Bioinorganic applications of magnetic circular dichroism spectroscopy: Copper, rare-earth ions, cobalt and non-heme iron systems

Dooley, David M.; Dawson, John H.

doi:10.1016/0010-8545(84)85061-4

Cited by 27 publications

(6 citation statements)

References 138 publications

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“…As the most extensive applications, electronic and magnetic properties of metalloproteins and inorganic complexes have been studied by MCD (127). There are various studies in the literature have been made on iron‐sulphur proteins (128), porphyrins and haeme proteins (129,130), copper, rare earth, cobalt and non‐haeme iron bioinorganic systems (131), and non‐haeme ferrous enzymes (132) using this technique. Both excited‐ and ground‐state information and a more powerful probe of the coordination geometry and structure of metal chromophores have been provided by employing MCD (127).…”

Section: Cd‐based Techniquesmentioning

confidence: 99%

Circular Dichroism Techniques: Biomolecular and Nanostructural Analyses‐ A Review

2009

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This paper reviews the best known techniques using circular dichroism spectroscopy such as conventional circular dichroism (i.e. electronic circular dichroism), magnetic circular dichroisms (magnetic vibrational circular dichroism, x-ray magnetic circular dichroism), fluorescence detected circular dichroism, near-infrared circular dichroism, vibrational circular dichroism, Fourier transform infrared circular dichroism, high pressure liquid chromatography circular dichroism, stopped-flow circular dichroism, and synchrotron radiation circular dichroism. Also, we have described here the most important applications of circular dichroism spectroscopy in structural biochemistry and nanoscience.

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Section: Cd‐based Techniquesmentioning

confidence: 99%

Circular Dichroism Techniques: Biomolecular and Nanostructural Analyses‐ A Review

2009

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“…MCD spectra, recording the difference in the absorption of left and right circular polarized light, measure magnetically induced chirality, caused by longitudinal fields applied along the light path. MCD intensity arises from three different mechanisms, of which essentially only the so-called C -term contributions − are interesting for Co(II) compounds, since they are dominant, and arise from the unequal Boltzmann populations of the ground state magnetic sublevels. Therefore, SH parameters can be deduced from field- and temperature-dependent MCD intensity data (even without knowing the nature of the underlying optical transitions). − In addition to this information, which is complementary to SQUID magnetization data, the MCD intensities reveal so-called effective transition dipole moment products identifying the optical transitions.…”

Section: Introductionmentioning

confidence: 99%

Magneto-Structural Correlations in Pseudotetrahedral Forms of the [Co(SPh)₄]^2– Complex Probed by Magnetometry, MCD Spectroscopy, Advanced EPR Techniques, and ab Initio Electronic Structure Calculations

et al. 2017

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The magnetic properties of pseudotetrahedral Co(II) complexes spawned intense interest after (PPh)[Co(SPh)] was shown to be the first mononuclear transition-metal complex displaying slow relaxation of the magnetization in the absence of a direct current magnetic field. However, there are differing reports on its fundamental magnetic spin Hamiltonian (SH) parameters, which arise from inherent experimental challenges in detecting large zero-field splittings. There are also remarkable changes in the SH parameters of [Co(SPh)] upon structural variations, depending on the counterion and crystallization conditions. In this work, four complementary experimental techniques are utilized to unambiguously determine the SH parameters for two different salts of [Co(SPh)]: (PPh)[Co(SPh)] (1) and (NEt)[Co(SPh)] (2). The characterization methods employed include multifield SQUID magnetometry, high-field/high-frequency electron paramagnetic resonance (HF-EPR), variable-field variable-temperature magnetic circular dichroism (VTVH-MCD), and frequency domain Fourier transform THz-EPR (FD-FT THz-EPR). Notably, the paramagnetic Co(II) complex [Co(SPh)] shows strong axial magnetic anisotropy in 1, with D = -55(1) cm and E/D = 0.00(3), but rhombic anisotropy is seen for 2, with D = +11(1) cm and E/D = 0.18(3). Multireference ab initio CASSCF/NEVPT2 calculations enable interpretation of the remarkable variation of D and its dependence on the electronic structure and geometry.

