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Li-Rong Zhu

Bio: Li-Rong Zhu is an academic researcher from Nankai University. The author has contributed to research in topics: Liquid crystal & Mesophase. The author has an hindex of 10, co-authored 11 publications receiving 208 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the properties of substituted 2,5−diaryl−1,3,4−thiadiazole derivatives (1a−1f, 3a and 3b) were investigated by polarised-light optical microscopy, differential scanning calorimetry and in-situ variable-temperature X-ray diffraction.
Abstract: Liquid crystals based on substituted 2,5‐diaryl‐1,3,4‐thiadiazole derivatives (1a–1f, 3a and 3b) and 1,3,4‐oxadiazole analogues (2a–2f, 4a and 4b) were synthesised and characterised by 1H, 13C nuclear magnetic resonance, Fourier transform infrared, mass spectrometry, high‐resolution mass spectrometry techniques and elemental analyses. The X‐ray crystal structure of 1e revealed that it contains tilted lamellar arrangement of molecules in the crystalline solid. The liquid crystal properties have been investigated by polarised‐light optical microscopy, differential scanning calorimetry and in‐situ variable‐temperature X‐ray diffraction. All compounds (except 2e and 2f) exhibited thermotropic liquid crystal behaviours with various mesophases (smectic A and C, nematic N or soft crystal E phases). Notably, the 1,3,4‐thiadiazole derivatives consistently have wider mesomorphic temperature ranges than those of the respective 1,3,4‐oxadiazole analogues. The solutions of all compounds in CH2Cl2 individually displaye...

46 citations

Journal ArticleDOI
Jie Han1, Juan‐Yu Wang1, Feng-Yan Zhang1, Li-Rong Zhu1, Mei-Li Pang1, Jiben Meng1 
TL;DR: In this article, a new class of thiophene-based 1,3,4-oxadiazole derivatives (n ‐OXD‐R) and corresponding 1, 3, 4-thiadiazoles derivatives ( n ‐THD•R) was synthesised and characterised by means of 1H NMR, 13C NMR and MS and HRMS techniques.
Abstract: A new class of thiophene‐based 1,3,4‐oxadiazole derivatives ( n ‐OXD‐R) and the corresponding 1,3,4‐thiadiazole derivatives ( n ‐THD‐R) was synthesised and characterised by means of 1H NMR, 13C NMR, MS and HRMS techniques. Liquid crystal properties were investigated by differential scanning calorimetry, polarising optical microscopy and variable temperature X‐ray diffraction measurements. All the 1,3,4‐thiadiazole compounds ( n ‐THD‐R) exhibited enantiotropic mesophases (smectic A, smectic C and nematic phases) with wide mesomorphic temperature ranges (68.5–109.5°C). In contrast, only the oxadiazole compounds 8‐OXD‐Cl, 9‐OXD‐Cl and 10‐OXD‐Cl, bearing electron‐withdrawing terminal group and longer alkoxy chain, displayed an enantiotropic smectic A phase with narrow mesomorphic temperature ranges (4.1–10.9°C). The effects of central heterocyclic rings, the terminal groups and the length of the terminal alkoxy on the mesomorphic behaviour are discussed.

33 citations

Journal ArticleDOI
Li-Rong Zhu1, Fei Yao1, Jie Han1, Mei-Li Pang1, Jiben Meng1 
TL;DR: In this article, two bent-shaped 1,3,4-oxadiazole-based compounds, namely 2-[4-(2-(4-methylphenyl)-(E)-1-ethenyl)]phenyl-5-( 4-pentyloxyphenyl)-1, 3, 4-oxADiazole 5a and 2[4-( 2-(4fluorophenyl)- (E)- ethenyl]-5-(4)-pentyl oxymhenyl-1,3
Abstract: Two bent-shaped 1,3,4-oxadiazole-based compounds, namely 2-[4-(2-(4-methylphenyl)-(E)-1-ethenyl)]phenyl-5-(4-pentyloxyphenyl)-1,3,4-oxadiazole 5a and 2-[4-(2-(4-fluorophenyl)-(E)- ethenyl-5-(4-pentyloxyphenyl)-1,3,4-oxadiazole 5b, were synthesised and their liquid crystalline properties were studied in this paper. Compound 5a exhibited an enantiotropic nematic mesophase, while 5b displayed an enantiotropic smectic A phase. No banana-shaped mesophases were found in these mesogens, although they adopt a bent-shaped molecular structure as confirmed by the single X-ray diffraction crystallography.

