- An effective dual sensor for Cu2+ and Zn2+ with long-wavelength fluorescence in aqueous media based on biphenylacrylonitrile Schiff-base
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Although some sensors for Cu2+ and Zn2+ had been reported, the sensor with long-wavelength emission in aqueous media for in-situ detecting Cu2+ and Zn2+ was always expected. Herein, a biphenylacrylonitrile Schiff-base (OPBS) with large aromatic conjugated system was designed and synthesized in yield of 82%. OPBS possessed excellent long-wavelength fluorescence at 550–750 nm in aqueous media, which selectively response to sense Cu2+ with quenched fluorescence and Zn2+ with chromotropic fluorescence from red to yellow. The detection of Cu2+ and Zn2+ were realized without mutual interference in their coexistence system by means of the assistance of ATP. The detection limits were 2.3 × 10?7 M for Cu2+ and 1.8 × 10?6 M for Zn2+, respectively. The sensing mechanism was elucidated by binding MS spectra, fluorescence Job's plot and 1H NMR spectra. Moreover, OPBS exhibited good bioimaging performance and the in-situ sensing abilities for Cu2+ and Zn2+ in living cells, suggesting the application potential for detecting Cu2+ and Zn2+ in both vitro assay and vivo environment.
- Chen, Huiling,Fang, Shuting,Guo, Hongyu,Yang, Fafu,Zha, Bowen
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- 1,3-Oxazine-2-one derived dual-targeted molecules against replicating and non-replicating forms of Mycobacterium tuberculosis
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The high mortality rate and increasing prevalence of resistant Mtb are the major concerns for the Tuberculosis (TB) treatment in this century. To curtail the prevalence of resistant Mtb, we have prepared 1,3-oxazine-2-one based dual targeted molecules. Compound 67 and 68 were found to be equally active against replicating and non-replicatiing form of Mtb (MICMABA 3.48 and 2.97 μg/ml; MICLORA 2.94 and 2.15 μg/ml respectively). They had found to suppress the biosynthesis of alfa, methoxy and keto-mycolate completely, as well as inhibit enzymatic activity of MenG (IC50 = 9.11 and 6.25 μg/ml respectively for H37Ra; IC50 = 11.76 and 10.88 μg/ml respectively for M smegmatis).
- Velappan, Anand Babu,Kesamsetty, Dhanunjaya,Datta, Dhrubajyoti,Ma, Rui,Hari, Natarajan,Franzblau, Scott G.,Debnath, Joy
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supporting information
(2020/10/02)
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- Synthesis and mesomorphic properties of coumarin derivatives with chalcone and imine linkages
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We report here design and synthesis of two new mesogenic homologous series of coumarin derivatives consisting of chalcone and imine central linkages along with terminal n-alkoxy chain. All the compounds were synthesized and characterized by combination of elemental analysis and standard spectroscopic methods. All compounds were screened under polarising optical microscope (POM) for liquid crystalline properties, thermogram of all compounds were studied using differential scanning calorimetry (DSC) to get phase transition temperatures, enthalpy and entropy. X-ray single crystal study of n-octyloxy coumarin derivative 16 g was resolved with imine central linkage, which showed linear rod like geometry.
- Durgapal, Sunil Dutt,Soni, Rina,Soman, Shubhangi S.,Prajapati
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- Anticancer, antimicrobial activities of quinoline based hydrazone analogues: Synthesis, characterization and molecular docking
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Based on the biologically active heterocycle quinoline, a series (18a-p) of quinoline hydrazone analogues were prepared, starting from 6-bromo/6-chloro-2-methyl-quinolin-4-yl-hydrazines. For all the newly synthesized compounds cytotoxic activities were carried out at the National Cancer Institute (NCI), USA, against full NCI 60 human cancer cell lines. Amongst all the tested compounds, nine compounds (18b, 18d, 18e, 18f, 18g, 18h, 18i, 18j, 18l) exhibited important anti-proliferative activity at 10 μM concentration and were further screened at 10-fold dilutions of five different concentrations (0.01, 0.1, 1, 10 and 100 μM) with GI50 values ranging from 0.33 to 4.87 μM and LC50 values ranging from 4.67 μM to >100j μM. Further, the mean values of GI50, TGI and LC50 of the most potent compound 18j were compared with the clinically used anticancer agents bendamustine and chlorambucil, revealed that the quinolyl hydrazones holds promise as a potential anticancer agents. Further all the newly prepared compounds were screened for their antimicrobial activity. All the quinolyl hydrazones displayed good to excellent antimicrobial activity with MIC values ranging from 6.25 to 100 μg/mL against the tested pathogenic strains. Molecular docking of the synthesized compounds into the active binding site of human DNA topoisomerase I (htopoI) was carried out to predict the binding mode to the DNA topoisomerase I inhibitors. Hopefully in future, compounds based on quinoline core could be used as a lead compounds for designing new anticancer agents.
- Katariya, Kanubhai D,Shah, Shailesh R.,Reddy, Dushyanth
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supporting information
(2019/11/26)
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- Synthesis of a new triple-responsive biocompatible block copolymer: Self-assembled nanoparticles as potent anticancer drug delivery vehicle
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There has been a continuous effort towards a synthesis of new stimuli-responsive polymer nanoparticle systems for improved cancer chemotherapy over the last decade. In this context, we have presently developed a temperature, pH, and redox-responsive amphiphilic block-copolymer capable of forming nanoparticles in the aqueous medium, targeted towards drug delivery applications. The copper-catalyzed azide-alkyne cycloaddition reaction was utilized to tie the ends of two copolymers - a thermo-responsive poly(N-isopropylacrylamide) based copolymer with an azide end group and a pH-responsive hydrophobic polymer with redox responsive disulfide bond and an alkyne end group, producing a new triple responsive amphiphilic block copolymer (PHNP) that self-assemble in water to produce nanoparticles. Upon heating above the cloud point of poly(N-isopropylacrylamide), these nanoparticles experienced further aggregation to produce larger sized particles as measured by dynamic light scattering, UV–visible spectroscopy, and scanning electron microscopy techniques. PHNP was found to be capable of encapsulating drugs like doxorubicin (DOX) and also fluorescent probes alike Nile Red. The drug release kinetics divulged that in a period of 24 h more than 90percent of the encapsulated DOX was released in pH 5.4 buffer having 10 mM glutathione (GSH) at 40 °C, an environment prevailing in cancer tissues. In vitro studies including live-dead assay and rhodamine-DAPI staining showed that PHNP was non-cytotoxic. DOX-loaded PHNP was observed to be more effective in prohibiting bone cancer cell (MG63) line in comparison to free DOX, demonstrated by the significant reduction of IC50 values. The uptake studies showed that DOX-encapsulated PHNP was more effective for morphometric distortion of MG63 cells in comparison to bare DOX. Therefore, the present research on the development of a biocompatible thermal, pH, and redox-responsive polymer opens up new opportunities in the area of polymeric carrier systems for drug delivery to cancer cells.
