Stepwise magnetic behavior of the liquid crystal iron(III) complex

Domracheva, N. E.; Vorobeva, V.E.; Pyataev, A. V.; Manapov, R. A.; Zueva, Ekaterina М.; Груздев, М. С.; Chervonova, U. V.

doi:10.1134/s0022476613070020

Cited by 7 publications

(4 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At 350 K, the EPR spectra of complexes 1 and 3·H 2 O show broadened doublet spectra around g ∼ 2 and a low field signal arises, which indicates the presence of high-spin Fe(III) species, which is in line with their solid-state magnetic data, and which shows that after 300 K both the complexes undergo SCO. At 400 K, EPR spectra of both complexes 1 and 3·H 2 O completely change and match closely with the spectra of complexes 2·MeOH , 4 , and 5 which indicates that at 400 K complexes 1 and 3·H 2 O are fully converted to high-spin states . To confirm that the EPR spectra are purely due to the high-spin state of the Fe(III) center, we collected EPR data of complex 2·MeOH at various temperatures, which shows that the nature of the spectra almost remains the same but the spectral feature gets sharp at low temperature (Figure S22).…”

Section: Resultsmentioning

confidence: 54%

“…At 400 K, EPR spectra of both complexes 1 and 3•H 2 O completely change and match closely with the spectra of complexes 2•MeOH, 4, and 5 which indicates that at 400 K complexes 1 and 3•H 2 O are fully converted to high-spin states. 59 To confirm that the EPR spectra are purely due to the high-spin state of the Fe(III) center, we collected EPR data of complex 2•MeOH at various temperatures, which shows that the nature of the spectra almost remains the same but the spectral feature gets sharp at low temperature (Figure S22).…”

Section: Structural Description Of [Fe(l3) 2 ]Ncse•h 2 O (3•h 2 O)mentioning

confidence: 95%

See 1 more Smart Citation

Steric Effects on Spin States in a Series of Fe(III) Complexes

Dey

Cirera

Mehta

et al. 2023

Crystal Growth & Design

View full text Add to dashboard Cite

Spin crossover (SCO) is very sensitive toward electronic and steric effects. The latter can lead to a distorted structure, which in turn can change the electronic properties of the complex possibly leading to a change in the spin state. Herein, we investigated the steric effects of the ligand substituents on the structure and magnetic properties of Fe(III) complexes by applying two different ligand systems. We chose the less bulky Nmethylethylenediamine and the bulkier N-phenylethylenediamine and coupled them with 3-methoxysalicylaldehyde affording HL1− HL2, while coupling with 3-ethoxysalicylaldehyde afforded HL3−HL4. Complexes [Fe(L1) 2 ]NCSe (1) and [Fe(L3) 2 ]•NCSe•H 2 O (3•H 2 O) formed with the less bulky ligand exhibit SCO behavior, while complexes [Fe(L2) 2 NCSe]•MeOH (2•MeOH), [Fe(L4) 2 NCSe] (4), and [Fe(L4) 2 NCS] ( 5) formed with the bulkier amine stay in the high-spin state. The effect of the bound anion was also investigated for complexes 4 and 5. Both experimental and theoretical methods were employed to understand the observed behavior.

show abstract

Section: Resultsmentioning

confidence: 54%

Section: Structural Description Of [Fe(l3) 2 ]Ncse•h 2 O (3•h 2 O)mentioning

confidence: 95%

Steric Effects on Spin States in a Series of Fe(III) Complexes

Dey

Cirera

Mehta

et al. 2023

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…Absorption bands in the range 450–800 nm are assigned to ligand-to-metal charge transfer (LMCT) bands. 35 Spectroscopic analysis of similar [Fe(5-X-SalEen) 2 ] + complexes revealed that the low-energy band (650 nm < λ max < 800 nm) is due to low-spin species and the high-energy band (450 nm < λ max < 650 nm) is due to the high-spin species. 20 If we focus on absorption bands in this region, then we will find out that for complex 1 there is only one peak in the region (λ = 575 nm), which corresponds to high-spin state, and for complex 2 there are two peaks (λ1 = 527 nm and λ2 = 660 nm), where λ1 corresponds to the high-spin state and λ2 corresponds to the low-spin state.…”

