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Qiong Wang

Bio: Qiong Wang is an academic researcher from Nankai University. The author has contributed to research in topics: Liquid crystal & Thiophene. The author has an hindex of 3, co-authored 3 publications receiving 37 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a series of fluorescent liquid crystalline compounds containing 1,3,4-oxadiazole and benzo[b]thiophene units have been prepared.
Abstract: A series of fluorescent liquid crystalline compounds containing 1,3,4-oxadiazole and benzo[b]thiophene units have been prepared. In CH2Cl2 solution, these compounds displayed a fluorescent emission with λmax at 422–426 nm and quantum yields of 41–48%. Most of them exhibited thermotropic liquid crystalline properties with nematic and/or smectic A phases with excellent thermal stability. This work revealed that longer terminal alkoxy chains would be detrimental to the formation of mesophases for such kind of compounds. The effect of the terminal groups on mesomorphic and spectroscopic property is discussed.

18 citations

Journal ArticleDOI
TL;DR: In this article, two H-shaped liquid crystalline 1,3,4-thiadiazole dimers D1 and D2 and the corresponding monomers M1 and M2 were synthesised and characterised by 1H/13C nuclear magnetic resonance (NMR) and high-resolution mass spectrometry.
Abstract: Two H-shaped liquid crystalline 1,3,4-thiadiazole dimers D1 and D2 and the corresponding monomers M1 and M2 were synthesised and characterised by 1H/13C nuclear magnetic resonance (NMR) and high-resolution mass spectrometry. The thermal properties of the dimers and monomers were investigated by polarised optical microscopy, differential scanning calorimetry and thermogravimetric analysis. All of these compounds exhibited liquid crystalline behaviours with excellent thermal stabilities. The dimers displayed an enantiotropic or a monotropic nematic phase, while the monomers showed nematic and/or smectic A phases enantiotropically. The nature of the mesophases was determined by the molecular shapes and the terminal groups. Notably, the H-shaped dimers exhibited much lower clearing temperatures than the corresponding rod-like monomers.

13 citations

Journal ArticleDOI
Jie Han1, Qiong Wang1, Xiao-Yong Chang1, Yu-Xin Liu1, Yan-Mei Wang1, Jiben Meng1 
TL;DR: The reactivity of trans-1,2-diarylethenes with thionyl chloride has been investigated in this article, showing that they can be converted into cholobenzo[b]thiophenes in moderate yields and a pair of threo-and erythro-1 2 -dichloro-1 1,2diarylethanes as minor products under mild condition.

10 citations


Cited by
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Journal ArticleDOI
Jie Han1
TL;DR: In this article, 1,3,4-oxadiazole-based liquid crystals are classified into three categories according to their different molecular shapes and molecular weight: calamitic and discotic monomers, symmetric and non-symmetric dimers, and polymers including main-chain, side-chain and mesogen-jacketed types.
Abstract: Liquid crystals with 1,3,4-oxadiazole units in the aromatic core have attracted considerable attention due to their rich mesophases, high photoluminescence quantum yields, good electron transporting ability and excellent thermal stabilities. In this feature article, 1,3,4-oxadiazole-based liquid crystals are classified into three categories according to their different molecular shapes and molecular weight: calamitic and discotic monomers, symmetric and non-symmetric dimers, and polymers including main-chain, side-chain and mesogen-jacketed types. The structure–property relationships of this kind of liquid crystal are discussed in-depth, with an emphasis on strategies to devise columnar and biaxial nematic mesophases with a low temperature range.

