Demonstration of the thermally induced high spin–low spin transition for a transparent spin crossover complex film [Fe(II)(H-trz)3]-Nafion (trz=triazole)

Polyhedron ◽  
2005 ◽  
Vol 24 (16-17) ◽  
pp. 2909-2912 ◽  
Author(s):  
Akio Nakamoto ◽  
Norimichi Kojima ◽  
Liu XiaoJun ◽  
Yutaka Moritomo ◽  
Arao Nakamura
Keyword(s):  
High Spin ◽  
Spin Crossover ◽  
Spin Transition ◽  
Thermally Induced ◽  
Complex Film

Optical Microscopy Imaging of the Thermally-Induced Spin Transition and Isothermal Multi-stepped Relaxation in a Low-Spin Stabilized Spin-Crossover Material

2021 ◽  
Author(s):  
Pradip Chakraborty ◽  
Mouhamadou Sy ◽  
Houcem Fourati ◽  
Maria Teresa Delgado Pérez ◽  
Mousumi Dutta ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
High Spin ◽  
Spin Relaxation ◽  
Spin Crossover ◽  
Spin Transition ◽  
Host Lattice ◽  
Microscopy Imaging ◽  
Thermally Induced ◽  
Optical Microscopy Imaging

The thermal spin transition and the photo-induced high-spin → low-spin relaxation of the prototypical [Fe(ptz)6](BF4)2 spin-crossover compound (ptz = 1-propyltetrazole) diluted in the isostructural ruthenium host lattice [Ru(ptz)6](BF4)2, which stabilizes...

Iron(II) and Nickel(II) Complexes of 2,6-Di(thiazol-2-yl)pyridine and Related Ligands

1991 ◽  
Vol 44 (8) ◽  
pp. 1041 ◽  
Author(s):  
AT Baker ◽  
P Singh ◽  
V Vignevich
Keyword(s):  
High Spin ◽  
Room Temperature ◽  
Spin Transition ◽  
Magnetic Behaviour ◽  
Diethyl Acetal ◽  
Thermally Induced ◽  
Field Strengths

2,6-Di(thiazol-2-yl]pyridine (1a), 2,6-di(4-methylthiazol-2-yl)pyridine (1b) and 2,6-di(2-imid-azolin-2-yl)pyridine (3) have been prepared by the reaction of pyridine-2,6-dicarbothioamide with bromoacetaldehyde diethyl acetal, bromoacetone and ethylenediamine, severally. Bis ( ligand ) iron(II) and nickel(II) complexes of all ligands have been prepared. The bis ( ligand ) iron(II) complexes of (1a) and (3) are low-spin whereas that of (1b) is high-spin at room temperature and undergoes a thermally induced spin transition. The field strengths of the ligands , determined from the spectra of their nickel(II) complexes, correlate well with the observed magnetic behaviour of their iron(II) complexes. The field strengths of (1a) and (1b) are found to be marginally less than those of the isomeric ligands 2,6-di(thiazol-4-yl)pyridine (2a) and 2,6-di(2-methylthiazol-4-yl)pyridine (2b).

scholarly journals Spin state switching in iron coordination compounds

2013 ◽  
Vol 9 ◽  
pp. 342-391 ◽  
Author(s):  
Philipp Gütlich ◽  
Ana B Gaspar ◽  
Yann Garcia
Keyword(s):  
Spin State ◽  
Coordination Compounds ◽  
Spin Crossover ◽  
Spin Transition ◽  
Pressure Sensors ◽  
Ligand Field ◽  
Thermally Induced ◽  
Practical Applications ◽  
State Switching ◽  
Switching Phenomenon

The 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.

Synthesis of Nanocrystals and Particle Size Effects Studies on the Thermally Induced Spin Transition of the Model Spin Crossover Compound [Fe(phen)2(NCS)2]

2015 ◽  
Vol 54 (16) ◽  
pp. 7906-7914 ◽  
Author(s):  
Francisco Javier Valverde-Muñoz ◽  
Ana B. Gaspar ◽  
Sergii I. Shylin ◽  
Vadim Ksenofontov ◽  
José A. Real
Keyword(s):  
Particle Size ◽  
Size Effects ◽  
Spin Crossover ◽  
Spin Transition ◽  
Thermally Induced ◽  
Particle Size Effects

Structural Changes in Iron(II) Polymeric Complexes upon Thermally and Optically Induced Spin Transition Determined by EXAFS Spectroscopy

1998 ◽  
Vol 524 ◽  
Author(s):  
S. B. Erenburg ◽  
N. V. Bausk ◽  
L. G. Lavrenova ◽  
Yu. G. Shvedenkov ◽  
L. N. Mazalov
Keyword(s):  
High Spin ◽  
Structural Changes ◽  
Mutual Influence ◽  
Chemical Shifts ◽  
Spin Transition ◽  
High Spin State ◽  
Local Environment ◽  
Thermally Induced ◽  
Polymeric Complexes ◽  
Electronic And Spatial Structure

ABSTRACTChanges in the electronic and spatial structure of polymeric Fe(II) complexes with 1,2,4- triazoles and various anions upon spin transition was studied using EXAFS and XANES spectroscopy. Spin transition and structural changes were induced by variations of the anion, dilution with Zn, under heating or the action of light. In all complexes, the spin transition is accompanied by drastic changes in the local environment of Fe atoms. The increase in spin transition temperature for the complexes with variable anions CIO4-, I-, Br-, BF4-, NO3- was found to correlate with changes in the Fe-N distances and changes in bond covalence determined from the chemical shifts in Mössbauer spectra. High spin metastable long life states were detected and studied in the polymeric complex Fe(atrz)3(ClO4)2. It was established that the changes in structure of polymeric complexes upon the transition to a metastable high spin state under the action of light differ from those in the thermally induced spin transition. Such differences are determined by mutual influence of Fe atoms in high spin and low spin states in polymeric chains.

