Liquid Crystalline Properties of 4,4and#39;-methylenebis(N-(4-Alkanoxybenzylidene)aniline): Synthesis, Characterization, and Theoretical study

2019 ◽  
Vol 41 (6) ◽  
pp. 1107-1107
Author(s):  
Mohammed Taha Yaseen and Abdullah Hussein Kshash Mohammed Taha Yaseen and Abdullah Hussein Kshash
Keyword(s):  
Liquid Crystalline ◽  
Theoretical Study ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Benzene Nucleus ◽  
Crystal Properties ◽  
Ft Ir ◽  
Alkoxy Groups ◽  
Gaussian Program ◽  
Mesomorphic Properties

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 and 1H-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.

Lyotropic liquid crystalline phthalocyanines containing 4-((S)-3,7-dimethyloctyloxy)phenoxy moieties

2017 ◽  
Vol 21 (01) ◽  
pp. 16-23 ◽  
Author(s):  
Sibel Eken Korkut ◽  
Hale Ocak ◽  
Belkıs Bilgin-Eran ◽  
Dilek Güzeller ◽  
M. Kasım Şener
Keyword(s):  
Liquid Crystalline ◽  
Spectroscopic Properties ◽  
The Novel ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
Ft Ir ◽  
Aggregation Behaviors ◽  
Mesomorphic Properties ◽  
Thermotropic Liquid Crystalline Behavior

The novel metal free phthalocyanine and its copper complex which are octa-substituted at the peripheral positions with 4-(([Formula: see text]-3,7-dimethlyoctyloxy)phenoxy moieties were synthesized and characterized by FT-IR, 1H NMR and mass spectroscopy. Their mesomorphic properties were studied by polarizing optical microscopy. The spectroscopic properties and aggregation behaviors of the novel phthalocyanines were also investigated by UV-vis spectroscopy in different solvents with same concentration as well as in a wide range of concentrations of chloroform. Both compounds with chloroform and [Formula: see text]-dodecane clearly show the lyotropic columnar mesophase in a wide temperature range whereas thermotropic liquid crystalline behavior for both compounds is not observed. Both of these novel compounds show no aggregation in toluene, tetrahydrofuran, dichloromethane and chloroform.

The Effect of Hydrogen Bonding on the Mesomorphic Properties for Side Chain Type Liquid Crystalline Polyurethanes

1996 ◽  
Vol 425 ◽  
Author(s):  
T. Mihara ◽  
N. Koide
Keyword(s):  
Hydrogen Bonding ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Flexible Chain ◽  
Remarkable Change ◽  
Polymer Backbone ◽  
Phase Transition Temperatures ◽  
Ft Ir ◽  
Mesomorphic Properties ◽  
Chain Type

AbstractMesomorphic properties and temperature dependence of the hydrogen bonding between urethane bonds (H-bonding) for side chain type liquid crystalline polyurethane(SLCPU)s were studied by thermally controlled FT-IR spectroscopy. A remarkable change in the strength of H-bonding for SLCPUs with a flexible chain in the polymer backbone(flexible SLCPUs) was displayed near the phase transition temperatures, while small changes in the strength of H-bonding for SLCPUs with a rigid moiety in the polymer backbone(rigid SLCPUs) was influenced by a mesogenic group in the side chain and the flexible chain length in the polymer backbone. Furthermore, in order to study the influence of H-bonding in rigid SLCPUs, polyurethane derivatives with methyl group were synthesized replacing hydrogen in urethane bonds. No mesomorphic properties for polyurethane derivatives obtained were exhibited. It was concluded that H-bonding played an important role to exhibit mesomorphic properties of rigid SLCPUs.

scholarly journals Synthesis, Characterization and DFT Study of 4,4′-Oxydianiline Imines as Precursors of Tetrahalo-1,3-oxazepine-1,5-dione

