scholarly journals Optical and Thermal Investigations of New Schiff Base/Ester Systems in Pure and Mixed States

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1687
Author(s):  
Abeer S. Altowyan ◽  
Hoda A. Ahmed ◽  
Sobhi M. Gomha ◽  
Ayman M. Mostafa
Keyword(s):  
13C Nmr Spectroscopy ◽  
Molecular Structures ◽  
Mixed States ◽  
Scanning Calorimetry ◽  
1H And 13C Nmr ◽  
Meta Position ◽  
Binary Phase Diagrams ◽  
Thermal Investigations ◽  
Ester Moiety ◽  
Ft Ir

New mesomorphic series, 4-hexadecyloxy phenyl-imino-4′-(3-methoxyphenyl)-4″-alkoxybenzoates (An), were prepared and investigated with different thermal and mesomorphic techniques. The synthesized homologous series constitutes four members that differ from each other in the terminal length of flexible chain (n) attached to phenyl ester moiety, which varies between n = 6, 8, 10, and 12 carbons. A lateral CH3O group is attached to the central benzene ring in the meta position with respect to the ester moiety. Molecular structures of all newly prepared homologues were elucidated via FT-IR, 1H and 13C NMR spectroscopy. Mesomorphic and thermal properties were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and the mesophases identified by polarized optical microscopy (POM). DSC and POM examinations revealed that all members of the present series (An) exhibit a purely enantiotropic nematic (N) phase. Comparative evaluations and binary phase diagrams were established between the present homologues and their corresponding shorter one (Bn). The examination revealed that, the length of the flexible alkoxy chain incorporated into the phenylimino moiety is highly effective on the temperature range and stability of the mesophase observed. With respect to the binary mixtures An/Bn, the exhibited N phase showed to cover the whole composition range with eutectic behavior.

scholarly journals Synthesis, Thermal and Optical Characterizations of New Lateral Organic Systems

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 551
Author(s):  
Laila Ahmed. Al-Mutabagani ◽  
Latifah A. Alshabanah ◽  
Sobhi M. Gomha ◽  
Hoda A. Ahmed
Keyword(s):  
Methoxy Group ◽  
13C Nmr Spectroscopy ◽  
Molecular Structures ◽  
Phenyl Ester ◽  
Scanning Calorimetry ◽  
1H And 13C Nmr ◽  
Polarized Optical Microscopy ◽  
Organic Systems ◽  
Temperature Ranges ◽  
Ft Ir

New laterally OCH3-substituted optical organic Schiff base/ester series, namely 4-(4-(hexyloxyphenyl)iminomethyl)-3-methoxyphenyl 4-alkoxybenzoates, were prepared and characterized with different thermal, mesomorphic, and photoactive techniques. The prepared group constitutes five homologues that differ from each other in the number of carbons in the terminal alkoxy chain (n), which varies between n = 6, 8, 10, 12, and 16 carbons. The laterally protruded methoxy group is attached to the central benzene ring that makes an angle of 120° with the molecular long axis. Molecular structures of all newly prepared homologues were fully elucidated via FT-IR, 1H and 13C NMR spectroscopy. Mesomorphic transitions were determined via differential scanning calorimetry (DSC) and the phases identified by polarized optical microscopy (POM). Independent of the length of the terminal alkoxy chain attached to phenyl ester ring, only a monomorphic nematic (N) phase was observed for all the synthesized compounds. A comparative study was made between the present lateral methoxy-substituted homologues and their corresponding laterally-neat analogues. The results revealed that, depending on the length of the alkoxy chain and the presence or absence of the lateral methoxy group, different mesophases with different thermal stability and temperature ranges were observed. Finally, UV-vis spectra showed that the present nematogenic series possess photoactive properties that are of importance for many applications.

scholarly journals Optical investigations and photoactive solar energy applications of new synthesized Schiff base liquid crystal derivatives

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fowzia S. Alamro ◽  
Sobhi M. Gomha ◽  
Mohamed Shaban ◽  
Abeer S. Altowyan ◽  
Tariq Z. Abolibda ◽  
...  
Keyword(s):  
Solar Energy ◽  
Liquid Crystalline ◽  
Molecular Structures ◽  
Light Illumination ◽  
Electrical Measurements ◽  
Scanning Calorimetry ◽  
Energy Applications ◽  
Meta Position ◽  
Chain Group ◽  
Liquid Crystalline Materials