High temperature spin crossover in [Fe(pyrazine){Ag(CN)2}2] and its solvate

2016 ◽  
Vol 40 (11) ◽  
pp. 9012-9016 ◽  
Author(s):  
Il'ya A. Gural'skiy ◽  
Sergii I. Shylin ◽  
Bohdan O. Golub ◽  
Vadim Ksenofontov ◽  
Igor O. Fritsky ◽  
...  
Keyword(s):  
High Temperature ◽  
Spin Crossover ◽  
Metal Organic Framework ◽  
Spin Transition ◽  
Thermally Induced ◽  
Metal Organic ◽  
Organic Framework

Thermally induced spin transition at 370 K has been observed in a Hofmann-clathrate-like metal–organic framework.

scholarly journals Structure:function relationships for thermal and light-induced spin-crossover in isomorphous molecular materials

2020 ◽  
Vol 8 (25) ◽  
pp. 8420-8429
Author(s):  
Rafal Kulmaczewski ◽  
Elzbieta Trzop ◽  
Eric Collet ◽  
Sergi Vela ◽  
Malcolm A. Halcrow
Keyword(s):  
High Spin ◽  
Spin State ◽  
Spin Crossover ◽  
Spin Transition ◽  
Molecular Materials

The complicated light-induced spin state trapping behaviour of a family of isomorphous solvate crystals reflects reorientation of the lattice solvent during the spin-transition (white = high-spin, brown = low-spin).

Metal-Complexes of 1,10-Phenanthroline Derivatives. XV. Complexes of 2-(3,5-Dimethylpyrazol-1-yl)-1,10-phenanthroline

1988 ◽  
Vol 41 (6) ◽  
pp. 873 ◽  
Author(s):  
AS Abushamleh ◽  
HA Goodwin
Keyword(s):  
Magnetic Properties ◽  
Solid State ◽  
Spectral Data ◽  
High Spin ◽  
Nickel Complex ◽  
Spin Transition ◽  
Critical Value ◽  
Magnetic Data ◽  
Strong Temperature Dependence ◽  
Thermally Induced

Iron(II) and nickel(II) bis ( ligand ) complexes of 2-(3,5-dimethylpyrazol-1-yl)-1,10-phenanthroline (L) have been prepared. The field strength of L as determined from spectral data for the nickel complex is in the range encompassing the critical value at the singlet (1A1) ↔ quintet (5T2) crossover for iron(II). The magnetic properties of the iron(II) complex both in solution and in the solid state are anomalous, and indicative of the occurrence of a thermally induced spin transition. Mossbauer spectral data confirm this, and reveal separate contributions from the singlet and quintet species with a strong temperature-dependence of their relative intensities. Magnetic data for the complex in solution are consistent with a simple high spin ↔ low spin equilibrium, and lead to values of ΔH = 23�0.5 kJ mol-1 and ΔS = 66�5 J K-1 mol-1 for the low spin → high spin transformation.

scholarly journals Elastic Origin of the Unsymmetrical Thermal Hysteresis in Spin Crossover Materials: Evidence of Symmetry Breaking

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 828
Author(s):  
Mamadou Ndiaye ◽  
Nour El Islam Belmouri ◽  
Jorge Linares ◽  
Kamel Boukheddaden
Keyword(s):  
Symmetry Breaking ◽  
High Spin ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
Point Of View ◽  
Self Organization ◽  
Spin States ◽  
Heating And Cooling

The jungle of experimental behaviors of spin-crossover materials contains a tremendous number of unexpected behaviors, among which, the unsymmetrical hysteresis loops having different shapes on heating and cooling, that we often encounter in literature. Excluding an extra effect of crystallographic phase transitions, we study here these phenomena from the point of view of elastic modeling and we demonstrate that a simple model accounting for the bond lengths misfits between the high-spin and low-spin states is sufficient to describe the situation of unsymmetrical hysteresis showing plateaus at the transition only on cooling or on heating branches. The idea behind this effect relates to the existence of a discriminant elastic frustration in the lattice, which expresses only along the high-spin to low-spin transition or in the opposite side. The obtained two-step transitions showed characteristics of self-organization of the spin states under the form of stripes, which we explain as an emergence process of antagonist directional elastic interactions inside the lattice. The analysis of the spin state transformation inside the plateau on cooling in terms of two sublattices demonstrated that the elastic-driven self-organization of the spin states is accompanied with a symmetry breaking.

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