2017 ◽  
Vol 17 (2) ◽  
pp. 330
Author(s):  
Abdullah Hussein Kshash ◽  
Mohammed Ghannam Mokhlef
Keyword(s):  
Schiff Bases ◽  
Phthalic Anhydride ◽  
Density Functional ◽  
Spectroscopic Techniques ◽  
Functional Theory ◽  
Homo And Lumo ◽  
Ft Ir ◽  
Gaussian Program ◽  
Theoretical Results ◽  
Direct Condensation

This work presents four Schiff bases derived from 4,4′-Oxydianiline, distinguished by the para substituted halogen of benzaldehyde. These bases were used to synthesize eight compounds of di-1,3-oxazepine by direct condensation with tetrachloro phthalic anhydride and tetrabromo phthalic anhydride. The reactions were monitored with TLC and all structures were characterized using spectroscopic techniques such as FT-IR, 1H-NMR, 13C-NMR and C, H, N techniques. On the other hand, a theoretical study by Density Functional Theory (DFT) for the electronic structures was intended to study the effects of para-substituted halogen of benzaldehyde on the electronic structure of synthesized Schiff bases by using the Gaussian program. Theoretical results indicate that there is no effect of halogen atoms except for bromine on HOMO and LUMO energies of the synthesized compounds.

Experimental (FT-IR, Laser-Raman and NMR) and theoretical spectroscopic analysis of 3-[(N-methylanilino)methyl]-5-(thiophen-2-yl)-1,3,4-oxadiazole-2(3H)-thione

2017 ◽  
Vol 16 (03) ◽  
pp. 1750024 ◽  
Author(s):  
Yusuf Sert ◽  
Nuri Öztürk ◽  
Fatmah A. M. Al-Omary ◽  
Can Alaşalvar ◽  
Mona M. Al-Shehri ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Chemical Shifts ◽  
Molecular Structures ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Nmr Chemical Shifts ◽  
Laser Raman ◽  
Ft Ir ◽  
Experimental Values ◽  
Vibrational Wavenumbers

The structure of a potential bioactive agent namely, 3-[([Formula: see text]-methylanilino)methyl]-5-(thiophen-2-yl)-1,3,4-oxadiazole-2(3[Formula: see text]-thione was characterized by proton and carbon-13 nuclear magnetic resonance (NMR) chemical shifts, Fourier transform infrared (FT-IR) and Laser-Raman spectroscopic techniques. The quantum chemical computations of molecular structures (disorder I and disorder II forms), vibrational wavenumbers, carbon-13 and proton chemical shifts and UV-Vis spectroscopic parameters have been performed with DFT/B3LYP method at 6-311[Formula: see text]G(d,p) basis set. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), nonlinear optical (NLO) properties and natural bond orbital (NBO) analyses have been theoretically examined with the mentioned calculation level. The calculated values have been compared with the recorded experimental data. The computed molecular geometric parameters, vibrational wavenumbers, NMR chemical shifts, and UV-Vis wavelengths have been found to be in a good harmony with the experimental values and spectral results of similar structures in the literature. We believe that the work will be of considerable interest to anyone working in the area of theoretical chemistry, whether in industry or academics.

scholarly journals Synthesis of New Star-Shaped Liquid Crystalline Cyclotriphosphazene Derivatives with Fire Retardancy Bearing Amide-Azo and Azo-Azo Linking Units

2020 ◽  
Vol 21 (12) ◽  
pp. 4267 ◽  
Author(s):  
Zuhair Jamain ◽  
Melati Khairuddean ◽  
Tay Guan-Seng
Keyword(s):  
Liquid Crystalline ◽  
Optical Microscope ◽  
Resonance Spectroscopy ◽  
Fire Retardancy ◽  
Limiting Oxygen Index ◽  
Smectic A ◽  
Terminal Substituent ◽  
Crystal Properties ◽  
Ft Ir ◽  
Positive Results

