National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA.
J Magn Reson. 2011 Dec;213(1):158-65. doi: 10.1016/j.jmr.2011.09.046. Epub 2011 Sep 29.
The complex [Fe(H2O)6]SiF6 is one of the most stable and best characterized high-spin Fe(II) salts and as such, is a paradigm for the study of this important transition metal ion. We describe high-frequency and -field electron paramagnetic resonance studies of both pure [Fe(H2O)6]SiF6 and [Zn(H2O)6]SiF6 doped with 8% of Fe(II). In addition, frequency domain magnetic resonance spectroscopy was applied to these samples. High signal-to-noise, high resolution spectra were recorded which allowed an accurate determination of spin Hamiltonian parameters for Fe(II) in each of these two, related, environments. For pure [Fe(H2O)6]SiF6, the following parameters were obtained: D=+11.95(1) cm(-1), E=0.658(4) cm(-1), g=[2.099(4),2.151(5),1.997(3)], along with fourth-order zero-field splitting parameters: B4(0)=17(1)×10(-4) cm(-1) and B4(4)=18(4)×10(-4) cm(-1), which are rarely obtainable by any technique. For the doped complex, D=+13.42(1) cm(-1), E=0.05(1) cm(-1), g=[2.25(1),2.22(1),2.23(1)]. These parameters are in good agreement with those obtained using other techniques. Ligand-field theory was used to analyze the electronic absorption data for [Fe(H2O)6]SiF6 and suggests that the ground state is 5A1, which allows successful use of a spin Hamiltonian model. Density functional theory and unrestricted Hartree-Fock calculations were performed which, in the case of latter, reproduced the spin Hamiltonian parameters very well for the doped complex.
六水合硅氟酸合铁([Fe(H2O)6]SiF6)是最稳定和特征研究最多的高自旋 Fe(II)盐之一，因此是研究这种重要过渡金属离子的典范。我们描述了高频和高场电子顺磁共振研究纯[Fe(H2O)6]SiF6和掺杂 8%Fe(II)的[Zn(H2O)6]SiF6。此外，还应用频域磁共振光谱对这些样品进行了研究。记录了高信噪比、高分辨率的光谱，这些光谱允许准确确定这两种相关环境中 Fe(II)的自旋哈密顿参数。对于纯[Fe(H2O)6]SiF6，得到了以下参数：D=+11.95(1)cm(-1)，E=0.658(4)cm(-1)，g=[2.099(4)，2.151(5)，1.997(3)]，以及四阶零场分裂参数：B4(0)=17(1)×10(-4)cm(-1)和 B4(4)=18(4)×10(-4)cm(-1)，这些参数很少通过任何技术获得。对于掺杂的配合物，D=+13.42(1)cm(-1)，E=0.05(1)cm(-1)，g=[2.25(1)，2.22(1)，2.23(1)]。这些参数与使用其他技术获得的参数非常吻合。配位场理论用于分析[Fe(H2O)6]SiF6的电子吸收数据，表明基态为 5A1，这允许成功使用自旋哈密顿模型。进行了密度泛函理论和非限制哈特利-福克计算，在后一种情况下，对于掺杂的配合物，很好地再现了自旋哈密顿参数。
