Influence of ligand substituent conformation on the spin state of an iron(ii)/di(pyrazol-1-yl)pyridine complex

2021 ◽  
Vol 50 (10) ◽  
pp. 3464-3467
Author(s):  
Rafal Kulmaczewski ◽  
Mark J. Howard ◽  
Malcolm A. Halcrow
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
Solution Phase ◽  
Pyridine Complex

The temperature of the solution-phase spin-crossover equilibrium in iron(ii) complexes of 4-alkylsulfanyl-2,6-di{pyrazol-1-yl}pyridine (bppSR) complexes depends strongly on the alkylsulfanyl substituent.

scholarly journals Spin-state-dependent electrical conductivity in single-walled carbon nanotubes encapsulating spin-crossover molecules

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Julia Villalva ◽  
Aysegul Develioglu ◽  
Nicolas Montenegro-Pohlhammer ◽  
Rocío Sánchez-de-Armas ◽  
Arturo Gamonal ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Spin State ◽  
Spin Crossover ◽  
Single Walled Carbon Nanotubes ◽  
Guest Molecules ◽  
Spintronic Devices ◽  
Single Walled Carbon ◽  
State Dependent ◽  
Lack Of Control ◽  
Walled Carbon Nanotubes

AbstractSpin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. However, SCO systems face several bottlenecks when downscaling into nanoscale spintronic devices: their instability at the nanoscale, their insulating character and the lack of control when positioning nanocrystals in nanodevices. Here we show the encapsulation of robust Fe-based SCO molecules within the 1D cavities of single-walled carbon nanotubes (SWCNT). We find that the SCO mechanism endures encapsulation and positioning of individual heterostructures in nanoscale transistors. The SCO switch in the guest molecules triggers a large conductance bistability through the host SWCNT. Moreover, the SCO transition shifts to higher temperatures and displays hysteresis cycles, and thus memory effect, not present in crystalline samples. Our results demonstrate how encapsulation in SWCNTs provides the backbone for the readout and positioning of SCO molecules into nanodevices, and can also help to tune their magnetic properties at the nanoscale.

scholarly journals Spin Crossover in Nickel(II) Tetraphenylporphyrinate via Forced Axial Coordination at the Air/Water Interface

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4155
Author(s):  
Alexander V. Shokurov ◽  
Daria S. Kutsybala ◽  
Andrey P. Kroitor ◽  
Alexander A. Dmitrienko ◽  
Alexander G. Martynov ◽  
...  
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
High Spin State ◽  
Water Interface ◽  
Metal Centers ◽  
Axial Coordination ◽  
Vis Spectroscopy ◽  
Air Water Interface ◽  
Nickel Cation

Coordination-induced spin crossover (CISCO) in nickel(II) porphyrinates is an intriguing phenomenon that is interesting from both fundamental and practical standpoints. However, in most cases, realization of this effect requires extensive synthetic protocols or extreme concentrations of extra-ligands. Herein we show that CISCO effect can be prompted for the commonly available nickel(II) tetraphenylporphyrinate, NiTPP, upon deposition of this complex at the air/water interface together with a ruthenium(II) phthalocyaninate, CRPcRu(pyz)2, bearing two axial pyrazine ligands. The latter was used as a molecular guiderail to align Ni···Ru···Ni metal centers for pyrazine coordination upon lateral compression of the system, which helps bring the two macrocycles closer together and forces the formation of Ni–pyz bonds. The fact of Ni(II) porphyrinate switching from low- to high-spin state upon acquiring additional ligands can be conveniently observed in situ via reflection-absorption UV-vis spectroscopy. The reversible nature of this interaction allows for dissociation of Ni–pyz bonds, and thus, change of nickel cation spin state, upon expansion of the monolayer.

