JOURNAL OF PHYSICAL AND THEORETICAL CHEMISTRY
Year:2011 | Volume:8 | Issue:2|Papers Count:10

In order to preparing strontium ion selective electrode 6-(4-nitrophenyl)-2-phenyl-4, 4-dipropyl-3, 5-diaza-bicyclo [3, 1, 0] hex-2-ene (NPDBH) was used as an ionophore. This electrode responds to Sr (II) ion with a sensitivity of 28.2±0.5 mV/decade over the range 1.0×10-6 to 1.0 M at pH 3.0-10.0. The limit of detection was 2.4×10-7 M. The influences of membrane composition, the pH of the test solution, the temperature effect and the interfering ions on the electrode performance for the proposed electrode were investigated. In the next step, electrolyte solution system SrCl2, KCl, H2O in the high concentration range were thermodynamically investigated. The thermodynamic investigations were performed by evaluation of potentiometric experimental data, successfully.

In this research, the Magnetite nanoparticles (Fe3O4) were prepared by coprecipitation of Fe3+ and Fe2+ solution in alkaline medium. Two kinds of surfactants, cetyl tri methyl ammonium bromide (CTAB) and cetyl pyridinum chloride (CPC) were used in the synthesis. Fe3O4 Nanoparticles were coated with human serum albumin (HSA) and bovine serum albumin (BSA). Characteristics of coated magnetic nanoparticles and no coated were carried out using scanning electron microscopy, X-ray diffraction and FT-IR spectroscopy. The interactions of colloidal iron oxide nanoparticles with serum albumins, including BSA and HSA, were investigated by UV-Vis spectroscopy at process different pH and temperatures. The thermodynamic parameters of coating were obtained from Van't Hoof equation. The results revealed that both DHo and DSo of reactants positive values. These results also demonstrate that pH can play an important role on adsorption of proteins on iron oxide nanoparticles.

The interaction of anticancer drug Sn (CH3)2(N-acetyl-L-cysteinate) with carbon nanotube (CNT) is investigated by Quantum chemical ab initio calculations at HF/ (LanL2DZ+STO-3G) and HF/ (LanL2DZ+6-31G) levels in gas phase and solution. The solvent effect is taken into account via the self-consistent reaction field (SCRF) method. Carbon nanotubes can act as a suitable drug delivery vehicle for internalization, transportation and translocation of Sn (CH3)2(NCA) within biological systems. Thermodynamical analysis indicate that the relative energies (DE), enthalpies (DH) and free Gibbs energies (DG) are negative for Sn (CH3)2(NCA)–CNT system but the calculated entropies (DS) are Positive, suggesting thermodynamic favorability for covalent attachment of Sn (CH3)2(NCA) into carbon nanotube. Also, the results show that with increasing dielectric constant of solvent the stability of Sn (CH3)2(NAC)–CNT complex decreases. Furthermore, anisotropic chemical shift tensor (Ds), total atomic charge and asymmetry parameter (h) have been calculated using the GIAO method, results being compared with CGST data. From the NMR calculations, it can be seen that the NMR (Ds, h) parameters at the sites of nitrogen, oxygen as well as C-2 and C-3 nuclei are significantly influenced by intermolecular hydrogenbonding interactions but the quantity at the site of S-27 is influenced by nonspecific solute-solvent interaction such as polarizability/polarity.

Genetic algorithm and partial least square (GA-PLS), the kernel PLS (KPLS) and Levenberg-Marquardt artificial neural network (L-M ANN) techniques were used to investigate the correlation between retention time (RT) and descriptors for 15 nanoparticle compounds which obtained by the comprehensive two dimensional gas chromatography system (GC×GC). Application of the dodecanethiol monolayer-protected gold nanoparticle (MPN) column was for a high-speed separation as the second column of GC×GC. The L-M ANN model with the final optimum network architecture of [9-4-1] gave a significantly better performance than the other models. This is the first research on the quantitative structure–retention relationship (QSRR) of the nanoparticle compounds using the GA-PLS, GA-KPLS and L-M ANN.

