Wide Nematogenic Azomethine/Ester Liquid Crystals Based on New Biphenyl Derivatives: Mesomorphic and Computational Studies

Induction of breast cancer cell apoptosis by novel thiouracil-fused heterocyclic compounds through boosting of Bax/Bcl-2 ratio and DFT study

Breast cancer is a common public health disease causing mortality worldwide. Thus, providing novel chemotherapies that tackle breast cancer is of great interest. In this investigation, novel pyrido[2,3-d]pyrimidine derivatives 3,4,(6a-c),(8a,b),9-20 were synthesized and characterized using a variety of spectrum analyses. The geometric and thermal parameters of the novel thiouracil derivatives 3,4,6a,(8a,b),11,12,17,18, 19 were measured using density functional theory (DFT) via DFT/B3LYP/6-31 + G(d,p) basis set. All synthesized compounds were evaluated by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) method using MCF-7 and MDA-MB-231 breast cancerous cells, compound 17 had the maximum anticancer activity against both breast cancerous cells, recording the lowest half-maximal inhibitory concentration (IC50) values (56.712 μg/mL for MCF-7 cells and 48.743 μg/mL for MDA-MB-231 cells). The results were confirmed in terms of the intrinsic mechanism of apoptosis, where compound 17 had the highest percentage in the case of both cancer cells and recorded Bax (Bcl-2 associated X)/Bcl-2 (B-cell lymphoma 2) ratio 17.5 and 96.667 for MCF-7 and MDA-MB-231 cells, while compound 19 came after 17 in the ability for induction of apoptosis, where the Bax/Bcl-2 ratio was 15.789 and 44.273 for both cancerous cells, respectively. Also, compound 11 recorded a high Bax/Bcl-2 ratio for both cells. The safety of the synthesized compounds was applied on normal WI-38 cells, showing minimum cytotoxic effect with undetectable IC50. Compounds 17, 11, and 19 recorded a significant increase of p53 upregulated modulator of apoptosis (PUMA) expression levels in the cancerous cells. The DFT method was also used to establish a connection between the experimentally determined values of the present investigated compounds and their predicted quantum chemical parameters. It was concluded that Compounds 17, 11, and 19 had anti-breast cancer potential through the induction of apoptotic Bax/Bcl-2 and PUMA expression levels.

Thermal Investigations of Annelated Triazinones-Potential Analgesic and Anticancer Agents

In this article, for the first time, TG-DSC and TG-FTIR investigations of potential pharmaceutics, i.e., analgesic and anticancer active annelated triazinones (1-9) have been presented. The thermal behaviour of these molecules was established in oxidative and inert conditions. The solid-liquid phase transition for each compound (1-9) was documented by one sharp DSC peak confirming the high purity of each sample studied. All the molecules were characterised in terms of calorimetric changes and mass changes during their heating. They revealed high thermal stability in oxidative and inert conditions. The observed tendency in thermal stability changes in relation to a substituent present at the phenyl moiety was found to be similar in air and nitrogen. It was confirmed that annelated triazinones 1-9 were stable up to a temperature range of 241-296 °C in air, and their decomposition process proceeded in two stages under oxidative conditions. In addition, it was established that their thermal stability in air decreased in the following order of R at the phenyl moiety: 4-Cl > 3,4-Cl2 > H > 3-Cl > 4-CH3 > 2-CH3 > 3-CH3 > 2-Cl > 2-OCH3. The volatile decomposition products of the investigated molecules were proposed by comparing the FTIR spectra collected during their thermogravimetric analysis in nitrogen with the spectra from the database of reference compounds. None of annelated triazinones 1-9 underwent any polymorphic transformation during thermal studies. All the compounds proved to be safe for erythrocytes. In turn, molecules 3, 6, and 9 protected red blood cells from oxidative damage, and therefore may be helpful in the prevention of free radical-mediated diseases.