AbstractNew homologues series of liquid crystalline materials namely, (E)-3-methoxy-4-[(p-tolylimino)methyl]phenyl 4-alkloxybenzoates (I-n), were designed and evaluated for their mesomorphic and optical behavior. The prepared series constitutes three members that differ from each other by the terminally attached alkoxy chain group, these vary between 6 and 12 carbons. A laterally OCH3 group is incorporated into the central benzene ring in meta position with respect to the ester moiety. Mesomorphic characterizations of the prepared derivatives are conducted using differential scanning-calorimetry (DSC), polarized optical-microscopy (POM). Molecular structures were elucidated by elemental analyses and NMR spectroscopy. DSC and POM investigations revealed that all the synthesized derivatives are purely nematogenic exhibiting only nematic (N) mesophase, except for the longest chain derivative (I-12) that is dimorphic possesses smectic A and N phases. Moreover, all members of the group have a wide mesomorphic range with high thermal nematic stability. A comparative study was established between the present derivative (I-6) and their previously prepared isomer. The results indicated that the location exchange of the polar compact group (CH3) influences the N mesophase stability and range. The electrical measurements revealed that all synthesized series I-n show Ohmic behaviors with effective electric resistances in the GΩ range. Under white light illumination, the effective electric conductivity for the compound I-8 is five times that obtained in dark conditions. This derivative also showed two direct optical band gaps in the UV and visible light range. In addition, I-6 has band energy gaps of values 1.07 and 2.79 eV, which are suitable for solar energy applications.

Trimesic Acid-Based Star Mesogens with Flexible Spacer: Synthesis and Mesophase Characterization

2012 ◽  
Vol 65 (10) ◽  
pp. 1426 ◽  
Author(s):  
A. Shanavas ◽  
T. Narasimhaswamy ◽  
A. Sultan Nasar
Keyword(s):  
13C Nmr Spectroscopy ◽  
Steric Repulsion ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Analysis Techniques ◽  
Trimesic Acid ◽  
Smectic A ◽  
Flexible Spacer ◽  
Ft Ir ◽  
Alkoxy Groups

A series of trimesic acid-based star mesogens containing an octamethylenoxy spacer and two-ring containing side arms with terminal alkoxy groups were synthesised by a divergent approach. A structurally similar mesogen containing a three-ring side arm was also synthesised. All the mesogens and intermediates were characterised thoroughly using FT-IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis techniques. The mesophase characteristics were identified by hot stage optical polarising microscopy (HOPM) and differential scanning calorimetry (DSC), while X-ray was used to confirm the existence of a smectic A (SA) phase. The HOPM and DSC results revealed the presence of rich polymesomorphism in the star mesogens. The dominance of a SA phase in the series is attributed to the steric repulsion associated with steric asymmetry. The change of the side arm from two rings to three rings was found to increase the mesophase stability.

scholarly journals Surface Properties of Poly(Hydroxyurethane)s Based on Five-Membered Bis-Cyclic Carbonate of Diglycidyl Ether of Bisphenol A

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5184
Author(s):  
Mariusz Tryznowski ◽  
Zuzanna Żołek-Tryznowska
Keyword(s):  
Bisphenol A ◽  
Surface Properties ◽  
Rheological Characteristic ◽  
13C Nmr Spectroscopy ◽  
Cyclic Carbonate ◽  
Contact Angles ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Static Contact ◽  
Ft Ir

Poly(hydroxyurethane)s (PHU) are alternatives for conventional polyurethanes due to the use of bis-cyclic dicarbonates and diamines instead of harmful and toxic isocyanates. However, the surface properties of poly(hydroxyurethane)s are not well known. In this work, we focus on the analysis of the surface properties of poly(hydroxyurethane) coatings. Poly(hydroxyurethane)s were obtained by a catalyst-free method from commercially available carbonated diglycidyl ether of bisphenol A (Epidian 6 epoxy resins) and various diamines: ethylenediamine, trimethylenediamine, putrescine, hexamethylenediamine, 2,2,4(2,4,4)-trimethyl-1,6-hexanediamine, m-xylylenediamine, 1,8-diamino-3,6-dioxaoctane, 4,7,10-trioxa-1,13-tridecanediamine, and isophorone diamine, using a non-isocyanate route. The structures of the obtained polymers were confirmed by FT-IR, 1H NMR and 13C NMR spectroscopy, and thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses were performed. The rheological characteristic of the obtained polymers is presented. The static contact angles of water, diidomethane, and formamide, deposited on PHU coatings, were measured. From the measured contact angles, the surface free energy was calculated using two different approaches: Owens–Wendt and van Oss–Chaudhury–Good. Moreover, the wetting envelopes of PHU coatings were plotted, which enables the prediction of the wetting effect of various solvents. The results show that in the investigated coatings, a mainly dispersive interaction occurs.

scholarly journals New Nitro-Laterally Substituted Azomethine Derivatives; Synthesis, Mesomorphic and Computational Characterizations