97 citations

Journal ArticleDOI
TL;DR: In this paper, the synthesis and characterisation of two new sets of non-symmetric liquid crystal dimers is reported, the 1-(4substitutedazobenzene-4′-yloxy)-6-(4-cyanobiphenyl-4''-yl)hexanes (CB6OABX) and 1-( 4-substitizedazobenensenes-4,''-methyl)-6''6''-pentanes (CBO5 OABX).
Abstract: The synthesis and characterisation of two new sets of non-symmetric liquid crystal dimers is reported, the 1-(4-substitutedazobenzene-4′-yloxy)-6-(4-cyanobiphenyl-4′-yl)hexanes (CB6OABX) and 1-(4-substitutedazobenzene-4′-yloxy)-6-(4-cyanobiphenyl-4′-yloxy)pentanes (CBO5OABX). The terminal substituents are methyl, methoxy, butyl, butyloxy, nitrile and nitro. All the CB6OABX dimers exhibit twist-bend nematic (NTB) and nematic (N) phases. The CBO5OABX dimers also all show an N phase but only the butyl and butyloxy homologues exhibit the NTB phase. The transitional behaviour of the non-symmetric dimers is compared to that of the corresponding symmetric dimers, the 1,5-bis(4-substitutedazobenzene-4′-yloxy)pentanes (XABO5OABX) and either 1,7-bis(4-cyanobiphenyl-4′-yl)heptane or 1,5-bis(4-cyanobiphenyl-4′-yloxy)pentane. The XABO5OABX dimers all show a nematic phase and in addition, the butyl homologue exhibits a smectic A phase. The difference in transitional behaviour between the CB6OABX and CBO5OABX di...

60 citations

Journal ArticleDOI
TL;DR: In this article, a review highlights remarkable mesophase stability and physical properties, and potential applications of various heterocyclic calamitic liquid crystal (LC) in modern devices.
Abstract: Liquid crystals (LCs) are ordered soft materials formed by self-assembling molecules, which combine anisotropic properties with the fluidity of a liquid. They can potentially be used as functional materials for electron, ion or molecular transport, which can be applied in opto-electronic devices, aligned electrolytes and biological systems. In particular, the calamitic LCs have been promising candidates from the very beginning of liquid crystal research, are applied successfully in various optical devices and are recently rediscovered in the field of organic semiconductors. New LCs with low viscosity, adapted mesophase range and structure, and high reliability were necessary to achieve the rapid transformation from flat computer monitors to large displays for television. This review highlights remarkable mesophase stability and physical properties, and potential applications of various heterocyclic calamitic LCs in modern devices.

50 citations

Journal ArticleDOI
TL;DR: In this paper, four series of symmetrically 2,5-disubstituted 1,3,4-oxadiazoles with different lateral substituents and terminal alkoxy chain length were synthesized and characterised.
Abstract: Four series of symmetrically 2,5-disubstituted 1,3,4-oxadiazoles with different lateral substituents and terminal alkoxy chain length were synthesised and characterised. Then, all these bent-shaped compounds were separately doped into the blue phase (BP) liquid crystal host and their effects on the BP range of the host were investigated, which shows that the BP ranges varied greatly with the difference in the structure of 2,5-disubstituted 1,3,4-oxadiazoles and their doped concentration. Moreover, in order to explore the influence of the inherent molecular geometry and properties of the bent-shaped molecules on the stability of BPs, the molecular structures of all the compounds were studied by using the theory of density functional theory, and the optimised structural parameters of the molecules were calculated at the B3LYP/6–31G* level.

41 citations

Journal ArticleDOI
TL;DR: In this article, a hockey-stick-shaped 2,5-diphenyl-1,3,4-thiadiazole-containing mesogens have been designed and synthesised.
Abstract: New hockey-stick-shaped 2,5-diphenyl-1,3,4-thiadiazole-containing mesogens have been designed and synthesised. These molecules possess 4-n-alkoxy chain at the elongated arm whereas and 4-n-butyloxy chain at the shorter arm of the molecule. The compounds are fluorescent and emission located in the violet to blue region with a large stoke shift observed in polar solvents. No substantial solvatochromic effect was found in the absorption maxima, but in the emission, a red shift was observed with increasing the solvent polarity. In the solid thin film, compounds emitted green light. The compounds having longer chain (n > 8) exhibit SmA and SmC phase, while the compounds with shorter chain at one end of the molecule display nematic and SmC phase. The density functional theory study has been carried out to investigate the stable configuration and the influence of solvent on bond length, bond angle, bending angle, dipole moment, polarisability of the molecule. It also enables us to predict the possible re...

32 citations