Estimation of Standard Reduction Potentials of Halogen Atoms and Alkyl Halides
Estimation of Standard Reduction Potentials of Halogen Atoms and Alkyl Halides
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DOI：
10.1021/jp109613t
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发表时间：
2011-02-03
影响因子：
3.3
通讯作者：
Gennaro, Armando
中科院分区：
文献类型：
--
作者：
Isse, Abdirisak A.;Lin, Ching Yeh;Gennaro, Armando
在适当的热化学循环的基础上，计算了卤素原子在水中的标准还原电位。利用文献中最新的热力学数据，我们计算了F中心点、Cl中心点、Br中心点和I中心点的E度(X中心点/X-)值分别为3.66、2.59、2.04和1.37V/SHE。此外，我们还计算了在乙腈(CH3CN)和二甲基甲酰胺(DMF)中的氯中心点、溴中心点和I中心点在水中从水到非水溶剂S的X中心和X-转移自由能以及水与S之间的溶剂间势。根据E度(X中心点/X-)的值，计算了一系列与原子转移自由基聚合有关的卤代烷在这两种溶剂中的SRPs。这是在热化学循环的帮助下完成的，热化学循环包括C-X键的气相均裂解离，RX，R中心点和X中心点的溶剂化，以及X中心点还原为X-In溶液。
Standard reduction potentials, SRPs, of the halogen atoms have been calculated in water on the basis of an appropriate thermochemical cycle. Using the best up-to-date thermodynamic data available in the literature, we have calculated E degrees(X center dot/X-) values of 3.66, 2.59, 2.04, and 1.37 V vs SHE for F-center dot, Cl-center dot, Br-center dot, and I-center dot, respectively. Additionally, we have computed the SRPs of Cl-center dot, Br-center dot, and I-center dot in acetonitrile (CH3CN) and dimethylformamide (DMF) by correcting the values obtained in water for the free energies of transfer of X-center dot and X- from water to the nonaqueous solvent S and the intersolvent potential between water and S. From the values of E degrees(X center dot/X-) in CH3CN and DMF, the SRPs of a series of alkyl halides of relevance to atom transfer radical polymerization and other important processes such as pollution abatement have been calculated in these two solvents. This has been done with the aid of a thermochemical cycle involving the gas-phase homolytic dissociation of the C-X bond, solvation of RX, R-center dot, and X-center dot, and reduction of X-center dot to X- in solution.