- Dhara, Dibakar,Dhara, Santanu,Maiti, Saikat,Maity, Pritiprasanna,Poddar, Puja,Sahoo, Satyagopal
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- Contribution of stilbene-imine additives on the structural, ionic conductivity performance and theoretical evaluation on CMC-based biopolymer electrolytes
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New solid biopolymer electrolytes (SBEs) were prepared by integrating stilbene-imine derivatives bearing vinylene (–CH[dbnd]CH–) and azomethine (–CH[dbnd]N–) as additives in carboxymethyl cellulose (CMC) based electrolyte. The investigation on their spectroscopic and theoretical assessments were conducted to alter the energy level in improving the structural and ionic conductivity performance. The simulated results from frontier molecular orbitals (FMO) and Mulliken-charge analysis revealed that -CF3 and -NO2 substituents significantly reduce the HOMO-LUMO gap up to 0.68 eV. The highest ionic conductivity of SBEs achieved at ambient temperature was ~8 × 10?3 Scm-1 upon the addition of additive, obeying an Arrhenius model with reciprocal of temperature (303 K–373 K). The coordination interaction of C–O bond and CH[dbnd]N band facilitated the dissociation of more cation (H+) of NH4Cl which permits alternative route for H+ to hop into coordinating site in CMC. The outcomes are ideal in the development of electrochemical devices.
- Isa, M. I. N,Khairul, Wan M.,Rahamathullah, Rafizah
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- 2-Aryl benzazole derived new class of anti-tubercular compounds: Endowed to eradicate mycobacterium tuberculosis in replicating and non-replicating forms
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The high mortality rate and the increasing prevalence of Mtb resistance are the major concerns for the Tuberculosis (TB) treatment in this century. To counteract the prevalence of Mtb resistance, we have synthesized 2-aryl benzazole based dual targeted molecules. Compound 9m and 9n were found to be equally active against replicating and non-replicating form of Mtb (MIC(MABA) 1.98 and 1.66 μg/ml; MIC(LORA) 2.06 and 1.59 μg/ml respectively). They arrested the cell division (replicating Mtb) by inhibiting the GTPase activity of FtsZ with IC50 values 45 and 64 μM respectively. They were also capable of kill Mtb in non-replicating form by inhibiting the biosynthesis of menaquinone which was substantiated by the MenG inhibition (IC50 = 11.62 and 7.49 μM respectively) followed by the Vit-K2 rescue study and ATP production assay.
- Datta, Dhrubajyoti,Debnath, Joy,Franzblau, Scott G.,Ghosh, Kalyan Sundar,Hari, Natarajan,Ma, Rui,Rana, Shiwani,Velappan, Anand Babu
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- Semiheterogeneous Dual Nickel/Photocatalytic (Thio)etherification Using Carbon Nitrides
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A carbon nitride material can be combined with homogeneous nickel catalysts for light-mediated cross-couplings of aryl bromides with alcohols under mild conditions. The metal-free heterogeneous semiconductor is fully recyclable and couples a broad range of electron-poor aryl bromides with primary and secondary alcohols as well as water. The application for intramolecular reactions and the synthesis of active pharmaceutical ingredients was demonstrated. The catalytic protocol is applicable for the coupling of aryl iodides with thiols as well.
- Cavedon, Cristian,Madani, Amiera,Seeberger, Peter H.,Pieber, Bartholom?us
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supporting information
p. 5331 - 5334
(2019/07/08)
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- Highly frustrated liquid crystal phases in optically active dimers: Synthesis and rich phase transitional behavior
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Herein we report on the synthesis and characterization of four new series of optically active, nonsymmetric dimers in which cholesterol is covalently linked to a Schiff base core through an ω-oxyalkanoyl spacer. While the Schiff base core is substituted with n-butyloxy, n-hexyloxy, n-octyloxy, n-decyloxy and n-dodecyloxy tails, three even-parity spacers, namely, 4-oxybutanoyl, 6-oxyhexanoyl, 8-oxyoctanoyl, and an odd-parity spacer, namely, 5-oxypentanoyl, have been used to join the two cores. The experimental results show that the length and parity of the spacer and the length of the terminal tail play a vital role in deciding the phase sequences of the dimers. In general, the dimers possessing an even-parity spacer display enantiotropic LC phases such as chiral nematic (N?), twist grain boundary (TGB), smectic A (SmA), chiral smectic C (SmC?) and twist grain boundary phase with SmC? slabs (TGBC?). Some of these dimers display TGBC? over a wide temperature range. The dimers with an odd-parity (5-oxypentanoyl) spacer display, unlike their even-membered counterparts, blue phases (BPIII/II/I); besides, they stabilize N? and/or unknown smectic (SmX) phases. The circular dichroism (CD) measurements were carried out as a function of temperature on the planar texture formed by three even-membered dimers and an odd-membered dimer. The occurrence of a strong negative CD band in the N? phase of the even-membered dimers suggests a left-handed screw sense of the macroscopic helical structure, and the scenario is opposite in the case of an odd-membered dimer.
- Nayak, Rashmi Ashwathama,Bhat, Sachin A.,Shanker,Rao, D. S. Shankar,Yelamaggad
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supporting information
p. 2148 - 2162
(2019/02/05)
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- “Effect of the linking unit on the calamitic-shaped liquid crystal: a comparative study of two homologous series of benzoate and cinnamate linked compounds”
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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.
- Kashyap, Dinesh,Patel, Sunil,Prajapat, Varsha,Sharma, Vinay,Vasava, Dilip
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- Mesomorphism behaviour and photoluminescent properties of new asymmetrical 1,2-di(4-alkoxybenzylidene) hydrazines
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{1-[4-(n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines (n-alkoxy = O(CH2)nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.
- Awad, Adil A.,Omarali, Al-Ameen Bariz,Al-Karawi, Ahmed Jasim M.,Al-Qaisi, Zyad Hussein J.,Majeed, Samer Ghanim
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- Effect of regioisomerism on the self-assembly, photophysical and gelation behavior of aroylhydrazone based polycatenars: Synthesis and characterization
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In this paper we report five series of aroylhydrazone based polycatenars differing from each other in number and position of alkoxy chains on one end of the core; keeping other end the same. A systematic variation in the structures was carried out to understand the effect of position and chain length on the mesophase behavior. In the case of single alkoxy chain at 4-position, there is a transition from Smectic C to Smectic A mesophase during cooling and Smectic A to Smectic C transition in heating cycle in all the homologues except n = 6 & n = 8. In the case of two alkoxy chains at 3-, 5-positions, the compounds are non-mesogenic in nature. On changing the position of alkoxy chains from 3-, 5-positions to 3-, 4-positions, intermolecular forces weaken and these compounds become liquid crystalline and show columnar rectangular mesophase resulting from the effect of regioisomerism. Moving on to the series with three alkoxy chains, it was observed that 2-, 3-, 4-trialkoxy substituted compounds exhibit columnar rectangular mesophase except lower chain length (n = 6 & 8) while 3-, 4-, 5-trialkoxy substituted aroylhydrazones show columnar rectangular mesophase; except n = 10 which shows columnar oblique mesophase. Thus it was established that on increasing density of alkoxy chains around one terminal, mesophase changes from smectic to columnar mesophase. Temperature dependent Raman studies confirm the presence of intermolecular hydrogen bonding. Further, effect of substitution pattern did not show much influence on the photophysical properties of the mesogenic series in solid and solution state. However, the non-mesogenic series showed a different absorption and emission transition from the mesogenic series in solid and solution state. Solid state fluorescence studies show almost similar emission maxima in all the series. However, it was also noticed that non-mesogenic series show maximum red shifted emission maxima in solid state as compared to that of solution. All the series showed good gelation properties with less than 1% CGC (wt%) suggesting the strong ability of molecules to form gel. These H-bonded liquid-crystalline gels have immense potential for applications in emissive displays.
