50625-44-0Relevant academic research and scientific papers
Surfactant lipids containing aromatic units produce vesicular membranes with high thermal stability
Bhattacharya, Santanu,Subramanian, Marappan,Hiremath, Uma S.
, p. 177 - 188 (1995)
Six new vesicle-forming, cationic surfacant lipids are synthesized.Four of them contain 'flat' aromatic units at different locations of hydrophobic segments.In order to estimate the influence of aromatic units in the lipid monomer two other surfactant lip
Synthesis and characterization of novel rod-like ester-based liquid crystalline homologous series: Effect of tert-butyl tail on mesomorphism
Thakur, Shavi,Patel, Hemant N.
, p. 76 - 89 (2021/04/14)
A new rod-like homologous series consisting twelve compounds with central ester linkage and terminal tert-butyl group, tert-butyl [4-(4’-n-alkoxybenzoyloxy)benzoates] has been synthesized and characterized through standard spectroscopic techniques like UV, FT-IR, 1HNMR, DSC, POM, and XRD. Methoxy and ethoxy derivatives are nonmesogenic. Nematic mesophase commences as enantiotropy from propyloxy derivative and persists up to the octadecyloxy derivatives. Smectic A mesophase commences as monotropy from propyloxy to the octadecyloxy derivatives. The mesomorphic properties of present series are compared with other structurally related series to evaluate the effect of terminal tert-butyl group on mesomorphism. Two derivatives are subjected to in?vitro antimicrobial activity.
Synthesis of novel liquid crystalline and fire retardant molecules based on six-armed cyclotriphosphazene core containing Schiff base and amide linking units
Guan-Seng, Tay,Jamain, Zuhair,Khairuddean, Melati
, p. 28918 - 28934 (2020/08/25)
Nucleophilic substitution reaction between 4-hydroxybenzaldehyde and hexachlorocyclotriphosphazene, HCCP formed hexakis(4-formlyphenoxy)cyclotriphosphazene, 1. Intermediates 2a-e was formed from the alkylation reaction of methyl 4-hydroxybenzoate with alkyl bromide which further reduced to form benzoic acid intermediates. Further reaction of 2a-e and other substituted benzoic acid formed 3a-h, which then reduced to give subsequent amines, 4a-h. Other similar reaction was used to synthesis 4i. Condensation reaction between 1 and 4a-i yielded hexasubstituted cyclotriphosphazene compounds, 5a-i having Schiff base and amide linking units, and these compounds consist of different terminal substituents such as heptyl, nonyl, decyl, dodecyl, tetradecyl, hydroxy, carboxy, chloro, and nitro groups, respectively. Compound 5j with amino substituent at terminal end was formed from the reduction of 5i. All the intermediates and compounds were characterized using Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR) and CHN elemental analysis. Mesophase texture of these compounds were determined using Polarized Optical Microscope (POM) and their mesophase transition were further confirmed using Differential Scanning Calorimetry (DSC). Only compounds 5a-e with alkoxy chains exhibited smectic A phase while other intermediates (1, 2a-e, 3a-h, and 4a-i) and final compounds (5f-j) are found to be non-mesogenic with no liquid crystal behaviour. The confirmation of the identity of the SmA phase was determined using XRD analysis. The study on the structure-properties relationship was conducted in order to determine the effect of the terminal group, length of the chains and linking units to the mesophase behaviour of the compounds. Moreover, the fire retardant properties of these compounds were determined using Limiting Oxygen Index (LOI) testing. Polyester resin with LOI value of 22.53% was used as matrix for moulding in the study. The LOI value increased to 24.71% when this polyester resin incorporated with 1 wt% of HCCP. Generally, all the final compounds showed a positive results with LOI value above 27% and the highest LOI value was belonged to compound 5i with 28.53%. The high thermal stability of the Schiff base molecules and the electron withdrawing group of the amide bonds and nitro group enhanced the fire retardant properties of this compound.
Dependence of mesomorphism on terminal polar group in novel azoester series
Kher, Seema N.,Prajapati,Makwana,Chandra, Raviprakash S.
, p. 44 - 53 (2019/10/14)
Novel homologous series 4-(4′-n-alkoxy benzoyloxy) napthyl azo 4″–bromo benzenes, consisted of 11 members of a series. All the 11 members (ethoxy to hexadecyloxy) except hexadecyloxy are only enantiotropically nematogenic without exhibition of any smectogenic character. Transition temperatures and the textures are determined by an optical polarizing microscopy equipped with a heating stage. Textures of a nematic phase are threaded or schlieren. Analytical and spectral data supported the molecular structure of homologs. Transition curves viz., solid-nematic and nematic-isotropic showing phase behavior of the mesophase in a phase diagram behave in normal manner. Alternation of transition temperatures is exhibited by N–I transition curve. Thus, novel series is entirely nematogenic and high ordered melting type. Thus, synthesis of a novel azoester homologous series is carried out with a view to understand and establish the effect of molecular structure on Liquid crystal (LC) behaviors of a substance.
