Namazian Mansoor, Lin Ching Yeh, Coote Michelle L
ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia.
J Chem Theory Comput. 2010 Sep 14;6(9):2721-5. doi: 10.1021/ct1003252. Epub 2010 Jul 30.
High-level ab initio molecular orbital theory is used to obtain benchmark values for the ferricenium/ferrocene (Fc(+)/Fc) couple, the IUPAC recommended reference electrode for nonaqueous solution. The gas-phase ionization energy of ferrocene is calculated using the high-level composite method, G3(MP2)-RAD, and two higher-level variants of this method. These latter methods incorporate corrections for core correlation and, in the case of the highest level considered, use (RO)CCSD(T)/6-311+G(d,p) in place of (RO)CCSD(T)/6-31G(d) as the base level of theory. All methods provide good agreement with one another and the corresponding experimental values. Solvation energies have been calculated using PCM, CPCM, SMD, and COSMO-RS. Using G3(MP2)-RAD-Full-TZ gas-phase energies and COSMO-RS solvation energies, the absolute redox potentials of the Fc(+)/Fc couple have been calculated as 4.988, 4.927, and 5.043 V in acetonitrile, 1,2-dichloroethane, and dimethylsulfoxide solutions, respectively.
采用高水平的从头算分子轨道理论来获取铁鎓/二茂铁（Fc(+)/Fc）电对的基准值，该电对是国际纯粹与应用化学联合会（IUPAC）推荐的非水溶液参考电极。使用高水平的复合方法G3(MP2)-RAD以及该方法的两个更高水平变体来计算二茂铁的气相电离能。后两种方法纳入了对核心相关的校正，并且在考虑的最高水平情况下，使用(RO)CCSD(T)/6-311+G(d,p)代替(RO)CCSD(T)/6-31G(d)作为理论的基础水平。所有方法相互之间以及与相应的实验值都有很好的一致性。使用PCM、CPCM、SMD和COSMO-RS计算了溶剂化能。利用G3(MP2)-RAD-Full-TZ气相能和COSMO-RS溶剂化能，分别计算出Fc(+)/Fc电对在乙腈、1,2-二氯乙烷和二甲基亚砜溶液中的绝对氧化还原电位为4.988、4.927和5.043 V。