- Kanth, Priyanka,Singh, Hemant Kumar,Kumar, Vijay,Singh, Sachin Kumar,Rao, D.S. Shankar,Prasad, S. Krishna,Singh, Bachcha
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- Studies on some thiazolidinones as antioxidants for local base oil
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In this work, 5 thiazolidinone derivatives of the type 5-benzylidene -2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (101), 5-(4-butoxybenzylidene)-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (102), 5-(4-hexyloxybenzylidene)-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (103), 5-(4-octyloxybenzylidene)-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (104) and 5-(4-decyloxybenzylidene)-2-(1-piperidinyl)-4-oxo-1,3-thiazolidine (105) are synthesized and characterized using conventional tools analyses. They are tested as antioxidants for local base stock and the efficiency of these compounds, as antioxidants, was monitored through studying the change in total acid number and viscosity, the results reveal that the efficiency order is ranked as follows 105 > 104 > 103 >102 > 101. The quantum chemical parameters such as the lowest unoccupied molecular orbital (LUMO), the highest occupied molecular orbital (HOMO) energy levels and the energy gap (EHOMO-ELUMO) were calculated. The experimental results were on the same line with the quantum chemical calculations.
- Mohammed, Hoda A.,Attia, Sayed K.,Nessim, Maher I.,Shaaban, Mohamed E.,El-Bassoussi, Ali A. M.
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p. 1619 - 1634
(2019/09/09)
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- Liquid Crystalline Properties of 4,4'-methylenebis(N-(4-Alkanoxybenzylidene)aniline): Synthesis, Characterization, and Theoretical study
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The paper presents six homologues series of Schiff bases ether compounds distinguished by the length of terminal alkoxy groups which substituted on a side benzene nucleus. The above structures were demonstrated through the use of spectroscopic techniques, like FT- IR and1H-NMR. Polarized hot stage optical microscopy was used to study both mesomorphic properties and phase transitions. The results showed that out of the six compounds only three (B2, B3 and B4) were pure (marble) nematic mesophase, while no liquid crystal properties for (B5, B6 and B7) compounds. The theoretical study for the electronic structures was intended to study the effects of alkyl chain length on the electronic structure by using Gaussian program, DFT and 6-31G as basis set. The theoretical results indicate that there is no effect to the terminal substituted alkoxy groups on the HOMO energies but there is an effect on LUMO energies through decreasing energy for the prepared compounds.
- Yaseen, Mohammed Taha,Kshash, Abdullah Hussein
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p. 1107 - 1114
(2020/01/08)
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- Unprecedented Regioregular Poly(1,4-arylene)s Prepared by Nickel(II)-Catalyzed Cross-Coupling Polymerization of 2,5-Disubstituted Bromo(chloro)arylene
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The unprecedented synthesis of regioregular head-to-tail-type poly(1,4-arylene)s bearing different substituents at the 2- and 5-positions is described. They were prepared by the polymerization of 2,5-disubstituted bromo(chloro)arylenes by selective halogen–metal exchange with a Grignard reagent and subsequent cross-coupling polymerization with a nickel catalyst [NiCl2(dppp)]. Formation of the regioregular poly(1,4-arylene)s were confirmed by NMR spectroscopy, and showed remarkable differences to those polymers having uncontrolled regioregularity. Polymerization of bromo(chloro)arylenes with a chiral alkoxy substituent also led to the regioregular head-to-tail-type polyarylene, which demonstrated circular dichroism, thus suggesting formation of a structure with higher-order regularity.
- Shibuya, Yushin,Nakagawa, Naoki,Miyagawa, Naoki,Suzuki, Toyoko,Okano, Kentaro,Mori, Atsunori
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p. 9547 - 9550
(2019/06/24)
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- Peripheral Substitution of Tetraphenyl Porphyrins: Fine-Tuning Self-Assembly for Enhanced Electroluminescence
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This study reports the synthesis of two novel zinc porphyrin families bearing four or eight alkoxy chains at their peripheral phenyl rings, with the length of the alkoxy chains ranging from 2, to 6, and to 12 carbon atoms. All zinc porphyrin derivatives were fully characterized with respect to their photophysical and electrochemical features. The zinc porphyrins could be processed into thin films which, depending on the length of the alkoxy chains on the aryl substituents, were found to be either of an ordered or a disordered nature, as it is revealed by spectroscopic and microscopic techniques. The films containing ordered self-assemblies displayed significantly enhanced electrical conductivity compared to the disordered films. This led to remarkable differences regarding their electroluminescence response that occurs at lower bias. Furthermore, their luminous efficiency was of almost one order of magnitude higher than that of disordered films.
- Charisiadis, Asterios,Bagaki, Anthi,Fresta, Elisa,Weber, Katharina T.,Charalambidis, Georgios,Stangel, Christina,Hatzidimitriou, Antonios G.,Angaridis, Panagiotis A.,Coutsolelos, Athanassios G.,Costa, Rubén D.
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p. 254 - 265
(2018/04/24)
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- Mesomorphism dependence on central bridge and tail ended polar group
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A novel azoester homologous series of laterally and terminally substituted viz, RO–C6H4–CH=CH–COO–C6H3–(CH3) –N=N–C6H4–Cl is synthesized, characterized and studied with a view to understand and establish the relation between molecular structure and thermotropic liquid crystalline property of its homologs. Series consists of twelve homologs. LC properties commence from very first member of a series and continue up to last homolog as enantiotropic nematic with absence of smectic property even in the monotropic condition. Transition temperatures of homologs were determined by polarizing optical microscopy equipped with a heating stage. The transition curves Cr?N and N?I behaved in normal manner. Thermal stability for nematic is 196.7?C whose mesophaselength ranges from 35°C to 131°C.
