Synthesis of and Structural Insights into Contact Ion Pair and Solvent-Separated Ion Pair Diphenyliridate Complexes

摘要

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 pi-back-donation from Ir to ligands than that of Rh.