Synthesis and Characterization of Palladacycles Complexes Containing Halide and Iminophosphorane Ligands

ABSTRACT This study presents an efficient synthesis and comprehensive characterization of novel organopalladium complexes bearing halide ligands. The synthetic route involves a multistep process beginning with the preparation of diazides, achieved through the sequential formation of diazonium salts in situ from diamines via sodium nitrite treatment, followed by azide incorporation. Given the inherent instability and tendency of azide compounds towards spontaneous decomposition at elevated temperatures, these reactions were rigorously carried out in an ice bath to maintain temperatures below 5°C, thereby ensuring reaction control and safety. Subsequent treatment of the amine azide intermediate with sodium azide and triethylamine, followed by reaction with tris ( para ‐methoxyphenyl)phosphine [P(p‐MeO‐C 6 H 5 ) 3 ], afforded iminophosphorane ligands in high yield. These ligands were then subjected to coordination with palladium(II) acetate in toluene, leading to the formation of dinuclear palladacycle complexes as air‐stable solids. These complexes exhibit remarkable stability and were thoroughly characterized by various spectroscopic techniques. Additionally, the acetate‐bridged palladacycles were successfully transformed into halide‐bridged analogues by treatment with aqueous sodium chloride or sodium bromide in dichloromethane, yielding chloride‐ and bromide‐bridged palladacycle complexes, respectively. These halide‐bridged species maintain robust air stability, demonstrating the versatility and tunability of the palladacycle framework. This work contributes valuable insights into the controlled synthesis of palladium complexes with tailored ligand environments, enhancing their potential utility in catalysis and organometallic chemistry.