- Ranchchh, Avani R.,Chavda, Kavita,Bhanderi, Roshani,Patel, Suman,Bhoya
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- Mesomorphism dependence on molecular rigidity and flexibility
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A novel homologous series of liquid crystalline properties is synthesized and studied with a view to understand the effect of molecular structure on its thermotropic properties. Novel homologous series consisted of thirteen homologs. All the homologs are enantiotropically smectogenic with absence of nematic property even in the monotropic condition. Textures of the homologs as observed through an optical hot stage polarizing microscopy. The mesophase temperature range vary minimum from 6.0°C to a maximum 37.0°C at the methyloxy and propyloxy derivatives of a series respectively with its thermal stability (Sm–I) 127.0°C. Transition curves of a phase diagram behaved in normal manner. Odd–even effect is observed for Sm–I transition curve.
- Ranchchh, Avani R.,Bhoya
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- “Dependence of Mesomorphism in Combination with Fluoro and Chloro Groups”
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A novel azoester homologous series with chloro lateral group and a fluoro terminal end group was synthesized and characterized for mesomorphic properties. It consists of thirteen azo ester derivatives from trans-4-n-alkoxy cinnamic acid with 4-hydroxy-3-chloro phenyl azo-3-chloro-4-fluoro benzene. Mesomorphic property commences from C4homologue as smectic.C1 to C3 member of the series are non-mesomorphic. C4 to C18 homologous are enantiotropic smectic A phase. The nematic mesophase is totally absent. Texture and transition temperatures of the homologues are determined by an optical polarizing microscopy equipped with heating stage. 1H NMR, IR spectra, mass spectra, of some member is included. The spectroscopic analysis supports the molecular structure. A phase diagram is used to illustrate the mesomorphic behaviour across the series. Mesophaselength for smectic is varying from18.0°C to 69.00C. Mesomorphic properties of the novel azoester series are compared with structurally similar series.
- Ranchchh, Avani R.,Tharesha, Bhavna R.,Bhoya
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- Method for synthesizing aromatic aldehyde, aromatic ketone and aromatic ester through catalytically oxidizing alkyl aromatic compound by iron
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The invention discloses a method for synthesizing aromatic aldehyde, aromatic ketone and aromatic ester through catalytically oxidizing an alkyl aromatic compound by iron, and belongs to the technical field of catalytic synthesis. According to the method, a low-cost and environment-friendly iron catalyst is used under a normal pressure; under the action of hydrogen and silicon reagents serving as an accelerant and an oxidant, a side chain of an aromatic hydrocarbon is oxidized into a carbonyl group for generating the corresponding aromatic aldehyde, aromatic ketone and aromatic ester. The method for preparing the aromatic aldehyde, the aromatic ketone and the aromatic ester through a catalytic oxidation reaction, which is provided by the invention, has numerous advantages that a catalyst, reaction raw materials, the oxidant and a silicon reagent are wide in sources and good in stability and is low-cost and environment-friendly; the alkyl aromatic compound is metered to participate in a reaction; the reaction condition is mild; the compatibility of functional groups is good; the scope of application is wide; the reaction selectivity is good; in an optimized reaction condition, the separation yield of a target product can be up to approximately 95 percent.
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Paragraph 0058; 0059
(2017/10/13)
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- Synthesis and Structure–Activity Relationships of Novel Benzylamine-Type Antifungals as Butenafine-Related Antimycotics
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Benzylamine-type antimycotics like naftifine, butenafine, or terbinafine are a well-known class of antimycotics since the 1980s. The following paper describes the synthesis and biological evaluation of a series of novel benzylamine-type antimycotics characterized by an isooctyl side chain and various substituents at the benzylamine moiety. The compounds were prepared from benzaldehyde derivatives and 2-amino-6-methylheptane by reductive amination with sodium triacetoxyborohydride and subsequent precipitation with hydrogen chloride. The antimycotic activity of the resulting compounds was evaluated in an agar diffusion assay against the yeasts C. glabrata and Yarrowia lipolytica, the mold Aspergillus niger and the dermatophyte H. burtonii. The compounds were also tested in a microdilution assay against the yeast Candida glabrata and the dermatophyte H. burtonii to determine the minimal inhibitory concentrations (MIC). Compounds with an aromatic ether side chain or a short alkyl ether side chain showed significant antimycotic activity against C. glabrata, comparable to terbinafine or clotrimazole.
- Krauss, Jürgen,Stadler, Martina,Bracher, Franz
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- Efficient and practical method for the synthesis of hydrophobic azines as liquid crystalline materials
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A series of hydrophobic symmetrical azines: 1,2-bis[4-(n-alkoxy)benzylidene]hydrazine (where, n-alkoxy: O(CH2)nH, n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16, or 18) have been prepared following an efficient and practical method. These compounds have been synthesized via the condensation reaction of hydrazine hydrate and appropriately 4-(n-alkoxy) benzaldehydes in acidic medium under ambient conditions. The prepared organic compounds have been characterized and their structures were elucidated depending upon micro-elemental analysis and spectral data (IR, UV-Vis, 1HNMR, 13C{1H}NMR, 2D 1H-1H-cozy, 2D 1H-13C-HSQC, and mass spectra). Liquid crystalline behavior of the prepared compounds was studied using polarized light optical microscopy and differential scanning calorimetry techniques. This study revealed that all the compounds displayed enantiotropic liquid crystal properties, exhibiting smectic and nematic mesophases.
- Hammood, Ali Jasim,Kased, Ahmed Fadhel H.,Al-Karawi, Ahmed Jasim M.,Raseen, Sameem R.,Tomi, Ivan Hameed R.,Omar Ali, Al-Ameen Bariz
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p. 114 - 129
(2017/07/04)
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- Role of molecular structural flexibility on mesomorphism
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A homologous series of novel chalconyl ester derivatives: RO.C6H4.COO.C6H4.CO.CH:CH.C6H4.OC6H13(n) shave been synthesized and studied for its thermotropic liquid crystal (LC) properties with a view to understanding and establishing the relation between molecular structure and LC properties. The homologous series consists of eleven members whose, mesomorphism commences from C3 of the series and continues up to the C16 homologue. The C1 and C2 homologues are nonliquid crystals. All the LC homologues are enantiotropically nematogenic with absence of smectogenic character. Transition temperatures were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren. Analytical and spectral data confirms the molecular structures of homologues. Transition curve Cr-N/I behaved in normal manner. N-I transition curve exhibits an odd even effect; descended at C10 homologue and then again rises at C12 and descended from and beyond C12 homologue. Thus it partly deviates from normal behaviour. Thermal stability for nematic is 95–89°C and nematogenic upper and lower mesophase lengths are 41.0°C and 07.0°C respectively. Group efficiency order for nematic on the basis of thermal stability is –OC8H17(n)> -OC6H13(n) > -OC10H21(n) and it is a low order melting type series.