Synthesis of New Liquid-Crystalline Compounds Based on Terminal Benzyloxy Group: Characterization, DFT and Mesomorphic Properties

The effect of the terminal benzyloxy group on the mesomorphic properties of liquid crystalline materials developed from rod-like Schiff base has been described. For this objective, a novel Schiff base liquid crystal family, specifically new series of Schiff base liquid crystals, namely, (E)-4-(alkyloxy)-N-(4-(benzyloxy)benzylidene)aniline, I_n, are prepared and investigated in detail. The length of the terminal alkyloxy chain (n) varies amongst the compounds in the series. Where n varies between 6, 8 and 16 carbons. At the other end of the compounds, benzyloxy moiety was attached. The molecular structures of all synthesized compounds were established using different spectroscopic techniques. The molecular self-assembly was explored using differential scanning calorimetry (DSC) and polarized optical microscope (POM). Depending on the length of the terminal alkyloxy chain, only one type of SmA phase with different stability was observed. The previously reported para-substituted systems and the present investigated compounds were compared and discussed. The calculated quantum chemical parameters were computationally correlated using the DFT method via the B3LYP 6-311G(d,p) basis set. The theoretical computations revealed that the length of the alkyl side chain influences the zero-point energy, reactivity and other estimated thermodynamic parameters of benzoyloxy/azomethine derivatives. Furthermore, the FMO energy analysis shows that molecule I₁₆ have higher HOMO energies than the other compounds, and I₆ has a much lower LUMO level than the rest.

Difluorovinyl Liquid Crystal Diluters Improve the Electro-Optical Properties of High-∆n Liquid Crystal Mixture for AR Displays

A liquid crystal (LC) mixture in liquid crystal on silicon (LCoS) is the core material for augmented reality (AR) displays. However, a LC mixture with high birefringence (Δn) and large dielectric anisotropy (Δε) possesses high viscosity (γ₁), which results in a slow response time of LCoS devices for AR displays. This work proposes to apply difluorovinyl-based LC diluters to fine balance the low viscosity, high ∆n, and large ∆ε of the LC mixture for a fast response time. Through studying their effects on the key electro-optical properties of a high-∆n LC mixture, it is found that doping these diluter molecules to a high-∆n LC mixture can decrease the viscoelastic coefficient (γ₁/K₁₁), increase ∆ε and the figure of merit, maintain a wide nematic phase temperature range, a high clearing point, and ∆n. It also means that these diluters could effectively regulate the relationship between ∆n, ∆ε, and γ₁ in the LC mixtures to achieve a fine balance of various excellent properties and further improve the LC device's response time. The widespread applications of these liquid crystal diluters in emerging liquid crystal optical devices are foreseeable.

Synthesis and characterization of new imine liquid crystals based on terminal perfluoroalkyl group

New organic derivatives named, (E)-3(or4) -(alkyloxy)-N-{(trifluoromethyl)benzylidene}aniline, 1a-f, were synthesized and examined their liquid crystalline behaviors. FT-IR, ¹H NMR, ¹³C NMR, ¹⁹F NMR, elemental analyses and GCMS were used to validate the prepared compounds' chemical structures. We used differential scanning calorimetry (DSC) and polarized optical microscopy (POM) to investigate the mesomorphic characteristics of the formed Schiff bases. All tested compounds of series 1a-c have mesomorphic behaviour of nematogenic temperature ranges while the group 1d-f show non-mesomorphic properties. Moreover, it was found that the enantiotropic N phases included all of the homologue 1a-c. Computational studies using DFT (density functional theory) validated the experimental mesomorphic behavior results. All the analyzed compounds had their dipole moments, polarizability, and reactivity characteristics explained. Theoretical simulations showed that as the length of the terminal chain is increased, the polarizability of the stuided compounds increases. Consequently, compounds 1a and 1d have the least polarizability.

TG-DSC and TG-FTIR Studies of Annelated Triazinylacetic Acid Ethyl Esters-Potential Anticancer Agents

To avoid problems associated with the storage and processing of newly developed potential medicines, there is a need to carry out thermal studies in the preclinical phase of drug development. The thermal behaviour and decomposition pathway of a whole novel class of patented potential molecular pharmaceutics, i.e., ethyl 2-[4-oxo-8-(R-phenyl)-4,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazin-3-yl]acetates (1-6) were reported for the first time in inert and oxidative atmospheres. The experiments were conducted with the use of simultaneous thermogravimetry/differential scanning calorimetry (TG-DSC) and simultaneous thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR). The decomposition pathways of compounds 1-6 were found to be different under oxidative and inert conditions. It was proven that the investigated molecules reveal higher thermal stability under a synthetic air atmosphere than under a nitrogen atmosphere, and their decomposition is preceded by the melting process. Among all the investigated compounds, only the meta-chloro derivative (4) was found to exhibit interesting polymorphic behaviour at a low heating rate (10 °C min^-1). It was proven that the oxidative decomposition process of the studied molecules proceeds in three overlapping stages accompanied by strong exothermic effects. Additionally, it was concluded that the title compounds were stable up to a temperature of 195-216 °C in an atmosphere of synthetic air, and their thermal stability decreased in the order of R at the benzene ring: 4-CH₃ > 3,4-Cl₂ > 4-Cl > H > 2-OCH₃ > 3-Cl.

