TY - JOUR
T1 - Consistent simulation of X- and Q-band EPR spectra of an unsymmetric dinuclear Mn2II, III complex
AU - Huang, Ping
AU - Shaikh, Nizamuddin
AU - Anderlund, Magnus F.
AU - Styring, Stenbjörn
AU - Hammarström, Leif
N1 - Funding Information:
We are grateful to the financial support from the Swedish Energy Agency, The Knut and Alice Wallenberg Foundation, The Swedish Research Council. We acknowledge valuable discussions with Dr. Ann Magnuson and Dr. Høgni Weihe.
PY - 2006/5
Y1 - 2006/5
N2 - Simulation of X- and Q-band electron paramagnetic resonance (EPR) spectra of an unsymmetric dinuclear [ Mn2II, III L ( μ - OAc )2 ] ClO4 complex (1), (L is the dianion of 2-{[N,N-bis(2-pyridylmethyl)amino]methyl}-6-{[N-(3,5-di-tert-butyl-2-hyd roxybenzyl)-N-(2-pyridylmethyl)amino]methyl}-4-methylphenol) was performed using one consistent set of simulation parameters. Rhombic g-tensors and hyperfine tensors were necessary to obtain satisfactory simulation of the EPR spectra. The anisotropy of the effective hyperfine tensors of each individual 55Mn ion was further analyzed in terms of intrinsic hyperfine tensors. Detailed analysis shows that the hyperfine anisotropy of the MnIII ion is a result of the Jahn-Teller effect and thus an inherent character. In contrast, the anomalous hyperfine anisotropy of the MnII ion is attributed as being transferred from the MnIII ion through the spin exchange interaction. The anisotropy parameter for the MnII is deduced as DII = -1.26 ± 0.2 cm-1. This is the first reported DII value for a MnII ion in a weakly exchange coupled mixed-valence Mn2II, III complex with a bis-μ-acetato-bridge. The dxy1 dyz1 dzx1 d x2 - y21 electronic configuration of the MnIII ion in 1 is revealed by the negative sign of its intrinsic hyperfine tensor anisotropy, ΔaIII = az - ax,y = -46 cm-1. Lower spectral resolution of the Q-band EPR spectrum as compared to the X-band EPR spectrum is associated to large line width broadening of the x- and y-components in contrast to the z-component. The origins of the unequal distribution of line width between the z- and x-, y-components are discussed.
AB - Simulation of X- and Q-band electron paramagnetic resonance (EPR) spectra of an unsymmetric dinuclear [ Mn2II, III L ( μ - OAc )2 ] ClO4 complex (1), (L is the dianion of 2-{[N,N-bis(2-pyridylmethyl)amino]methyl}-6-{[N-(3,5-di-tert-butyl-2-hyd roxybenzyl)-N-(2-pyridylmethyl)amino]methyl}-4-methylphenol) was performed using one consistent set of simulation parameters. Rhombic g-tensors and hyperfine tensors were necessary to obtain satisfactory simulation of the EPR spectra. The anisotropy of the effective hyperfine tensors of each individual 55Mn ion was further analyzed in terms of intrinsic hyperfine tensors. Detailed analysis shows that the hyperfine anisotropy of the MnIII ion is a result of the Jahn-Teller effect and thus an inherent character. In contrast, the anomalous hyperfine anisotropy of the MnII ion is attributed as being transferred from the MnIII ion through the spin exchange interaction. The anisotropy parameter for the MnII is deduced as DII = -1.26 ± 0.2 cm-1. This is the first reported DII value for a MnII ion in a weakly exchange coupled mixed-valence Mn2II, III complex with a bis-μ-acetato-bridge. The dxy1 dyz1 dzx1 d x2 - y21 electronic configuration of the MnIII ion in 1 is revealed by the negative sign of its intrinsic hyperfine tensor anisotropy, ΔaIII = az - ax,y = -46 cm-1. Lower spectral resolution of the Q-band EPR spectrum as compared to the X-band EPR spectrum is associated to large line width broadening of the x- and y-components in contrast to the z-component. The origins of the unequal distribution of line width between the z- and x-, y-components are discussed.
KW - Dinuclear Mn
KW - EPR simulation
KW - Electron configuration
KW - Hyperfine tensor
KW - X- and Q-band EPR
KW - Zero field splitting
KW - g-Tensor
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U2 - 10.1016/j.jinorgbio.2006.02.006
DO - 10.1016/j.jinorgbio.2006.02.006
M3 - Article
C2 - 16574232
AN - SCOPUS:33745348687
VL - 100
SP - 1139
EP - 1146
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
SN - 0162-0134
IS - 5-6
ER -