Synthesis and mesomorphic behaviour of heterocycle‐based liquid crystals containing 1,3,4‐oxadiazole/thiadiazole and thiophene units

Han, Jie; Wang, Juan-Yu; Zhang, Feng‐Yan; Zhu, Liya; Pang, Meili; Ji, Meng

doi:10.1080/02678290802444129

Cited by 34 publications

(4 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the larger angles in Th 3 (10) and Th-Thd-Th(10) favor LC phases, whereas the more bent structure of Th-Oxd-Th(10) would be detrimental for mesophase formation. This is consistent with previous literature suggesting that thiadiazole derivatives have a greater tendency to exhibit smectic mesophases than oxadiazole analogues [88,89,90,91].…”

Section: Resultssupporting

confidence: 93%

Heterocycle Effects on the Liquid Crystallinity of Terthiophene Analogues

et al. 2019

View full text Add to dashboard Cite

Liquid crystalline self-assembly offers the potential to create highly ordered, uniformly aligned, and defect-free thin-film organic semiconductors. Analogues of one of the more promising classes of liquid crystal semiconductors, 5,5”-dialkyl-α-terthiophenes, were prepared in order to investigate the effects of replacing the central thiophene with either an oxadiazole or a thiadiazole ring. The phase behaviour was examined by differential scanning calorimetry, polarized optical microscopy, and variable temperature x-ray diffraction. While the oxadiazole derivative was not liquid crystalline, thiadiazole derivatives formed smectic C and soft crystal lamellar phases, and maintained lamellar order down to room temperature. Variation of the terminal alkyl chains also influenced the observed phase sequence. Single crystal structures revealed the face-to-face orientation of molecules within the layers in the solid-state, a packing motif that is rationalized based on the shape and dipole of the thiadiazole ring, as corroborated by density functional theory (DFT) calculations. The solution opto-electronic properties of the systems were characterized by absorption and emission spectroscopy, cyclic voltammetry, and time-dependent density functional theory (TD-DFT).

show abstract

Section: Resultssupporting

confidence: 93%

Heterocycle Effects on the Liquid Crystallinity of Terthiophene Analogues

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Due to their beneficial capacity to impart lateral and/or longitudinal dipoles, together with variations in their molecular geometries, which are reflected in their optical and electrical behaviors, heterocyclic-based LC materials have been of great interest to many researchers [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Pyridine exhibits a dipole moment of 2.19 D, which is about fivehundredths of that of a cyano group (~4.0 D) [25]; consequently, it influences the stability of the mesophase when it is utilized as a moiety within the mesogens [25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Phase Behavior and Computational Simulations of a Pyridyl-Based Liquid Crystal System

et al. 2021

View full text Add to dashboard Cite

A homologous set of liquid crystalline materials (Tn) bearing Schiff base/ester linkages were prepared and investigated via experimental and theoretical techniques. Terminal flexible groups of different chain lengths were connected to the end of phenylbenzoate unit while the other end of molecules was attached to the heterocyclic pyridine moiety. The molecular structures of the designed molecules were evaluated by FT-IR, NMR spectroscopic analyses, whereas their mesomorphic properties were investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). They all exhibited dimorphic properties with the exception of the members having the shortest and longest terminal flexible chains (n = 6 and 16), which were monomorphic. The T16 derivative was further found possessing purely smectic A (SmA) mesophase while others have their lengths covered by nematic (N) phase. Moreover, the computational evaluation of the azomethine derivatives was carried out using a DFT approach. The polarity of the investigated derivatives was predicted to be appreciably sensitive to the size of the system. Furthermore, the Frontier molecular orbitals analysis revealed various distributions of electron clouds at HOMO and LUMO levels.

show abstract

“…Choosing an appropriate mesogenic core unite, the appropriate length of one or more chains, and connecting groups are common steps in the design and synthesis of new thermotropic liquid crystals. Modifying the mesogenic core signi cantly alters its properties, such as molecular polarity [9] and can be further altered by adding heteroatoms [10,11].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization and investigation of liquid crystalline properties for some cross-link polymers containing melamine

Sultan,

Ahmed,

Tomma

et al. 2024

Preprint

View full text Add to dashboard Cite

In this study condensation polymerization was used to synthesize a number of novel liquid crystal polymers with 1,3,4-oxadiazole rings based on melamine. The new synthesized polymers were characterized by Fourier Transform Infrared (FTIR) and proton nuclear magnetic resonance (1HNMR) spectroscopy. Differential scanning calorimetry (DSC) and optical polarization microscopy (OPM) were used to investigate their liquid crystalline properties. The results demonstrated that throughout a wide temperature range, most of the polymers exhibited columnar (CohX) and nematic (N) liquid crystalline phases.

show abstract

Synthesis and mesomorphic behaviour of heterocycle‐based liquid crystals containing 1,3,4‐oxadiazole/thiadiazole and thiophene units

Cited by 34 publications

References 15 publications

Heterocycle Effects on the Liquid Crystallinity of Terthiophene Analogues

Heterocycle Effects on the Liquid Crystallinity of Terthiophene Analogues

Synthesis, Phase Behavior and Computational Simulations of a Pyridyl-Based Liquid Crystal System

Synthesis, characterization and investigation of liquid crystalline properties for some cross-link polymers containing melamine

Contact Info

Product

Resources

About