- Pandya,Patel
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- Mesogenic naphthyl derivatives
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Two new mesogenic homologous series of liquid crystalline naphthalene derivatives with different central linkages: 2- Naphthyl-4-n-alkoxybenzoates (I) and trans-2-Naphthyl -4-n –alkoxycinnamates(II), have been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. Twelve compounds have been synthesized in both the series I and II. In series I, methoxy to n-pentyloxy derivatives are non mesogenic, n-hexyloxy to n-hexadecyloxy derivatives exhibit monotropic nematic mesophase. Smectic A mesophase commences from n-decyloxy derivatives as a monotropy and persist up to the last member synthesized. All the 12 compounds of series II exhibit mesomorphism. Methoxy to n-propyloxy derivatives exhibit monotropic nematic mesophse, and n-butyloxy to n-tetradecyloxy derivatives exhibit enantiotropic nematic mesophase. n-Hexayloxy to n-hexadecyloxy derivatives also exhibit enantiotropic smectic A mesophase. The mesomorphic properties of present series were compared with each other and with a structurally related mesogenic homologous series to evaluate the effects of central linkage on mesomorphism.
- Patel,Prajapati
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p. 106 - 115
(2017/03/08)
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- Study the effects of terminal side chain and –nitro group on mesomorphic behaviour of cinnamate-chalconyl based liquid crystal
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The influence of the terminal side chain and lateral nitro on mesomorphism due to the flexibility and polarity of lateral group is investigated. A new homologues series is synthesized to accomplish this aim. The C1 to C3 homologue are nonmesomorphic, while the rest of the homologues exhibit enantiotropic nematic and smectic properties. The texture of the nematic mesophase is of threaded, Schlieren and droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques of FTIR and 1H Nuclear magnetic resonance (NMR). The phase behaviour was studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction techniques.
- Sharma, Vinay S.,Patel
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- Mesomorphic study of novel chalconyl-ester-based nonisomeric series: Synthesis and characterization
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A newly designed homologues series: 3-(3-(4-(Dimethylamino) phenyl) acrylonyl) phenyl 3-(4-n-alkoxyphenyl) acrylate has been synthesized and studied through chalconyl ester linking group at (meta) position. The series consists of 13 compounds, in which C1 to C4 homologue are nonliquid crystal, while C5 to C18 exhibit nematic phase, and C12 to C18 shows smectic and nematic phase with enantiotropically manner. Mesophase image of present compounds are rod like, needle and threaded type textures investigated by POM. All this compounds were characterized by elemental analysis, FT-IR and 1H NMR. The mesomorphism is measured by POM, DSC, and molecular packing is determined by XRD technique. The following synthesized chalconyl ester-based compounds C5 to C12 shows antibacterial as well as antifungal activity compared with corresponding standard drugs. Analytical and spectral data confirmed the molecular structures of homologous series.
- Sharma, Vinay S.,Patel
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- Tuning the mesomorphic properties of nonisomeric chalconyl-ester bases homologous series: The effect of tail group
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The mesomorphic properties of nonlinear chalconyl ester homologous series can be tuned in a predictable fashion with tail groups (-OC16H33) substituents on the terminal side. Novel series consisted thirteen members (C1–C8, C10, C12, C14, C16, C18). C1 to C5 homologues are nonliquid crystal, C6 to C14 homologues shows nematic mesophase enantiotropically, while C16, C18 exhibits smectic as well nematic properties. The texture of the nematic mesophase is of fan shaped, schlieren and nematic droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques such as [FTIR] and 1H Nuclear magnetic resonance [NMR] spectroscopy. The mesomorphic properties of these compoundswere observed by optical polarized light microscopy (POM) and differential scanning calorimetry (DSC).
- Sharma, Vinay S.,Patel
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- Synthesis and study of mesomorphic properties in rod-like chalconyl compounds
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In order to investigate the influence of the central linking group and effect on flexibility on mesophase behavior of liquid crystal we have synthesized newly homologous series viz. 3-(4-Octyloxyphenyl)-1-(4′-n-alkoxy phenyl) prop-2-en-1-one (Series-l) consists of thirteen homologues (C1 to C8, C10, C12, C14, C16, C18). Textures of a nematic phases are threaded or Schlieren type. The textures of smectic and nematic phase are directly judged from the heating and cooling condition. Group efficiency order for mesophases is derived on the basis of thermal stabilities from the comparative study of thermometric data determined from structurally analogous series. A transition curve as depicted in a phase diagram behaves in normal manner. Structural and conformational characterization of these new compounds had achieved by 1H NMR, 13C NMR, IR, and elemental analysis.
- Sharma, Vinay S.,Patel
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- Synthesis and mesomorphic properties of new chalconyl-linkage-based liquid crystal compounds: The effect of flexibility
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A new series of liquid crystals involving chalconyl-based mesogenic units interlinked between two benzene cores were designed and synthesized. The target chalconyl compounds were obtained by the reaction of 4-n-alkoxy benzaldehyde with 4-n-hexadecyloxy (–OC16H33) acetophenone in presence of base. The liquid crystalline properties of synthesized compounds were observed by polarizing optical microscope study. The molecular structures of the compounds were confirmed by Fourier transform infrared, 1H, and 13C nuclear magnetic resonance spectra. The compounds of the series C3 to C8, C10, C12, C14, C16, and C18 exhibited mesophase in enantiotropically manner. The transition temperature reduced as alkyl spacer of left side group increased. The observed texture images are droplets, broken fan, and threaded like. Thermal stability of current homologous series for (N-I/I-N) is 69.8°C and for smectic phase (Sm + N) is 58.0°C.
- Sharma, Vinay S.,Patel
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p. 129 - 140
(2017/03/08)
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- Molecular flexibility dependence on mesogenic behaviors of isomeric and nonisomeric series
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A novel homologous series containing vinyl ester and azomethane central bridges and n-alkoxy as well as 3″,4″-dimethyl groups as flexible terminal/lateral groups viz. RO?C6H4?CH = CH?COO?C6H4?N?CH?C6H3-(CH3)2 have been synthesized and studied with a view to establishing the relation between molecular structure and thermotropic liquid crystal (LC) properties with reference to molecular flexibility within the series. The series consists of twelve homologues (C1 to C16). C6 and C7 homologues are smectogenic plus nematogenic and C8 to C16 homologues are only smectogenic, and the rest of the homologues (C1 to C5) are nonmesomorphic. Transition temperatures and the textures of the homologues were determined using an optical polarizing microscope equipped with a heating stage (POM). The textures of a nematic phase are threaded or Schlieren and that of a smectic phase are of the A or C type. Analytical, thermal and spectral data support the molecular structures. Smectic and nematic thermal stabilities are 116.85°C and 147.5°C, respectively. Whose Sm?N/I and N-I mesophase lengths are varied between 15°C to 21°C and 25°C to 62°C, respectively. The novel compounds are compared with structurally-similar series.
