Structural changes associated with the spin transition in bis(isothiocyanato)bis(1,10-phenanthroline)iron: a single-crystal x-ray investigation

Gallois, B.; Real, José Antonio; Hauw, C.; Zarembowitch, J.

doi:10.1021/ic00331a009

Cited by 279 publications

(219 citation statements)

References 6 publications

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“…with the experimental values (2219 Å 3 at 130 K and 2338 Å 3 at 293 K -measured by Gallois et al [25], 2186 Å 3 at 15 K and 2248 Å 3 at the same temperature after irradiation with light -measured by Legrand et al [26]), in contrast to previous LDA calculations, where good agreement could be reached only for the volume expansion upon spin transition [12], due to the notorious underestimation of bond lengths by LDA methods [27]. The proper choice of the Hubbard parameter U is obviously connected to the choice of the density functional.…”

Section: Nosupporting

confidence: 81%

“…It certainly is one of the most intensively studied SCO complex and also one of the very few that have been studied by periodic DFT calculations [12,[19][20][21][22][23][24]. High precision crystal structures are available for the HS and LS phases at different temperatures down to 15 K [25,26]. An abrupt transition from a S = 0 low spin to a S = 2 high spin state has been observed at about 176 K, together with a narrow thermal hysteresis.…”

Section: Ising-like Modelsmentioning

confidence: 99%

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Cooperativity of Spin Crossover Complexes: Combining Periodic Density Functional Calculations and Monte Carlo Simulations

Kreutzburg

Hübner

Paulsen

2017

Preprint

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Abstract:The total enthalpies of the 16 different spin configurations that can be realized in the unit cell of the archetype spin crossover complex [Fe(phen) 2 (NCS) 2 ] (phen=1,2-phenanthroline) were calculated applying periodic density functional theory combined with the Hubbard model and the Grimme-D2 dispersion correction (DFT+U/D2). The obtained enthalpy differences between the individual spin configurations were used to determine spin couplings of an Ising-like model and subsequent Monte Carlo simulations for this model allowed to estimate the phenomenological interaction parameter Γ of the Slichter-Drickamer model, which is commonly used to describe the cooperativity of the spin transition. The calculational procedure described here, which led to an estimate of about 3 kJ mol −1 for Γ, in good agreement with experiment, may be used to predict from first principles how modifications of spin crossover complexes can change the character of the spin transition from gradual to abrupt and vice versa.

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Section: Nosupporting

confidence: 81%

Section: Ising-like Modelsmentioning

confidence: 99%

Cooperativity of Spin Crossover Complexes: Combining Periodic Density Functional Calculations and Monte Carlo Simulations

Kreutzburg

Hübner

Paulsen

2017

Preprint

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“…The first compound undergoes two reversible SCO transitions at 91 and 192 K, assigned to each one of the two sites, whereas in the second compound both sites undergo a simultaneous spin transition at 213 K. 64 The crystal structure of Fe(phen) 2 (NCS) 2 has been studied showing the existence of a LS-HS transition at around 176 K which is accompanied by an increase of 0.20 and 0.10 Å of the Fe-N(phen) and Fe-N(CS) distances, respectively. 65 The crystal structure of [Fe(pic) In the present work, it will be shown that the combination of DFT calculations for geometry and vibrational frequencies and multiconfigurational methods for energy differences between different electronic states, allows to achieve an overall proper description of the thermodynamic and vibrational properties of the thermal SCO process in the systems studied.…”

Section: Introductionmentioning

confidence: 94%

Computational approach to the study of thermal spin crossover phenomena

Rudavskyi

Sousa

Graaf

et al. 2014

The Journal of Chemical Physics

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The key parameters associated to the thermally induced spin crossover process have been calculated for a series of Fe(II) complexes with mono-, bi-, and tridentate ligands. Combination of density functional theory calculations for the geometries and for normal vibrational modes, and highly correlated wave function methods for the energies, allows us to accurately compute the entropy variation associated to the spin transition and the zero-point corrected energy difference between the low-and high-spin states. From these values, the transition temperature, T 1/2 , is estimated for different compounds.

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“…The average Fe-to-N distance, d(F e − N ), is also longer by about 0.2Å in the HS than in the LS state. 20 Experimental measurements estimate that the energy splitting between LS and HS states is E HS − E LS ≈ 0.13eV . 21 This difference is much greater than the contribution k B T · ln5 ≈ 0.025eV to the free energy from the change in electronic entropy.…”

mentioning

confidence: 99%

Density functional plus dynamical mean-field theory of the spin-crossover moleculeFe(phen)2(NCS)2

2015

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We study the spin-crossover molecule Fe(phen)2(NCS)2 using density functional theory (DFT) plus dynamical mean-field theory, which allows access to observables not attainable with traditional quantum chemical or electronic structure methods. The temperature dependent magnetic susceptibility, electron addition and removal spectra, and total energies are calculated and compared to experiment. We demonstrate that the proper quantitative energy difference between the high-spin and low-spin state, as well as reasonably accurate values of the magnetic susceptibility can be obtained when using realistic interaction parameters. Comparisons to DFT and DFT+U calculations demonstrate that dynamical correlations are critical to the energetics of the low-spin state. Additionally, we elucidate the differences between DFT+U and spin density functional theory (SDFT) plus U methodologies, demonstrating that DFT+U can recover SDFT+U results for an appropriately chosen on-site exchange interaction.

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Structural changes associated with the spin transition in bis(isothiocyanato)bis(1,10-phenanthroline)iron: a single-crystal x-ray investigation

Cited by 279 publications

References 6 publications

Cooperativity of Spin Crossover Complexes: Combining Periodic Density Functional Calculations and Monte Carlo Simulations

Cooperativity of Spin Crossover Complexes: Combining Periodic Density Functional Calculations and Monte Carlo Simulations

Computational approach to the study of thermal spin crossover phenomena

Density functional plus dynamical mean-field theory of the spin-crossover moleculeFe(phen)2(NCS)2

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