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PBEO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的相瓦作用较弱,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)PBEO method witt 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 σ bonding 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 0.5794sd0.05Gg+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.