Polyacetylenes Bearing Mesogenic Side Groups: Synthesis and Properties, 2

Stagnaro, Paola; Conzatti, Lucia; Costa, Giovanna; Gallot, Bernard; Tavani, Cinzia; Valenti, Barbara

doi:10.1002/macp.200390041

Cited by 12 publications

(11 citation statements)

References 27 publications

(66 reference statements)

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“…Following the general synthetic methods [4,5], we synthesized the monosubstituted polyacetylene PHBOP. After purification and drying in a vacuum oven, PHBOP in the form of powders were obtained.…”

Section: Methodsmentioning

confidence: 99%

“…For examples, Davey et al [1] and Whitehead et al [2] investigated the polarized photoluminescence (PL) from liquid crystalline polymers. Recently, several research groups synthesized a novel class of side-chain liquid crystalline polyacetylenes by introducing orientable mesogenic pendant onto the rigid backbone of polyacetylene [3][4][5][6]. Their optical characterization has demonstrated that the dilute solutions of these side-chain liquid crystalline polyacetylenes can give off efficient deep-blue or blue PL [5][6][7][8][9][10] although the pristine polyacetylenes can give off weak PL only in the infrared region [11].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Huang

Zhai

2009

Molecular Crystals and Liquid Crystals

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Optical absorption and emission properties of a monosubstituted polyacetylene poly[(4-hexylcarbonyl-biphenyl-4 0 -oxy)-1-propyne] have been investigated by means of ultraviolet-visible spectrophotometry, fluorescence spectroscopy, and electronic structure calculations, respectively. Under ultraviolet excitations, dilute tetrahydrofuran solutions of the side-chain polymer can give off deep-blue photoluminescence. Our results have demonstrated that the optical properties of the liquid crystalline polymer are both concentration and temperature dependent. The origin of the deep-blue photoluminescence of polymer can be ascribed to the biphenyl chromophors in its pendants. Comparative studies to a biphenyl-containing liquid crystal give further evidence to our discussion on the origin of the deep-blue photoluminescence of the polymer.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Huang

Zhai

2009

Molecular Crystals and Liquid Crystals

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“…Years ago, we observed intense deep-blue emissions from a class of mono-substituted polyacetylenes with biphenyl side-chains, and our results have demonstrated that the biphenyl pendants are responsible for the deep-blue emissions of those mono-substituted polyacetylenes [4][5][6][7]. Recently, Stagnaro et al [8] observed blue emission from polyacetylenes bearing biphenyl mesogens to the backbone via short methylene spacers; they suggested that both the polymer backbone and the biphenyl chromophore in the side group play a role in the blue emission. Due to the complexity in the photo-physics of conjugated polymers [9], it is clear that the origin of the blue emissions is still open to question for the polyacetylenes with side chains.…”

Section: Introductionmentioning

confidence: 90%

Origin of the blue emissions of polyacetylenes bearing carbazole side groups

Huang¹,

Song²,

Huang³

et al. 2005

Journal of Luminescence

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The optical properties and electronic structures of one mono-substituted polyacetylene and two di-substituted polyacetylenes have been investigated. Each of the substituted polyacetylenes bears a carbazole unit in the side chain. In spite of the differences in their molecular structures, the dilute solutions ($1 Â 10 À6 M) of these substituted polyacetylenes exhibit the same absorptions and the same deep-blue emissions ($360 nm). Interestingly, the absorption and emission spectra of these substituted polyacetylenes are similar to those of the small molecule carbazole. As the concentration of the substituted polyacetylenes increases to about 1 Â 10 À3 M, we have detected intense blue emissions at about 475 nm. Using Hu¨ckel tight binding programs, we have calculated the electronic structures of the carbazolecontaining polyacetylenes. Our results indicate that the absorption, the deep-blue emission ($360 nm) and the intense blue emission ($475 nm) originate from the carbazole chromophores in the side chain. r

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“…As mentioned above, Hsu and co-workers find that the cis-rich polymers without spacer do not show LC behavior. However, in the study of the influence of short flexible spacer, [80][81][82] Costa and coworkers found that, with only a single methylene spacer, the SCLCPAs can form Sm phases. Such a short spacer cannot decouple the dynamics of main and side-chains.…”

Section: Sheet-like Mspas and Their Smectic Lc Phasesmentioning

confidence: 99%

Molecular Shapes of Monosubstituted Polyacetylenes in their Liquid Crystalline Phases

Liu¹,

Yu²,

Chen³

2009

Macro Chemistry & Physics

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In this short review, we discuss the molecular shapes of monosubstituted polyacetylenes (MSPAs) in their liquid crystalline (LC) phases. Their rigid backbone with high stereoregularity can endow MSPAs with significant shape persistency, which largely determines their LC structures. Helical cis‐cisoidal and cis‐transoidal MSPAs render rod‐like shapes and can form columnar LC (Φ) phases. In the smectic LC (Sm) phases of MSPAs with mesogenic side‐chains, the main chain, with trans‐cisoidal, trans‐transoidal or extended cis‐transoidal conformation, is in fact largely coplanar with the side‐chains, resulting in a sheet‐like molecular shape. From a simple geometric point of view, the rod‐ or sheet‐like MSPA molecules serve as the building block of their LC phases.magnified image

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Polyacetylenes Bearing Mesogenic Side Groups: Synthesis and Properties, 2

Cited by 12 publications

References 27 publications

Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Origin of the Deep Blue Photoluminescence of a Liquid Crystalline Polymer Poly[(4-Hexylcarbonyl-Biphenyl-4′-Oxy)-1-Propyne]

Origin of the blue emissions of polyacetylenes bearing carbazole side groups

Molecular Shapes of Monosubstituted Polyacetylenes in their Liquid Crystalline Phases

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