scholarly journals New Homologues Series of Heterocyclic Schiff Base Ester: Synthesis and Characterization

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yee-Ting Chong ◽  
Norazilawati Muhamad Sarih ◽  
Sie-Tiong Ha ◽  
Md. Rezaul Karim Sheikh
Keyword(s):  
Schiff Base ◽  
Relative Phase ◽  
Structural Information ◽  
Optical Microscope ◽  
Spectroscopic Techniques ◽  
Ester Synthesis ◽  
Scanning Calorimetry ◽  
Smectic C ◽  
Heating And Cooling ◽  
C Nmr

A homologous series of liquid crystal bearing with heterocyclic thiophene Schiff base ester with alkanoyloxy chain (CH3(CH2)nCOO–, where n=4, 6, 8, 10, 12, 14, 16) was successfully synthesized through the modification of some reported methods. The structural information of these compounds was isolated and characterized through some spectroscopic techniques, such as FTIR, 1H, and 13C NMR and elemental analysis. Textural observation was carried out using a polarizing optical microscope (POM) over heating and cooling cycles. It was found that all synthesized compounds (3a–g) exhibited an enantiotropic nematic phase upon the heating and cooling cycle with high thermal stability. Moreover, a characteristic bar transition texture was observed for compounds 3f and 3g which have shown transition of nematic-to-smectic C phase. This has been further confirmed by obtaining relative phase transition temperature using the differential scanning calorimetry (DSC).

scholarly journals Synthesis and Phase Transition Behaviours of New Chalcone Derivatives

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. T. Ha ◽  
Y. W. Low
Keyword(s):  
Phase Region ◽  
Spectroscopic Techniques ◽  
Organic Solution ◽  
Scanning Calorimetry ◽  
Chalcone Derivatives ◽  
Heating And Cooling ◽  
Phenyl Rings ◽  
Mesomorphic Property ◽  
Dsc Thermograms ◽  
C Nmr

A series of new chalcone derivatives with a general formula of C11H27COOC6H4COCH=CHC6H4X where X=F, Cl, Br, and NO2were well synthesized and crystallized from organic solution. The physical properties as well as the chemical formulations of these compounds were determined by spectroscopic techniques (FTIR, and1H and13C NMR). Differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) techniques were employed to study their transition temperatures and mesophase characteristics. DSC thermograms of compounds with fluoro and nitro substituents displayed direct isotropization and recrystallization during heating and cooling processes. Chloro and bromo analogues exhibited Cr1-to-Cr2transition within the crystal phase region. It was also found that enone linkage showed fewer tendencies to exhibit mesomorphic property compared to imine linkage. However, when enone linkage is combined with other central linkages and additional phenyl rings, it turns conducive to mesomorphism.

Design, Synthesis and Characterization of Hydrogen Bonded Binary Liquid Crystal Complex from 4-Methoxycinnamic Acid and 4-Hexyloxybenzoic Acid (4MCA:6OBA)

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Thamilarasan Ranjeeth Kumar ◽  
Sankaran Sundaram ◽  
Thangaiyan Chitravel ◽  
Ramasamy Jayaprakasam ◽  
Vellalapalayam Nallagounder Vijayakumar
Keyword(s):  
Liquid Crystal ◽  
Binary Mixture ◽  
Tilt Angle ◽  
Phase Variation ◽  
Optical Microscope ◽  
Scanning Calorimetry ◽  
Smectic C ◽  
Ir Studies ◽  
Methoxycinnamic Acid ◽  
Hydrogen Bonded

AbstractHydrogen bonded liquid crystal (HBLC) binary mixture has been synthesized from mesogenic 4-methoxycinnamic acid (4MCA) and mesogenic 4-hexyloxybenzoic acid (6OBA) with different mole ratio. The mesomorphic phase behavior and corresponding phase transition temperatures along with the enthalpy values were investigated by differential scanning calorimetry (DSC). The characteristic textures of 4MCA+6OBA binary mixture were observed by using polarizing optical microscope (POM). Fourier transform infrared spectroscopic (FT-IR) studies confirm the formation of hydrogen bond in the present binary mixture. A note worthy observation in this complex is that pure mesogens have no smectic phase where as 4MCA+6OBA binary mixture exhibits a nematic phase along with higher order smectic C (Sm C) phase. Variation of mole ratio influences thermal properties such as phase peak, enthalpy values and thermal span width of the present HBLC binary mixture complex. The optical tilt angle of 4MCA+6OBA for smectic C phase and thermal stability factors have been investigated. Optical tilt angle for smectic C phase is determined and same is fitted to a power law.