Two series of new hexasubstituted cyclotriphosphazene derivatives were successfully synthesized and characterized. These derivatives are differentiated by two types of linking units in the molecules such as amide-azo (6a–j) and azo-azo (8a–j). The homologues of the same series contain different terminal substituents such as heptyl, nonyl, decyl, dodecyl, tetradecyl, hydroxyl, carboxyl, chloro, nitro, and amino groups. All the intermediates and final compounds were characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), and Carbon, Hydrogen, and Nitrogen (CHN) elemental analysis. Liquid crystal properties for all compounds were determined using polarized optical microscope (POM). It was found that only intermediates 2a–e with nitro and alkoxyl terminal chains showed a smectic A phase. All the final compounds with alkoxyl substituents are mesogenic with either smectic A or C phases. However, other intermediates and compounds were found to be non-mesogenic. The study on the fire retardancy of final compounds was determined using limiting oxygen index (LOI) method. The LOI value of pure polyester resin (22.53%) was increased up to 24.71% after treating with 1 wt% of hexachlorocyclotriphosphazene (HCCP). Moreover, all the compounds gave positive results on the LOI values and compound 6i with the nitro terminal substituent showed the highest LOI value of 27.54%.

Synthesis, characterization and structural computational investigation of novel Zn(II) phthalocyanines containing peripheral anthracene moieties

2019 ◽  
Vol 23 (07n08) ◽  
pp. 943-959
Author(s):  
Nilgün Kabay ◽  
Burak Doğan Bozer ◽  
Aslı Öztürk Kiraz ◽  
Yasemin Baygu ◽  
İzzet Kara ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Ground State ◽  
Atomic Orbital ◽  
Molecular Geometry ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Computational Investigation ◽  
Ft Ir ◽  
Experimental Chemical Shift ◽  
C Nmr

New zinc(II) phthalocyanines (ZnPc-I and ZnPc-II) containing four peripheral anthracene pendant groups were synthesized by cyclotetramerization of (E)-4-(3-(4-((anthracen-9-yl-methylene)amino)phenoxy)propoxy)phthalonitrile and 4-(3-(4-((anthracen-9-ylmethyl)amino)phenoxy)propoxy)phthalonitrile. All compounds were characterized using a combination of analytical and spectroscopic techniques such 1H, [Formula: see text]C NMR, FT-IR, UV-vis and MS spectral data. The molecular geometry and gauge including atomic orbital (GIAO) 1H and [Formula: see text]C chemical shift values of the compounds in the ground state have also been calculated using B3LYP with the 6–31G([Formula: see text] basis set. The chemical shift of the optimized molecular structure is compared with the experimental chemical shift values.

Study on the 4-ethoxy-2-methyl-5-(4-morpholinyl)-3(2H)-pyridazinone using FT-IR, 1H and 13C NMR, UV-vis spectroscopy, and DFT/HSEH1PBE method

2018 ◽  
Vol 96 (9) ◽  
pp. 1042-1052 ◽  
Author(s):  
Bülent Dede ◽  
Davut Avcı ◽  
Semiha Bahçeli
Keyword(s):  
Gas Phase ◽  
Electronic Absorption ◽  
Vibrational Frequencies ◽  
Oscillator Strengths ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Vis Spectroscopy ◽  
Td Dft ◽  
Ft Ir ◽  
C Nmr

In this work, the 4-ethoxy-2-methyl-5-(4-morpholinyl)-3(2H)-pyridazinone (or emarfazone, C11H17N3O3) compound, which has many biological functions, has been investigated using FT-IR, 1H and 13C NMR (in CDCl3 solvent), and UV-vis (in ethanol solvent) spectroscopic techniques. Furthermore, the optimized molecular structure, conformational analysis, vibrational frequencies and their assignments, 1H and 13C NMR chemical shift values (in gas phase and CHCl3 solvent), HOMO–LUMO, MEP (molecular electrostatic potential), NBO (natural bond orbital) analyses, and nonlinear optical (NLO) parameters of the title compound in the ground state have been explored by using DFT/HSEH1PBE method with the 6-311++G(d,p) basis set. The electronic absorption maximum wavelengths and oscillator strengths (in gas phase and ethanol solvent) were also obtained at TD-DFT/HSEH1PBE level. A comparison among the experimental and calculated results at the mentioned level indicates that the vibrational frequencies and maximum electronic absorption wavelengths are in good agreement with each other.

