40654-33-9Relevant academic research and scientific papers
New chalcone based liquid crystals with allylidene amino linking unit: Synthesis and characterization
Sharma, Vinay S.,Sharma, Anuj S.,Jadeja, Upendra H.,Suthar, Deepak
, p. 64 - 81 (2018)
In this study, the synthesis, structural characterization and mesomorphic properties of newly thirteen calamitic shaped compounds derived from allylidene amino chalcone and 4-n-alkoxy benzoyloxy benzoic acid. Comp.H1 to H3 exhibited nonliquid crystalline nature, while comp.H4 to comp.H18 displayed enantiotropical smectic C phase. Phase transition temperatures of present synthesised compounds were determined by optical polarising microscopy (POM), differential scanning calorimetric (DSC) and powder X-ray diffraction (PXRD) techniques. Thermal stabilities of smectic to isotropic phase are 150.0 °C and temperature range of mesophase is in decreasing order from comp.H3 to comp.H18 respectively. The presences of SmC phase are the type of broken fan and needle type in present synthesized series. It is also shown that presence of chalcone amino allylidene central linking group favors a calamitic liquid crystalline behaviour in molecules with lower member to higher member aliphatic side chain in alkoxy group (-OR).
Photoconductive bent-core liquid crystalline radicals with a paramagnetic polar switchable phase
Shivakumar, Kilingaru I.,Pociecha, Damian,Szczytko, Jacek,Kapu?ciński, Szymon,Monobe, Hirosato,Kaszyński, Piotr
supporting information, p. 1083 - 1088 (2020/02/05)
A series of self-organizing bent-core derivatives 1[12,n], containing a highly π-delocalized stable radical as the central angular structural element, is described. The planarity of the open-shell core permits efficient π-π stacking, which results in the formation of B2 and soft crystalline phases above 100 °C. Optical, XRD and dielectric analyses of 1[12,12] indicate that the ground state of the observed B2 phase is polar antiferroelectric of type SmCAPA exhibiting tristable electro-optical switching. SQUID and EPR measurements revealed strong antiferromagnetic spin-spin exchange interactions below the isotropic phase, which have been estimated at θ = -46 cm-1 with the Curie-Weiss law. Transient photoconductivity was observed in the B2 phase with a hole carrier mobility μh of 1.4 × 10-4 cm2 V-1 s-1
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.
“Effect of the linking unit on the calamitic-shaped liquid crystal: a comparative study of two homologous series of benzoate and cinnamate linked compounds”
Kashyap, Dinesh,Patel, Sunil,Prajapat, Varsha,Sharma, Vinay,Vasava, Dilip
, p. 58 - 70 (2019/08/28)
Two homologous series based on three linking groups have been synthesized and well characterized by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by using optical polarized microscopy (POM) and confirmed by differential scanning calorimetry (DSC) analysis. In this present investigation, we have synthesized two homologous series viz. (E)-4-(3-(4-(tetra decanoyloxy) phenyl) acryloyl) phenyl-4-n-alkoxy benzoate (Series-1) and 4-((E)-3-(4-(((E)-3-(4-n-alkoxy phenyl) acryloyl) oxy) phenyl)-3-oxo prop-1-en-1-yl) phenyl tetradecanoate (Series-2). Both of the series are differing with respect to the first linking group. All the homologous in following series displays LC properties on heating as well as cooling condition except first four homologous (C1 to C4) in series-1 and six homologous (C1 to C6) in series-2. To get more insights, the HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens.
“Synthesis, Mesomorphic and DFT Studies of Chalcone Derived Room Temperature Liquid Crystal with Presence of Lateral Nitro and N, N-Dimethyl Amino Terminal Group”
Shukla, Devendra K.,Sharma, Vinay S.,Prajapat, Varsha,Patel
, p. 8 - 26 (2019/10/14)
In this present article, we wish to report on the liquid-crystalline properties of chalcone-ester based homologous series of compounds having aliphatic chain length in n-alkoxy group (n = 1 to 10, 12, 14, 16, 18). The present series consisted thirteen compounds, in which comp.C1 and C2 shows nonliquid crystalline properties, while comp.C3 to C7 display SmC phase and comp.C8 to C18 exhibits only nematic phase. Textural pattern of presently synthesized compounds are schlieren and threaded type. All this compounds were well characterized by elemental analysis, FT-IR and 1H NMR. Phase transition temperatures of present synthesised compounds were determined by optical polarising microscopy (POM), differential scanning calorimetric (DSC). Detailed XRD investigation endorses the presence of the nematic phase in higher homologues and SmC phase in lower homologues. It is shown that chalcone with ester as linking unit favors a calamitic liquid crystalline behaviour in molecules. To get more insights, the DFT based HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens. Chalconyl ester based compounds C3 to C12 shows antibacterial as well as antifungal activity compared with corresponding standard drugs.
