Chemical Methodologies
Volume:4 Issue: 2, May-Apr 2020

Aromatic and aliphatic diamines are key components in polyamides, polyimides, polyurea and polyurethanes. To prepare high performance and well-featured materials, attempts are directed to synthesize novel diamine in which thermo-resistant, soluble and easy-process polymers are obtained. To improve the solubility and decrease the glass transition temperature, flexible bonds are necessary for the polymer-repeating unit. These bonds decrease the internal rotational energies. In this sense, by using the heterocyclic rings as well as introducing polar functional groups such as amide in the main synthetic polymer chain, convenient polarity and solubility of the polymers are reached. Till now, extensive investigations have been conducted to prepare the aromatic monomers with high solubility and processing capabilities. In the current study, our main aim is to prepare diamines with applications in thermo-resistant polymers such as polyamide, polyimide, polyurea, and polyurethanes.

In order to study the nature, type, and magnitude of interactions in the binary mixtures of methyl-ethyl-ketone and a series of 2-alkanol from 2-propanol up to 2-heptanol, excess (or deficit) numbers of i and j molecules around a central molecule j ( Δnij ), by being linked  to the KB integrals, have been used and reported at T=298.15 K. Negative values of Δnij and Δnji and positive values of Δnii and Δnjj indicate the fact that in the mixtures the tendency of the similar molecular components to form the new interactions and stay together is much higher than the dissimilar molecular components. Investigating the changes in the calculated quantities for different mixtures shows that with the increase in the length of the alcoholic chain, the tendency of the heterogeneous molecules to interact with each other decreases.

The physical properties, chemical and biological properties are evaluated through the Density Functional Theory (DFT) of molecular mechanics. The difference between Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) is starting from -5.91 to 6.15, which means that chemical reactions change the same for all anions. The biological activity of predictions given by QSAR calculation is forecasted where the PIC50 of all ionic liquids is near or less than -4.00, as a result, these are considered as the highly bioactive ionic liquids. To identify these molecules, computational data is used to determine the vibrational and electronic spectrum.

In this study, the reaction of 4-methoxy-2-hydroxybenzophenone (HL) with copper(II) nitrate three hydrate in a 1:2 molar ratio in methanol as solvent resulted in the formation of the complex CuL2. In order to prepare a suitable single crystal, slow evaporation technique was used, while for preparing complex nanoparticles, assisted ultrasound was used. Crystal structure of CuL2 was determined by single crystal X-ray diffraction. A square-planar geometry was found for CuL2. Finally, the complex was calcinated at 600 °C for 2.5 h. The final residue was CuO nanoparticles which were characterized by SEM and XRD. There is no peak for impurity in the XRD pattern. In this study, the reaction of 4-methoxy-2-hydroxybenzophenone (HL) with copper(II) nitrate three hydrate in a 1:2 molar ratio in methanol as solvent resulted in the formation of the complex CuL2. In order to prepare a suitable single crystal, slow evaporation technique was used, while for preparing complex nanoparticles, assisted ultrasound was used. Crystal structure of CuL2 was determined by single crystal X-ray diffraction. A square-planar geometry was found for CuL2. Finally, the complex was calcinated at 600 °C for 2.5 h. The final residue was CuO nanoparticles which were characterized by SEM and XRD. There is no peak for impurity in the XRD pattern.

In this work, silver thin films were prepared using sputtering at different deposition times with the nanoscale thickness. To investigate their surface morphology, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were employed. The surface topography of the samples studied using the AFM. The results revealed that, the roughness of the thin films enhanced by increasing the sputtering time. The permutation entropy (PE) was introduced as an interesting parameter to characterize the surface morphology. At the best of our knowledge, it is the first time one uses the PE for characterizing the thin films. Although the roughness might always enhance by increasing the film thickness, it was not the case for PE. The PE was found to be an independent parameter for characterizing the surface of thin film.

