pyrrole-CH2 chemical shifts and more resonances are observed for [(oxo-OEC)Fe(Im-d4)2]Cl due to its lower symmetry. Full proton resonance assignments for both complexes have been made from COSY, NOESY, and NOE difference experiments.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson, Arizona 85721-0041, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Cai
authors.forename: Elena
authors.initials: E
authors.lastname: Belikova
authors.forename: Liliya A
authors.initials: LA
authors.lastname: Yatsunyk
authors.forename: Alan M
authors.initials: AM
authors.lastname: Stolzenberg
authors.forename: F Ann
authors.initials: FA
authors.lastname: Walker
mesh_terms: D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000138:chemical synthesis* / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure
chemical_list: C499740:(monooxooctaethylchlorinato)iron(III) chloride; D007093:Imidazoles; D008665:Metalloporphyrins; D007501:Iron