Journal of Physical and Theoretical Chemistry
Volume:12 Issue: 4, Winter 2016

In this work, polypyrrole/CeO2 nanocomposite (NC) was synthesized in the presence of methylorange as a reactive self-degraded soft template. The field emission scanning electron microscopy(FESEM) images indicate that the CeO2 NPs have a nucleus effect and cause a homogenous PPycore–shell type morphology with an encapsulation of the CeO2 core by the PPy shell. The effect ofNC on acrylic waterborne coatings for preventing the corrosion of mild steel in 0.50 M HCl solutionwas evaluated by electrochemical impedance spectroscopy (EIS). The choice of waterborne coatingswas made on the basis of environment and human health considerations. The electrochemicalimpedance data obtained from both blank and coating with polypyrrole/CeO2 nanocomposite sampleswere ?tted with an equivalent circuit containing two time constants. The protection ef?ciency (PE)was measured from EIS method. According to the obtained PE values the coating withnanocomposite demonstrated higher corrosion resistance compared to blank coating.

In this work, we have studied binding of Clonidine drug (C9H9Cl2N3) with zigzag single walled carbonnanotubes (SWCNT) (5, 0) by theoretical methods of theory using Gaussian 09 software package.Binding energies, NMR parameters and HOMO- LUMO Gap energy were calculated. Results frombinding energies indicate that it is possible thermodynamically to bind Clonidine drug to SWCNT.The calculated NMR parameters exhibit that Cl57 and H83 atoms have the highest and smallestanisotropic magnetic shielding (aniso) constants. The plots of iso, aniso and @ indicatedall shieldingvalues but ,  show more negative shielding values at the HFin B-C1G* basis set.The values of HOMO, LUMO and HOMO–LUMO Gap energies are calculation for Clonidine drugand Clonidine drug to SWCNT using HF method and 6-31G* basis set. From HOMO–LUMO Gapcalculation, it can be seen that HOMO- LUMO Gap energy of decrease in the order: Clonidine>Clonidine-SWCNT and by decreasing of HOMO- LUMO Gap energy, would be more stablecompound. So, Clonidine beside SWCNT can act better as an electron donor and probably all of itsbiochemical and molecular functions can be accounted for by this function.

A new kinetic spectrophotometic method for the determination of trace amount Chromium (III) in Teareal samples has been described based on it s the catalytic effect on the oxidations of 1 - ( 2 –PyridylAzo ) - 2 - Naphthol, (PAN), by potassium bromated in sulfuric acid. The reaction is followedspec- trophotometrically by measuring the decrease in the absorbance at 469 nm. Under the optimumconditions of0.2 molL-1 sulfuric acid, 1.0 × 10-4 molL-1, 1- ( 2 -PyridylAzo ) - 2 - Naphthol, (PAN),0.01 molL-1 potassium bromate at 35oC, calibration graph in the rang of 0.001-0.06 ngL-1 Chromium(III). Concentration was obtained with detection limit of 0.2303 g mL-1 by the fixed-time method of5.5 min. The relative standard deviation for 0.05AngL-1 Chromium (III) is %90. No serious interferencewas identified. The applicability of the method was demonstrated by the determination of theChromium (III) in Water, Vegetables and blood samples.

The formation constants (log K), of the complexes formed between a number of amino acids(glycine , L-valine and L-alanine) with p-sulfonatocalix [4] arene at varying temperatures (25± 0.1to 65 ± 0.1 °C) in aqueous solutions and at natural pH of p-sulphonato-calix [4] arene (pH=3.2) bymeans of UV-Vis spectrophotometeric technique have been investigated. At this pH the guestmolecule is in its cationic and zwitterionic forms. The results revealed that the host is q ui t ecapable of complexing with the guest in 1:1 guest-to-host ratio. Regarding the formation constantvalues, the binding selectivity of the host towards the guests proves in the order (alanine > valine >glycine). The thermodynamic parameters have been assessed and interpreted in matters of thesignificance of the various interactions responsible for the complexation. A roughly linear relationshipbetween BHo and TBSo has been observed for the studied complexes and it is discussed.

The thermodynamic functions such as enthalpy (H), Gibbs free energy (G) and entropy (S) of Serineand Threonine amino acids were theoretically studied at different condition (solvents andtemperatures) by using Gussian o3, software. First, the structural optimization of isolated Serine andThreonine were done in the gas phase by using the Hartree-Fock (HF) level of theory with 3-21G, 6-31G and 6-311G basis sets. Moreover, vibrational frequencies were calculated in gas phase on theoptimized geometries at the same level of theory to obtain enthalpy (H) Gibbs free energy (G) andentropy (S) at 7 different temperatures such as (25, 27, 29, 31, 33, 35 and 37°C).Then, the solventeffects are taken into via the self-consistent reaction field (SCRF=PCM) model. Therefore, all of thecalculations were repeated in various solvents (Water, Methanol and Ethanol) and 7 differenttemperatures (25, 27, 29, 31, 33, 35 and 37°C). Thermodynamically analysis shows the relativeenthalpy changes (H) Gibbs free energy changes (G) are negative values but the entropy changes(S) are positive values for Serine and Threonine molecules. Also, the results shows, with increasingdielectric constant of solvent and increasing of temperature the stability of considered moleculesincreases.

