High-Frequency and -Field EPR of a Pseudo-octahedral Complex of High-Spin Fe(II):  Bis(2,2‘-bi-2-thiazoline)bis(isothiocyanato)iron(II)

• Published in: Journal of the American Chemical Society 2004-06, Vol.126 (21), p.6574-6575
• Main Authors: Ozarowski, Andrew, Zvyagin, S. A, Reiff, William M, Telser, Joshua, Brunel, Louis-Claude, Krzystek, J
• Format: Article
• Language: English
• Subjects: Computer Simulation; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron paramagnetic resonance and relaxation; Electron Spin Resonance Spectroscopy; Exact sciences and technology; Ferrous Compounds - chemistry; Iron group (3d) ions and impurities (ti-cu); Magnetic resonances and relaxations in condensed matter, mössbauer effect; Models, Molecular; Molecular Structure; Organometallic Compounds - chemistry; Physics; Thiazoles - chemistry; Thiocyanates - chemistry
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja048336m

A pseudo-octahedral complex of high-spin Fe(II), bis(2,2‘-bi-2-thiazoline)bis(isothiocyanato)iron(II), which has a cis-FeN‘2N4 chromophore, has been investigated by high-frequency, high-field electron paramagnetic resonance (HFEPR). Complementary Mössbauer and DC magnetic susceptibility studies were also performed. HFEPR spectra of powder samples were recorded at frequencies up to 700 GHz and over a magnetic field range of 0−25 T. Analysis of the field−frequency data set yields the following set of spin Hamiltonian parameters for S = 2:  D = +12.427(12) cm-1, E = +0.243(3) cm-1; g x = 2.147(3), g y = 2.166(3), g z = 2.01(1). The parameters are analyzed by use of a simple crystal-field model. This study represents the first precise determination by HFEPR of spin Hamiltonian parameters in six-coordinate high-spin Fe(II) and indicates the applicability of HFEPR to the study of high-spin Fe(II) in coordination complexes and biological model compounds.