24 research outputs found
A Dihydroxo-Bridged Ferric Dimer
Recent investigations have produced a large number
of dimeric complexes containing the oxo-bridged
structural unit Fe_2O^(4+).
Here we report the isolation and characterization of [Fe (pic)_2OH]_2 which apparently
is the first example of a crystalline iron(III) dimer which
utilizes dihydroxo bridging in its coordination structure
Doping of copper(II) into the macrocyclic amine tet a: structural and spectroscopic studies
This article does not have an abstract
Characterization of [dimethyl N,N'-ethylenebis(L-cysteinato)(2-)-S,S']copper(II), a stable copper(II) aliphatic dithiolate
This article does not have an abstract
Simultaneous pair electronic excitations in a binuclear iron(III) complex
The ultraviolet absorption spectrum of an isolated metal complex containing the bridging unit Fe(III)⋯O-Fe(III) shows several bands due to the simultaneous electronic excitation of the two Fe(III) centers. The band positions are in excellent agreement with calculated sums of one-center d-d transitions
Characterization of [rac-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane]copper(II) 3-sulfidopropionate dimethanolate, [Cu(tet b)SCH<SUB>2</SUB>CH<SUB>2</SUB>CO<SUB>2</SUB>]·2CH<SUB>3</SUB>OH, a stable copper(II)-aliphatic thiolate complex
This article does not have an abstract
Magnetic Behavior and Infrared Spectra of Jarosite, Basic Iron Sulfate, and Their Chromate Analogs
The magnetic behavior and infrared spectroscopic features of KFe_3(SO_4)_2(OH)_6 (jarosite), (H_3O)Fe_3(SO_4)_2(OH)_6 (hydronium jarosite), KFe_3(CrO_4)_2(OH)_6, Fe(OH)SO_4 (basic iron sulfate) and Fe(OH)CrO_4 (basic iron chromate) are reported. Spectroscopic data are in accord with X-ray data which show that KFe_3(SO_4)_2(OH)_6, (H_3O)Fe_3(SO_4)_2(OH)_6, and KFe_3(CrO_4)_2(OH)_6 are isostructural with KAl_3(SO_4)_2(OH)_6 (akunite). All the species exhibit negative deviations from Curie-Weiss behavior over the temperature range 300-76°K. The compounds KFe_3(CrO_4)_2(OH)_6 and Fe(OH)CrO_4 undergo ferrimagnetic transitions at 73 and 71°K, respectively. Maxima occur in the susceptibilities of KFe_3(SO_4)_2(OH)_6 and (H_3O)Fe_3(SO_4)_2(OH)_6 at 45 and 50°K
Electronic Structure of Oxo-Bridged Iron(III) Dimers
Magnetic susceptibility results and extensive electronic, infrared, and Mi:issbauer spectral data are presented for enH_2[(FeHEDT A)_2O]· 6H_2O_3, Na_4[(FeEDTA)_2O]· 12H_2O, FeHEDTA· H_2O, and NaFeEDT A· 3H_2O (HEDTA = N-hydroxoethylethylenediaminetriacetate, EDTA = ethylenediaminetetraacetate, and enH_2^(2+) =
ethylenediammonium cation). The magnetic and spectral data establish an electronic structural model for the
oxo-bridged dimers in which pairs of S = 5/2 Fe(III) ions interact antiferromagnetically, with J ≃ -95 cm^(-1). The
oxo-bridged dimers show marked intensity enhancement of the one-center Fe(III) ligand-field bands. There are
also several uv bands which are interpreted as arising from simultaneous electronic excitations of Fe(III) pairs. A
simple high-spin ligand-field model modified by spin-spin interaction is judged to be considerably more appropriate
than the Dunitz-Orgel molecular orbital approach as a vehicle for describing oxo-bridged Fe(IIl) dimers