- Rakhasia,Ranchchh, Avani R.,Bhoya
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p. 159 - 167
(2017/03/08)
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- Mesomorphism dependence on molecular rigidity and substitution of same functional group on lateral or terminal position of tailed phenyl ring
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Novel liquid crystal materials (LCs) of low temperature range (53°C to 75°C) have been synthesized through a series of chalconyl derivatives consisting of two phenyl rings bonded through a –CH?CH?CO? central bridge to study the effect of molecular structure on LC properties in general and with a focus on molecular rigidity. The novel homologues series (C1 to C18) consists of thirteen homologues with general formula RO?C6H4?CH?CH?CO?C6H4?OC10H21(n) (meta). The C1, C2, C3 homologues are nonliquid crystals (NLC) and the rest of the homologues (C4 to C18) are either monotropic or enantiotropic liquid crystals. C4 to C6 homologues are enantiotropicnematic and the rest of the mesomorphic homologues are (C7 to C18) monotropicsmectic in addition to monotropicnematic character. Transition and melting temperatures including textures of homologues were determined by an optical polarizing (POM) microscopy equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren, and that of the smectic phase are of the type Smectic A or C as judged directly from the heating top of the microscope. Thermal stability for smectic is very poor and of the nematic is (N-I) 69.3°C whose, total mesophase length ranges between 07.0 to 14.0°C at C8 and C4 homologues respectively.
- Sharma, Vinay S.,Patel
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p. 178 - 187
(2017/03/08)
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- The effect of position of octadecyloxy tail on the formation of liquid crystal with chalconyl-ester and chalconyl-vinyl ester series: Comparison with corresponding linkage group
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Two series of chalconyl-based liquid crystals which differ from each other in the position of the first linking group have been synthesized and characterized by elemental analyses and spectroscopic techniques such as Fourier transform infrared and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and differential scanning calorimetry (DSC). We have synthesized two homologous series viz. 3-(3-(4-(Octadecyloxy) phenyl) acrylonyl) phenyl 3-(4-n-alkoxyphenyl) acrylate (series-1) and 3-(3-(4-(Octadecyloxy) phenyl) acryloyl) phenyl 4-n-alkoxy benzoate (series-2). Series-1 has chalconyl-ester central linkage group while in series-2 chalconyl-vinyl ester group is present and tail octadecyloxy side chain is common in both homologous series. All the homologous in present series display LC property in enantiotropical manner except first three homologous in both series.
- Solanki,Sharma, Vinay. S.,Patel
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p. 216 - 232
(2017/03/08)
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- Synthesis, characterization, and mesomorphic investigation of vinyl ester-substituted chalcones and effect of lateral ?NO2 and ?OCH3 group
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A novel homologous series of α-4-(4′-n-alkoxy cinnamoyloxy) phenyl β-2″-nitro, 3″–4″ di methoxy benzoyl ethylenes, H2n + 1CnO?C6H4?CH?CH?COO?C6H4?CO?CH?CH?C6H2(NO2) (OCH3)2 (n = 1–8, 10, 12, 14, 16, 18) has been synthesized. All these compounds have been characterized by suitable spectroscopic techniques. C1 homologue is nonmesogenic, while C2 homologue shows enantiotropic nematogenic property and the rest of the homologous (C3?C18) displayed enantiotropically smectogenic plus nematogenic phase. Phase transition temperatures and textures of the LC phase were determined by an optical polarizing microscopy (POM) equipped with a heating stage. The mesomorphic properties of these compounds were confirmed by differential scanning calorimetry (DSC) analysis.
- Sharma, Vinay S.,Patel
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p. 241 - 251
(2017/03/08)
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- Synthesis and mesomorphic properties of new chalconyl-ester based liquid crystals: The effect of tail group
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A new homologous series viz. 4-(3-(3, 4-dioctadecyloxy) phenyl)-3- oxoprop-1-en-1-yl) phenyl-3-(4-n-alkoxy phenyl) cinnamate) based on two linking groups have been synthesized and characterized. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). All synthesized compounds exhibited LC behaviour except compound C1. Thermal stability of smectic and nematic phase of present series are 79.0°C and 120.0°C whose temperature range is vary from 14 to 20°C and 24 to 56°C respectively. The mesomorphic properties of present series were compared with other structurally related mesogenic homologous series to evaluate the effects of tail group on mesomorphism.
- Sharma, Vinay S.,Vekariya, Rajesh H.,Sharma, Anuj S.,Patel
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- Synthesis and mesomorphic properties of quinoline-8-yl-4-((4-n-alkoxy benzylidene) amino) benzoate: The effect of linkage group
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A new homologous series viz. quinoline-8-yl-4-((4-n-alkoxy benzylidene) amino) benzoate based on two central linking groups have been designed and characterised by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and protonmagnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by polarizing optical light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). All synthesized compounds displayed LC property except first two homologue. The lower homologues (n = 4 to 8) display SmA and SmC phase while, in higher homologues (n = 10 to 18) SmC and nematic phasewere seen in heating and cooling condition.
- Sharma, Vinay. S.,Vekariya, Rajesh H.,Sharma, Anuj. S.,Patel
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- Synthetic pathway for a new calamitic series of liquid crystal: Comparison with corresponding linkage group
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Reduction-responsive cystamine-incorporated gelatin microspheres were prepared by an emulsification method. On SEM micrograph, the microsphere, prepared at pH 9.0 and at the carboxyl/amino group molar ratio of 1:1, was sphere-like and its diameter was a few to 100 μm. The gelatin to cystamine ratio of the microsphere was about 1:0.2 (w/w), determined by energy dispersive X-ray spectroscopy. Two endothermic peaks were observed around 92°C and 126°C, which were thought to be the melting point of gelatin-rich phase and that of cystamine-rich phase, respectively. The microsphere released its payload (FITC-dextran) in dithiothreitol (a reducing agent) concentration-dependent manner.
- Sharma, Vinay S.,Vekariya, Rajesh H.,Sharma, Anuj S.,Patel
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p. 143 - 157
(2017/10/27)
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- New hockey stick shaped amino allylidene (?N?CH?CH?CH) based compounds: Effect of linkage group on mesomorphic properties
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Two nonlinear hockey stick shaped homologous series based on three linking groups have been synthesized and characterized by elemental analyses and spectroscopic techniques. The mesomorphic properties of these compounds were observed by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In this present investigation, we have synthesized two homologous series viz. 2-((3-phenyl allylidene) amino) phenyl 4-((4-n-alkoxy benzylidene) amino) benzoate (series-1) and 4-((2-((3-phenyl allylidene) amino) phenoxy) carbonyl) phenyl-4-n-alkoxy benzoate (series-2). Both the series are differing with respect to first linking group. In series-1, comp.C4-C18 shows nematic as well as smectic phase while in series-2, comp.C10-C16 shows smectic and nematic phase while comp.C4-C18 shows only nematic phase.
