Lithium diphenyliridate complexes bearing cycloocta-1,5-diene (COD) as a ligand were synthesized by treating [IrCl(cod)]₂ with phenyllithium and subsequent recrystallization. X-ray crystallographic analysis of the complexes showed both contact ion pair and solvent-separated ion pair structures depending on the coordination environment around the Li cation. Natural bond orbital analysis revealed that the anionic charge formally described on Ir efficiently delocalizes to not only the phenyl moieties but also the COD ligand. This result contrasts to the rhodium-analogues, where the anionic charge is more localized at the metal center, suggesting stronger π-back-donation from Ir to ligands than that of Rh.

中文翻译：

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接触离子对和溶剂分离的离子对二苯基铱酸酯配合物的合成和结构研究

通过用苯基锂处理[IrCl（cod）] ₂并随后重结晶，合成了带有环辛基-1,5-二烯（COD）作为配体的_二苯基铱酸锂络合物。配合物的X射线晶体学分析显示接触离子对和溶剂分离的离子对结构均取决于Li阳离子周围的配位环境。天然键轨道分析表明，在Ir上正式描述的阴离子电荷不仅有效地离域到了苯基部分，而且还有效地离解了COD配体。该结果与铑类似物相反，在铑类似物中，阴离子电荷更多地位于金属中心，这表明从Ir到配体的π背向供体比Rh更强。