Coumarin-based emissive liquid crystals

Buchs, Jens; Gäbler, Michael; Janietz, Dietmar; Sawade, Hans

doi:10.1080/02678292.2014.936530

Cited by 24 publications

(2 citation statements)

References 70 publications

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“…Thermotropic characteristics, photophysical, and photochemical behavior were examined for coumarin-containing side-group polymers [5] and the cyclic oligosiloxanes [6]. It was discovered that thermomesomorphism occurs in low molecular mass systems when aryl substituents are linked to the 6-or 7-position of the benzopyran-2H-one core through an ester linkage [7]. Conversely, by modifying the coumarin heterocycle with a carbonyl hydrazide function or fusing with an extra pyrazolone ring [8], hydrogen bonding between the molecules drives mesophase development.…”

Section: Introductionmentioning

confidence: 99%

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2023

J. Med. Chem. Sci.

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The synthesis, characterization, and mesomorphic investigation of new liquid crystals are described. The goal was to synthesize esters starting with 6-and 7-hydroxycoumarin. The structures of the synthesized compounds were actually determined by FT-IR and 1 H-NMR. The mesophase behavior of the synthesized compounds was characterized and investigated by using (DSC) differential scanning calorimetry and (POM) polarizing the optical microscopy. The mesophase transitions are enantiotropic, the peaks being sharp and the mesomorphic range wide. The synthesized compounds exhibit a nematic phase.

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Section: Introductionmentioning

confidence: 99%

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2023

J. Med. Chem. Sci.

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“…Moreover, they exhibit an excellent and wide range of biological activity, such as antibiotic, anticancer, antifungal, ant-coagulating, anti-inflammatory, plant growth regulating agents and analytical reagents [5][6][7]. Additionally, polymeric and non-polymeric coumarin derivatives display liquid-crystalline properties [8][9][10][11]. Thus, coumarins have become an interesting molecular framework to be incorporated in numerous electronic organic materials, with potential applications in OLED, solar cells and photo alignment technologies for liquid crystal displays [12,13].…”

Section: Introductionmentioning

confidence: 99%

DFT Calculations and Mesophase Study of Coumarin Esters and Its Azoesters

2018

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Two groups of coumarin derivatives, 4-methyl-2-oxo-2H-chromen-7-yl 4-alkoxybenzoates (coumarin esters), In, and 4-methyl-2-oxo-2H-chromen-7-yl 4-(2-(4-alkoxyphenyl)diazenyl) benzoates (coumarin azoesters), IIn, were synthesized and investigated for their mesophase behavior and stability. Each group constitutes five series that differ from each other by length of the mesogenic part. Within each homologous series, the length of the terminal alkoxy group varies between 6, 8, 10, 12 and 16 carbons. Mesophase behavior was investigated by differential scanning calorimetry (DSC) and identified by polarized light microscopy (PLM). Density functional theory (DFT) calculations for coumarin derivatives were discussed. The results revealed that the incorporation of azo group incorporated in the mesogenic core decreases the energy differences, increases the dipole moments and stabilities of coumarin azoesters series more than coumarin esters.

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Linear Coumarinacenes Beyond Benzo[g]coumarins: Synthesis and Promising Characteristics

et al. 2020

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New heteroacenes, named coumarinacenes, have been designed, synthesized and characterized. They possess visible absorption and orange-red emission that are far beyond those of benzo[g]coumarins. They exhibit deep HOMO energy levels, and reveal excellent thermal, photochemical and air sta-Coumarins are pyranone-annulated benzenes (2H-benzopyran-2-ones) that are ubiquitous in nature. [1] They are actually popular for their wide spectrum of biological and pharmacological activities, [2a] such as, antioxidant, [2b] antidepressant, [2c] anticoagulant, [2d] anti-inflammatory, [2e] antifungal, [2f ] antitumor, [2g] anti-HIV, [2h] antibiotic, [2i] etc., and for their excellent biocompatibility. [1] Structurally simple derivatives of coumarin exhibit rich photophysical and photochemical properties (high photoluminescence quantum yields, large Stokes shifts and good photostability) paving their entry into modern photonic applications; laser dyes, [3a,3b] non-linear optics, [3c] two-photon bioimaging [3d] and sensing [3e] are some examples. Moreover, coumarin derivatives are recently being exploited as functional materials in organic light emitting devices, [4a,4b] liquid crystals, [4c] dye-sensitized solar cells, [4d,4e] electron and energy transfer systems, [4f,4g] and fluorescent probes. [4h] Despite the broad utility of coumarins, the low-lying absorption and emission wavelengths (due to shorter conjugation lengths) are primarily the bottlenecks in furthering their applications. In an effort to overcome the limitations, considerable attention is devoted in recent times for the development of novel π-expanded coumarin dyes. [5] Benzocoumarins-the simplest π-expanded benzene-fused coumarins-indeed absorb and emit light in the longer wavelength region when compared to parent coumarins (Scheme 1). [6] Among the other isomeric [a] A

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Coumarin-based emissive liquid crystals

Cited by 24 publications

References 70 publications

Untitled

Untitled

DFT Calculations and Mesophase Study of Coumarin Esters and Its Azoesters

Linear Coumarinacenes Beyond Benzo[g]coumarins: Synthesis and Promising Characteristics

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