Journal of Physical and Theoretical Chemistry
Volume:8 Issue: 4, Winter 2012

The Density Functional Theory (DFT) and the Natural Bond Orbital (NBO) calculations basedmethod B3LYP/6-31G were carried out to study the interaction of Dopamine with carbon nanotube.The nanotube used in this study, includes 60 C atoms (6, 6) type. Relative and formation energies ofcompounds, Muliken charges, occupancy, the highest occupied molecular orbital (HOMO) and thelowest unoccupied molecular orbital (LUMO), the HOMO-LUMO band gap and the electronicchemical potential (μ) were calculated. The NBO analysis showed there is a hyperconjugativeinteraction between Oxygen and Nitrogen lone — pair electrons of dopamine and a' or I orbitals ofcarbon atom of nanotube. Results indicated that the composite between nanotubes and the Ncentereddopamine is more stable than 01 - centered dopamine and both of them are stable than thesingle agent.

BCN compounds have been researched theoretically and experimentally widely. In this paper, weintroduce the theoretical prediction of ternary B-C-N compounds. NMR spectroscopy was employedextensively to study these ternary nanostructures. We discuss the utilization of chemical shiftinformation as well as ab initio calculations of nuclear shielding for H20134C9N4 structuredetermination. We calculated B NMR and N NMR spectra with computational aspects of the NMRspectra using the gauge-invariant atomic orbital (GIAO) and continuous set of gauge transformations(CSGT) methods at different DFT computational methods (BILYP and LSDA), with a 6-31 G basisset at the GAUSSIAN 98 program package which are discussed. The purpose of this study is to carryout a more detailed analysis of the H20134C9N4 as a new nanosemiconductor system.

Ethylammonium Propionate with high polarity and ionic conductivity was synthesized andcharacterized with 1HNMR and IR. This ionic liquid which is prepared from readily available startingmaterial in high yield shows reasonably high at viscosity and heat stability up to 150 °C. This IonicLiquid is able to dissolve most of organic solvents due to the hydrogen interaction between IonicLiquid and these solvents.

Sulforaphane, an isothiocyanate found in broccoli and other cruciferous vegetables. it is an antioxidantand anti-cancer agent, and reduces blood pressure, and also has anti-allergic Effects.In this article, six theoretical methods have been used for calculation of physical parameters insolforaphane and several similar compounds. We calculated physical parameters like atomic charges.energy (AE) , chemical shift anisotropy (5) , asymmetry parameter (T) , chemical shift anisotropy(An) , dipole moment , isotropic , anisotropic , NMR determinant and distance matrix determinant,and in this work we used Gaussian 98 at NMR and natural bond orbital( NBO) calculation by usingHF method with 6-31G,6-31G* and 6-31+G basis set and B3LYP , BLYP and B3PW9 I methodswith 6-31G basis set. The CIAO magnetic shielding for studied molecules was obtained by usingGauss view program. Chemical shift curve was drawn for all of the atoms in each molecular.

Al3+-Potentiometric sensor, based on (2Z) -methyl 2- ((z) (p-tolylimino)-3-ethyl -4-oxothiazolidin -5- ylidene) Acetate (MTEOY) as a neutral ionophore, was successfully developed for the detectionof Al3+ in aqueous solutions. The electrode responds to Al3+ ion with a sensitivity of 19.8 ± 0.1 mV/decade over the range 1.0 x 10-8- 1.0 x 10-1 mol LT' and in a pH range of 3.0-9.0. The electrodeshows a detection limit of 3.5 x 10 mo1 U'. The influence of membrane composition, the pH of thetest solution, and the interfering ions on the electrode performance was investigated. The proposedelectrode shows good discrimination of Al3+ ion from several cations. The effect of temperature onthe electrode response shows that the temperature higher than 50 °C deteriorates the electrodeperformance. The electrode was found to work well under laboratory conditions. This sensor not onlywas used in determination of AV. i n real samples but also was used to determination of Ali'concentration in the presence of certain interfering ions.

