An iron(II) complex tripodally chelated with 1,1,1-tris(pyridin-2-yl)ethane showing room-temperature spin-crossover behaviour

2016 ◽  
Vol 72 (11) ◽  
pp. 797-801 ◽  
Author(s):  
Takayuki Ishida ◽  
Takuya Kanetomo ◽  
Masaru Yamasaki
Keyword(s):  
High Spin ◽  
Room Temperature ◽  
Spin Crossover ◽  
Spin Transition ◽  
Complex Salt ◽  
Magnetic Study ◽  
The Novel ◽  
Bond Lengths ◽  
External Stimuli ◽  
Spin Species

The spin-crossover phenomenon is a reversible low- and high-spin transition caused by external stimuli such as heat. In the novel iron(II) complex salt tetraphenylphosphonium tris(thiocyanato-κN)[1,1,1-tris(pyridin-2-yl)ethane-κ3N,N′,N′′]ferrate(II), (C24H20P)[Fe(NCS)3(C17H15N3)], the Fe—N bond lengths are in the range 2.027 (2)–2.089 (2) Å, indicating that the specimen consists of comparable molar fractions of the low- and high-spin species at 296 K. A magnetic study confirmed that spin-crossover takes place at around 290 K.

scholarly journals Structural Insights into the Two-Step Spin-Crossover Compound Fe(3,4-dimethyl-pyridine)2[Ag(CN)2]2

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 316 ◽  
Author(s):  
José Alberto Rodríguez-Velamazán ◽  
Kosuke Kitase ◽  
Elías Palacios ◽  
Miguel Castro ◽  
Ángel Fernández-Blanco ◽  
...  
Keyword(s):  
High Spin ◽  
Spin Crossover ◽  
Spin Transition ◽  
Long Range Order ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Step Transition ◽  
Structural Insights ◽  
Spin Species

The crystal structure of the polymeric spin crossover compound Fe(3,4-dimethyl-pyridine)2[Ag(CN)2]2 has been solved and its temperature dependence followed by means of single-crystal and powder X-ray diffraction. This compound presents a two-step spin transition with relatively abrupt steps centred at ca. 170 K and 145 K and a plateau at around 155 K. The origin of the two-step transition is discussed in light of these structural studies. The observations are compatible with a mostly disordered state between the two steps, consisting of mixing of high-spin and low-spin species, while weak substructure reflections in the mixed phase could indicate some degree of long-range order of the high-spin and low-spin sites.

The Flexibility of Long Chain Substituents Influences Spin-Crossover in Isomorphous Lipid Bilayer Crystals

2021 ◽  
Author(s):  
Iurii Galadzhun ◽  
Rafal Kulmaczewski ◽  
Namrah Shahid ◽  
Oscar Cespedes ◽  
Mark J Howard ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
High Spin ◽  
Room Temperature ◽  
Spin Crossover ◽  
Pyridine Derivatives ◽  
Long Chain

[Fe(bpp)2][BF4]2 (bpp = 2,6-di{pyrazol-1-yl}pyridine) derivatives bearing a bent geometry of hexadec-1-ynyl or hexadecyl substituents pyrazole are isomorphous, and high-spin at room temperature. However, only the latter compound undergoes an abrupt,...

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 Quantum Chemical Modeling of Pressure-Induced Spin Crossover in Octahedral Metal-Ligand Complexes

2019 ◽  
Author(s):  
Tim Stauch ◽  
Romit Chakraborty ◽  
Martin Head-Gordon
Keyword(s):  
Carbon Monoxide ◽  
Molecular Electronics ◽  
Spin Crossover ◽  
Strong Field ◽  
Spin Transition ◽  
Nuclear Forces ◽  
Chemical Modeling ◽  
Metal Centers ◽  
State Switching ◽  
External Stimuli

Spin state switching on external stimuli is a phenomenon with wide applicability ranging from molecular electronics to gas activation in nanoporous frameworks. Here we model spin crossover as a function of hydrostatic pressure in octahedrally coordinated transition metal centers by applying a field of effective nuclear forces that compress the molecule towards its centroid. For spin crossover in first-row transition metals coordinated by hydrogen, nitrogen, and carbon monoxide, we find the pressure required for spin transition to be a function of ligand position in the spectrochemical sequence. While pressures on the order of 1 GPa are required to flip spins in homogeneously ligated octahedral sites, we demonstrate a five-fold decrease in spin transition pressure for the archetypal strong field ligand carbon monoxide in octahedrally coordinated Fe<sup>2+</sup> in [Fe(II)(NH<sub>3</sub>)<sub>5</sub>CO]<sup>2+</sup>.

One Shot Laser Pulse Induced Reversible Spin Transition in the Spin-Crossover Complex [Fe(C4H4N2){Pt(CN)4}] at Room Temperature

2005 ◽  
Vol 117 (26) ◽  
pp. 4137-4141 ◽  
Author(s):  
Sébastien Bonhommeau ◽  
Gábor Molnár ◽  
Ana Galet ◽  
Antoine Zwick ◽  
José-Antonio Real ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Room Temperature ◽  
Spin Crossover ◽  
Spin Transition

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...

Matrix-free synthesis of spin crossover micro-rods showing a large hysteresis loop centered at room temperature

2015 ◽  
Vol 51 (45) ◽  
pp. 9346-9349 ◽  
Author(s):  
Haonan Peng ◽  
Gábor Molnár ◽  
Lionel Salmon ◽  
Azzedine Bousseksou
Keyword(s):  
Hysteresis Loop ◽  
Room Temperature ◽  
Spin Crossover ◽  
The Novel ◽  
Large Hysteresis ◽  
Crossover Behavior ◽  
Matrix Free

Acicular micro-rods of the novel [Fe(Htrz)3](CF3SO3)2 complex exhibiting large hysteretic spin crossover behavior perfectly centered at room temperature.

Structural, Magnetic and Mössbauer Studies of Bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II) Triflate and its Hydrates

1997 ◽  
Vol 50 (9) ◽  
pp. 869 ◽  
Author(s):  
Kristian H. Sugiyarto ◽  
Karyn Weitzner ◽  
Donald C. Craig ◽  
Harold A. Goodwin
Keyword(s):  
Electronic Properties ◽  
Low Temperatures ◽  
Room Temperature ◽  
Spin Transition ◽  
Water Molecules ◽  
Triclinic Space Group ◽  
Discontinuous Transition ◽  
A Minor ◽  
Spin Species ◽  
Anhydrous Complex

The electronic properties of bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II) triflate depend markedly on the extent of hydration. The trihydrate is low spin while the monohydrate is high spin at room temperature but undergoes a discontinuous transition to low spin at low temperatures. In the anhydrous complex magnetic and Mössbauer spectral data indicate that there is a minor fraction of low-spin species at room temperature and this fraction increases at low temperatures. The spin transition in the anhydrous salt is continuous and incomplete at 80 K. The structure of the trihydrate reveals an extensive hydrogen-bonding network which involves the uncoordinated >NH groups of the pyrazolyl groups in the ligands, the water molecules and the anions. The disruption of this network on loss of water is believed to be responsible for the change in electronic properties. Bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II) triflate trihydrate: triclinic, space group P-1, a 11·490(5), b 12·218(6), c 13·666(6) Å, α 104 ·67(2), β 104·58(2), γ 104·35(2)°, Z 2.

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