Probing the Magnetic Anisotropy of Lanthanide‐Containing Metallomesogens by Luminescence Spectroscopy

Binnemans, Koen; Malykhina, Larisa; Mironov, V. S.; Haase, Wolfgang; Driesen, Kris; Deun, Rik Van; Fluyt, Linda; Görller‐Walrand, Christiane; Galyametdinov, Yu. G.

doi:10.1002/1439-7641(20011119)2:11<680::aid-cphc680>3.0.co;2-#

Cited by 49 publications

(26 citation statements)

References 22 publications

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“…These characteristics enable them to have wide application in responsive luminescent stains for biomedical analysis with temporal and spectral discrimination, [1][2][3][4][5][6][7][8][9] and to find use in development for liquid-crystal displays, [10][11][12][13] laser materials [14][15] and optoelectronic emitters. [16][17] Generally, the excellent luminescence properties of lanthanide complexes are attributed to the intramolecular energy transfer between the organic ligands and chelated metal ("antenna effect").…”

Section: Introductionmentioning

confidence: 99%

Listening to Lanthanide Complexes: Determination of the Intrinsic Luminescence Quantum Yield by Nonradiative Relaxation

Yang

Liu

et al. 2008

ChemPhysChem

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The photophysical properties of lanthanide complexes have been studied extensively; however, fundamental parameters such as the intrinsic quantum yield as well as radiative and nonradiative decay rates are difficult or even impossible to measure experimentally. Herein, a photoacoustic (PA) method is proposed to determine the intrinsic quantum yield of lanthanide complexes with lifetimes in the order of milliseconds. This method is used to determine the intrinsic quantum yields for europium(III)‐containing metallomesogens as well as terbium(III) complexes. The results show that the PA signal is sensitive to both the lifetime and the ratio of the fast‐to‐slow heat component of the samples. It is found that there is an efficient ligand sensitization and a moderate intrinsic quantum yield for the complexes. The intrinsic quantum yield of Eu3+ in the metallomesogens exhibits an obvious increase upon the isotropic liquid to smectic A transition. The proposed PA method is quite simple, and can contribute to a clearer understanding of the photophysical processes in luminescent lanthanide complexes.

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Section: Introductionmentioning

confidence: 99%

Listening to Lanthanide Complexes: Determination of the Intrinsic Luminescence Quantum Yield by Nonradiative Relaxation

Yang

Liu

et al. 2008

ChemPhysChem

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“…7 F 1 transition in order to assess the magnetic anisotropy of europium-containing metallomesogens. 10,11 Here we present a new mesogenic class of luminescent lanthanide complexes built from a substituted diaza-18-crown-6 macrocyclic ligand, and we show, for the first time, how luminescence intensity and lifetime can be used to monitor the transitions from crystalline to liquid crystalline phases and vice-versa.…”

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confidence: 97%

Luminescence-detected phase transitions in lanthanide-containing liquid crystals

et al. 2003

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Complexes between lanthanide nitrates and a pro-mesogenic 18-membered diaza-substituted coronand are luminescent both as powders and liquid crystals (between 87 and 195°C ), and the phase transitions are detected by monitoring luminescence intensity and lifetime.Liquid crystals are the main components of new-generation cost-saving colour displays and a great deal of research effort has been devoted to their development during the last two decades. 1 One disadvantage of these devices is their relatively low brightness, due to the use of polarisers and colour filters, and one way to overcome this shortcoming is the design of luminescent liquid crystals. While it is rather easy to find either photoluminescent sheets acting as filters or, even, organicbased luminescent liquid crystals, these materials display a broad-band, and usually blue, emission which is of little use in this context. On the other hand cathode-ray tubes rely on trichromatic phosphors emitting narrow bands in three basic colours, blue, green and red, and so do energy-saving luminescent lamps and tubes. Most of these phosphors contain rare-earth ions, Eu II (blue), Tb III (green) and Eu III (red). Henceforth the idea of introducing lanthanide ions in mesogenic phases. Metallomesogens are relatively new in the area of liquid crystals and they combine the properties of a liquid crystalline phase with the optical and magnetic properties of the metal ions they incorporate. The first liquid crystalline phase containing Ln III ions was reported by Piechocki. 2 Initially, it was thought that introducing bulky spherical ions in potentially mesogenic compounds could disrupt the required order to produce mesophases, but it turned out that many lanthanide-containing systems are amenable to form liquid crystalline phases, as reported in a recent comprehensive review article. 3 Basically, there are two ways of designing luminescent lanthanide-containing mesophases. The first, historical, one is the introduction of highly luminescent complexes into known liquid crystalline phases and successful attempts with bdiketonates have been reported. [4][5][6][7] The other one is the synthesis of luminescent complexes displaying mesogenic properties. 8,9 Metal-centred luminescent properties, particularly those of Eu III , have been taken advantage of to probe, at very low temperature, the degree of disorder around the metal ion in metastable liquid crystals based on europium laurate, 8 and to determine the second-rank crystal-field parameter through analysis of the 5 D 0 ? 7 F 1 transition in order to assess the magnetic anisotropy of europium-containing metallomesogens. 10,11 Here we present a new mesogenic class of luminescent lanthanide complexes built from a substituted diaza-18-crown-6 macrocyclic ligand, and we show, for the first time, how luminescence intensity and lifetime can be used to monitor the transitions from crystalline to liquid crystalline phases and vice-versa.Synthetic macrocycles are selective and versatile ligands for the complexation of trivalent ...

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“…Until now, only few papers have exploited the Eu III ion to probe liquid crystalline phases. For instance, the degree of disorder around the metal ion in metastable liquid crystals based on europium laurate has been established at very low temperature [50], and secondrank crystal-field parameters have been worked out through analysis of the 5 D 0 → 7 F 1 transition in order to assess the magnetic anisotropy of europium-containing metallomesogens [51]. Luminescence parameters, such as emission intensity and excited state lifetime, are temperature dependent, and this dependence is usually monotonous.…”

Section: A Derivatised Coronand For Generating a Luminescent Mesophasementioning

confidence: 99%

Lanthanide-containing luminescent molecular edifices

Bünzli

2006

Journal of Alloys and Compounds

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Probing the Magnetic Anisotropy of Lanthanide‐Containing Metallomesogens by Luminescence Spectroscopy

Cited by 49 publications

References 22 publications

Listening to Lanthanide Complexes: Determination of the Intrinsic Luminescence Quantum Yield by Nonradiative Relaxation

Listening to Lanthanide Complexes: Determination of the Intrinsic Luminescence Quantum Yield by Nonradiative Relaxation

Luminescence-detected phase transitions in lanthanide-containing liquid crystals

Lanthanide-containing luminescent molecular edifices

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