Synthesis and Liquid Crystalline Properties of Low Molecular Weight Bis-Chalcone Compounds

2021 ◽  
Vol 18 ◽  
Author(s):  
Anju K Sasidharan ◽  
Jomon Mathew ◽  
Ammathnadu S. Achalkumar ◽  
Manoj Mathews
Keyword(s):  
Molecular Weight ◽  
Liquid Crystalline ◽  
Low Molecular Weight ◽  
Aliphatic Chain ◽  
Aromatic Rings ◽  
Property Relationship ◽  
Crystalline Property ◽  
Liquid Crystalline Property ◽  
Mesomorphic Properties ◽  
Structure Liquid

Aim: In this paper, we report on the synthesis and liquid crystalline properties of some low molecular weight bis-chalcone compounds derived from acetone, cyclopentanone and cyclohexanone mesogenic cores. Background: Structurally bis-chalcones belong to a broader family of chalcone compounds. Chalcone is a compound that consists of two aromatic rings linked by an unsaturated objective. Liquid crystalline chalcones are prepared by aliphatic chain substituents on two aromatic rings. Chalcones are well studied for their mesomorphic properties. Compared to a large number of chalcone based LCs reported, only a few articles have been published on the mesomorphic properties of bis-chalcone compounds. The target compounds of the present study varied not only in their central core but also in number and position of terminal aliphatic chain substitutiona key structural unit in deciding the liquid crystalline properties of a compound. Method: All target compounds were synthesized in good yield by base catalyzed Claisen-Schmidt condensation reaction. Molecular structures were confirmed by FT-IR, 1H NMR, 13C NMR, and mass spectroscopic methods. Liquid crystalline property of these compounds was evaluated using polarizing optical microscopy and differential scanning calorimetry. Results: Although none of the acetone based compounds exhibited mesomorphism, cyclopentanone and cyclohexanone based compounds with octyloxy chain at para position on either side of the dibenzylidine ring stabilized liquid crystalline smectic (SmA and SmC) and nematic (N) phases. The observed structure-liquid crystalline property relationship was explained by structural analysis of molecules using DFT calculations. Considering the inherent photoluminescence nature of the chalcone moiety, a preliminary study was carried out on a selected compound to reveal its fluorescence property. Conclusion: Our study brings about an important structure-liquid crystalline property relationship in a relatively unexplored class of bis-chalcone liquid crystals.

A Novel Anisotropic Electroactive Liquid Crystalline Polyimide Containing Aniline Trimer Segments

2011 ◽  
Vol 239-242 ◽  
pp. 1269-1274
Author(s):  
Si Wei Liu ◽  
Qiao Ying Cao ◽  
Yi Zhang ◽  
Zhen Guo Chi ◽  
Jia Rui Xu
Keyword(s):  
Molecular Weight ◽  
Liquid Crystalline ◽  
Sulfonyl Chloride ◽  
Dimethyl Formamide ◽  
Hydroxybenzoic Acid ◽  
Shear Direction ◽  
Crystalline Property ◽  
Liquid Crystalline Property

A novel type of liquid crystalline polyimide with good electroactive properties has been successfully synthesized through polycondensation in the component solvent of benzene sulfonyl chloride, dimethyl formamide and pyridine byN,N’-hexane-1,6-diylbis(trimellitimides),p-hydroxybenzoic acid, 4,4'-dihydroxybenzophenone and double amino-capped aniline trimer (N1,N1'-(1,4-phenylene)bis(benzene-1,4-diamine)). The structure of the obtained polymer was characterized and verified. The polymer can be dissolved in the component solvent of phenol and chloroform or DMF, NMP alone,et al. The molecular weight (Mn=1.7×104,Mw=8.2×104，PDI=4.8) was determined by gel permeantion chromatography using DMF as eluent. By combining the excellent properties of both polyimide and oligoaniline, such material could be used in more broad fields. Furthermore, due to the orientation properties of liquid crystalline property, the conductivity of this polymer is anisotropic, with 10-6S/cm along the shear directionvs.10-7S/cm perpendicular to the shear direction.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

scholarly journals Thermally tunable selective formation of self-assembled fibers into two orthogonal directions in oriented liquid-crystalline smectic templates

