Half-Sandwich Iridium Complexes Bearing a Diprotic Glyoxime Ligand: Structural Diversity Induced by Reversible Deprotonation.

Synthesis and deprotonation reactions of half-sandwich iridium complexes bearing a vicinal dioxime ligand were studied. Treatment of [{Cp*IrCl(μ-Cl)} ] (Cp*=η -C Me ) with dimethylglyoxime (LH ) at an Ir:LH ratio of 1:1 afforded the cationic dioxime iridium complex [Cp*IrCl(LH )]Cl (1). The chlorido complex 1 undergoes stepwise and reversible deprotonation with potassium carbonate to give the oxime-oximato complex [Cp*IrCl(LH)] (2) and the anionic dioximato(2-) complex K[Cp*IrCl(L)] (3) sequentially.