Cigarette smoke is injurious to both oral cavity and internal body environment. Saliva is the firstbody fluid to encounter the dangerous smoke. The aim of our present study was, therefore, toevaluate the influence of smoking on the antioxidant activity of saliva of healthy smokers.Antioxidant capacity of saliva was determined using different methods in the centrifuged saliva from25 male smokers and 25 non-smokers in a similar age range. Chemical methods and highperformance liquid chromatography (HIQC) revealed a significant decrease in total antioxidantcapacity and values of non-enzymatic antioxidants in saliva of smokers. Based on the results obtainedin the present study, we concluded that smoking could significantly affect the anitoxidant behavior ofnormal human saliva. Thus, smoking may induce several oral diseases as well as respiratory andcardiovascular disorders and could cause different cancers.

The photocatalytic process using semiconductors with a nanostructure is one of the technologies usedfor the destructive oxidation of organic compounds such as surfactants. In this paper, thephotocatalytic degradation of Cetyl pyridinium chloride (CPC), was investigated in aqueous phaseusing various semiconductors such as titanium dioxide (Ti02), zinc oxide (ZnO), stannic oxide(Sn02). The degradation was studied under different conditions including the amount ofphotocatalyst, pH of the system, initial concentration and presence of anions. The results showed thatthe photocatalytic degradation of CPC was strongly influenced by these parameters and the bestconditions for the photocatalytic degradation of CPC were obtained. The experimental resultsindicated that maximum degradation (87%) of surfactant occurred when ZnO was used as catalyst.The photodegradation efficiency was enhanced by increasing amount of photocatalyst, and decreaseswith the increase in the initial concentration of Cetyl pyridinium chloride. Finally, the kineticsprocess was studied and the photodegradation rate of CPC was found to obey pseudo-first-orderkinetics equation represented by the Langmuir—Hinshelwood model.

A cluster model for active site of nanotube (C48) was presented and investigated the geometricstructure and thermochemical parameters. Quantum-mechanical calculations were performed at theHF / 510-30, 6-310, 6-3 IG• and 6-310" levels of theory in the gas phase and three solvents atfour temperatures. Also, nuclear shielding parameters of the active site of nanotube have been takeninto account using GIAO method at the HF / STO-3G,6-310,6-310* and 6-310" levels of theory inthe gas phase and in different solvents such as water, methanol, ethanol. The results were revealedthat the NMR chemical shielding parameters are strongly affected by inducing different solventmedia. According to these theoretical results of energy values, some important relationships havebeen found between the dielectric constant and structural stability of active site of nanotube.

The structural stabilities, geometry and electronic properties of C24 and some its heterofullerenederivatives are compared at the B3LYP/6-311-EFG**//B3LYP/6-31+G* level of theory. Vibrationalfrequency calculations show that all the systems are true minima. The calculated binding energies ofheterofullerenes show C24 as the, most stable fullerenes by 9.03eV/atom. While decreasing bindingenergy in C12B6N6, B6N6C12 and B12Ni2 through increasing their HOMO-LUMO gap, theconductivity of them is increasing. High point charges are predicted to establish an overall chargetransfer on the surface of heterofullerene. 13C NMR of C24 fullerene consists of two lines. Dopedmodels show several lines at different positions relative to lines for C24 fullerene. Boron, nitrogen,and carbon adopt different roles around carbon sites. The Nucleus-independent chemical shift(NICS) calculations show more negative NICS values in BN-substituted heterofullerenes than thoseOf C24.

The solubility of CdF2 in the mixed solvent (water(1)+ethanol(2)) with mass fraction, W1 = 0.9,was determined by using solvent evaporating method in the presence of various concentrations(0.100, 0.200, 0.300, 0.400, 0.500, 0.600, 0.800 and 1.500 mo1.1)) of NaCI at 25°C. The values ofsolubility and solubility product constant of CdF2 in the mixed solvent were evaluated at zero ionicstrength upon the extrapolation method. Then, the ion - pairing extension was calculated in theconsidered solution.