The star-shaped molecules present some of the important electronic delocalization between the attractive central ring, i.e. benzene, and the three ends p-electron donor groups. The star-shaped molecules are currently considered because of their wide potential applications. Some of them can act as discotic liquid crystals (DLCs). The 1, 3, 5-benzene core acts as an effective p-electron center to conjugate with the oligoaryleneethynylene groups of the 1, 3, 5-trisubstituted oligoaryleneethynylene benzene star-shaped molecules. The electrochemical properties of some of the fullerenes have been studied before. Since the discovery of fullerenes, one of the main classes of carbon compounds, the unusual structures and properties of these molecules and by the many potential applications and physicochemical properties have been discovered and were introduced. In this study, were studied the photophysical properties of the star-shaped molecules 1-9 during the photoelectron transfer (PET) with fullerenes. Some of the photophysical data that were communicated in the literature were: fluorescence emission maximum FEM (lem) and absorbance maximum wavelength AMWL (labs). The free energies and the activation free energies and maximum wave length of the PET process, based on the FEM and AMWL amounts, DGet, DG#et and let, respectively, were calculated in this study. The interesting results of the relationships and the photo-physical data of the supramolecular complexes of star-shaped molecules and the selected fullerenes were presented.

In this research, the Magnetite nanoparticles (Fe3O4) were prepared by coprecipitation of Fe3+ and Ginger is a well known spice and flavoring agent which has also been used in traditional medicine in many countries. Ginger contains essential oils including gingerol and zingiberene. It also contains pungent principles such as zingerone, and shogaol. In the paper six theoretical methods were used to calculation of physical parameters for gingerol and zingiberene. Used to Gaussian 98, NMR and NBO calculations by using HF method with 6-31G, 6-31G* and 6-31+G basis set and B3LYP, BLYP and B3PW91 methods with 6-31G basis set. Chemical shift was drown curve for all of the atoms in each molecule. The thermochemical parameters including Thermal Energy (DE), Atomic charges, Chemical Shift Anisotropy (d), Asymmetry parameter (h), Chemical Shift anisotropy (Ds), Dipole orientation, Isotropic, anisotropic and NMR determinant for gingerol and zingiberene. Also the natural bond orbital (NBO) analysis has been performed which seem edquite informative to show some important atomic and structural features. Also we obtained Shielding value for the each atom with GaussView program (GIAO Magnetic shielding).

The interaction of p-sulphonatocalix [6] arene towards L-arginine and L-lysine has been studied in acidic aqueous solution (pH 2) using UV-Vis spectrophotometric titration technique. The psulphonatocalix [6] arene was found to be able to form 1:1 complexe with amino acids in water. The values of the association constant were determined at different temperatures to evaluate the thermodynamic functions of the complexation reaction. The thermodynamics values of complexes were compared to each other.

A novel composite adsorbent, Silica aerogel activated carbon was synthesized by sol-gel process at ambient pressure drying method. The composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Nitrogen adsorption / desorption isotherms (BET).In the present study, the mentioned adsorbent was used moderately for removal of cadmium ions from aqueous solutions and was compared with two other adsorbents of cadmium, activated carbon and silica aerogel. The experiments of Cd adsorption by adsorbents were performed at different initial ion concentration, pH of the solution, adsorption temperature, adsorbent dosage and contact time.Moreover, the optimum pH for the adsorption was found to be 6.0 with corresponding adsorbent dosage level of 0.1 g at 60oC temperature. Subsequently, the equilibrium was achieved for Cd with 120 minutes of contact time. Consequently, the results show that using this composite adsorbent could remove more than 60% of Cd under optimum experimental conditions. Langmuir and Freundlich isotherm model was applied to analyze the data, which the adsorption equilibrium data were correlated well with the Freundlich isotherm model and equilibrium adsorption capacity (qe) was found to be 0.384mg/g in the 3mg/L solution of cadmium.

Glycine, Alanine and Valine are taken as amino acids with an equal polar head and with the difference in the length of hydrocarbon chains. The structural optimizations show the results of the isolated Glycine, Alanine and Valine in the gases phase, at the Hartree-Fock level by means of STO-3G,3-21G, 6-31G and 6-31+G basis sets. The calculations were performed for the ten (1-10) solvents using PCM model method at HF/6-31+G and then the dielectric effects of the surrounding were analyzed. The solvent effect on the stability of Glycine, Alanine and valine molecules was discussed.

The molecular dynamics (MD) simulation method is used to assess structural details for human prion protein (hereafter PrPN) and its Asp178 Asn mutant (hereafter PrPM) which causes fatal familial insomnia disease. The results reveal that the flexibility and instability increase in PrPM could be related to specific amino acids exposed to the solvent. Solvation free energy of PrPM is 20 kjmol-1nm-2 more than PrPN that is caused by solvent accessible surface area (SASA) especially hydrophobic area, Spho. The study of time interval properties indicates a number of critical amino acids in prion proteins, which exposed to the solvent. They can be ideal anchor-points for initial intermolecular contacts, or affect metal-ion occupancy. The present achievements may be used in drug design for the prevention or treatment of disease.