Yan Liuming, Lu Yi, Li Xuejiao
Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Phys Chem Chem Phys. 2016 Feb 21;18(7):5529-36. doi: 10.1039/c5cp06638g.
A density functional theory (DFT) protocol for the calculation of redox potentials of copper complexes is developed based on 13 model copper complexes. The redox potentials are calculated in terms of Gibbs free energy change of the redox reaction at the theory level of CAM-B3LYP/6-31+G(d,p)/SMD, with the overall Gibbs free energy change being partitioned into the Gibbs free energy change of the gas phase reaction and the Gibbs free energy change of solvation. In addition, the calculated Gibbs free energy change of solvation is corrected by a unified correction factor of -0.258 eV as the second-layer Gibbs free energy change of solvation and other interactions for each redox reaction. And an empirical Gibbs free energy change of solvation at -0.348 eV is applied to each water molecule if the number of inner-sphere water molecule changes during the redox reaction. Satisfactory agreements between the DFT calculated and experimental results are obtained, with a maximum absolute error at 0.197 V, a mean absolute error at 0.114 V and a standard deviation at 0.133 V. Finally, it is concluded that the accurate prediction of redox potentials is dependent on the accurate prediction of geometrical structures as well as on geometrical conservation during the redox reaction.
基于13种模型铜配合物，开发了一种用于计算铜配合物氧化还原电位的密度泛函理论（DFT）方法。氧化还原电位是在CAM-B3LYP/6-31+G(d,p)/SMD理论水平下，根据氧化还原反应的吉布斯自由能变化来计算的，总吉布斯自由能变化被划分为气相反应的吉布斯自由能变化和溶剂化的吉布斯自由能变化。此外，对于每个氧化还原反应，计算得到的溶剂化吉布斯自由能变化通过-0.258 eV的统一校正因子进行校正，作为溶剂化的第二层吉布斯自由能变化和其他相互作用。如果在氧化还原反应过程中内球水分子的数量发生变化，则对每个水分子应用-0.348 eV的经验溶剂化吉布斯自由能变化。DFT计算结果与实验结果之间取得了令人满意的一致性，最大绝对误差为0.197 V，平均绝对误差为0.114 V，标准偏差为0.133 V。最后得出结论，氧化还原电位的准确预测取决于几何结构的准确预测以及氧化还原反应过程中的几何守恒。