scholarly journals Spectral and Structural Characterization of Metformin with Different Counter Anions: Comparative Analysis and DFT Calculations

2021 ◽  
Vol 33 (11) ◽  
pp. 2817-2825
Author(s):  
Mohammed Alsawat ◽  
Hamdy S. El-Sheshtawy ◽  
Tariq Altalhi ◽  
Amine Mezni ◽  
Tushar Kumeria ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Chemical Potential ◽  
Crystal Packing ◽  
Spectroscopic Studies ◽  
Basis Set ◽  
Chemical Hardness ◽  
Spectroscopic Techniques ◽  
Ft Ir ◽  
Chemical Descriptors

The metformin perchlorate (MetH+·ClO4 −) with a new crystal structure was synthesized, characterized and comparatively studied with other metformin salts of Cl− and NO3 − by different spectroscopic techniques such as TGA-DSC and FT-IR as well as UV-visible spectroscopic studies. DFT calculations were performed by rwb97xd and 6-31G+(d,p) basis set for structure optimization and frequency calculations. Similar to MetH+·Cl−, the crystal packing of MetH+·ClO4 −andMetH+·NO3 − were stabilized by hexagonal hydrogen bond elongated network. The relative stability and reactivity of these salts were determined by exploring the DFT chemical descriptors such as chemical hardness, electronegativity, electronic chemical potential, electrophilicity and hardness. These calculations were employed to get the subset of variables that could categorize the metformin salts according to their reactivity.

Density functional theory, Comparative vibrational spectroscopic studies, HOMO-LUMO, and NBO analysis of Trichloro isocyanuric acid and Trithio cyanuric acid

2015 ◽  
Vol 8 (3) ◽  
pp. 2197-2221
Author(s):  
Theraviyum Chithambarathanu ◽  
M. Darathi ◽  
J. DaisyMagdaline ◽  
S. Gunasekaran
Keyword(s):  
Density Functional ◽  
Cyanuric Acid ◽  
Nbo Analysis ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Point Energy ◽  
Isocyanuric Acid ◽  
Ft Ir ◽  
Homo Lumo ◽  
Ft Raman

The molecular vibrations of Trichloro isocyanuric acid (C3Cl3N3O3) and Trithio cyanuric acid (C3H3N3S3) have been investigated in polycrystalline sample at room temperature by Fourier Transform Infrared (FT-IR) and FT-Raman spectroscopies in the region 4000-450 cm-1 and 4000-50 cm-1 respectively, which provide a wealth of structural information about the molecules. The spectra are interpreted with the aid of normal co-ordinate analysis following full structure optimization and force field calculations based on density functional theory   (DFT) using standard B3LYP / 6-311++ G (d, p) basis set for investigating the structural and spectroscopic properties. The vibrational frequencies are calculated and the scaled values are compared with experimental FT-IR and FT-Raman spectra. The scaled theoretical wave numbers shows very good agreement with experimental ones. The complete vibrational assignments are performed on the basis of potential energy distribution (PED) of vibrational modes, calculated with scaled quantum (SQM) method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that change in electron density (ED) in σ* and π* anti-bonding orbitals and second order delocalization   energy (E2) confirm the occurrence of Intra molecular Charge Transfer (ICT) within the molecule. The thermodynamic properties like heat capacity, entropy, enthalpy and zero point energy have been calculated for the molecule. The frontier molecular orbitals have been visualized and the HOMO-LUMO energy gap has been calculated. The Molecular Electrostatic Potential (MEP) analysis reveals the sites for electrophilic attack and nucleophilic reactions in the molecule.

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