EPR detection of presumable magnetoelectric interactions in the liquid-crystalline state of an iron mesogen

Domracheva, N. E.; Овчинников, И. В.; Туранов, А. Н.; Konstantinov, V. N.

doi:10.1016/s0304-8853(03)00635-8

Cited by 22 publications

(10 citation statements)

References 9 publications

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“…Murav’ev on the example of similar HS iron(III) complexes estimated that the D- parameter should be in the following range: 0.01 cm –1 < | D | < 0.04 cm –1 . D values evaluated by him agree with our experimental EPR data ( g = 2.1, | D | = 0.043 cm –1 ) obtained for the liquid-crystalline HS iron(III) complex with Schiff-based ligands . Therefore, fitting the model spectra of the II-type HS Fe 3+ ions, we used the D parameter which changed in the range 0.01–0.045 cm –1 .…”

Section: Resultssupporting

confidence: 77%

Detailed EPR Study of Spin Crossover Dendrimeric Iron(III) Complex

et al. 2013

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The unusual magnetic behavior of the first dendritic Fe(3+) complex with general formula [Fe(L)2](+)Cl(-)·H2O based on a branched Schiff base has been investigated by electron paramagnetic resonance (EPR) and Mössbauer spectroscopy. EPR displays that complex consists of the three types of magnetically active iron centers: one S = 1/2 low-spin (LS) and two S = 5/2 high-spin (HS) centers with strong low-symmetry and weak distorted octahedral crystal fields. Analysis of the magnetic behavior reflected by I versus T (where I is the EPR lines integrated intensity of the spectrum) demonstrates that the dendritic Fe(3+) complex has sufficiently different behavior in three temperature intervals. The first (4.2-50 K) interval corresponds to the antiferromagnetic exchange interactions between LS-LS, LS-HS, and HS-HS centers. The appearance of a presumable magnetoelectric effect is registered in the second (50-200 K) temperature interval, whereas a spin transition process between LS and HS centers occurs in the third (200-330 K) one. The coexistence of the magnetic ordering, presumable magnetoelectric effect, and spin crossover in one and the same material has been detected for the first time. The Mössbauer spectroscopy data completely confirm the EPR results.

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Section: Resultssupporting

confidence: 77%

Detailed EPR Study of Spin Crossover Dendrimeric Iron(III) Complex

et al. 2013

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“…Comparison of the IR spectra of the metal complexes with those of the free ligands shows that the stretching frequency of the C=N bond is shifted to lower wavenumbers (11-12 cm À1 ) after coordination. This shift is due to reduction of the double-bond character of the C = N bond as a result of coordination of the nitrogen to the metal center and is in agreement with the results obtained for other similar complexes described previously [25][26][27]. The broad band of medium intensity in the 3,404-3,450 cm À1 region is due to the O-H stretching vibration of the lattice ethanol.…”

Section: Synthesissupporting

confidence: 92%

Synthesis and Liquid-Crystalline Properties of N,N′-di-(5-(4-Alkoxyphenyl)azo)-Salicylidene-1,2-Phenylene Diiminato Nickel(II) Complexes

Rezvani

Nejati

Alizadeh

et al. 2010

Molecular Crystals and Liquid Crystals

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The synthesis, characterization, and liquid-crystal properties of two new tetradentate N,N 0 -di-(5-(4-alkoxyphenyl)azo)-salicylidene-1,2 phenylene diimine ligands (alkoxy ¼ octloxy, decyloxy) and their nickel(II) complexes are reported. The ligands were prepared by the condensation of the 5-((4-alkoxyphenyl)azo)salicylaldehydes homologous with 1,2 phenylene diamine. The ligands and their nickel complexes have been characterized by infrared (IR), 1 H nuclear magnetic resonance (NMR), mass spectroscopy, and elemental analyses. The liquid-crystalline properties of the ligands and the related nickel complexes were studied by differential scanning calorimetry (DSC) and by using a polarizing microscope equipped with a heating and cooling stage. None of the free ligands exhibited liquid-crystalline behavior but the copper complexes demonstrated an enantiotropic smectic A mesophase.

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“…В смектической мезофазе ЖК-комплекса железа FeCl 2 обнаружены диэлектрическая аномалия, обусловленная локальным упорядочением диполь-ных моментов связей (FeCl) вдоль одномерных цепочек, заполняющих смектическую плоскость [64], и необычный способ ориентирования мезогенных молекул железа во внешнем магнитном поле, который вызван магнитоэлектрическим эффектом (перекрестным влиянием внутреннего электрического поля сегнетоэлектрической фазы на магнитные свойства комплексов). Установлено также, что парамагнитная восприимчивость металломезогенов железа в смектической фазе имеет возросшие значения и аномальное температурное поведение, аналогичное поведению статической диэлектрической проницаемости, что связано с возникновением добавочной намагни-ченности за счет действия внутреннего электри-ческого поля [65].…”

Section: к истории возникновения и развития области металломезогеновunclassified