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

Spin-State Ordering on One Sub-lattice of a Mononuclear Iron(III) Spin Crossover Complex Exhibiting LIESST and TIESST

2014 ◽  
Vol 20 (19) ◽  
pp. 5613-5618 ◽  
Author(s):  
Kevin D. Murnaghan ◽  
Chiara Carbonera ◽  
Loic Toupet ◽  
Michael Griffin ◽  
Marinela M. Dîrtu ◽  
...  
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
Mononuclear Iron

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

scholarly journals Structural movies of the gradual spin-crossover in a molecular complex at various physical scales

2016 ◽  
Vol 18 (40) ◽  
pp. 28307-28315 ◽  
Author(s):  
S. Lakhloufi ◽  
M. H. Lemée-Cailleau ◽  
G. Chastanet ◽  
P. Rosa ◽  
N. Daro ◽  
...  
Keyword(s):  
Spin State ◽  
Molecular Complex ◽  
Spin Crossover ◽  
Structural Determination ◽  
Thermally Induced ◽  
Mononuclear Iron

The thermally induced Spin-CrossOver (SCO) undergone by the mononuclear iron(ii) complex [Fe(PM-AzA)2(NCS)2] (PM = N-2′-pyridylmethylene, AzA = 4-(phenylazo)aniline) is fully pictured by a quasi-continuous structural determination all along the spin-state modification within the sample.

scholarly journals Threefold Spiral Structure Constructed by 1D Chains of [[M(NCS)2(bpa)2]·biphenyl]n (M = Fe, Co; bpa = 1,2-bis(4-pyridyl)ethane)

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 97 ◽  
Author(s):  
Satoshi Tokinobu ◽  
Haruka Dote ◽  
Satoru Nakashima
Keyword(s):  
Spin Crossover ◽  
Spiral Structure ◽  
Diffusion Method ◽  
Central Metal ◽  
X Ray ◽  
Pyridine Complex ◽  
1D Chain ◽  
One Step ◽  
Spiral Structures ◽  
1D Chains

Assembled complexes [[M(NCS)2(bpa)2]·biphenyl]n (M = Fe, Co; bpa = 1,2-bis(4-pyridyl)ethane) have been synthesized because [Fe(NCBH3)2(bpa)2·biphenyl]n has a novel threefold spiral structure and shows stepwise spin-crossover phenomenon. We attempted to obtain spiral structures for [[Fe(NCS)2(bpa)2]·biphenyl]n and [[Co(NCS)2(bpa)2]·biphenyl]n using a one-step diffusion method, while the reported spiral structure of [[Fe(NCBH3)2(bpa)2]·biphenyl]n was obtained by diffusion method after synthesizing Fe(II)-pyridine complex. X-ray structural analysis revealed that [[Fe(NCS)2(bpa)2]·biphenyl]n and [[Co(NCS)2(bpa)2]·biphenyl]n had a chiral propeller structure of pyridines around the central metal, and they had a novel spiral structure and chiral space group P3121 without the presence of chiral auxiliaries. It was shown that the host 1D chain, having a chiral propeller structure of pyridines around the central metal along with its concerted interaction with an atropisomer of biphenyl, made a threefold spiral structure.

scholarly journals Spin State Behavior of A Spin-Crossover Iron(II) Complex with N,N′-Disubstituted 2,6-bis(pyrazol-3-yl)pyridine: A Combined Study by X-ray Diffraction and NMR Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 793
Author(s):  
Elizaveta K. Melnikova ◽  
Dmitry Yu. Aleshin ◽  
Igor A. Nikovskiy ◽  
Gleb L. Denisov ◽  
Yulia V. Nelyubina
Keyword(s):  
Nmr Spectroscopy ◽  
Spin State ◽  
Metal Ion ◽  
Spin Crossover ◽  
Molecular Design ◽  
Chemical Shifts ◽  
Variable Temperature ◽  
High Spin State ◽  
X Ray Diffraction ◽  
X Ray

A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing ‘molecular’ design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand.

scholarly journals Probing the unpaired Fe spins across the spin crossover of a coordination polymer

2021 ◽  
Author(s):  
Thilini K. Ekanayaka ◽  
Hannah Kurz ◽  
Ashley S. Dale ◽  
Guanhua Hao ◽  
Aaron Mosey ◽  
...  
Keyword(s):  
Schiff Base ◽  
Coordination Polymer ◽  
Spin State ◽  
Spin Crossover ◽  
State Transition ◽  
Spin State Transition

For the spin crossover coordination polymer [Fe(L1)(bipy)]n (where L1 is a N2O22− coordinating Schiff base-like ligand bearing a phenazine fluorophore and bipy = 4,4′-bipyridine), there is compelling additional evidence of a spin state transition.

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