Synthesis, characterization, crystal structure and liquid crystal studies of some symmetric naphthalene derivative molecules
Srinivasa,Palakshamurthy,Devarajegowda,Hariprasad
, p. 620 - 626 (2018/09/18)
The synthesis of a series of symmetrical liquid crystals having naphthalene as the central rigid core and attached to long chain flexible 4′-alkoxybenzoate moiety at positions 2,6 - of the aromatic ring are reported. The mesophase behavior of the molecules was investigated using differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction studies. The studies reveal that the synthesized compounds exhibit stable enantiotropic mesophase of Smectic A (SmA) and Nematic (N) phase. The mesophase appearance is independent of the length of the alkyl chain. The molecular structure was determined by single crystal X-ray diffraction technique. The derivative with n-heptyloxy- flexible chain crystallizes under triclinic, P1ˉspace group with unit cell dimension a = 5.569(3) ? b = 10.540(5) ? c = 15.254(9) ? α = 73.434(18)o, β = 80.807(19)o and γ = 82.02(2)o, V = 843.1(8) ?3. The dihedral angle between the naphthalene ring system and the benzoate moiety is 63.63(2)o.
λ-Shaped mesogens based on chalconyl ester core having variable side chain: Synthesis and characterisation
Sharma, Vinay S.,Suthar, Deepak,Sharma, Anuj S.
, p. 100 - 118 (2019/02/24)
In present study, we have synthesized two newly chalconyl-ester core LCs having variable side chain and fixed disubstituted butoxy group at another terminal end. All this compounds were well characterized by elemental analysis, FT-IR, 1H NMR. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and also confirmed by using differential scanning calorimetry (DSC) and X-ray diffraction pattern (XRD). Detailed XRD investigation endorses the presence of the nematic phase in higher angle region and SmC phase in lower angle region. In addition, it is found that all the prepared materials display enantiotropic LCs phases except first four members in series-1 and first member in series-2. Thermal stability of SmC and nematic phase of series-1 is higher as compare to series-2. To get more insights, the DFT based HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions and stability in this class of mesogens.
Benzimidazole based mesogenic Schiff-bases: Synthesis and characterization
Dubey, Ragini,Yerrasani, Rajasekhar,Karunakar,Singh, Angad Kumar,Gupta, Rupali,Ganesan, Vellaichamy,Rao
, p. 106 - 114 (2017/05/25)
Two homologous series of mesogenic Schiff-bases, N-4-((alkoxy)-(phenyl-3-hydroxy-4-(4-(5-methylbenzimidazol))-2-alkoxysalicylaldimine)benzoate (7a–d) and N-4′-(5-methyl-benzimidazole)-phenyl-4-alkoxysalicylaldimine (8a–d) incorporating benzimidazole moiety have been prepared and the molecular structures studied by FT-IR, NMR and ESI-MS spectrometry. Mesogenic behaviour was investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and variable temperature powder X-ray diffraction (PXRD) techniques. Changing the spacer (ester-linked to non-ester linked) of the Schiff-base results in enhancement of thermal stability and phase transition temperature. The members of series-I show monotropic SmA while those of series-II reflect enantiotropic SmA mesomorphism. An electrochemical study of a representative Schiff base in each series (7d and 8c) showed an electrical band gap 1.26?eV and 1.22?eV respectively.
Calamitic-rod-shaped mesogens based on chalcone esters comprising varying alkoxy and lauryl ester chains: Synthesis, mesomorphism and computational study
Sharma, Vinay S.,Patel, Sunil B.,Sharma, Anuj S.,Patel
, p. 32 - 47 (2017/12/26)
In this studywe have synthesized a new class of compounds incorporating of chalconyl-ester and terminally substituted lauryl group. A series of new chalcones with three aromatic rings is synthesized and characterised by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). It is found that all the prepared materials display enantiotropic LCs phases except first two homologue in present series. The lowermember comp. (C3 to C6) display only SmC phase while comp. (C7 to C12) shows smectic C as well as nematic phase. The higher member comp. (C14 to C18) display only nematic phase in heating and cooling condition. To get more insights, the HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens. (Figure presented.).
Rigidified merocyanine dyes with different aspect ratios: Dichroism and photostability
Kre?, Katharina Christina,Bader, Korinna,Stumpe, Joachim,Eichhorn, S. Holger,Laschat, Sabine,Fischer, Thomas
, p. 46 - 56 (2015/06/02)
A series of new rigidified merocyanines were investigated with regard to their optical properties as dichroic dyes. Guest/host-mixtures of the dyes were prepared using a liquid crystal and a reactive mesogen mixture. Their dichroism was studied using linearly-polarized UV/Vis-spectroscopy. A strong dependence of the dichroic ratio on the aspect ratio, the number of double bonds in the molecular structure, and on the maximum wavelength of absorption was found. A strategy to increase the aspect ratio has also been demonstrated. Additionally, the photostability was characterized using continued irradiation with polychromatic light from a xenon source. High photostability was found in all host mixtures in the absence of oxygen by alignment in a matrix. The suitability for their application as dichroic dyes in thin layer polarizers and guest/host-displays is herein discussed.
