Preparation of di--chlorobis(1,5-cyclooctadiene)diiridium (I) [Ir(cod)Cl]2

To a 150.0 mL 3-neck flask was added IrCl₃·3H₂O (1.0 g, 3.0 mmol) followed by addition of 95% of ethanol (17.0 mL), water (8.5 mL) and 1,5-cyclooctadiene (3.0 mL, 24.5 mmol) under nitrogen atmosphere. The resulting mixture was stirred under reflux for 24 h and formed a brick red precipitate. It was allowed to cool to room temperature and filtered. The precipitate was rinsed with cold methanol to remove the trace amount of 1,5-cyclooctadiene unreacted. Then the product was dried in vacuum for 8 h. And [Ir(COD)Cl]₂ was obtained in 67% yield as a brick red solid. mp 200–202 °C.