Spin transition in [Fe(PM-BiA)2(NCS)2] studied by the electron paramagnetic resonance of the Mn2+ion

Daubric, Hervé; Kliava, Janis; Guionneau, Philippe; Chasseau, D.; Létard, Jean‐François; Kahn, Olivier

doi:10.1088/0953-8984/12/25/312

Cited by 14 publications

(17 citation statements)

References 33 publications

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“…This variation exists between each two bands, and its magnitude seems to be uncorrelated with the temperature difference. Variations of ZFS with temperature were previously observed, for instance, for Mn(II) impurities in magnetically dense iron-based metalloorganic crystals [60] and for a Manganese Superoxide Dismutase [61], and were related to the sensitivity of zero-field interactions to metal-ligand distances and/or angular ligand positions. For the studied model Gd(III) complexes, we presume that the ligand sphere stays approximately constant in the studied temperature range.…”

Section: Discussionmentioning

confidence: 88%

Quantitative analysis of zero-field splitting parameter distributions in Gd(iii) complexes

Clayton

Keller

et al. 2018

Phys. Chem. Chem. Phys.

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The magnetic properties of paramagnetic species with spin S > 1/2 are parameterized by the familiar g tensor as well as "zero-field splitting" (ZFS) terms that break the degeneracy between spin states even in the absence of a magnetic field. In this work, we determine the mean values and distributions of the ZFS parameters D and E for six Gd(iii) complexes (S = 7/2) and critically discuss the accuracy of such determination. EPR spectra of the Gd(iii) complexes were recorded in glassy frozen solutions at 10 K or below at Q-band (∼34 GHz), W-band (∼94 GHz) and G-band (240 GHz) frequencies, and simulated with two widely used models for the form of the distributions of the ZFS parameters D and E. We find that the form of the distribution of the ZFS parameter D is bimodal, consisting roughly of two Gaussians centered at D and -D with unequal amplitudes. The extracted values of D (σD) for the six complexes are, in MHz: Gd-NO3Pic, 485 ± 20 (155 ± 37); Gd-DOTA/Gd-maleimide-DOTA, -714 ± 43 (328 ± 99); iodo-(Gd-PyMTA)/MOMethynyl-(Gd-PyMTA), 1213 ± 60 (418 ± 141); Gd-TAHA, 1361 ± 69 (457 ± 178); iodo-Gd-PCTA-[12], 1861 ± 135 (467 ± 292); and Gd-PyDTTA, 1830 ± 105 (390 ± 242). The sign of D was adjusted based on the Gaussian component with larger amplitude. We relate the extracted P(D) distributions to the structure of the individual Gd(iii) complexes by fitting them to a model that superposes the contribution to the D tensor from each coordinating atom of the ligand. Using this model, we predict D, σD, and E values for several additional Gd(iii) complexes that were not measured in this work. The results of this paper may be useful as benchmarks for the verification of quantum chemical calculations of ZFS parameters, and point the way to designing Gd(iii) complexes for particular applications and estimating their magnetic properties a priori.

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Section: Discussionmentioning

confidence: 88%

Quantitative analysis of zero-field splitting parameter distributions in Gd(iii) complexes

Clayton

Keller

et al. 2018

Phys. Chem. Chem. Phys.

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“…In the particular case of the orthorhombic phase of [Fe(PM-BiA) 2 (NCS) 2 ], it has been previously shown that unit cell changes due to the HS to LS SCO correspond to an increase of c, a decrease of a and a slight decrease of b [23]. Owing to such a characteristic modification, the spin state can be deduced, for this complex, directly from the unit cell changes.…”

Section: Unit Cell Parametersmentioning

confidence: 98%

Thermal trapped iron(II) high spin state investigated by X-ray diffraction

Marchivie

Guionneau

Létard

et al. 2004

Journal of Physics and Chemistry of Solids

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The possibilities to trap by flash cooling the high spin (HS) state of iron(II) in the [Fe(PM -BiA) 2 (NCS) 2 ] complex have been investigated by X-ray diffraction. This study reveals that trapping the HS state is possible under some conditions depending on the final temperature. If the latter is lower than the T(LIESST) temperature, the HS ! LS (low spin) relaxation is slow enough to determine the trapped HS crystal structure by X-ray diffraction. The crystal structure of this complex in the 30 K trapped HS state shows differences from either the room temperature (HS) or the 30 K (LS) crystal structures, as for example differences in the strength of the S· · ·H -C hydrogen bond like intermolecular interaction or the p-p interactions, known to play a crucial role in this compound for the propagation of the change in spin at the spin crossover (SCO), i.e. the cooperativity. The differences in intermolecular interactions are directly linked to the differences between the crystallographic unit cell modifications induced by pure thermal effects and those induced by the SCO. q

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“…They determined the D and E values for both spin states and verified the existence of two structurally different LS phases, which are formed by fast or slow cooling. This method of doping SCO systems with Cu(II) and Mn(II) as EPR probes has proven to be very informative and easy to apply to spin crossover studies [122–126]. …”

Section: Reviewmentioning

confidence: 99%

Spin state switching in iron coordination compounds

Gütlich¹,

Gaspar²,

Garcia³

2013

Beilstein J. Org. Chem.

669

608

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SummaryThe article deals with coordination compounds of iron(II) that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and pressure sensors as well as optical devices.The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the chemical nature that is important for the occurrence of spin crossover will be made. A subsequent section describes the molecular consequences of spin crossover and the variety of physical techniques usually applied for their characterization. The effects of light irradiation (LIESST) and application of pressure are subjects of two separate sections. The major part of this account concentrates on selected spin crossover compounds of iron(II), with particular emphasis on the chemical and physical influences on the spin crossover behavior. The vast variety of compounds exhibiting this fascinating switching phenomenon encompasses mono-, oligo- and polynuclear iron(II) complexes and cages, polymeric 1D, 2D and 3D systems, nanomaterials, and polyfunctional materials that combine spin crossover with another physical or chemical property.

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Spin transition in [Fe(PM-BiA)₂(NCS)₂] studied by the electron paramagnetic resonance of the Mn²⁺ion

Cited by 14 publications

References 33 publications

Quantitative analysis of zero-field splitting parameter distributions in Gd(iii) complexes

Quantitative analysis of zero-field splitting parameter distributions in Gd(iii) complexes

Thermal trapped iron(II) high spin state investigated by X-ray diffraction

Spin state switching in iron coordination compounds

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