- Sharma, Vinay. S.,Vekariya, Rajesh. H.,Sharma, Anuj. S.,Patel
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- The effect of position of tert-butyl tail group on the formation of liquid crystal in Schiff base ester based homologous series
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We report a newly rod like calamatic liquid crystalline materials, which are constructed by the self-organization of a rod-like carboxylic acid derivative based on Schiff base ester as the linking group with tert butyl tail group. A newly series of 4-(tert-butyl) phenyl 4-((4-alkoxybenzylidene) amino) benzoate with different alkyl chain spacer (n = 1 to 8, 10, 12, 14, 16, and 18) were synthesized and their mesomorphic properties were investigated by differential scanning calorimetry and polarized optical microscopy. All homologous in present series displays mesophase in enantiotropically manner. Thermal stability of SmC-SmA is 137.5 °C. All the compounds were characterized by spectroscopic and elemental analysis. The effects of varying left alkyl side spacer on mesomorphism with its structurally related compounds in series have been discussed.
- Sharma,Patel
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- Synthesis, spectroscopic and computational characterization of the tautomerism of pyrazoline derivatives from chalcones
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In the present study a series of novel pyrazolines derivatives has been synthesized, and their structures assigned on the basis of FT-Raman, 1H and 13C NMR spectral data and computational DFT calculations. A joint computational study using B3LYP/6-311G(2d,2p) density functional theory and FT-Raman investigation on the tautomerism of 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carbothioamide and 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carboxamide are presented. The structures were characterized as a minimum in the potential energy surface using DFT. The calculated Raman and NMR spectra were of such remarkable agreement to the experimental results that the equilibrium between tautomeric forms has been discussed in detail. Our study suggests the existence of tautomers, the carboxamide/carbothioamide group may tautomerize, in the solid state or in solution. Thermodynamic data calculated suggests that the R(CS)NH2 and R(CO)NH2 species are more stable than the R(CNH)SH and R(CNH)OH species. Additionally, results found for the 1H NMR shifting, pointed out to which structure is present.
- Miguel, Fbio Balbino,Dantas, Juliana Arantes,Amorim, Stefany,Andrade, Gustavo F.S.,Costa, Luiz Antnio Sodr,Couri, Mara Rubia Costa
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p. 318 - 326
(2015/08/06)
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- Mesomorphism dependence on heterocyclic end group
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An ester homologous series containing a heterocyclic end group was synthesized and studied with a view to understanding and establishing the effect of molecular structure on liquid crystal behavior. The novel series consists of 13 homologues. All members of the series are enantiotropically smectogenic without exhibition of nematogenic character. The textures of smectogenic homologues are of the type smectic A or C. The transition temperatures were determined by an optical polarizing microscope equipped with a heating stage. The Sm-I transition curve in a phase diagram behaves partly in an abnormal manner with the exhibition of an odd-even effect. The average thermal stability for smectic is 141.45°C and the mesomorphic phase length ranges from 8.1°C to 30.3°C. Analytical and spectral data confirm the molecular structures. The liquid crystal properties of present series are compared with the structurally similar known homologous series.
- Bhola,Bhoya
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- Dependence of mesomorphism on molecular rigidity of nonlinear and linear isomeric and nonisomeric chalconyl esters
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The novel thermotropic liquid crystalline (LC) materials have been synthesized and studied through chalconyl ester nonlinear (meta substituted) homologous series RO-C6H4?CH?CH?COO?C6H4-CO?CH?CH?C6H4-OC14H29(n) with a view to understand the effect of molecular structure on LC behavior with reference to determine the difference between linear and nonlinear shaped molecules. Novel series consisted of thirteen members, whose nematogenic enantiotropic mesomorphism commences from C6 homologue and continued up to C18 homologue with the absence of smectogenic character. C1 to C5 homologues are nonliquid crystals as determined through an optical polarising microscope (POM) equipped with a heating stage. Transition temperatures of LC homologues alternate and are lower than the corresponding n-alkoxy cinnamic acids. Cr-N/I and N-I transition curve behaved in normal manner. N-I transition curve exhibited odd-even effect in a phase diagram. Textures of nematic phase are threaded or Schlieren or determined by miscibility method and from observing mesophase on the top of the POM. Thermal stability for nematic is 92.5 and mesophase length minimum to maximum is 19.0 to 32.0°C at the C10/18and C6 homologue. Group efficiency order on the basis of thermal stability is (Formula presented.) Thus, novel series is nematogenic and low melting type. Analytical and spectral data confirmed the molecular structures of homologues.
- Jain,Patel
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- Mesomorphism dependence on halogenated chalconyl esters in terms of molecular flexibility/rigidity
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Vinyl carboxy central group containing a novel chalconyl ester homologous series: RO.C6H4.CH ? CH.COO.C6H4.CH ? CH.CO.C6H4.I (para) have been synthesized and studied with a view to understand and establish the relation between thermotropic liquid crystalline (LC) behaviors and the molecular structure. Novel chalconyl ester homologous series consists of thirteen homologs (C1–C18). C1–C3 homologs are nonmesogenic, C4 homolog is enantiotropic nematogenic and the rest of the homologs (C5–C18) are enantiotropically smectogenic plus nematogenic. Phase transition temperatures and textures of LC phase were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Cr-M/I, Sm-N, N-I transition curves in a phase diagram behaved in normal manner. Sm-N and N-I transition curves exhibited odd-even effect from C4–C10 or nearby C10 homolog. Textures of nematic phase are threaded or Schlieren and that of the smectic phase are of the type smectic A or C. Analytical and spectral data confirms the molecular structure of homologs. Thermal stabilities for smectic and nematic mesophases are 155.0 and 180.7, respectively, and their corresponding mesophaselengths are varied from minimum to maximum at 17.0°C–39.0°C as well as 15.0°C–30.0°C. Thus, it is middle ordered melting type series. The group efficiency orders derived on the basis of smectic and nematic thermal stabilities are as under: Sm: -C6H4.I > -C6H4.Cl > -C4H3S and N:- C6H4.I > -C6H4.Cl > -C4H3S from comparative study of structurally similar analogous series
- Sharma, Vinay S.,Patel
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- Mesomorphism dependence of a terminal or lateral alkoxy group
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A novel homologous series of thermotropic mesomorphs has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on mesomorphic properties with reference to rigidity and flexibility of the homologues series: RO-C6H4-CH?CH-CO-C6H4-OC18H37(n). The novel homologous series comprises 13 novel homologues (C1 to C18), from which 11 homologues are enantiotropically mesogenic (C3 to C18). Smectogenic mesophase commences from C7 homologue, and nematogenic mesophase is exhibited by C3 to C18 homologues in enantiotropic manner. Thus, C7 to C18 homologues are enantiotropically smectogenic plus nematogenic. Textures of smectic phase are of the type A or C, and that of nematic phase are threaded or Schlieren as confirmed through an optical polarizing microscope equipped with a heating stage. Transition curve of a phase diagram behaved in a normal manner except N-I transition curve, which shows minor deviating trend (C12 to C18) from expected normal behavior. An odd-even effect is exhibited by N-I and Sm-N transition curves. Analytical, spectral, and thermal data confirm the molecular structures of novel homologues. Thermal stabilities for smectic and nematic are 52.7°C and 66.6°C, respectively, whose total mesophase lengths range from 12.0°C to 28.0°C. Thus, novel series of chalcones is a low melting series whose mesogenic transition temperatures vary between 38.0 and 86.0°C.
