Synthesis and mesomorphism of fluoroalkylated organometallic mesogens

Bilgin‐Eran, Belkız; Tschierske, Carsten; Diele, Siegmar; Baumeister, Ute

doi:10.1039/b511758e

Cited by 34 publications

(12 citation statements)

References 44 publications

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“…Indeed, lowering the temperature leads to a logical increase of d 1 due to the rigidification of the ammonium cation akyl chains but to a slight decrease of d 2 which shows that d 1 and d 2 are not in the 1:2 ratio. A broad and weak scattering located at q = 1.15 Å −1 ( d = 5.43 Å) is also observed and corresponds to the perfluorinated chains interactions between clusters apical ligands . For ( 1 ), an additional sharper signal at q = 1.54 Å −1 ( d = 4.02 Å) can be observed.…”

Section: Resultsmentioning

confidence: 81%

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters

Prévôt

Amela-Cortés

Manna³

et al. 2015

Adv Funct Materials

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wileyonlinelibrary.comare also very well known as smart materials to respond easily to external stimuli such as a change of temperature, application of a magnetic or electric fi eld. Thus, conferring new functionalities such as luminescence, redox states, and/or magnetism to LC is a challenge of particular interest to design new materials that would improve the efficiency of existing technologies or develop new ones. [ 3 ] In particular, photoluminescent materials play a key role in photonics, optoelectronics or lighting applications. [ 4 ] In this frame, inorganic luminophores appear as the most appropriate materials in terms of stability as compared to organic compounds which suffer from photo bleaching. Thus, luminescent transition metals, [ 3a,c , 5 ] lanthanide(III), [ 3d , 6 ] quantum dots or nanoparticles [ 7 ] have been introduced in LC giving birth to metallomesogens and liquid crystal nanosciences. [ 5,8 ] Recently, we discovered a new class of luminescent hybrid LC material called clustomesogen that contains transition metal clusters. [ 9 ] These inorganic entities were defi ned by Cotton as a fi nite group of metal atoms linked together by metal-metal bonds and are obtained, as ceramic-like powders, by high temperature solid state synthesis. [ 10 ] So far, three strategies were developed to design clustomesogens: i) a covalent approach in which organic LC promoters are covalently linked on an octahedral metallic cluster core, ii) a supramolecular one that combines electrostatic and host guest interactions to associate the LC organic promoters with an alkali Cs 2 Mo 6 Br 14 ternary salt, and, iii) an ionic approach that takes advantage of the cluster units anionic character to associate them with organic cations bearing the mesogenic promoters. Indeed, the octahedral [M 6 X i 8 X a 6 ] n − cluster units (M = Mo, W, or Re; X i = chalcogen/halogen; X a = halogen; i = inner, a = apical, 2 ≤ n ≤ 4) exhibit emission in the red-NIR area upon excitation in the UV-blue with high photoluminescence quantum yields and possess excited state lifetimes in the range of several tenths of microseconds, thanks to the full delocalization of their valence electrons on the all metallic octahedral scaffold. [ 11 ] These last decades, many efforts have been dedicated to their integration in supramolecular architectures, polymeric frameworks or nanomaterials that take advantage of their intrinsic properties. [ 12 ] Very recently, highly luminescent cluster compounds By combining [Mo 6 I 8 (C n F 2 n +1 COO) 6 ] 2− ( n = 1, 2, 3) nanocluster units with liquid crystalline ammonium cations, a new series of hybrid materials is developed that show a nematic liquid crystal phase, the most fl uid of all LC phase, on a large range of temperatures including room temperature. The photophysical studies performed in the LC state show that these selfassembled hybrid materials emit in the red-NIR with absolute quantum yields up to 0.7 and show a very good photostability under continuous irradiation. They are further integrated up t...

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Section: Resultsmentioning

confidence: 81%

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters

Prévôt

Amela-Cortés

Manna³

et al. 2015

Adv Funct Materials

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“…This shows that under bulk conditions the compound 3‐Fla‐1 has no stable mesophase, but under planar anchoring liquid crystalline properties can be observed. Reentrant phases have already been reported for compounds in which two SmA phases were separated by a nematic phase, but the sequence I re ‐Col‐I is quite rare and, to the best of our knowledge, an I re phase has never been reported for thermotropic ionic liquid crystals.…”

Section: Resultsmentioning

confidence: 84%

Flavylium Salts: A Blooming Core for Bioinspired Ionic Liquid Crystals

Forschner

Knelles

Bader

et al. 2019

Chemistry A European J

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Thermotropic ionic liquid crystals based on the flavylium scaffold have been synthesized and studied for their structure‐properties relationship for the first time. The mesogens were probed by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X‐ray diffraction (XRD). Low numbers of alkoxy side chains resulted in smectic (SmA) and lamello‐columnar (LamCol) phases, whereas higher substituted flavylium salts showed Colro as well as ordered and disordered columnar (Colho, Colhd) mesophases. Mesophase width ranged from 13 K to 220 K, giving access to room temperature liquid crystals. The optical properties of the synthesized compounds were probed towards absorption and emission properties. Strong absorption with maxima between 444 and 507 nm was observed, and some chromophores were highly emissive with quantum yields up to 99 %. Ultimately, mesogenic and dye properties were examined by temperature‐dependent emissive experiments in the solid state.

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“…A 3:1 mixture of 1 [12] and 1 [14], mimicking the 1[12.5] homologue, exhibits both N and Tet phases separated by a monotropic reentrant isotropic phase (I re ), also observed in quickly cooled samples of 1 [12]. This rare I re phase has been reported for several other mesogens in which it separates nematic and cubic, 22 nematic and columnar, 23 smectic and columnar phases, 24,25 or two discotic phases. 26,27 More interestingly, all compounds exhibiting the Tet phase exhibit two adjacent optically isotropic phases.…”

mentioning

confidence: 91%

Tetragonal Phase of 6-Oxoverdazyl Bent-Core Derivatives with Photoinduced Ambipolar Charge Transport and Electrooptical Effects

Jasiński

Pociecha²,

Monobe

et al. 2014

J. Am. Chem. Soc.

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Bent-core mesogens containing 6-oxoverdazyl radical as the angular central unit exhibit rich polymorphism that includes isotropic-isotropic transition, re-entant isotropic (I(re)), and a novel 3D tetragonal (Tet) phases. Surprisingly, the paramagnetic Tet phase interacts linearly with applied electric field and exhibits photoinduced ambipolar charge transport (μ ≈ 10(-3) cm(2) V(-1) s(-1)). Magnetic analysis showed gradual increase of antiferromagnetic interactions upon cooling.

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Synthesis and mesomorphism of fluoroalkylated organometallic mesogens

Cited by 34 publications

References 44 publications

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters

Flavylium Salts: A Blooming Core for Bioinspired Ionic Liquid Crystals

Tetragonal Phase of 6-Oxoverdazyl Bent-Core Derivatives with Photoinduced Ambipolar Charge Transport and Electrooptical Effects

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Synthesis and mesomorphism of fluoroalkylated organometallic mesogens

Cited by 34 publications

References 44 publications

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo6I8(OCOCnF2n+1)6]2− (n = 1, 2, 3) Nanoclusters

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo6I8(OCOCnF2n+1)6]2− (n = 1, 2, 3) Nanoclusters

Flavylium Salts: A Blooming Core for Bioinspired Ionic Liquid Crystals

Tetragonal Phase of 6-Oxoverdazyl Bent-Core Derivatives with Photoinduced Ambipolar Charge Transport and Electrooptical Effects

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Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters