Thermal Spin Crossover in Mn(II), Mn(III), Cr(II) and Co(III) Coordination Compounds

2012 ◽  
pp. 49-62 ◽  
Author(s):  
Yann Garcia ◽  
Philipp Gütlich
Keyword(s):  
Coordination Compounds ◽  
Spin Crossover

Spin-crossover in iron(ii) coordination compounds with 2,6-bis(benzimidazol-2-yl)pyridine

2020 ◽  
Vol 44 (15) ◽  
pp. 5834-5840 ◽  
Author(s):  
A. D. Ivanova ◽  
E. V. Korotaev ◽  
V. Yu. Komarov ◽  
L. A. Sheludyakova ◽  
V. A. Varnek ◽  
...  
Keyword(s):  
High Temperature ◽  
Coordination Compounds ◽  
Spin Crossover

Novel iron(ii) bromide, nitrate and dicyanamide complexes with 2,6-bis(benzimidazol-2-yl)pyridine possessing high-temperature 1A1 ↔ 5T2 spin crossover were obtained.

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.

scholarly journals Spin Crossover in New Iron(II) Coordination Compounds with Tris(pyrazol-1-yl)Methane

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 843
Author(s):  
Olga G. Shakirova ◽  
Ludmila G. Lavrenova
Keyword(s):  
Coordination Compounds ◽  
Spin Crossover ◽  
Thermally Induced

We review here new advances in the synthesis and investigation of iron(II) coordination compounds with tris(pyrazol-1-yl)methane and its derivatives as ligands. The complexes demonstrate thermally induced spin crossover accompanied by thermochromism. Factors that influence the nature and temperature of the spin crossover are discussed.

New Iron(II) Complexes [Fe(HC(Pz)3)2]A2 with Spin-Crossover

2015 ◽  
Vol 233-234 ◽  
pp. 534-537 ◽  
Author(s):  
Оlga G. Shakirova ◽  
Natalia V. Kuratieva ◽  
Evgeny V. Korotaev ◽  
Ludmila G. Lavrenova
Keyword(s):  
Magnetic Susceptibility ◽  
High Temperature ◽  
Ir Spectroscopy ◽  
Structure Analysis ◽  
Coordination Compounds ◽  
Spin Crossover ◽  
Color Change ◽  
Static Magnetic Susceptibility ◽  
X Ray ◽  
Magnetochemical Study

Three new coordination compounds of iron (II), [Fe (HC(Pz)3)2](C8H5O4)2.C8H6O4(I), [Fe (HC(Pz)3)2](C10H7SO3)2.2H2O (II) and Fe (HC(Pz)3)2](C12H25SO4)2(III), where HC(Pz)3is the tridentate chelatortris(pyrazol-1-yl) methane, have been synthesized and investigated by X-ray structure analysis, electronic and IR spectroscopy, static magnetic susceptibility method. The magnetochemical study of complexes I–III in the interval from 300 to 500 K showed that they possessed the high-temperature spin crossover1A1↔5T2accompanied by thermochromism (the pink ↔ white color change).

scholarly journals Effect of ligand substitution in [Fe(H-trz)2(trz)]BF4 spin crossover nanoparticles

2015 ◽  
Vol 3 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Iurii Suleimanov ◽  
José Sanchez Costa ◽  
Gábor Molnár ◽  
Lionel Salmon ◽  
Igor Fritsky ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transition Temperature ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Spin Crossover ◽  
Magnetic Measurements ◽  
Ligand Substitution ◽  
Crossover Temperature ◽  
Transition Electron Microscopy ◽  
Transition Electron

Spin crossover iron(II) 1,2,4-triazole-based coordination compounds in the form of nanoparticles were prepared using a reverse microemulsion technique. Ligand substitution approach was applied to decrease the spin crossover temperature towards room temperature in the well-known [Fe(Htrz)2(trz)]BF4 complex. The compositions of the particles were determined by elemental analysis and thermogravimetry. The morphology was monitored by transition electron microscopy (TEM). The effect associated with the ligand substitution was investigated by optical and magnetic measurements. Transition temperature has been reduced by 33 K comparing the unsubstituted sample to that with 5 % substitution.

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