- Solanki, Ravindra,Patel
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- Dependence of mesomorphism on molecular rigidity of chalconyl liquid crystals with two phenyl rings
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A novel homologues series: RO-C6H4?CH=CH?CO?C6H4?OC16H33(n) (meta) of chalcones with two phenyl rings is synthesized and studied with a view to understanding and establishing the relationship between molecular structure and mesogenic behavior. The series consists of 13 homologues (C1 to C18). Mesomorphism commences from the second member of the series. C2 to C6 homologues are enantiotropicnematic and the rest of the homologues (C7 to C8) are monotropicnematic plus monotropicsmectic. C1 homologue is nonmesogenic. Transition temperatures were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of nematic and smectic phases are threaded, Schlieren or smectic-A, respectively, as judged directly from the heating top of microscopic observations. Thermal, analytical and spectral data confirms the molecular structures. Thermal stabilities for smectic and nematic are few (1 or 2°C) degrees and 72.6°C, respectively. The mesophase lengths are relatively shorter with low mesomorphic transition temperatures (44.0°C to 85.0°C).
- Sharma, Vinay S.,Patel
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- Synthesis, characterization and study of liquid crystal properties of new homologous chalcone series
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Onenewmesogenic homologous series of chalconyl derivativewith two ring (3/-(4/- (decyloxy) phenyl-1-(4-(alkoxy) phenyl) prop-2-en-1-one) has been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. In the series, the lower members (C4 and C5) exhibit only enantiotropic nematic mesophase but middle and higher members exhibit enantiotropic nematic as well as smecticmesophase. The nematicmesophase commence from C4 homologue and smectic mesophase (smectic-A type texture) commence from C6 homologue as enantiotropic and persists up to the lastmember synthesized. The mesomorphic properties of present serieswere compared with other two structurally similar series to study the effects of change of meta and para position on the mesomorphism.
- Jain,Patel
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- Synthesis and study of new homologous series of ester-chalcone exhibiting nematic phases
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A novel homologous series of ester-chalcone have been synthesized and their liquid crystals (LCs) properties are studied. All the homologue shows nematic phase except C1-C4 homologue. Classical nematic textures are observed in this homologous series with the help of polarizing optical microscope (POM) equipped with hot stage. The role of flexible methylene group spaces, degree of polymerization and central linkage on the exhibition of all the homologue is discussed. The novel homologous series has been characterized by the standard methods (1HNMR, IR, and elemental analysis).
- Jain,Patel
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- Mesomorphism and molecular flexibility in novel chalconyl derivatives with two phenyl rings
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A novel chalconyl liquid crystalline (LC) homologous series with two phenyl rings and one central bridge RO?C6H4?CH=CH–CO?C6H4(O?C18H37) (meta) has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC behaviors or properties. Homologous series of present investigation (C1–C18) consists of thirteen homologues, and thermotropic mesomorphism for nematic and smectic commences from C3 and C6 homologues respectively. The C3, C4, and C5 homologues are enantiotropically nematic, whereas, the homologues from C6 to C18 are monotropically smectic plus nematic. Melting points and transition temperatures were determined using a polarizing optical microscope (POM) equipped with a heating stage. The textures of the nematic phase are threaded or Schlieren and that of a smectic phase are fan shaped of smectic-A or smectic-C type. The Cr?I/M, N?I/I?N, and N-Sm transition curves behave in the normal manner, and the Cr-I/M exhibits an odd-even effect. Analytical, thermal, and spectral data confirm the molecular structures. Thermal stabilities of smectic and nematic are low. Mesophase lengths are very short, ranging between 1–8°C and 14°C. The novel compounds are compared with a known series.
- Sharma, Vinay S.,Jain,Patel
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- Mesomorphism dependence on heterocyclic tail
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A novel homologous series of liquid crystal materials containing a heterocyclic ring was synthesized with a view to understanding and establishing the relation between liquid crystal (LC) properties and a molecular structure; and with a view to curing skin-related diseases following biological activity studies. The series consist of 13 (C1 to C18) members. All the members are liquid crystals. The C4 to C18 members are smectogenic of which C4 and C5 are monotropic and remaining members (C6 to C18) are enantiotropic in nature; whereas all C1 to C18 members are enantiotropically nematogenic. Hence the C1, C2, C3 members are only nematogenic and the rest of the homologues are smectogenic in addition to nematogenic. Transition temperatures were determined by an polarizing optical microscope equipped with heating stage. Analytical and spectral data confirmed the molecular structures of homologues. It is a middle ordered melting type series. LC properties of a series are compared with the structurally known series.
- Bhola,Bhoya
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- Mesomorphism dependence on central bridges and the efficiency order of the tail group
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A novel homologous series: RO-C6H4?CH?CH?COO?C6H4?CH?N-C6H3 (CH3)2 of ortho-meta Schiff's bases has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on mesomorphic properties and to provide a source of novel liquid crystalline (LC) materials. The series consists of 13 homologues (C1 to C8, C10, C12, C14, C16 & C18). C1 and C3 homologues are nonmesomorphic, C2 and C4monotropicnematic, C6 and C7monotropicsmectic in addition to enantiotropicnematic, C5 is only enantiotropicnematic, C8, C10, C12 are enantiotropically smectogenic plus nematogenic and C14, C16, C18 homologues are enantiotropically smectic only. Textures and transition temperatures were determined using an optical polarizing microscope equipped with a heating stage. Analytical and spectral data confirm the molecular structures. Average smectic and nematic thermal stabilities are 100.16°C and 110.83°C, respectively. Mesomorphic properties of present novel series are compared with structurally similar homologous series.
- Bhola,Bhoya
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p. 154 - 161
(2016/07/14)
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- Synthesis of new series of 4, 5-dihydroisoxazole-5-carboxylate derivatives for the study of their liquid crystalline properties
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A new series of 4,5-dihydroisoxazole-5-carboxylate derivatives were synthesized via [3 + 2] cycloaddition reaction between ethyl acrylate and nitrile oxide generated in situ in presence of Chloramine-T. The synthesized derivatives were characterized by Mass, IR and NMR Spectroscopy and their mesomorphic behavior were studied using DSC and Polarising Optical Microscopy. [Figure not available: see fulltext.]
- Kotian, Sumana Y.,Kudva N, Narayana U.,Lokanatha Rai,Byrappa
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p. 1033 - 1036
(2016/07/15)
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