Ir(CO)Cla(Ph2Ppy)2HgClb(HgCl2)c (a,b=1, 2, c=0, 1)的Ir-Hg相互作用和氧化还原反应性质

应用密度泛函理论(DFT)的PBE0方法, 金属原子采用SDD基组, H、C、O和N原子采用6-31G*基组, P和Cl原子采用6-311G*基组, 对单核配合物Ir(CO)Cl(Ph2Ppy)2(1), 双核配合物Ir(CO)(Cl)2(Ph2Ppy)2HgCl(2)、Ir(CO)Cl(Ph2Ppy)2HgCl2(3)和Ir(CO)(Cl)2(HgCl2)(Ph2Ppy)2HgCl(4)进行结构优化, 并在优化的基础上采用基组重叠误差(BSSE)校正计算相互作用能, 通过自然键轨道(NBO)和前线轨道分析研究Ir-Hg相互作用和氧化还原反应的实质. 通过计算发现, Ir(CO)Cl(Ph2Ppy)2与HgCl2发生氧化还原反应得到的产物2和4比非氧化还原产物3稳定. Ir-Hg相互作用强度顺序为3<4<2, 且随着Ir-Hg相互作用强度增大, HOMO轨道中Ir和Hg成分逐渐趋于接近. 配合物2和4都具有一对Ir-Hg成键与反键轨道, 其成键轨道的组成分别为0.5985sd0.06Hg+0.8012sd2.48Ir和0.5794sd0.05Hg+0.8151sd2.48Ir, 但3中Ir与Hg的相互作用较弱, 只存在弱相互作用(电荷转移作用), 表现为nIr→nHg的直接作用和σIr—P(1)→nHg、σIr—C(1)→nHg的间接作用.

Ir-Hg Interactions and the Nature of Redox Reactions in Ir(CO)Cla(Ph2Ppy)2HgClb(HgCl2)c (a,b=1, 2|c=0, 1)

Structures of the mononuclear complex Ir(CO)Cl(Ph2Ppy)2(1), binuclear complexes Ir(CO)(Cl)2(Ph2Ppy)2·HgCl (2), Ir (CO)Cl (Ph2Ppy)2HgCl2 (3), and Ir (CO) (Cl)2 (HgCl2) (Ph2Ppy)2HgCl (4) were optimized using the density functional theory (DFT) PBE0 method with SDD basis sets for Ir and Hg, 6-31G* basis sets for H, C, O, and N atoms and 6-311G* basis sets for P and Cl atoms. Based on the optimized geometries of complexes 1-4, a counterpoise correction was carried out for the basis-set superposition error (BSSE) of the interaction energies. Nature bond orbital (NBO) and frontier orbital analyses were also performed for all the complexes to study the Ir-Hg interactions and the nature of the redox reactions. Our conclusions are as follows: products of the redox reactions (complexes 2 and 4) are more stable than that of the nonredox reaction (complex 3). The strength of the Ir-Hg interaction increases as follows: 3<4<2. As the strength of the Ir-Hg interaction increases, the difference between the Ir and the Hg contribution to the HOMO gradually decreases. Ir-Hg σbonding and antibonding orbitals all exist in complexes 2 and 4, and can be described as 0.5985sd0.06Hg+0.8012sd2.48Ir for complex 2 and 0.5794sd0.05Hg+0.8151sd2.48Ir for complex 4. However, in complex 3, the Ir-Hg interaction results from nIr→nHg, σIr—P(1)→nHg, and σIr—C(1)→nHg charge transfer interactions.