Solvent Dependent Spin-State Behaviour via Hydrogen Bonding in Neutral FeII Diimine Complexes

2014 ◽  
Vol 67 (11) ◽  
pp. 1595 ◽  
Author(s):  
Kelsey A. Schulte ◽  
Stephanie R. Fiedler ◽  
Matthew P. Shores
Keyword(s):  
Hydrogen Bonding ◽  
Spin State ◽  
Spin Crossover ◽  
Magnetic Measurements ◽  
Ligand Field ◽  
Hydrogen Bonding Interactions ◽  
State Switching ◽  
State Behaviour ◽  
Acetonitrile Solutions ◽  
Diimine Complexes

We report the syntheses, structures, and magnetic properties of cis-[Fe(pizR)2(NCS)2] complexes based on the pyridyl imidazoline ligands 2-(2′-pyridinyl)-4,5-dihydroimidazole (pizH, 1) and 2-(2′-pyridinyl)-4,5-dihydro-1-methylimidazole (pizMe, 2). The ligands, complexes, and magnetic measurements are chosen to separate hydrogen-bonding and intrinsic ligand field properties, so as to improve our understanding of the effect of hydrogen-bonding interactions on spin-state switching. In the solid state, both complexes are high spin between 5 and 300 K. In deuterated methanol and acetonitrile solutions, both complexes show gradual thermal spin crossover. Complex 1, capable of hydrogen bonding, shows solvent-sensitive spin crossover, whereas spin crossover in the methylated analogue 2 is insensitive to solvent identity.

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 Programmable spin-state switching in a mixed-valence spin-crossover iron grid

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Takuto Matsumoto ◽  
Graham N. Newton ◽  
Takuya Shiga ◽  
Shinya Hayami ◽  
Yuta Matsui ◽  
...  
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
Mixed Valence ◽  
State Switching

scholarly journals Stabilization of the Low-Spin State in a Mononuclear Iron(II) Complex and High-Temperature Cooperative Spin Crossover Mediated by Hydrogen Bonding

2015 ◽  
Vol 22 (1) ◽  
pp. 331-339 ◽  
Author(s):  
Sipeng Zheng ◽  
Niels R. M. Reintjens ◽  
Maxime A. Siegler ◽  
Olivier Roubeau ◽  
Elisabeth Bouwman ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
High Temperature ◽  
Spin State ◽  
Spin Crossover ◽  
Mononuclear Iron

Unidirectional electric field-induced spin-state switching in spin crossover based microelectronic devices

2016 ◽  
Vol 644 ◽  
pp. 138-141 ◽  
Author(s):  
Constantin Lefter ◽  
Reasmey Tan ◽  
Julien Dugay ◽  
Simon Tricard ◽  
Gábor Molnár ◽  
...  
Keyword(s):  
Electric Field ◽  
Spin State ◽  
Spin Crossover ◽  
Microelectronic Devices ◽  
State Switching

Modeling of Surface and Size Effects on Various Shape of Spin-Crossover Nanoparticles

2014 ◽  
Vol 793 ◽  
pp. 77-83
Author(s):  
Azusa Muraoka ◽  
Kamel Boukheddaden
Keyword(s):  
High Spin ◽  
Spin State ◽  
Spin Crossover ◽  
Surface Effect ◽  
High Spin State ◽  
Coordination Shell ◽  
Square Lattice ◽  
Rectangular Lattice ◽  
Ligand Field ◽  
Effect Of Surface

We performed of Monte Carlo simulations using Ising-like model on two-dimensional core/shell rectangular lattice L×2L for different sizes in order to study the effect of surface and size on the thermal behavior of spin-crossover nanoparticles. The surface effect is accounted for by constraining all the atoms situated in the boundary in the high-spin state as a result of the weak ligand-field prevailing in the coordination shell. This result is similar to square lattice of spin-crossover nanoparticles, and in agreement with experimental data. Such a non-trivial change is explained as due to the competition between the negative pressures induced the high spin state surface and the bulk properties. We also described the way in which the usual occurrence condition of the first-order transition has to be adapted to the nanoscale.

scholarly journals Soft-x-ray-induced spin-state switching of an adsorbed Fe(II) spin-crossover complex

