Density Functional Method Estimation of Redox Potentials of Metals in Electrochemical Reactions

用密度泛函方法计算了金属-金属阳离子和金属-金属络合物体系的标准氧化还原电位。在玻恩-哈伯循环中，标准氧化还原电位由结合能、电离能和溶剂化能组成。在金属络合物的情况下，增加了配体交换能。在极化连续介质模型（PCM）水平上，采用自洽反应场理论考虑了溶剂效应。在本项目中，检查了以下21种离子：Li^+、K^+、Ca^<2+>、Na^+、Mg^<2+>、Al^<3+>、Ti^<2+>、Mn^<2+>、Zn^<2+>、Cr^<3+>、Fe^<2+>、Co^<2+>、Ni^<2+>、Fe^<3+>、Cu^<2+>、Cu^+、Ag^+、Pd^<2 +>、Pt^<2+>，Au^<3+>、Au^+。在最高级别的计算中，几何优化和谐波频率分析在PCM下进行了评估。利用金属的内聚能的实验值，计算值和实验SRP值之间的标准偏差为0.20至0.27 V，这取决于所使用的计算水平和基组。对于CN^-、S_2O_3^-和NH_3配体的三种Ag配合物<2->，其差异均在0.3V以内。

The DFT method calculation was carried out to evaluate standard redox potential (SRP) for metal to metal cation and metal to metal complex systems. With the Born-Haber cycle, standard redox potential was composed of the cohesive energy, ionization energy, and solvation energy. The ligand exchange energy was added in case of metal complex. The solvent effects were incorporated by the self consistent reaction field theory at the level of the polarized continuum model (PCM). In the present project, following 21 ions were examined : Li^+, K^+, Ca^<2+>, Na^+, Mg^<2+>, Al^<3+>, Ti^<2+>, Mn^<2+>, Zn^<2+>, Cr^<3+>, Fe^<2+>, Co^<2+>, Ni^<2+>, Fe^<3+>, Cu^<2+>, Cu^+, Ag^+, Pd^<2+>, Pt^<2+>, Au^<3+>, Au^+. At the highest level of calculations, the geometry optimization and harmonic frequency analysis were evaluated under the PCM. Utilizing experimental values of the cohesive energy of metals, the standard deviations between the calculated and experimental SRP values were 0.20 to 0.27 V depending on the calculation levels and basis sets used. For three Ag complexes with CN^-, S_2O_3^<2->, and NH_3 ligands, the discrepancy was within 0.3 V.