Detailed EPR Study of Spin Crossover Dendrimeric Iron(III) Complex

Domracheva, N. E.; Pyataev, A. V.; Vorobeva, V.E.; Zueva, Ekaterina М.

doi:10.1021/jp403682p

Cited by 37 publications

(22 citation statements)

References 46 publications

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“…The difference in spectra of complexes C3 , C4 and C6 – C11 and complexes C1 , C2 , C5 and C12 agrees very well with the distinction in structure (monomers vs. supramolecular dimers). The above obtained values of the g ‐factor and zero field splitting are in a good accordance with those presented for the similar HS Fe(III) complexes in the literature ,,…”

Section: Resultssupporting

confidence: 91%

High‐Spin Mononuclear Iron(III) Complexes with Pentadentate Schiff Base Ligands: Structural Analysis and Magnetic Properties

et al. 2019

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Various substituted 2-hydroxybenzophenones were combined with aliphatic linear triamines to form pentadentate Schiff base ligands. Twelve new iron(III) complexes with the general formula [Fe(L n )X].mCH 3 CN (n = 1-10; X = N 3 À , NCS À or NCSe À ; m = 0-2) have been synthesized, and spectrally as well as structurally characterized. The structural analysis revealed a notable dependence of coordination polyhedra deformation as well as the spatial configuration of donor atoms on the length and symmetry of the Schiff base ligands. The magnetic proper-ties of the compounds were investigated and the permanent high-spin state (S = 5/2) for all reported compounds was established, and allowed calculation of zero-field-splitting parameters as well as coupling constants, which were further confirmed with DFT calculations. The solid-state EPR spectra were recorded at 293 K and 98 K, and in accordance with the magnetic measurements, showed a high-spin state in the measured temperature range.[a] Dr.

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Section: Resultssupporting

confidence: 91%

High‐Spin Mononuclear Iron(III) Complexes with Pentadentate Schiff Base Ligands: Structural Analysis and Magnetic Properties

et al. 2019

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“…Each doublet has its own observed values of the g‐tensor components. For a low‐spin Fe(III) complex of cubic symmetry with tetragonal and orthorhombic distortions, the EPR spectrum is described by hamiltonian

true normalH^{sh} = β (g_{xx} H_{normalx} S_{normalx} + g_{yy} H_{normaly} S_{normaly} + g_{zz} H_{normalz} S_{normalz})

…”

Section: Resultsmentioning

confidence: 99%

Effect of Ligand Field Strength on the Spin Crossover Behaviour in 5‐X‐SalEen (X=Me, Br and OMe) Based Fe(III) Complexes

Dey

Mondal

Konar

2020

Chemistry An Asian Journal

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The reaction of Fe(NCS) 3 prepared in situ in MeOH with 5-X-SalEen ligands (5-X-SalEen = condensation product of 5-substituted salicylaldehyde and N-ethylethylenediamine) provided three Fe(III) complexes, [Fe(5-X-SalEen) 2 ]NCS; X=Me (1), X=Br (2), X=OMe (3). All the complexes reveal similar structural features but a very different magnetic profile. Complex 1 shows a gradual spin crossover while complexes 2 and 3 show a sharp spin transition. The T 1/2 for complex 2 is 237 K while for complex 3 it is much higher with a value of 361 K. The spin transition temperature is shifted towards higher temperature with increasing electron-donation ability of the ligand substituents. This experimental observation has been rationalized with DFT calculations. UV-Vis and cyclic voltammetry studies support the fact that the electron density on the ligand increases from Me to Br to OMe substituents. To understand the change in spin states, temperature-dependent EPR spectra have been recorded. The spin state equilibrium in the liquid state has been probed with Evans NMR spectroscopic method, and thermodynamic parameters have been evaluated for all complexes.

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“…[98] The cyclohexyl termini of the dendrons sterically hindered the complex exhibiting irreversible endothermic solid-solid phase transitions. The magnetic properties of this complex were extensively studied by variable temperature EPR and Mössbauer spectroscopies, [99] suggesting that there is a sequence of magnetic ordering, magneto-electric and spin transition phenomena, making it an intriguing multifunctional material. EPR revealed three magnetically active iron centers, one low spin (LS) and two high spin (HS).…”

Section: Sco Dendrimersmentioning

confidence: 99%

Spin crossover polymer composites, polymers and related soft materials

Enríquez-Cabrera

Rapakousiou

Piedrahita‐Bello

et al. 2020

Coordination Chemistry Reviews

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We review the synthesis, properties and applications of spin crossover polymer composites, polymers and some related 'soft' materials. These materials have received recently much attention because they provide an efficient way for the processing of spin crossover complexes in various shapes at various size scales and can give rise also to unique physical properties. First, we discuss in detail the state of the art of the elaboration of spin crossover polymer composites, using either inorganic complex precursors in solution or pre-formed spin crossover powder. A particular attention is paid on the influence of the polymer matrix on the spin crossover properties and on the use of 'active' polymers for development of synergies between the properties of the matrix and the load. Polymer composite devices for applications in the fields of artificial muscles, energy harvesting and thermochromic sensors are also highlighted. Then, more recent works, in which organic polymeric chains are used as ligands for the transition metal ions are presented. Finally, we overview various related 'soft' spin crossover compounds including spin crossover dendrimers, gels, liquid crystals and Langmuir Blodgett films with particular emphasis on compounds with supramolecular interactions of alkyl chains.

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Detailed EPR Study of Spin Crossover Dendrimeric Iron(III) Complex

Cited by 37 publications

References 46 publications

High‐Spin Mononuclear Iron(III) Complexes with Pentadentate Schiff Base Ligands: Structural Analysis and Magnetic Properties

High‐Spin Mononuclear Iron(III) Complexes with Pentadentate Schiff Base Ligands: Structural Analysis and Magnetic Properties

Effect of Ligand Field Strength on the Spin Crossover Behaviour in 5‐X‐SalEen (X=Me, Br and OMe) Based Fe(III) Complexes

Spin crossover polymer composites, polymers and related soft materials

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