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“…Challenges with sample preparation and background scatter often further limit the low energy side of the detection range. 16,17 Further, we note that, while ΔS = 2 transitions have been reported in magnetically ordered transition metal oxides, to the best of our knowledge, the observation of ΔS = 2 d-to-d transitions in molecular systems has not been discussed. 18 This is, however, possible in a RIXS measurement since it is a resonant second order process.…”

Section: ■ Introductionmentioning

confidence: 99%

Probing the Valence Electronic Structure of Low-Spin Ferrous and Ferric Complexes Using 2p3d Resonant Inelastic X-ray Scattering (RIXS)

et al. 2018

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Understanding the detailed electronic structure of transition metal ions is essential in numerous areas of inorganic chemistry. In particular, the ability to map out the many particle d-d spectrum of a transition metal catalyst is key to understanding and predicting reactivity. However, from a practical perspective, there are often experimental limitations on the ability to determine the energetic ordering, and multiplicity of all the excited states. These limitations derive in part from parity and spin-selection rules, as well as from the limited energy range of many standard laboratory instruments. Herein, we demonstrate the ability of 2p3d resonant inelastic X-ray scattering (RIXS) to obtain detailed insights into the many particle spectrum of simple inorganic molecular iron complexes. The present study focuses on low-spin ferrous and ferric iron complexes, including [Fe(tacn)] and [Fe(CN)]. This series thus allows us to assess the contribution of d-count and ligand donor type, by comparing the purely σ-donating tacn ligand to the π-accepting cyanide. In order to highlight the conceptual difference between RIXS and traditional optical spectroscopy, we compare first RIXS results with UV-vis and magnetic circular dichroism spectroscopy. We then highlight the ability of 2p3d RIXS to (1) separate d-d transitions from charge transfer transitions and (2) to determine the many particle d-d spectrum over a much wider energy range than is possible by optical spectroscopy. Our experimental results are correlated with semiempirical multiplet simulations and ab initio complete active space self-consistent field calculations in order to obtain detailed assignments of the excited states. These results show that Δ S = 1, and possibly Δ S = 2, transitions may be observed in 2p3d RIXS spectra. Hence, this methodology has great promise for future applications in all areas of transition metal inorganic chemistry.

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Bioinorganic applications of magnetic circular dichroism spectroscopy: Copper, rare-earth ions, cobalt and non-heme iron systems

Cited by 27 publications

References 138 publications

Circular Dichroism Techniques: Biomolecular and Nanostructural Analyses‐ A Review

Circular Dichroism Techniques: Biomolecular and Nanostructural Analyses‐ A Review

Magneto-Structural Correlations in Pseudotetrahedral Forms of the [Co(SPh)₄]^2– Complex Probed by Magnetometry, MCD Spectroscopy, Advanced EPR Techniques, and ab Initio Electronic Structure Calculations

Probing the Valence Electronic Structure of Low-Spin Ferrous and Ferric Complexes Using 2p3d Resonant Inelastic X-ray Scattering (RIXS)

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Bioinorganic applications of magnetic circular dichroism spectroscopy: Copper, rare-earth ions, cobalt and non-heme iron systems

Cited by 27 publications

References 138 publications

Circular Dichroism Techniques: Biomolecular and Nanostructural Analyses‐ A Review

Circular Dichroism Techniques: Biomolecular and Nanostructural Analyses‐ A Review

Magneto-Structural Correlations in Pseudotetrahedral Forms of the [Co(SPh)4]2– Complex Probed by Magnetometry, MCD Spectroscopy, Advanced EPR Techniques, and ab Initio Electronic Structure Calculations

Probing the Valence Electronic Structure of Low-Spin Ferrous and Ferric Complexes Using 2p3d Resonant Inelastic X-ray Scattering (RIXS)

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Magneto-Structural Correlations in Pseudotetrahedral Forms of the [Co(SPh)₄]^2– Complex Probed by Magnetometry, MCD Spectroscopy, Advanced EPR Techniques, and ab Initio Electronic Structure Calculations