This research aimed at evaluating the stability of the 2-halo-1,3,2-dioxaphosphinanes conformers at the LC-BLYP/aug-cc-pVTZ level of theory. The estimation of the total energy and the dipole moments of the axial and equatorial conformations were first done for the aforementioned molecules. Intermediate states of the transformations of the axial to equatorial conformer were determined. In the basis of the calculations, the axial conformer was found to be more stable than the equatorial conformer in these molecules. Transition states of these transformations were studied, as well. IN addition, the energetic and thermodynamics parameters of these transformations were investigated. Change of the P=O bond distances were illustrated with endo and exo-anomeric effects. The comparison of the P-O bond distances indicated the shorter bonds in the axial conformer compared to the equatorial conformer. These changes attributed to a dominant LP (2)O ® σ* (P-X) negative hyperconjugation interaction between a pair of non-bonded electrons on oxygen and the adjacent P-X bond in axial conformer. The partitioning of the total electronic energy E(tot) into Lewis E(L) and non-Lewis E(NL) parts was performed using the concept of the natural bond orbital (NBO) analysis. Then, the natural coulomb electrostatic (NCE) potential energies, total energies into Lewis components, and total steric exchange energies were estimated.  Calculations revealed that axial conformer was more stable than the equatorial conformer in the studied molecules. In addition, the barrier energy values of the transformations of axial®boat®equatorial conformers enhanced with decreasing the electronegativity of halogen.

Spirulina platensis is a green-blue microalgae and a rich source of many nutrients such as protein, vitamins, and minerals. Spirulina contains peptides that have therapeutic and beneficial effects on the human body. In this study, peptide Ile-Gln-Pro from spirulina platensis was extracted using alcalase enzyme and purified by ultrafiltration and silica gel columns, and the fractions were identified using RP-HPLC analysis. The molecular weight of the tripeptide was determined by GC/mass spectroscopy. The peptide extracted with a concentration of 6.23 mg/mL and a purity of 75.72%. Then its inhibitory effect on angiotensin I-converting enzyme (ACE) and its anti-oxidant properties were investigated using DDPH (2,2-diphenyl-1-picrylhydrazyl) assay.

This work investigates the efficiency of date palm fiber as a biosorbent to the removal of Cr(VI) from aqueous solution. The effect of four main factors including, the initial pH, initial Cr(VI) concentration, biosorbent dosage, and time were assessed. The results revealed that, the maximum 89% removal of Cr(VI) at time 50 min, initial pH 3.2, initial Cr(VI) 181 ppm, and biosorbent dosage 0.8% (w/v) was obtained. The artificial neural network (ANN) model was developed to predict the Cr(VI) removal as a function of the studied variables. A number of data points were considered as test data to validate the model. The results indicated a high accuracy of the ANN modeling in estimating the target variable.

In this study, chemical reactivity of (4,0) and (5,0) AlN nanotubes by interaction with nitrosamine molecule as a carcinogen agent was investigated using the B3LYP/6-311++G (d) level of theory. The HOMO–LUMO gap, electronic chemical potential (m), hardness (ƞ), softness (S), the maximum amount of electronic charge (DNmax), and electrophilicity index (ω) for the monomers and complexes were calculated. The results show that the interaction of NA with nanotubes cab be changes electronic properties of nanotubes. To investigate the interactions between the NA molecule and nanotubes, analysis of atoms in molecules was performed at B3LYP/6-311++G (d) level of theory. The Multiwfn program was used to calculation of electron density of states (DOS). The charge transfer in complexes was calculated using the NBO analysis. The results of this work were compared with the results of adsorption of NA molecule on BN nanotubes. It is expected that the AlN nanotubes can be used as sensor for detection of NA molecules.

In this work, conjugated polymers based on thiophene: polythiophene, poly (3-alkythiophene) and poly (alkylbithiophene) were characterized using the nuclear magnetic resonance (NMR) and UV spectroscopy to determine their spectroscopic properties. Then, their structural, electronic and vibrational properties were investigated using the density functional theory (DFT) calculations by the oligomeric approach. The optoelectronic properties were assessed, as well. The obtained results were discussed basing on the influence of substitution on the properties of the oligomers.   The possibility of thiophene based oligomers photovoltaic application was also studied. We have shown that the octithiophene (8T) its derivatives have a very good conversion rate and it serves as a candidate for the photovoltaic application.