Exchange Coupling in Di- and Polynuclear Complexes

Ruiz, Eliseo

doi:10.1016/b978-0-08-097774-4.00922-0

Cited by 8 publications

(3 citation statements)

References 689 publications

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“…The accurate calculation of this energy difference remains a challenge for DFT methods. While DFT has widely succeeded in the calculation of other physical properties, such as exchange coupling constants, the calculation of energy gaps between electronic states remains a difficult task. The TPSSh functional has been widely used in the field of SCO systems, but basically focused on Fe II systems, ,− while its application to other SCO systems of the first transition metal remained undisclosed.…”

Section: Discussionmentioning

confidence: 99%

Benchmarking Density Functional Methods for Calculation of State Energies of First Row Spin-Crossover Molecules

2018

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A systematic study of the performance of several density functional methodologies to study spin-crossover (SCO) on first row transition metal complexes is reported. All functionals have been tested against several mononuclear systems containing first row transition metal complexes and exhibiting spin-crossover. Among the tested functionals, the hybrid meta-GGA functional TPSSh with a triple-z basis set including polarization functions on all atoms provides with the best results across different metals and oxidation states, and its performance in both predicting the correct ground state and the right energy window for SCO to occur is quite satisfactory. The effect of some additional contributions, such as zeropoint energies, relativistic effects and intramolecular dispersion interactions, has been analyzed. The reported strategy thus expands the use of the TPSSh functional to other metals and oxidation states other than Fe II , making it the method of choice to study SCO in first row transition metal complexes. Additionally, the presented results validate the potential use of the TPSSh functional for virtual screening of new molecules with SCO, or its use in the study of the electronic structure of such systems.

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Section: Discussionmentioning

confidence: 99%

Benchmarking Density Functional Methods for Calculation of State Energies of First Row Spin-Crossover Molecules

2018

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“…Experimentally, the magnetic exchange interaction J is evaluated by fitting the temperature dependent magnetic susceptibility data. 20 For dinuclear complexes, extracting the J values is rather straightforward; however, for polynuclear complexes with multiple J values, two issues mainly arise: (i) employing several J values for polynuclear complexes is likely to lead to over-parameterization in the fitting procedure, where featureless susceptibility data are often employed to fit a number of variables. At the same time, if fewer than the minimum required number of parameters are employed, this can lead to an over-simplified Hamiltonian (note that next-nearest-neighbour interactions are often ignored, and similar J parameters for interactions not equivalent by symmetry are assumed).…”

Section: Modelling Spin Hamiltonian Parametersmentioning

confidence: 99%

Modelling spin Hamiltonian parameters of molecular nanomagnets

Gupta

Rajaraman

2016

Chem. Commun.

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Molecular nanomagnets encompass a wide range of coordination complexes possessing several potential applications. A formidable challenge in realizing these potential applications lies in controlling the magnetic properties of these clusters. Microscopic spin Hamiltonian (SH) parameters describe the magnetic properties of these clusters, and viable ways to control these SH parameters are highly desirable. Computational tools play a proactive role in this area, where SH parameters such as isotropic exchange interaction (J), anisotropic exchange interaction (Jx, Jy, Jz), double exchange interaction (B), zero-field splitting parameters (D, E) and g-tensors can be computed reliably using X-ray structures. In this feature article, we have attempted to provide a holistic view of the modelling of these SH parameters of molecular magnets. The determination of J includes various class of molecules, from di- and polynuclear Mn complexes to the {3d-Gd}, {Gd-Gd} and {Gd-2p} class of complexes. The estimation of anisotropic exchange coupling includes the exchange between an isotropic metal ion and an orbitally degenerate 3d/4d/5d metal ion. The double-exchange section contains some illustrative examples of mixed valance systems, and the section on the estimation of zfs parameters covers some mononuclear transition metal complexes possessing very large axial zfs parameters. The section on the computation of g-anisotropy exclusively covers studies on mononuclear Dy(III) and Er(III) single-ion magnets. The examples depicted in this article clearly illustrate that computational tools not only aid in interpreting and rationalizing the observed magnetic properties but possess the potential to predict new generation MNMs.

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“…The solution-phase magnetic moment is weakly temperature dependent over the range from 200 K to 298 K, suggesting the complex has an S = 2 ground state with low-lying excited states that are thermally-accessible. Electronic structure calculations of a truncated model of the cluster (Fe9O6(H)6(NH3)6) using the broken-symmetry formalism 31,32 are consistent with strong antiferromagnetic coupling leading to an S = 2 ground state (5 α Fe(II) + 4 β Fe(II)), with an energetically-accessible S = 6 excited state (6 α Fe(II) + 3 β Fe(II), +6.8 kcal/mol, expected μeff value = 13.0). The two electronic configurations differ in the relative spin orientation of one of the axial Fe atoms, wherein the first excited state has all the axial Fe environments antiferromagnetically coupled to the equatorial environments (Figure S4).…”

mentioning

confidence: 99%

Self-assembly of an organometallic Fe₉O₆ cluster from aerobic oxidation of (tmeda)Fe(CH₂^tBu)₂

et al. 2020

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Exchange Coupling in Di- and Polynuclear Complexes

Cited by 8 publications

References 689 publications

Benchmarking Density Functional Methods for Calculation of State Energies of First Row Spin-Crossover Molecules

Benchmarking Density Functional Methods for Calculation of State Energies of First Row Spin-Crossover Molecules

Modelling spin Hamiltonian parameters of molecular nanomagnets

Self-assembly of an organometallic Fe₉O₆ cluster from aerobic oxidation of (tmeda)Fe(CH₂^tBu)₂

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Exchange Coupling in Di- and Polynuclear Complexes

Cited by 8 publications

References 689 publications

Benchmarking Density Functional Methods for Calculation of State Energies of First Row Spin-Crossover Molecules

Benchmarking Density Functional Methods for Calculation of State Energies of First Row Spin-Crossover Molecules

Modelling spin Hamiltonian parameters of molecular nanomagnets

Self-assembly of an organometallic Fe9O6 cluster from aerobic oxidation of (tmeda)Fe(CH2tBu)2

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Self-assembly of an organometallic Fe₉O₆ cluster from aerobic oxidation of (tmeda)Fe(CH₂^tBu)₂