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The adsorption mechanism of a series of macroporous adsorption resins ( p-(CHNH)PhL (L = NH, OH, COOH)) with rutin have been investigated using density functional theory calculations at B3LYP/6-31G(d,p) level of theory. Solvent effects on these species were explored using calculations that included a polarizable continuum model for the aqueous solvent. In this article, the geometry structure, interaction energies and the infrared spectra for the stable reactants and the adsorption complexes were obtained and analyzed. The results show that the hydrogen-bonding have been formed in the adsorption complexes. The higher interaction energy is calculated for the carboxyl group, while the resin with amino group has the highest adsorption capacity for rutin. The adsorption complexes become more and more stable as increasing the number of adsorbents. Our theoretical study is in good explanation for the experimental results. [ABSTRACT FROM AUTHOR]

Abstract: A computational study of the [2+2] cycloaddition reaction pathways for formaldehyde–ketene and formaldehyde–isocyanic acid has been presented by using the DFT(B3LYP) method. These cycloaddition reactions could yield to eight different four-membered molecules. In the two considered reactions, the reactions for the β-propiolactone and oxazetidinone products have the lower barriers of 26.40 and 32.88kcalmol−1 and are exothermic by 27.68 and 4.00kcalmol−1, respectively. The β-propiolactone and oxazetidinone ring compounds have been predicted to be the most stable thermodynamically. Simulation of the solvent environment (toluene, THF, acetone, acetonitrile and water) has been investigated by using polarized continuum model method, yet only small differences have been found to occur in energetics between the studied structures in the gas-phase and in the solvent. [Copyright &y& Elsevier]

Abstract: A computational study of methane to methanethiol Conversion by first-row transition-metal sulfide ion reactions of MnS+ with CH4 is presented. The reaction proceeds through two competing pathways: pathway A via intermediate formation of CH3MnSH+ (IM2). The second pathway, which leads to the insertion isomer HMnSCH3 + (IM4). Both pathway barriers to reactions become systematically lower as quintet state system(47.52 and 67.66 kJmol−1 for pathway A and pathway B, respectively). In contrast, the reaction barriers for septet state via both pathway remain high (>125kJmol−1). Mn+ and MnSH+ are formed as major ionic products in the reaction of MnS+ with CH4, The computational results are briefly compared to other reactions and related species. [Copyright &y& Elsevier]

Abstract: The mechanisms for the abstraction reactions of germylenes with oxirane and thiirane have been characterized in detail using density functional theory. All the stationary points were determined at the B3LYP/6-311++G (d, p) level of the theory. As a result, our theoretical investigations suggest that, irrespective of deoxygenation and desulfurization, the alkyl-substituted germylene abstractions are much more favorable than those of the π-donor-substituted germylenes. Moreover, for a given germylene, the desulfurization reaction is more exothermic as well as more kinetically favorable. Furthermore, a configuration mixing model based on the work of Pross and Shaik is used to rationalize the computational results. A comparison with carbene and silylene also led to the same result and the results obtained allowed a number of predictions to be made. [Copyright &y& Elsevier]