Binary Mixtures of Hydrogen-Bonded Ferroelectric Liquid Crystals: Thermal Span Enhancement in Smectic X* Phase

2015 ◽  
Vol 70 (9) ◽  
pp. 757-774 ◽  
Author(s):  
Gopal Sangameswari ◽  
Nataraj Pongali Sathya Prabu ◽  
Mathukumalli Lakshmi Narayana Madhu Mohan
Keyword(s):  
Binary Mixtures ◽  
Thermal Equilibrium ◽  
Optical Microscope ◽  
Stability Factor ◽  
Benzoic Acids ◽  
Scanning Calorimetry ◽  
Ferroelectric Liquid Crystals ◽  
Binary Liquid ◽  
Smectic C ◽  
Hydrogen Bonded

AbstractThermotropic hydrogen-bonded ferroelectric binary liquid crystal mixtures comprising of N-carbamyl-l-glutamic acid (CGA) and p-n-alkyloxy benzoic acids (BAO) are investigated. Variation in the molar proportion of X and Y (where X=CGA+5BAO and Y=CGA+9BAO, CGA+10BAO, CGA+11BAO, and CGA+12BAO) comprising of four series yielded 36 binary mixtures. Optical and thermal properties of these mixtures are meticulously studied in the present article. In addition to the traditional phases, a novel smectic ordering namely smectic X* is observed in all the four series. The aim of the investigation is to obtain abundance occurrence of smectic X* with a large thermal span, and hence, the proportions of the binary mixtures are so chosen that the prelude task is accomplished. Optical tilt angle in smectic X* and smectic C* phases is experimentally determined, and a theoretical fit is performed. Phase diagrams of the four series are constructed from the data obtained from the differential scanning calorimetry and correlated with the phases recorded by the polarising optical microscope studies. Thermal stability factor and thermal equilibrium are also premeditated.

scholarly journals Preparation and spectroscopic studies of Fe(II), Ru(II), Pd(II) and Zn(II) complexes of Schiff base containing terephthalaldehyde and their transfer hydrogenation and Suzuki-Miyaura coupling reaction

2019 ◽  
Vol 17 (1) ◽  
pp. 571-580 ◽  
Author(s):  
Nevin Turan ◽  
Kenan Buldurun ◽  
Naki Çolak ◽  
İsmail Özdemir
Keyword(s):  
Schiff Base ◽  
Coupling Reaction ◽  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Transfer Hydrogenation ◽  
Spectroscopic Techniques ◽  
Catalytic Activities ◽  
H Nmr ◽  
Optimized Conditions ◽  
C Nmr

AbstractThis study describes synthesis, spectroscopic characterization and catalytic activities of Fe(II), Ru(II), Pd(II) and Zn(II) complexes with a novel Schiff base ligand (L) derived from methyl 2-amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate and terephthalaldehyde. We used spectroscopic techniques including IR, UV-Vis, 1H-NMR, 13C-NMR, elemental analysis and also mass analysis and magnetic susceptibility measurements to identify the products. The Pd(II) complex was used as a potential catalyst for Suzuki-Miyaura coupling reaction of some aryl halides under optimized conditions. The effect of various bases such as NaOH, KOH, and KOBut was investigated in transfer hydrogenation (TH) of ketones by isopropyl alcohol as the hydrogen source. Ru(II) and Pd(II) complexes showed catalytic activity while Zn(II) and Fe(II) metal complexes failed to do that.

Simultaneous Thermal and Structural Measurements of Oriented Polymers by DSC/XRD Using an Area Detector

1988 ◽  
Vol 32 ◽  
pp. 617-623
Author(s):  
Steven T. Correale ◽  
N. Sanjeeva Murthy
Keyword(s):  
Structural Information ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Oriented Polymers ◽  
X Ray ◽  
Precise Control ◽  
Area Detector ◽  
Heating And Cooling ◽  
Complementary Techniques

Differential scanning calorimetry (DSC) and variable temperature x-ray diffraction (XRD) are two complementary techniques which provide thermal and structural information. By using DSC and XRD simultaneously, one can directly correlate the results from the two techniques. The simultaneous measurements eliminate problems which might arise due to sample inhomogeneity and instrumental differences. In addition, the DSC provides precise control over temperature, and heating and cooling rates.

