A novel homologous series of liquid crystalline 4-(4′-n-alkoxy cinnamoyloxy)-4″-methoxy benzyl cinnamates was synthesized and studied with a view to understand and establish the effects of molecular structure on liquid crystal behavior. The series consists of eleven members of the series. None of the homologue derivatives are either nonliquid crystal or smectogenic, i.e. all the eleven members of the novel homologous series are enantiotropcially nematogenic only. Transition and melting temperatures as well as textures of the nematic mesophase were determined on an optical polarizing microscope equipped with a heating stage. The transition curves of the phase diagram show phase behavior in a normal expected manner. An odd-even effect is observed for the nematic-isotropic transition curve. The textures of the nematic mesophase are threaded or Schlieren as determined a by miscibility method. Analytical and spectral data confirm the molecular structures of the homologues. The average thermal stability for nematic is 213.8°C. The isotropic temperatures vary between 190°C and 240°C. The nematogenic mesophase length varies from 17°C to 102°C. Thus, the novel homologous series is entirely nematogenic without the exhibition of smectogenic character. The liquid crystal (LC) properties of the present novel series are compared with structurally similar other known homologous series.
Abstract A novel homologous series α-4-[4′-n-alkoxy benzoyloxy] benzoyl-β-3″,4″-dimethoxy phenyl ethylenes has been synthesized and studied for liquid crystal (LC) properties to understand and establish the relation between molecular structure and liquid crystalline behavior. Twelve members of series were synthesized. All the members except first member of the series are mesomorphic. The hexyloxy to tetradecyloxy homologoues are smectogenic and nematogenic in character. The ethoxy to pentyloxy and the hexadecyloxy homologues exhibit only nematogenic character with the absence of smectogenic mesophase formation. An odd–even effect is observed for the smectic-nematic and the nematic-isotropic transition curves in the phase diagram. The smectic mesophase showed as either the SmA or SmC. The nematic mesophase shows a threaded or Schlieren type texture. Spectral and analytical data confirms the molecular structures of the homologues. The thermal stabilities for the smectic and the nematic are 115.6°C and 156.6°C. The smectogenic and nematogenic mesophase length vary from 7°C to 28°C and from 7°C to 52°C respectively. The transition temperatures were observed through an optical polarizing microscope equipped with heating stage. Thus, the presently investigated novel homologous series is predominantly nematogenic and partly smectogenic with a middle ordered melting type and a considerable mesophase length. The LC properties of the novel series are compared with structurally similar homologous series. Keywords: Anisotropic liquidliquid crystalmesomorphismnematicsmectic Acknowledgments Authors thank the president and all members of the management of Bai Jivkor Lalubhai Trust as well as the principal Dr. R. R. Shah and head of chemistry department, Dr. R. B. Patel of K. K. Shah Jarodwala Maninagar Science College, Ahmedabad, for their valuable cooperation in this work. Also, thanks are due to the Vaibhav Laboratory and head of chemistry department of S. P. T. Science College, Godhra, for their valuable cooperation in facilitating microscopic observations and analytical services.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Microdroplet systems can drastically reduce costs and increase throughput in high throughput screening (HTS) assays. While droplets are well suited for biomolecular screening, cell-based screens are more problematic because eukaryotes typically require attachment to solid supports to maintain viability and function. This paper describes an economical, off-the-shelf microfluidic system which encapsulates eukaryotic cells in gelatinous alginate capsules for the purpose of HTS. The flow-through system consists of i) a cross junction, which forms monodisperse droplets of alginate and cell suspension in an immiscible carrier fluid, followed by ii) a T junction which delivers BaCl(2) to crosslink and solidify each droplet. With an appropriate carrier fluid, the system is self-synchronized and can produce cell-alginate-BaCl(2) capsules with virtually 100% reliability. Droplet volumes and frequency are determined by flow rates and the diameter of the cross junction. The present implementation, which utilizes 1.5 mm Teflon tubing and plastic junctions, can generate 0.4-1.4 microL droplets at frequencies >10 droplets/sec. Cell viability is >80% at 4 hours post-encapsulation. With low recurring cost (
The titled azoester liquid crystalline homologous series consists of eleven homologues. The pentyl to tetradecyl derivatives of the series are nematogenic without exhibition of smectogenic character. Rest of the members of the series are nonliquid crystalline in nature. Textures of the nematic mesophase are schlieren or threaded type. Transition curves in the phase diagram showed normal phase behavior. Transition temperatures and liquid crystal behavior observed under an optical polarizing microscope equipped with a heating stage. An odd even effect is observed for nematic-isotropic transition curve. Analytical and spectral data confirms the structures of the molecules. Present homologous series is predominant nematogenic and partly nonmesogenic. Average thermal stability for nematic is 125.33°C and nematogenic mesophase length varies between 12°C to 48°C at tetradecyl (C14) and octyl (C8) derivatives, respectively.
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