Journal of Physical and Theoretical Chemistry
Volume:10 Issue: 1, Spring 2013

In this paper, the structural properties of the B30N20 molecule have been investigated at B3LYP/6-31G (d) level of theory. The optimized structure and electronic properties calculations for the studiedmolecule have been performed using Gaussian 03 program. A mathematical equation of third degreewas exploited for the correlation and exchange energy with the number of primitives. The NaturalBonding Orbital (NBO) analysis were performed on the B30N20 at the B3LYP/6-31G level of theory.

In this paper, the effect of penicillin G drug as a green corrosion inhibitor on mild steel in 1.0 Mhydrochloric acid solution has been investigated using potentiodynamic polarization, electrochemicalimpedance spectroscopy (EIS) and electrochemical noise (EN) techniques. The inhibition efficiencywas found to increase with increasing inhibitor concentration. Potentiodynamic polarizationmeasurements indicated that penicillin G is a mixed type inhibitor. Furthermore, it has beendemonstrated that the electrochemical noise (EN) technique under open circuit conditions as the onlytruly noninvasive electrochemical method can be employed for the quantitative evaluation ofcorrosion inhibition. This can be done using the standard deviation of partial signal (SDPS) forcalculation of the amount of noise charges at the particular interval of frequency, thereby calculatethe inhibition efficiency (IE) of an inhibitor. These IE values show a reasonable agreement with thoseobtained from potentiodynamic polarization and EIS measurements.

An interaction potential at different orientation for the CH4 and CO2 complex was derived at theB3LYP level of theory and 6-31+G* basis sets. The potential energy surface was computed on somemolecular geometries. The complete basis set limit of the interaction energies were fitted to wellknownanalytical functions. To determine the second virial coefficients B, U(r) is used to obtain themodel’s parameters over the range of temperatures of interest.

In this paper we have down three theoretical study by using Monte Carlo simulation and Mm+,AMBER and OPLS force field. The calculations were carried out using Hyper Chem professional,release 7.01 package of program. first we have studied the interaction of H2 molecule and He atomwith single-walled carbon nanotube at different temperature. For doing this study we placed H2 andHe in the center and outside the nanotube, permitting them to close the nearest carbon atom fromnanotube. Then we plotted the potential energy versus distance of interaction, and at minimum pointof energy we calculated potential energy for physical adsorption process. Second we placed tow H2molecules and tow He atoms at tow ends of nanotube separately, permitting them to close each otherstep by step then we calculated Ekin,Epot and Etot for H2---H2 and He---He interaction at differenttemperature. In another activity we added 2 to 100 H2 molecules and 2 to 100 He atoms across thenanotube and after each time increased the number of H2 and He we have estimated the potentialenergy, then we plotted the potential energy versus the number of H2 molecules and He atoms so thatthe shape of potential curve will be determined.

Over the past decade, the chemical behavior of flavonoids as antioxidants has become the subject ofintense experimental research. Plants represent a main source of natural antioxidants that might serveas leads for the development of novel drugs. Malva sylvestris L. known to have various medicinalproperties since several decade ago, were evaluated for their antioxidant compounds ,Most of thesebioactive properties correlated with antioxidant activity of phenolic compounds found in the plant ,11phenolic composed were isolated from water leaf extract of Malva sylvestris L. ,the main phenolicacids identified in Malva sylvestris L. leave's are gallic , pyrogalllol ,vanillic , synergic , cinnamic andchrisin acid .antioxidant and antiprotozoic activities quercetin is the major flavonoid in the humandiet and has been reported for their radical scavenging effect .They have been proved to havepotential preventive and therapeutic effects in many diseases . This study involves substitution of thefunctional group of methyl in the active site of some terpenoids isolated from Malva sylvestris L.with other functional groups such as F,Cl,and Br and calculations by keywords Opt, NMR,and Freqfor optimization and chemical shift calculations and drive thermodynamic parameters includingEnthalpy ,Gibbs free energy respectively. The quantum mechanics (QM) calculations were carriedout GAUSSIAN98 at NMR by using B3LYP methods with 6-31G basis set

The thermodynamic functions such as enthalpy (H), Gibbs free energy (G) and entropy (S) ofPyrazole was theoretically studied at 5 different temperatures 25, 30, 35, 40 and 45°C by usingGussian o3, software. First, the structural optimization of isolated Pyrazole was done in the gas phaseby appling the Density Functional Theory (B3LYP) level with 3-21G, 6-31G and 6-31+G(d) basissets. Moreover, vibrational frequencies were calculated in gas phase on the optimized geometries atthe same level of theory to obtain enthalpy, Gibbs free energy and entropy at 5 differenttemperatures.Finally the temperature effects on the thermodynamic functions were discussed.

A batch adsorption study was applied to investigate the adsorption of Pb2+ ions from aqueous solutionby nanographene (nG).The adsorption percentage of Pb2+ions onto nG samples at different initial pH,contact time (tc), adsorbent dosage (mnG) and temperature (T) were investigated. The results showedthat nG is an excellent adsorbent for Pb2+ions removal from aqueous solutions with an adsorptionpercentage of up to 79.8% at initial Pb2+concentration of 20ppm and temperature of 298K.Theexperimental data could be well described by the Freundlich and Langmuire isotherm model;thermodynamic parameters of adsorption process (AG0, AH0, ASo) were also evaluated. The overalladsorption process was exothermic and spontaneous in nature .The results indicate that Pb2+ionsadsorption onto nG may be chemisorption.

This review reports recent advances in the field of polymer–layered silicate nano composites. Thesematerials have attracted both academic and industrial attention because they exhibit dramaticimprovement in properties at very low filler contents. Herein, the structure, preparation andproperties of polymer–layered silicate nanocomposites are discussed in general, and finally the effectof clay nanoparticles on optical and Rheological properties of polymeric products were alsodiscussed.