2017 ◽  
Vol 29 (39) ◽  
pp. 394003 ◽  
Author(s):  
Lalminthang Kipgen ◽  
Matthias Bernien ◽  
Fabian Nickel ◽  
Holger Naggert ◽  
Andrew J Britton ◽  
...  
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
X Ray ◽  
State Switching

Fe(Me2-bpy)2(NCSe)2spin-crossover micro- and nanoparticles showing spin-state switching above 250 K

2015 ◽  
Vol 39 (3) ◽  
pp. 1603-1610 ◽  
Author(s):  
Luong Lam Nguyen ◽  
Régis Guillot ◽  
Jérôme Laisney ◽  
Lionel Rechignat ◽  
Salma Bedoui ◽  
...  
Keyword(s):  
Solid State ◽  
Spin State ◽  
Spin Crossover ◽  
State Switching

Nano- and microparticles or polycrystalline powders of the Fe(Me2-bpy)2(NCSe)2spin-crossover complex were easily elaborated from the diamagnetic precursor [Fe(Me2-bpy)3](NCSe)2·S by precipitation in an anti-solvent or by solid-state thermolysis.

scholarly journals Anomalous Light‐Induced Spin‐State Switching for Iron(II) Spin‐Crossover Molecules in Direct Contact with Metal Surfaces

2020 ◽  
Vol 59 (32) ◽  
pp. 13341-13346 ◽  
Author(s):  
Luqiong Zhang ◽  
Yongfeng Tong ◽  
Massine Kelai ◽  
Amandine Bellec ◽  
Jérôme Lagoute ◽  
...  
Keyword(s):  
Spin State ◽  
Direct Contact ◽  
Metal Surfaces ◽  
Spin Crossover ◽  
State Switching

A homochiral 3D framework of mechanically interlocked 1D loops with solvent-dependent spin-state switching behaviors

2020 ◽  
Vol 56 (1) ◽  
pp. 133-136
Author(s):  
Xiao-Peng Sun ◽  
Zheng Tang ◽  
Zi-Shuo Yao ◽  
Jun Tao
Keyword(s):  
Single Crystal ◽  
Spin State ◽  
Spin Crossover ◽  
Crystal Transformation ◽  
State Switching ◽  
One Step ◽  
3D Framework

A homochiral 3D mechanically interlocked framework based on 1D loops is presented, which shows reversible single-crystal-to-single-crystal transformation and enables the interconversion between one-step and two-step spin crossover behaviors.

scholarly journals Spin-Crossover 2-D Hofmann Frameworks Incorporating an Amide-Functionalized Ligand: N-(pyridin-4-yl)benzamide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 360-372
Author(s):  
Xandria Ong ◽  
Manan Ahmed ◽  
Luonan Xu ◽  
Ashley T. Brennan ◽  
Carol Hua ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Spin State ◽  
Spin Crossover ◽  
Variable Temperature ◽  
Spin Transition ◽  
Single Step ◽  
Amide Group ◽  
State Transitions ◽  
Structure Property ◽  
Scanning Calorimetry

Two analogous 2-D Hofmann-type frameworks, which incorporate the novel ligand N-(pyridin-4-yl)benzamide (benpy) [FeII(benpy)2M(CN)4]·2H2O (M = Pd (Pd(benpy)) and Pt (Pt(benpy))) are reported. The benpy ligand was explored to facilitate spin-crossover (SCO) cooperativity via amide group hydrogen bonding. Structural analyses of the 2-D Hofmann frameworks revealed benpy-guest hydrogen bonding and benpy-benpy aromatic contacts. Both analogues exhibited single-step hysteretic spin-crossover (SCO) transitions, with the metal-cyanide linker (M = Pd or Pt) impacting the SCO spin-state transition temperature and hysteresis loop width (Pd(benpy): T½↓↑: 201, 218 K, ∆T: 17 K and Pt(benpy): T½↓↑: 206, 226 K, ∆T: 20 K). The parallel structural and SCO changes over the high-spin to low-spin transition were investigated using variable-temperature, single-crystal, and powder X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry. These studies indicated that the ligand–guest interactions facilitated by the amide group acted to support the cooperative spin-state transitions displayed by these two Hofmann-type frameworks, providing further insight into cooperativity and structure–property relationships.

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