scholarly journals The Number and Shape of Lattice Solvent Molecules Controls Spin-Crossover in an Isomorphous Series of Crystalline Solvate Salts

2021 ◽  
Author(s):  
Izar Capel Berdiell ◽  
Rafal Kulmaczewski ◽  
Namrah Shahid ◽  
Oscar Cespedes ◽  
Malcolm Halcrow
Keyword(s):  
Spin Crossover ◽  
Spin Transition ◽  
Solvent Molecules ◽  
Crystalline Solvate

Crystals of [FeL2][BF4]2·nMeCN (L = N-(2,6-di{pyrazol-1-yl}pyrid-4-yl)acetamide; n = 1 or 2) and [FeL2][ClO4]2·MeCN are isomorphous. When n = 1 the compounds exhibit an abrupt, hysteretic spin-transition below 200 K, but...

scholarly journals Structural studies of a flexible 2D layer spin crossover coordination polymer

2014 ◽  
Vol 70 (a1) ◽  
pp. C1238-C1238
Author(s):  
Yu-Chun Chuang ◽  
Chung-Kai Chang ◽  
Ching-Che Kao ◽  
Jey-Jau Lee ◽  
Chih-Chieh Wang
Keyword(s):  
Magnetic Property ◽  
Spin State ◽  
Spin Crossover ◽  
Layer Structure ◽  
Dominant Role ◽  
Spin Transition ◽  
High Spin State ◽  
Structural Studies ◽  
Synchrotron Powder Diffraction ◽  
Solvent Molecules

The first coordination sphere of spin crossover material has been comprehended to play a dominant role to its magnetic property. However, the intermolecular interactions, such as π···π interaction and hydrogen bonding, also play a crucial factor. The contents of the solvent in a 2D layer structure, Fe (μ-atrz)(μ-pyz)(NCS)2·nH2O where n=4, 2 and 0, has been reported to be able to affect the spin transition behavior dramatically.[1] As loss of solvent molecules, the inter-layer distance becomes shorter and the transition temperature shifts to lower temperature and accompanies a larger hysteresis loop. To further understand the correlation between the inter-layer distance and magnetic property, the guest ab/desorption and pressure-induced synchrotron powder diffraction experiments were performed at BL01C2 in NSRRC. Based on the cyclic TGA measurements, the guest molecules, H2O, MeOH and EtOH, all can be removed and retaken repeatedly. The pressure-induced PXRD experiment was performed using a Boehler-Almax design diamond anvil cell (DAC). The detail structural studies attempt to understand not only the spin state changes from HS (high spin state) to LS (low spin state) but also the cooperative effect through the inter-layer distance.

scholarly journals Solvent Effects on the Spin-Transition in a Series of Fe(II) Dinuclear Triple Helicate Compounds

Crystals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 376 ◽  
Author(s):  
Alexander Craze ◽  
Mohan Bhadbhade ◽  
Cameron Kepert ◽  
Leonard Lindoy ◽  
Christopher Marjo ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Condensation Product ◽  
Variable Temperature ◽  
Spin Transition ◽  
Single Step ◽  
Spin Conversion ◽  
Dinuclear Iron ◽  
Solvent Molecules ◽  
State Spin ◽  
Triple Helicate

