Calamitic metallomesogens: metal-containing liquid crystals with rodlike shapes

Hudson, Sarah A.; Maitlis, Peter M.

doi:10.1021/cr00019a002

Cited by 482 publications

(164 citation statements)

References 35 publications

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“…[1][2][3][4][5][6][7] In contrast to conventional diamagnetic liquid crystals, which can be oriented only in strong magnetic fields, paramagnetic metallomesogens can be oriented in rather weak magnetic fields. 8,9 For easy alignment of these metallomesogenic molecules in a magnetic field a pronounced magnetic anisotropy is required.…”

Section: Introductionmentioning

confidence: 99%

On the magnetic anisotropy of lanthanide-containing metallomesogens

Mironov

Galyametdinov

Ceulemans

et al. 2000

The Journal of Chemical Physics

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A general theoretical model of the origin of the magnetic anisotropy in paramagnetic metal-containing liquid crystals is developed. General relations between the molecular magnetic anisotropy of mesogenic lanthanide complexes and the macroscopic magnetic anisotropy of these liquid crystals in the mesophase are obtained. The net magnetic anisotropy of a real metallomesogen is shown to be the result of a complex interplay between the molecular magnetic anisotropy, orientation of the long molecular axis, and disorder effects. The sign of the magnetic anisotropy ⌬ depends not only on the anisotropy of the tensor of molecular magnetic susceptibility, but also on the orientation of the long molecular axis of rodlike lanthanide complexes with respect to the principal magnetic axes of the molecular tensor of magnetic susceptibility. The influence of microand macroscopic disorder in real liquid crystals is discussed. Numerical parametric calculations were used to rationalize the variation of the magnitude and sign of the magnetic anisotropy in a series of isostructural lanthanide-containing metallomesogens. Experimental magnetic susceptibility and magnetic anisotropy of a series of ͓Ln͑LH͒ 3 ͑NO 3 ͒ 3 ͔ compounds ͑LH is a Schiff base͒ are well reproduced by calculations based on the present model. Limitations of the Bleaney theory of magnetic anisotropy are analyzed.

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Section: Introductionmentioning

confidence: 99%

On the magnetic anisotropy of lanthanide-containing metallomesogens

Mironov

Galyametdinov

Ceulemans

et al. 2000

The Journal of Chemical Physics

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“…В литературе содержится большое количество обзорных статей [2][3][4][5][6][7], многочис-ленные главы к книгам [8][9][10][11][12][13], а также монография Хосе-Луиса Серрано [14], практически полностью охватывающих исследования в области металл-содержащих ЖК вплоть до 2000-х годов. Кроме того, вышло много обзоров по отдельным направлениям в области металломезогенов, например лантанидомезогенов [15][16][17], золото-содержащих жидких кристаллов [18,19], ферро-ценомезогенов [20][21][22], ионных металломезогенов [23,24], полимерных металломезогенов [25,26], лиотропных металломезогенов [27], неоргани-ческих или металлоколлоидных жидких крис-таллов [28][29][30] и жидкокристаллических металло-дендримеров [31].…”

Section: к вопросу о классификации металломезогеновunclassified

Metallomesogens: Retrospectives and Perspectives

Kadkin¹,

Domracheva²,

Ovchinnikov³

2015

Liq. Cryst. and their Appl.

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“…Most paramagnetic liquid crystal materials are formed from metal-containing mesogens, for which the optical anisotropy is determined by the ligands; hence, it is usually possible to determine at least the sign of the optical anisotropy independently, thus revealing the sign of the molecular magnetic anisotropy. Known paramagnetic liquid crystals have a variety of metal centers and coordination geometries (24,25]. A requirement for paramagnetism is an unpaired electron spin, but to have an influence on the magnetic anisotropy, there must also be coupling between the spin angular momentum and the orbital angular momentum.…”

Section: Paramagnetic Liqu Id Crystalsmentioning

confidence: 99%