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Theoretical investigation on the reaction of N₂O and CO catalyzed by Fe(C₆H₆)

Li-Guo Gao Xiao-Li Song Yong-Cheng Wang 《Journal of Molecular Structure》2009,910(1-3):136-140

The reaction of N₂O with CO, catalyzed by Fe⁺(C₆H₆) and producing N₂ and CO₂, has been investigated at the UB3LYP/6-311+G(d) level. The computation results revealed that the reaction of Fe⁺(C₆H₆), N₂O and CO, is an O-atom abstraction mechanism. For the reaction channels, the geometries and the vibrational frequencies of all species have been calculated and the frequency modes analysis also have been given to elucidate the reaction mechanism. On the basis for geometry optimizations, the thermodynamic data of these reactions channels have been calculated using the statistical theory at 295.15 K and pressure of 0.35 Torr. Using Eyring transition state theory with Wigner correction, the activation thermodynamic data, rate constant and frequency factors for the these reaction channels also have been given. The results showed that CO and N₂O do not react without catalyst and Fe⁺(C₆H₆) can excellently mediate the reaction of N₂O and CO. 相似文献

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Theoretical investigation on the reaction of adhesion unit dopa in mussel with electrolyzing seawater

Shuang-Kou Chen Bo-Chu Wang Tai-Gang Zhou Ying-Zhu Feng Hua-Ming Liang Wen-Zhang Huang 《Colloids and surfaces. B, Biointerfaces》2009,70(2):243-247

Adhesive proteins secreted by the marine mussel could bind strongly to all kinds of surfaces, for instance, ship hulls and petroleum pipelines. Studies indicated that there was an unusual amino acid 3,4-dihydroxy-l-phenylanine (dopa), which was the crucial super adhesive unit in the proteins. The technology of electrolyzing seawater was employed to generate HOCl solution to hinder the adhesion. However, the detailed anti-fouling mechanism of HOCl solution remained unknown to be fully explained. Herein, we theoretically reported a study of single molecular (dopa) reaction under the HOCl solution environment, which would be helpful to reveal the anti-fouling mechanism through electrolyzing seawater. By using the density functional theory (DFT) quantum mechanics procedure, we theoretically studied the reaction mechanism of the adhesive unit dopa in mussel with electrolyzing seawater. Two possible pathways (1 and 2) were obtained (Fig. 6). The transition state for each pathway was determined, the intrinsic reaction coordinate (IRC) was analyzed and the mechanism had been confirmed. The calculations indicated dopa tended to have electrophonic attacking substitution reaction to generate 3-chlorine-4,5-dihydroxyphenylalanine (dopa-Cl) with different pathways, which hindered the formulation of conjuncted dopa–dopa and thus the stickiness among mussel adhesive proteins reduced. The transition states computation showed that pathway (1) had one transition state (TS1-1) with an activation energy of 102.22 kJ mol⁻¹, while pathway (2) had two transition states (TS2-1, TS2-2) with activation energies of 191.98 kJ mol⁻¹ and 42.00 kJ mol⁻¹ respectively and one intermediate (IM2-1). Rate constant value of pathway (1) was much bigger than that of pathway (2) regardless of high or low temperature, which meant that in the reaction process, pathway (1) was the favorable reaction step; but as the temperature rose, the competitiveness of pathway (2) gradually increased. After the theoretical calculation, we found that it was Cl⁺ played an important and direct role in the dopa's modification. 相似文献

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