The present work reports the detailed B3LYP/6-311++G(d,p) study of most stable transand cisconfigurations photoisomerization in the core system of computational photochemistry-the 5,5'-disubstituted-1,1'-azobis (tetrazole) molecules. All computations were carried out in gas phase attemperature 293.15 K and pressure 1 atm. Firstly; the potential energy surface (PES) of the groundstate of the molecules has been directly optimized and scanned using a multistate multiconfigurationsecond-order perturbation theory. We characterize the cis and trans molecules geometric domains ofthe ground states. The imaginary frequencies were not shown in frequency computation analysis ofthe optimized molecules. Also we calculate the electronic and thermal energy, polarizability,equilibrium constant, HOMO-LUMO energies gap and chemical hardness of the configurations in theground state. In general, the DFT results confirm the stability of the trans configurations among allstructures. In the last section of this study, the detonation parameters of the compounds are calculated.

The dual diene/1,3-dipolar character of 1-H-imidazole 3-oxide, HIO 1, allows this compound toparticipate in a competitive Diels-Alder (DA)/1,3-dipolar cycloaddition (13DC) reaction toward C=Sdouble bond of the electro-deficient sulfonyl methane SFM 2. The B3LYP/6-311++G(d,p) calculatedrelative Gibbs free energies indicate that among the studied 13DC and DA reactions, former iscompletely preferred over the latter in the gas phase as well as in the presence of dichloromethane(DCM). This 13DC reaction takes place through a one-step mechanism to generate correspondingfive-membered cycloadduct via a quite C1-S5 regioselective fashion which is controlled bytheHOMO(HIO 1)- LUMO(SFM 2) interaction.The aromatic character of HIO 1 which is lost along thestudied cycloaddition reaction is responsible for the relatively high activation Gibbs free energies andthe endergonic character of these thermodynamically reversible reactions. The quite C1-S5regioselectivity, resulted from energetic studies, in the investigated 13DC reactioncan be explainedusingcalculated electrophilic and nucleophilic Parr functions at the reactive sites of reagents.

Compound (N,N-bis (salicylidene) 1,2-diaminophenylene) was prepared by condensation of ethanolsolution of 2-Hydroxybanzaldehyde and 1,2-diaminophenylene. The compound was characterized by1H NMR, infrared spectroscopy (FT-IR) data and analytical data. The geometrical parameters andenergies have been obtained from Density Functional Theory (DFT) B3LYP method and Hartree-Fock (HF) method with 3-21G* (6D, 7F) basis sets calculations. In the first instance, the full geometryoptimization of the studied molecule was performed at the gradient corrected density functional levelof theory using the hybrid B3LYP method based on Becke’s three parameters functional of DFT andGauge Including Atomic Orbital (GIAO). HF/3-21G* (6D, 7F) calculations on B3LYP geometrieswere done for all the reactants and HOMO-LUMO energy gaps. The force fields calculated with theB3LYP functional yield infrared spectra in very good agreement with the experiment. All of thesecalculations were performed using Gaussian 03 program.

Stability of the ;-; stacking interactions in the substituted-coronene||cyclooctatetraene complexes wasstudied using the computational quantum chemistry methods (where || denotes ;–; stackinginteraction, and substituted-coronene is coronene which substituted with four similar X groups; X =OH, SH, H, F, CN, and NO). There are meaningful correlations between changes of geometricalparameters and topological properties of the electron charge densities at ring critical points due toformation of complexes and ;-; stacking binding energies. In these complexes both electronwithdrawingand electron-donating substituents lead to larger binding energies compared to X = H(unsubsitituetted-coronene||cyclooctatetraene complex).This finding was interpreted on the basis ofNMR data, especially spin-spin coupling constants between C atoms of cyclooctatetraene and C atomsat central rings of substituted-coronenes. Herein, relationships between the ;–; stacking bindingenergy (-E) values and, through-space C-C spin-spin coupling constants (JC-C) in the substitutedcoronene||cyclooctatetraene complexes has been investigated in the complexes without directelectrostatic effects of substituents.

Malicorium supported Ni0.5Zn0.5Fe2O4 magnetic nanoparticles were synthesized by a low-cost, simple,and environmentally benign procedure. The adsorbent was characterized by several methods includingX-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infraredspectroscopy (FT-IR). Then, the potential of malicorium supported Ni0.5Zn0.5Fe2O4 magneticnanoparticles was investigated for adsorption of Manganes (II). The effect of different parametersincluding contact time, pH, adsorbent dosage and initial Mn (II) concentration on the Mn (II) removalyield was studied. The experimental data were fitted well with the Langmuir isotherm model. Themaximum monolayer adsorption capacity based on Langmuir isotherm is90.91 mg g-1. The preparedmagnetic adsorbent can be well dispersed in the aqueous solution and easily separated from thesolution with the aid of an external magnet after adsorption. The process for purifying water treatmentpresented here is clean and safe using the magnetic nanoparticles. Therefore, this adsorbent wasconsidered to be applicable for managing water pollution caused by Mn (II) ions.