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1927
Author(s):  
Mohamed A. El-atawy ◽  
Magdi M. Naoum ◽  
Salma A. Al-Zahrani ◽  
Hoda A. Ahmed
Keyword(s):  
Experimental Data ◽  
Molecular Geometry ◽  
Alkoxy Group ◽  
Molecular Structures ◽  
The Other ◽  
Molecular Architecture ◽  
Scanning Calorimetry ◽  
Elemental Analyses ◽  
Ft Ir ◽  
Chain Lengths

Two new homologues series, based on two rings of the azomethine central group bearing the terminal alkoxy group of various chain lengths, were prepared. The alkoxy chain length varied between 6 and 16 carbons. The other terminal wing in the first series was the F atom, and the compound is named N-4-florobenzylidene-4-(alkoxy)benzenamine (In). The second group of compounds included a lateral NO2 substituent in addition to the terminal F atom, named N-(4-fluoro-3-nitrobenzylidene)-4-(alkyloxy)aniline (IIn). Mesomorphic and optical properties were carried out via differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Elemental analyses, FT-IR, and NMR spectroscopy were carried out to elucidate the molecular structures of the synthesized groups. Mesomorphic investigations indicated that all the synthesized homologues (In) were monomorphic, possessing the smectic A (SmA) phase monotropically, while the second group (IIn) members were non-mesomorphic. The experimental data indicated that the formation of the mesophase is affected by the protrusion of the lateral nitro group. The disruption of the mesophase in the second group was attributed to the increase of its molecular width, which affects its lateral intermolecular interactions. The computational simulations were in agreement with the experimental data. On the other hand, the location of NO2 group within the molecular geometry increased the melting temperature of the molecule, and thus, affected their thermal and physical properties. By discussing the estimated parameters, it was found that the molecular architecture, the dipole moment, and the polarizability of the investigated compounds are highly affected by the electronic nature and position of the terminal and lateral substituents as well as their volumes.

scholarly journals Induced Nematic Phase of New Synthesized Laterally Fluorinated Azo/Ester Derivatives

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4546
Author(s):  
Fowzia S. Alamro ◽  
Hoda A. Ahmed ◽  
Mohamed A. El-Atawy ◽  
Salma A. Al-Zahrani ◽  
Alaa Z. Omar
Keyword(s):  
Theoretical Data ◽  
Molecular Structures ◽  
Scanning Calorimetry ◽  
Polar Groups ◽  
Ir And Nmr Spectroscopy ◽  
Terminal Substituent ◽  
Computational Calculations ◽  
Elemental Analyses ◽  
Ft Ir ◽  
Polar Substituents

A new series of laterally fluorinated mesomorphic compounds, namely 2-fluoro-4-((4-(alkyloxy)phenyl)diazenyl)phenyl 4-substitutedbenzoate (Inx) were prepared and evaluated for their mesophase behavior. The synthesized series constitutes five members that possess different terminally attached polar groups (X). Their molecular structures were confirmed by elemental analyses and both FT-IR and NMR spectroscopy. Examination of the prepared derivatives was conducted via experimental and theoretical tools. Mesomorphic investigations were carried by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). DSC and POM measurements indicated that except for the un-substituted analogue, all other derivatives were purely nematogenic, possessing their nematic (N) mesophase enantiotropically. This is to say that insertions of terminal polar substituents on their mesogenic structures induced the N phase. In addition, the location of lateral and terminal polar moieties played a considerable role in achieving good thermal N stability. Computational calculations were investigated to determine the deduced optimized molecular structures. Theoretical data indicated that both size and polarity of the terminal substituent (X) have essential impact on the thermal parameters and optical properties of possible geometries.

scholarly journals FACILE SYNTHESIS OF PHENOLIC DERIVATIVES, CONTAINIG LACTAMOMETHYL SUBSTITUENTS

2019 ◽  
Vol 62 (10) ◽  
pp. 40-48
Author(s):  
Stepan V. Vorobyev ◽  
Olga V. Primerova ◽  
Ludmila V. Ivanova ◽  
Vladimir D. Ryabov ◽  
Vladimir N. Koshelev
Keyword(s):  
13C Nmr Spectroscopy ◽  
Hydroxyl Group ◽  
1H And 13C Nmr ◽  
Mineral Oils ◽  
Ft Ir ◽  
Low Toxicity ◽  
Phenolic Derivatives ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Low Solubility