24 citations

Journal ArticleDOI
TL;DR: In this paper, a series of new compounds based on aromatically 2,5disubstituted 1,3,4oxadiazoles without flexible chains, formulated as p•R•C6H4−(OC2N2)2−R′ with (i) R•CH3O, R`=CH3S, CH3S.
Abstract: A series of new compounds based on aromatically 2,5‐disubstituted 1,3,4‐oxadiazoles without flexible chains, formulated as p‐R–C6H4–(OC2N2)–(p‐C6H4)2–R′ with (i) R = CH3O, R′ = CH3O, CH3S, F, H (Ia–Id), (ii) R = CH3S, R′ = CH3O, CH3S, F, H (IIa–IId) and (iii) R = F, R′ = CH3O, CH3S, F, H (IIIa–IIId) (p‐C6H4 and OC2N2 represent a p‐phenylene spacer and a 1,3,4‐oxadiazole ring, respectively), were synthesised and characterised by 1H and 13C NMR, MS and HRMS techniques. Mesomorphic properties were investigated using differential scanning calorimetry and polarizing optical microscopy. All of the target compounds (except Id, IId, IIIc and IIId) exhibited an enantiotropic nematic mesophase with high melting temperatures. The liquid crystalline properties of these compounds were influenced greatly by polarity, steric factors and positions of the terminal groups. The effect of the terminal groups on the liquid crystal properties is discussed.

20 citations

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


Cited by
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Journal ArticleDOI
TL;DR: An overview of the current state of research in the field of biaxial nematic liquid crystalline materials is given in this paper, where the major theoretical concepts are outlined, including the classification to different symmetries, the importance of cooperativity and cluster formation for the development of BN order and the conditions for the establishment of field induced and spontaneous BN in nematic phases.
Abstract: An overview over the current state of research in the field of biaxial nematic liquid crystalline materials is given. After a short introduction, providing some general aspects and summarizing the classical approaches, the main part focuses on recent developments of new concepts for designing biaxial nematics. First, the major theoretical concepts are outlined, including the classification to different symmetries, the importance of cooperativity and cluster formation for the development of biaxial order and the conditions for the establishment of field induced and spontaneous biaxiality in nematic phases. These new concepts also require the re-evaluation of the tools used for the identification of phase biaxiality, which are discussed briefly. In the second part, recent progress in the design of potential biaxial nematic materials, especially focussing on bent-core molecules with nematic phases, is reported and, finally, comparisons with phase biaxiality as observed in smectic liquid crystals are made.

299 citations

Journal ArticleDOI
TL;DR: Ruthenium(II) complexes have emerged as effective catalysts for C-H arylations of tetrazolyl-substituted arenes by chelation assistance.

243 citations

Journal ArticleDOI
TL;DR: Significant progress has been made in direct C-H bond arylations of arenes and heteroarenes with readily accessible, inexpensive phenol derivatives as discussed by the authors, such as ruthenium biscarboxylate complexes and inexpensive cobalt compounds.

127 citations

Journal ArticleDOI
TL;DR: In this paper, a review summarizes the important advances in fluorescent chemosensors for Cu 2+, mainly made in the recent five years, and categorizes three types of chemOSensors according to fluorescence signal changes, and each type is further classified into several sections according to the molecular structure features and/or recognition mechanisms.
Abstract: Among the transition metal ions, copper is the third most abundant essential trace metal element in human body, and is also required by many living organisms for normal physiological processes, while excessive levels of Cu 2+ are highly toxic to organisms and generate enormous quantities of pollution to our living environment. It is an essential and key issue to devise more sensitive and selective fluorescent chemosensors to efficiently evaluate the Cu 2+ levels in environmental and biological systems. This review summarizes the important advances in fluorescent chemosensors for Cu 2+ , mainly made in the recent five years. Three types of chemosensors, namely ‘on-off’, ‘off-on’ and ‘ratiometric’, are categorized according to fluorescence signal changes, and each type is further classified into several sections according to the molecular structure features and/or recognition mechanisms. Additionally, the Cu 2+ -promoted reaction based chemosensors are also discussed by the different reactions like hydrolysis, oxidation and reduction. The molecular structures, recognition mechanism and applications of the fluorescent chemosensors are emphatically discussed, and the future perspective is overviewed briefly.

122 citations

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