Synthesis and evaluation of novel series of Schiff base cationic surfactants as corrosion inhibitors for carbon steel in acidic/chloride media: experimental and theoretical investigations

RSC Advances ◽  
2016 ◽  
Vol 6 (11) ◽  
pp. 8681-8700 ◽  
Author(s):  
Hany M. Abd El-Lateef ◽  
Ahmed H. Tantawy
Keyword(s):  
Schiff Base ◽  
Cationic Surfactants ◽  
Chemical Structure ◽  
Spectroscopic Techniques ◽  
H Nmr ◽  
New Family ◽  
Theoretical Investigations ◽  
Acidic Chloride ◽  
Chain Lengths ◽  
C Nmr

A new family of Schiff base cationic surfactants (CSSB) having various alkyl chain lengths were prepared and their chemical structure was elucidated by using different spectroscopic techniques (FTIR, 13C-NMR and 1H-NMR).

scholarly journals Synthesis and Characterization of Lateral Fluoro-substituents Liquid Crystals

2021 ◽  
Vol 11 (5) ◽  
pp. 12495-12505
Keyword(s):  
Molecular Structure ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Linkage Group ◽  
Optical Microscope ◽  
Synthesis And Characterization ◽  
Spectroscopic Techniques ◽  
Dielectric Measurements ◽  
Scanning Calorimetry

Lateral difluoro substituent liquid crystal based on a three-aromatic core has been synthesized. It has been designed to correlate the molecular structure and mesomorphism with reference to the difluoro substituent and -COO- linkage group. This compound was characterized by elementary analyses and spectroscopic techniques such as FTIR and 1H-NMR. The synthesis compound's mesomorphic behavior was studied by polarizing optical microscope, differential scanning calorimetry, and dielectric measurements. The recent investigation reveals only SmB phase.

Electron microscopy and diffraction of crystalline dendrimers and macrocycles

1993 ◽  
Vol 51 ◽  
pp. 1218-1219
Author(s):  
C. J. Buchko ◽  
P. M. Wilson ◽  
Z. Xu ◽  
J. Zhang ◽  
S. Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Liquid Crystalline ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Scanning Calorimetry ◽  
Tertiary Butyl ◽  
Phenyl Acetylene ◽  
Selected Area Electron Diffraction ◽  
Liquid Crystalline Phases ◽  
Resolution Electron

The synthesis of well-defined organic molecules with unique geometries opens new opportunities for understanding and controlling the organization of condensed matter. Here, we study dendrimers and macrocycles which are synthesized from rigid phenyl-acetylene spacer units, Both units are solubilized by the presence of tertiary butyl groups located at the periphery of the molecule. These hydrocarbon materials form crystalline and liquid crystalline phases which have been studied by differential scanning calorimetry, hot stage optical microscopy, and wide-angle x-ray scattering (WAXS).The precisely defined architecture of these molecules makes it possible to investigate systematic variations in chemical architecture on the nature of microstructural organization. Here we report on the transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high resolution electron microscopy (HREM) studies of crystalline thin films formed by deposition of these materials onto carbon substrates from dilute solution. Electron microscopy is very attractive for gaining structural information on new molecules due to the scarcity of material to grow single crystals suitable for conventional crystallography.

Notizen: Reaction Product of Formaldehyd and O-Benzylhydroxylamine: A Schiff Base?

1984 ◽  
Vol 39 (8) ◽  
pp. 1154-1155 ◽  
Author(s):  
Johannes Respondek
Keyword(s):  
Schiff Base ◽  
Structure Elucidation ◽  
Nmr Spectra ◽  
C Nmr

Abstract200 MHz 1H and 50 MHz 13C NMR spectra were recorded from the reaction product of form aldehyd 1 and O -benyzlhydroxylamine 2 for the purpose of its structure elucidation

scholarly journals Crystallization Behavior and Mechanical Properties of Poly(ε-caprolactone) Reinforced with Barium Sulfate Submicron Particles

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2368
Author(s):  
Hegoi Amestoy ◽  
Paul Diego ◽  
Emilio Meaurio ◽  
Jone Muñoz ◽  
Jose-Ramon Sarasua
Keyword(s):  
Barium Sulfate ◽  
Thermal Studies ◽  
Polarized Light ◽  
Optical Microscope ◽  
Submicron Particles ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Nucleation Effect ◽  
Crystal Fraction ◽  
Light Optical Microscope

Poly(ε-caprolactone) (PCL) was mixed with submicron particles of barium sulfate to obtain biodegradable radiopaque composites. X-ray images comparing with aluminum samples show that 15 wt.% barium sulfate (BaSO4) is sufficient to present radiopacity. Thermal studies by differential scanning calorimetry (DSC) show a statistically significant increase in PCL degree of crystallinity from 46% to 52% for 25 wt.% BaSO4. Non-isothermal crystallization tests were performed at different cooling rates to evaluate crystallization kinetics. The nucleation effect of BaSO4 was found to change the morphology and quantity of the primary crystals of PCL, which was also corroborated by the use of a polarized light optical microscope (PLOM). These results fit well with Avrami–Ozawa–Jeziorny model and show a secondary crystallization that contributes to an increase in crystal fraction with internal structure reorganization. The addition of barium sulfate particles in composite formulations with PCL improves stiffness but not strength for all compositions due to possible cavitation effects induced by debonding of reinforcement interphase.

Sign in / Sign up

Export Citation Format

Share Document