Design of Liquid Crystal Materials Based on Palmitate, Oleate, and Linoleate Derivatives for Optoelectronic Applications

Herein, liquid crystalline derivatives based on palmitate, oleate, and linoleate moieties with azomethine cores were synthesized, and their physical, chemical, optical, and photophysical properties were investigated in detail. The mesomorphic activity of these materials was examined through polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The observed results revealed that the stability of the thermal mesophase depends on the terminal polar as well as on the fatty long-chain substituents. Purely smectogenic phases were detected in all three terminal side chains. A eutectic composition with a low melting temperature and a broad smectic A range was found by constructing a binary phase diagram and addressing it in terms of the mesomorphic temperature range. The energy bandgap of the palmitate-based derivative (Ia) was determined as 3.95 eV and slightly increased to 4.01 eV and 4.05 eV for the oleate (Ib) and linoleate (Ic) derivatives, respectively. The optical constants (n, κ, ε_r, and ε_i) were extracted from the fitting of measured spectroscopic ellipsometer data. The steady-state spectra of these samples exhibited a broad emission in the range 400-580 nm, which was found to be blue shifted to 462 nm for both Ib and Ic derivatives. The average fluorescence decay lifetime of the Ia derivative was found to be 598 ps, which became faster for the Ib and Ic derivatives and slower for the sample with a chloride end polar group.

Mesomorphic, Computational Investigations and Dyeing Applications of Laterally Substituted Dyes

Two groups of laterally substituted non-mesomorphic and liquid crystalline materials bearing monoazo group were prepared and investigated via experimental and theoretical techniques. The molecular structures of the designed dyes were evaluated by FT-IR and NMR spectroscopic analyses. Mesomorphic examinations for all synthesized dyes were investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). Results revealed that, the thermal and optical properties of investigated compounds are mainly dependent on their molecular geometry. The optimized geometries of the azo derivatives and their electronic absorption of the dyes were carried out using the B3LYP/6-311G level of the DFT method. The azo dyes were measured for their dyeing performance on polyester fabrics. The dyed fabrics have excellent fastness properties with a color strength of 1.49-3.43 and an exhaustion rate of 82-64%. The chemical descriptor parameters of disperse azo dyes in gas phase were calculated and correlated with dyeing parameters.

Preparation of a Montmorillonite-Modified Chitosan Film-Loaded Palladium Heterogeneous Catalyst and its Application in the Preparation of Biphenyl Compounds

The natural polymer chitosan was modified with polyvinyl alcohol to enhance the mechanical properties of the membrane, and then, the montmorillonite-modified chitosan-loaded palladium catalyst was prepared using the excellent coordination properties of montmorillonite. The results showed that the catalyst has good tensile strength, thermal stability, catalytic activity, and recycling performance and is a green catalytic material with industrial application potential.

Novel Imidazole Liquid Crystals; Experimental and Computational Approaches

The liquid crystalline materials named (E)-4-(2-(4-oxo-5,5-diphenyl-4,5-dihydro-1H-imidazol-2-yl)hydrazineylidene)methyl)phenyl and 4-(alkoxy)benzoate, In, were synthesized and their mesomorphic behaviors were examined. The chemical structures of the produced compounds were confirmed by Fourier-transform infrared spectroscopy (FT-IR), NMR, and elemental analysis. Differential scanning calorimetry (DSC) and polarized optical microscopy were used to investigate the mesomorphic properties of designed heterocyclic derivatives. All the compounds tested had suitable thermal stability and enantiotropic behavior of smectogenic temperature ranges. Furthermore, the enantiotropic smectic C phases were observed to cover all the homologues. Moreover, computational investigations corroborated the experimental findings of the mesomorphic behavior. The reactivity parameters were computed for the derivatives and linked with the experimental data. Theoretical calculations revealed that the polarizability of the studied series increases with the chain length, whereas the HOMO–LUMO energy gap or other reactivity descriptors were less sensitive to the size of the system. On the other hand, the predicted thermodynamic parameters revealed the size dependence of thermal stability of the compounds.