Mesomorphism dependence on terminal polar group in the nonlinear novel azoester series
Kher, Seema N.,Prajapati,Chandra, Raviprakash S.,Makwana
, p. 1 - 9 (2019/02/24)
Synthesis of a novel azoester homologous series is carried out with a view to understand and establish the effect of molecular structure on liquid crystal (LC) behaviors of a substance. Novel series consists of ten LC substances. All the homologs are enantiotropically nematogenic without exhibition of smectic property. Transition and melting temperatures, textures of LC are determined by an optical polarizing microscopy equipped with a heating stage. Textures of nematic phase are threaded or schlieren. Transition curves of a phase diagram behaved in normal manner. Nematic–isotropic transition curve exhibited odd–even effect. Analytical and spectral data supported and confirmed the structures of homologues.
Study of Y-shaped liquid crystalline materials with polar nitro substituent
Dixit, Sandhya
, p. 77 - 84 (2018/06/27)
A new homologous series of Y-shaped liquid crystals namely 4-Nitro-[2′4′bis (4″-n-alkoxybenzoyloxy)] phenyl bisazobenzenes have been synthesized and its thermotropic properties studied on the hot stage of a polarizing microscope. The compounds consist four phenyl rings joined through ester and bisazo linkages with alkoxy and nitro as terminal substituents. The structures of synthesized compounds were confirmed by spectroscopic techniques such as FTIR, 1HNMR as well as elemental analysis. The compounds were found to exhibit enantiotropic nematic and smectic mesophases. The role of molecular shape, size and polarity of functional groups in the mesophases formation is discussed.
LIQUID CRYSTAL ALIGNING AGENT, LIQUID CRYSTAL ALIGNMENT FILM AND LIQUID CRYSTAL DISPLAY ELEMENT
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, (2017/07/23)
PROBLEM TO BE SOLVED: To provide liquid crystal aligning agents, alignment layers, and liquid crystal display elements which make it possible to form liquid crystal alignment films which are easy to handle, have excellent applicability, and have optical a
Synthesis and liquid crystalline properties of novel fluorinated N-benzoyl thiourea compounds. Effect of perfluoroalkyl chains on the thermal behavior and smectic phases stability
Ili?, Monica,Micutz, Marin,Pasuk, Iuliana,Staicu, Teodora,C?rcu, Viorel
, p. 84 - 89 (2017/11/15)
A series of novel N-benzoyl-N’-aryl thiourea derivatives (BTU) bearing different number of alkoxy groups in terminal positions of benzoyl unit and a perfluorooctyl group on the other side have been designed and prepared. Their liquid crystalline properties were investigated by a combination of three techniques: polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and variable-temperature powder X-ray diffraction (XRD). Their thermal stability was studied by thermogravimetric analysis (TG). It was found that only the compounds which have only one alkoxy chain attached to benzoyl unit, 1a and 1b, show calamitic mesomorphic behavior, with smectic A and C phases being displayed. The type and stability of these mesophases are greatly influenced by the alkyl chain length as well as by the presence of perfluorooctyl group. The clearing and the mesophase ranges are significantly increased with the incorporation of perfluoroalkyl chains when compared to non-fluorinated analogues, with almost 40 °C. The attachment of additional alkoxy groups on the benzoyl moiety led to a significant decrease of the clearing points and suppression of the mesogenic character.
Mesomorphism dependence on central bridge (-COO-CH2-) and terminal end group (-Br)
Marathe, Rajesh B.,Doshi
, p. 122 - 131 (2016/02/19)
A novel series of liquid crystalline (LC) ester materials has been synthesized and studied with a view to understanding the effects of molecular structure on LC behavior. The homologous series of eleven members is entirely enantiotropically smectogenic without exhibition of a nematic phase. Transition temperatures and the texture of smectic phase was determined by an optical polarizing microscope equipped with a heating stage (POM). Transition curves (Cr-Sm and Sm-I) showing phase behavior in a phase diagram behave in a normal manner. Textures of smectic phase are focal conic fan shaped of the type Smectic-A or Smectic-C. An odd-even effect is exhibited by the Sm-I transition curve. The average thermal stability for smectic is 91.2°C and the mesogenic phase length ranges between 3.6°C and 39.3°C. Thus, the novel smectogenic homologous series is a middle-ordered melting type whose LC phase is relatively middle ordered. The LC properties of the present series are compared with a structurally similar homologous series. Analytical and spectral data support the molecular structures.
Mesomorphism of azo-esters and chalcone-esters
Jain,Sharma, Vinay S.,Chauhan,Patel
, p. 102 - 111 (2016/07/14)
AOne chalcone-ester homologous series of mesogens α-4-[4/-n-alkoxybenzoyloxy phenyl β-4//methoxy benzoyl ethylenes (A) and one azo-ester homologous series of mesogens p-(p/-n-alkoxybenzoyloxy) phenyl azo-p//-methoxy benzene (B) being structurally similar are discussed. Both series (A) and (B) differ in respect of central bridges linking two phenyl rings. Mesomorphic properties start from 6th and 1st member of series (A) and (B) respectively. In series (A), 6th to 12th members show both smectogenic and nematogenic properties, and the 14th and 16th members show only nematogenic property. While in series (B), 1st to 10th members show nematogenic properties, 11th member shows both smectogenic and nematogenic properties, while 12th member shows only smectogenic property. Thermal stability of series (A) is relatively high as compared to series (B). Transition temperatures are observed through hot stage polarizing microscope by the miscibility method. Analytical data support the structure of molecules. Textures of series (A) in nematic are threaded and Schlieren in SmecticSmectic A type, while that of series (B) in nematic are threaded in SmecticSmectic A and smectic C.