Section: Resultsmentioning

confidence: 99%

“…Absorption bands in the range 450–800 nm are assigned to ligand-to-metal charge transfer (LMCT) bands . Spectroscopic analysis of similar [Fe(5-X-SalEen) 2 ] + complexes revealed that the low-energy band (650 nm < λ max < 800 nm) is due to low-spin species and the high-energy band (450 nm < λ max < 650 nm) is due to the high-spin species .…”

Section: Resultsmentioning

confidence: 99%

Push and Pull Effect of Methoxy and Nitro Groups Modifies the Spin-State Switching Temperature in Fe(III) Complexes

et al. 2022

View full text Add to dashboard Cite

We have explored the impact of electron-donating (methoxy) and electron-withdrawing (nitro) substituents on SalEen ligand based spin crossover (SCO) behavior of Fe(III) complexes. Thus, 3-X-substituted SalEen ligands were employed to prepare [Fe(3-X-SalEen)2]·NCSe, where X = OMe (1), H (2), and NO2 (3) (3-X-SalEen is the condensation product of 3-substituted salicylaldehyde and N-ethylethylenediamine). The characteristic spin transition temperature (T 1/2) is shown to shift to a lower temperature when an electron-donating substituent (OMe) is used and to a higher temperature when an electron-withdrawing substituent (NO2) is used. We used experimental and theoretical methods to determine the reasons for this behavior. The solid-state magnetic data revealed the transition temperatures for complexes 1, 2, and 3 to be 219, 251, and 366 K, respectively. The solution-state magnetic data also support this trend in T 1/2 values. UV–vis spectra analysis indicates that there is greater delocalization in the π-manifold of the ligand when the nitro group is the substituent. Theoretical studies through density functional theory methods suggest the methoxy substituent decreases the energy gap between the t2g and eg orbitals (explaining the lower T 1/2 value), while the nitro substituent increases the energy gap between the t2g and eg orbitals and thus increases the T 1/2 value.

show abstract

Effect of Ligand Field Strength on the Spin Crossover Behaviour in 5‐X‐SalEen (X=Me, Br and OMe) Based Fe(III) Complexes

Dey

Mondal

Konar

2020

Chemistry An Asian Journal

View full text Add to dashboard Cite

The reaction of Fe(NCS) 3 prepared in situ in MeOH with 5-X-SalEen ligands (5-X-SalEen = condensation product of 5-substituted salicylaldehyde and N-ethylethylenediamine) provided three Fe(III) complexes, [Fe(5-X-SalEen) 2 ]NCS; X=Me (1), X=Br (2), X=OMe (3). All the complexes reveal similar structural features but a very different magnetic profile. Complex 1 shows a gradual spin crossover while complexes 2 and 3 show a sharp spin transition. The T 1/2 for complex 2 is 237 K while for complex 3 it is much higher with a value of 361 K. The spin transition temperature is shifted towards higher temperature with increasing electron-donation ability of the ligand substituents. This experimental observation has been rationalized with DFT calculations. UV-Vis and cyclic voltammetry studies support the fact that the electron density on the ligand increases from Me to Br to OMe substituents. To understand the change in spin states, temperature-dependent EPR spectra have been recorded. The spin state equilibrium in the liquid state has been probed with Evans NMR spectroscopic method, and thermodynamic parameters have been evaluated for all complexes.

show abstract

Stepwise magnetic behavior of the liquid crystal iron(III) complex

Cited by 7 publications

References 38 publications

Steric Effects on Spin States in a Series of Fe(III) Complexes

Steric Effects on Spin States in a Series of Fe(III) Complexes

Push and Pull Effect of Methoxy and Nitro Groups Modifies the Spin-State Switching Temperature in Fe(III) Complexes

Effect of Ligand Field Strength on the Spin Crossover Behaviour in 5‐X‐SalEen (X=Me, Br and OMe) Based Fe(III) Complexes

Contact Info

Product

Resources

About