In this work we suggest the new method for the synthesis of novel phenolic derivatives, containing lactamomethyl substituents. Oxidation processes of fuels and mineral oils lead to losing of their properties, so the search for new and effective inhibitors of these processes is very actuel. We suggest a facile system for lactamomethylation reaction. Heating in the water some of phenols (resorcinol, phloroglucinol, methylphloroglucinol, pyrogallol, salicylic, resorcilic and gallic acids) with N-hydroxymethyl derivatives of pyrrolidone, valerolactam, caprolactam and 4-phenylpyrrolidone in the presence of catalytic amounts of acetic acid led to the target compounds with nearly quantitative yields. Time of the reaction ranged 1.5-2 h. As the products have low solubility in water, in contrast with the reagents, filtration was used for their extraction. The advantages of this method are also that it is eco-friendly because of small amounts of wastes and low toxicity of the reagents and solvent, and cheapness of starting compounds. Eighteen novel compounds were obtained. The composition of target substances was determined by elemental analysis whereas the structures of the synthesized compounds were confirmed by FT-IR spectroscopy methods, 1H- and 13C-NMR spectroscopy. In IR spectra there are carbonyl group stretching vibrations peaks in lower frequencies (about 1600 cm-1) than expected due to the formation of inter- and intramolecular hydrogen bonds between this group and phenolic hydroxyl group.

scholarly journals N-[2-(1H-Indol-3-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)ethyl]-4-methylbenzenesulfonamide

Molbank ◽  
10.3390/m1008 ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. M1008
Author(s):  
Nikil Purushotham ◽  
Boja Poojary
Keyword(s):  
Mass Spectrometry ◽  
Mycobacterium Tuberculosis ◽  
Potassium Hydroxide ◽  
Inhibitory Action ◽  
13C Nmr Spectroscopy ◽  
Enoyl Reductase ◽  
1H And 13C Nmr ◽  
Ft Ir ◽  
Non Covalent Interactions ◽  
Covalent Interactions

N-[1-Hydrazinyl-3-(1H-indol-3-yl)-1-oxopropan-2-yl]-4-methylbenzenesulfonamide (1) on cyclization with carbon disulfide in ethanolic potassium hydroxide affords N-[2-(1H-indol-3-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)ethyl]-4-methylbenzenesulfonamide (2) in 84% yield. The structure of compound 2 was supported by mass spectrometry, FT-IR and 1H- and 13C-NMR spectroscopy. To investigate the potential of compound 2 to act as antitubercular agent, it was docked against the enoyl reductase (InhA) enzyme of Mycobacterium tuberculosis. The docking pose and non-covalent interactions gave insights on its plausible inhibitory action.

scholarly journals Bimetallic Aluminum 5,6-Dihydro-7,7-dimethyl quinolin-8-olates as Pro-Initiators for the ROP of ε-CL; Probing the Nuclearity of the Active Initiator

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 764 ◽  
Author(s):  
Qiurui Zhang ◽  
Wenjuan Zhang ◽  
Gregory Solan ◽  
Tongling Liang ◽  
Wen-Hua Sun
Keyword(s):  
Nmr Spectroscopy ◽  
Good Control ◽  
13C Nmr Spectroscopy ◽  
Molecular Structures ◽  
Linear Polymers ◽  
X Ray Diffraction ◽  
1H And 13C Nmr ◽  
Operational Temperature ◽  
Species Being ◽  
Active Initiator

Six examples of aluminum 5,6-dihydro-7,7-dimethylquinolin-8-olates, [{2-R1-7,7-Me2-8-R2C9H6N-8-O}AlR32]2 (R1 = R2 = H, R3 = Me C1; R1 = R2 = H, R3 = Et C2; R1 = R2 = H, R3 = i-Bu C3; R1 = Cl, R2 = H, R3 = Me C4; R1 = H, R2 = R3 = Me C5; R1 = Cl, R2 = R3 = Me C6), have been prepared by treating the corresponding pro-ligand (L1–L4) with either AlMe3, AlEt3 or Al(i-Bu)3. All complexes have been characterized by 1H and 13C NMR spectroscopy and in the case of C1 and C4 by single crystal X-ray diffraction; dimeric species are a feature of their molecular structures. In the presence of PhCH2OH (BnOH), C1–C6 displayed good control and efficiency for the ROP of ε-CL with almost 100% conversion achievable in 10 min at 90 °C; the chloro-substituted C4 and C6 notably exhibited the lowest activity of the series. However, in the absence of BnOH, C1 showed only low activity with 15% conversion achieved in 30 min forming a linear polymer capped with either a methyl or a L1 group. By contrast, when one or more equivalents of BnOH was employed in combination with C1, the resulting catalyst was not only more active but gave linear polymers capped with BnO end-groups. By using 1H and 27Al NMR spectroscopy to monitor solutions of C1, C1/BnOH and C1/BnOH/10 ε-CL over a range of temperatures, some support for a monomeric species being the active initiator at the operational temperature is presented.

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