2020 ◽  
Vol 56 (69) ◽  
pp. 9954-9957
Author(s):  
Daisuke Yamaguchi ◽  
Yuka Ikemoto ◽  
Takashi Kato
Keyword(s):  
Molecular Weight ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Layered Structures ◽  
Low Molecular Weight ◽  
Smectic A ◽  
Orthogonal Grid ◽  
Self Assembled ◽  
Low Molecular Weight Gelators ◽  
Selective Formation

Two orthogonal (grid-like) and one directional fibrous structures are selectively formed through anisotropic self-assembly of low-molecular-weight gelators in liquid-crystalline smectic A templates depending on thermally tuned layered structures.

scholarly journals Current Status of- and Future Perspectives in- Bacterial Degradation of Benzo[a]pyrene

2020 ◽  
Author(s):  
Alexis Nzila ◽  
Musa M. Musa
Keyword(s):  
Molecular Weight ◽  
Current Knowledge ◽  
Bacterial Degradation ◽  
Current Status ◽  
Low Molecular Weight ◽  
Future Perspectives ◽  
Aromatic Rings ◽  
Compound A ◽  
Current Review ◽  
Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAHs), which consist of low-molecular-weight PAHs (LMW-PAHs) and high-molecular-weight PAHs (HMW-PAHs), form an important class of pollutants. Pyrene and benzo[a]pyrene (BaP) are the main pollutants belonging to HMW-PAHs, and their degradation by microorganisms remains an important strategy for their removal from the environments. Extensive studies have been carried out on the isolation and characterisation of microorganisms that actively degrade LMW-PAHs, and to a certain extent, the HMW-PAH pyrene. However, so far, limited work has been carried out on BaP biodegradation. BaP consists of five fused aromatic rings, which confers this compound a high stability, rendering it less amenable to biodegradation. The current review summarizes the emerging reports on BaP biodegradation. More specifically, work carried out on BaP bacterial degradation and current knowledge gaps that limit our understanding of BaP degradation are highlighted. Moreover, new avenues of research on BaP degradation are proposed, specifically in the context of the development of “omics” approaches

scholarly journals Preferential Circularly Polarized Luminescence from a Nano-Segregated Liquid Crystalline Phase Using a Polymerized Twisted Nematic Platform

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2529
Author(s):  
Jae-Jin Lee ◽  
Suk-Won Choi
Keyword(s):  
Molecular Weight ◽  
Liquid Crystalline ◽  
Guest Molecule ◽  
Mixed System ◽  
Low Molecular Weight ◽  
Circularly Polarized ◽  
Molecular Systems ◽  
Circularly Polarized Luminescence ◽  
Twisted Nematic ◽  
Polarized Luminescence

In this study, a polymerized twisted nematic (TN) network was used as an extrinsic chiral platform to overcome the heterogeneity during spontaneous symmetry breaking in a mixed system comprising an achiral bent-core molecule and rod-like mesogen. The TN platform was prepared by photopolymerizing a reactive mesogen dispersed in a low molecular weight liquid crystal with TN orientation. The use of TN orientation to correct the degeneracy in bent-core molecular systems has been previously reported; however, to the best of our knowledge, this is the first study that uses an extrinsic chiral platform of a polymerized TN network. The heterogeneity in the nano-segregated phase of the achiral mixture was suppressed using the extrinsic TN platform with a twisted angle θ of ≥ |±30°|. When an achiral mixture doped with a luminescent guest molecule was refilled into the extrinsic chiral platform, preferential deracemization with one-handedness occurred, corresponding to the handedness of the TN platform. Therefore, circularly polarized luminescence with a preferential handedness can be achieved using this extrinsic chiral platform.

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