Journal of Physical & Theoretical Chemistry4220070801Interaction of Dioxovanadium(V) Ion with Methionine at Different Ionic Strengths386588ENM.Kia-F.Gharib-G.Ghasemi-Journal Article20150425The dependence on ionic strength of protonation of methionine and its complexation with dioxovanadium(V) is<br />reported in sodium perchlorate solution as supporting electrolyte. The measurements have been performed at 25<br />C using a combination of potentiometric and spectrophotometric techniques. The overall analysis of the present<br />and the previous data dealing with determination of stability constants at different ionic strengths allowed us to<br />obtain a general equation, by which a formation constant determined at a fixed ionic strength can be<br />recalculated, with a good approximation for another ionic strength in the range of 0.1 – 0.7 mol dm-3.https://jptc.srbiau.ac.ir/article_6588_660a910c4ee542e8998f3e5da1bd5aae.pdfJournal of Physical & Theoretical Chemistry4220070801Kinetic study on the electrodecolorization of C.I. Acid Yellow 239166589ENN.Modirshahla-M.A.Behnajady-S.Kooshaiian-Journal Article20150425The electrocoagulation (EC) is a simple and efficient method for the treatment of many water and wastewaters.<br />The kinetics of decolorization of Acid Yellow 23 by EC using iron electrodes was studied. The<br />electrodecolorization rate follows pseudo-first order kinetic with respect to the AY23 concentration having<br />kapp= 5.65 cm min-1 at T= 295 K. The rate equation is as follows:<br />ln [AY23]t – ln [AY23]0 = -kapp<br />2<br />3<br />36 cm t<br />250 cm<br />The pseudo-first order rate constant (kapp) is sensitive to the operational parameters. The kapp is low in both<br />highly acidic and basic conditions. For the optimum operating conditions in electrodecolorization of AY23, the<br />activation energy was 41.15 kJ mol-1, sludge volume was about 8 ml from 250 ml of the original AY23 solution.<br />The electrical energy consumption required for this treatment was 7.74 × 10-4 kW h and the electrode<br />consumption was 37.4 mg.https://jptc.srbiau.ac.ir/article_6589_8aaf402670bc343a881aa1cb98d2a7fb.pdfJournal of Physical & Theoretical Chemistry4220070801Ab initio and DFT studies on tautomerism of 5-methyl cytosine in gaseous phase17286590ENK.Zare-M.Monajjemi-E.Zahedi-H.Aghaie-Journal Article20150425Ab initio and DFT methods have been used to study the seven tautomeric forms of 5-methylcytosine molecule.<br />The related tautomer in gas phase have been studied at HF/6-31G, HF/6-31G* and B3LYP/6-31G* levels of<br />theory. The structures,enthalpies,entropies,Gibbs free energies,relative tautomerization energies of tautomers<br />and tautomeric equilibrium constants were compared and analyzed along with full geometry optimization. The<br />calculations showed that the Oxo-amino(6), Oxo-imino(7) and Hydroxy-amino(4) tautomers are the most stable<br />in the gas phase. The results are in a good agreement with the available experimental data. The entropy effect<br />on the Gibbs free energy of the 5-methylcytosine bases is very small and it has a little significance on the<br />tautomeric equilibria of pyrimidine bases.Therefore the enthalpic term is dominant in the determination of the<br />equilibrium constants. 13C-NMR studies have been carried out for these tautomers and the results are<br />discussed.We have also evaluated the hybridation coefficient for bonds and hetero atom LPS in the aromatic<br />ring for the stable tautomers. Natural Bond Orbital Theory (NBO) calculation showed that the stable tautomers<br />must be considered aromatic.https://jptc.srbiau.ac.ir/article_6590_95b061a3a6d306310f22e0f438edb01b.pdfJournal of Physical & Theoretical Chemistry4220070801Studies of Hydrogen Bonding Effects on DiPalmitoyl Phosphatidyl Etanolamine (DPPE) by theoretical Methods29386591ENA.Nouri-M.Monajjemi-Journal Article20150425Hydrogen bonding of DPPE with water that surrounded of membrane, plays an important role in permeability of<br />membrane that we were presented this matter with analysis of bond angles and torsion angles before and after of<br />added water molecules.<br />Interaction with water molecules causes some changes in the geometry of DPPE which were explained by<br />the contribution of zwitterionic form of DPPE molecule, also hydrated DPPE becomes stabilized. Comparison<br />between theoretical and experimental values of geometry of DPPE molecule calculations at HF/3-21G level<br />produce results in better agreement with the crystallography structure. The NMR shielding tensor of selected<br />atoms in the hydrated complexes of DPPE were reported by ab initio level of theory.https://jptc.srbiau.ac.ir/article_6591_5d43c966c51ccd15ea6b9b90216d0c18.pdfJournal of Physical & Theoretical Chemistry4220070801Quantitative Correlation of Randić Indices and Adjacency Matrixes With Dewar Resonance Energy of Annulene Compounds39506592ENA.Taherpour-F.Shafiee-Journal Article20150425Topological indices are the numerical value associated with chemical constitution purporting for correlation of<br />chemical structure with various physical properties, chemical reactivity or biological activity. Graph theory is a<br />delightful playground for the exploration of proof techniques in Discrete Mathematics and its results have<br />applications in many areas of sciences. One of the useful indices for examination of structure-proeprty<br />relationship is Randić index. In this study, is represented the relationship between the Randić index and the<br />determinants of the adjacency matrix to the Dewar resonance energy (DRE) of annulene compounds by using<br />ab-initio calculations (B3LYP/6-31G*). The alternative double bonds and conjugation are one of the main<br />properties in annulene compounds. DRE is the quantity which allows one to account for the effects of cyclic<br />electron delocalization and thus serves as a measure of the aromatic stabilization of an annulene molecular<br />entity. For calculation the Dewar resonance energy (DRE) of the compounds could use the equation of DRE.<br />The interesting results of concerning among DRE and the above indices are presented.https://jptc.srbiau.ac.ir/article_6592_eceb87edfd67fbb19b8a20aef1eed2aa.pdfJournal of Physical & Theoretical Chemistry4220070801Theoretical study of hydrogen bond effects on Diphenylphosphorylazide51566593ENS.Reihani-Z.Azizi-M.Khaleghian-H.Passdar-L.Pishkar-R.Ahmadi-L.Saedi-Journal Article20150425The interaction of DPPA which is an important component in cellular membrane with molecules of water as<br />media, cause some changes in geometry of DPPA .In this study we focused our attention on comparing this<br />molecule with related hydrated complexes employing different basis sets at hartree-fock levels of theory. The<br />theoretical NMR shielding tensor of some imported atoms were also reported.https://jptc.srbiau.ac.ir/article_6593_4de687cf3456130199669ce4e92a29b5.pdfJournal of Physical & Theoretical Chemistry4220070801Interaction of alanine with lithium. I- the alanine–Li -n (H20) n (0–2) complexes57626594ENA.V.Moradi-M. T.Baei-F.Mollaamin-Journal Article20150425The energy minima of systems made of an alanine molecule, a lithium cation and a various number of water<br />molecules have been determined with the help of quantum mechanical computations at the B3LYP Density<br />Functional Theory level of computation and the standard 6-311++G (d,p) basis set. Several structures, close in<br />energy are found and the presence of one or two water molecules around the cation modifies the order of<br />stability. The results are discussed in view of better understanding the structure of aqueous solutions of these<br />species and the possible interactions of lithium cations with peptides.https://jptc.srbiau.ac.ir/article_6594_05077db8844eb71cc4fb2b3795e56840.pdf