This work explores the effect of lattice solvent on the observed solid-state spin-transition of a previously reported dinuclear Fe(II) triple helicate series 1–3 of the general form [FeII2L3](BF4)4(CH3CN)n, where L is the Schiff base condensation product of imidazole-4-carbaldehyde with 4,4-diaminodiphenylmethane (L1), 4,4′-diaminodiphenyl sulfide (L2) and 4,4′-diaminodiphenyl ether (L3) respectively, and 1 is the complex when L = L1, 2 when L = L2 and 3 when L = L3 (Craze, A.R.; Sciortino, N.F.; Bhadbhade, M.M.; Kepert, C.J.; Marjo, C.E.; Li, F. Investigation of the Spin Crossover Properties of Three Dinuclear Fe(II) Triple Helicates by Variation of the Steric Nature of the Ligand Type. Inorganics. 2017, 5 (4), 62). Desolvation of 1 and 2 during measurement resulted not only in a decrease in T1/2 and completeness of spin-crossover (SCO) but also a change in the number of steps in the spin-profile. Compounds 1 and 2 were observed to change from a two-step 70% complete transition when fully solvated, to a single-step half complete transition upon desolvation. The average T1/2 value of the two-steps in the solvated materials was equivalent to the single T1/2 of the desolvated sample. Upon solvent loss, the magnetic profile of 3 experienced a transformation from a gradual SCO or weak antiferromagnetic interaction to a single half-complete spin-transition. Variable temperature single-crystal structures are presented and the effects of solvent molecules are also explored crystallographically and via a Hirshfeld surface analysis. The spin-transition profiles of 1–3 may provide further insight into previous discrepancies in dinuclear triple helicate SCO research reported by the laboratories of Hannon and Gütlich on analogous systems (Tuna, F.; Lees, M. R.; Clarkson, G. J.; Hannon, M. J. Readily Prepared Metallo-Supramolecular Triple Helicates Designed to Exhibit Spin-Crossover Behaviour. Chem. Eur. J. 2004, 10, 5737–5750 and Garcia, Y.; Grunert, C. M.; Reiman, S.; van Campenhoudt, O.; Gütlich, P. The Two-Step Spin Conversion in a Supramolecular Triple Helicate Dinuclear Iron(II) Complex Studied by Mössbauer Spectroscopy. Eur. J. Inorg. Chem. 2006, 3333–3339).

Abrupt spin crossover in iron(iii) complexes with aromatic anions

2019 ◽  
Vol 48 (41) ◽  
pp. 15515-15520 ◽  
Author(s):  
Sharon E. Lazaro ◽  
Adil Alkaş ◽  
Seok J. Lee ◽  
Shane G. Telfer ◽  
Keith S. Murray ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Spin Crossover ◽  
Spin Transition ◽  
Halogen Bonds ◽  
Aromatic Anions

Two iron(iii) complexes, [Fe(qsal-X)2]OTs·nH2O, are found to exhibit abrupt spin crossover with the spin transition temperature substituent dependent, and X⋯O halogen bonds linking the spin centres.

scholarly journals Electrical read-out of light-induced spin transition in thin film spin crossover/graphene heterostructures

2021 ◽  
Author(s):  
Nikita Konstantinov ◽  
Arthur Tauzin ◽  
Ulrich Nguetchuissi Noumbé ◽  
Diana Dragoe ◽  
Bohdan Kundys ◽  
...  
Keyword(s):  
Thin Film ◽  
Spin Crossover ◽  
Spin Transition ◽  
Switching Device ◽  
Electronic Switching ◽  
Spin Transitions

An opto-electronic switching device made from an evaporated spin crossover thin film over a graphene sensor is presented. The electrical transduction of both temperature and light-induced reversible spin transitions are demonstrated.

Spin-crossover in a trans-[FeL2(NCS)2] family (L = triaryltriazole): remote substituent effects on spin transition modes and temperature

2013 ◽  
Vol 42 (28) ◽  
pp. 10144 ◽  
Author(s):  
Guo-Ping Shen ◽  
Li Qi ◽  
Lei Wang ◽  
Yan Xu ◽  
Jing-Jing Jiang ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Spin Transition ◽  
Substituent Effects ◽  
Transition Modes ◽  
Remote Substituent

scholarly journals Thermal and near-infrared light induced spin crossover in a mononuclear iron(ii) complex with a tetrathiafulvalene-fused dipyridophenazine ligand

2016 ◽  
Vol 45 (28) ◽  
pp. 11267-11271 ◽  
Author(s):  
F. Pointillart ◽  
X. Liu ◽  
M. Kepenekian ◽  
B. Le Guennic ◽  
S. Golhen ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Near Infrared ◽  
Spin Transition ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Mononuclear Iron

A thermal and photo-induced spin transition in a tetrathiafulvalene-based Fe(ii) complex.

Polymorphism-Dependent Spin-Crossover: Hysteretic Two-Step Spin Transition with an Ordered [HS–HS–LS] Intermediate Phase

2015 ◽  
Vol 54 (11) ◽  
pp. 5145-5147 ◽  
Author(s):  
Jie Luan ◽  
Jian Zhou ◽  
Zhan Liu ◽  
Bowen Zhu ◽  
Huisi Wang ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Intermediate Phase ◽  
Spin Transition

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>.

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