Synthesis and characterization of strongly electron-donating bidentate phosphines containing imidazolin-2-ylidenamino substituents and their electron-rich nickel(0), palladium(II) and gold(I) chelate complexes

摘要

Bidentate phosphines are important ligands in inorganic and organometallic chemistry. However, their electron-donating ability is generally limited by the use of alkyl groups at the phosphorus atoms. Herein, we report two different approaches to strongly electron-donating bidentate phosphines: In the first strategy imidazolin-2-ylidenamino-substituted phosphorus atoms were linked by 1,1'-ferrocene (5) or 1,2-benzene (4) ligand backbones. The second synthetic access is based on linking the imidazolin-2-ylidenamino substituents by an alkyl chain (3). The bidentate phosphines 3-5 were used to synthesize the cationic gold(I) complex [(3)Au][SbF6], the palladium(II) complex [(3)PdCl2], as well as the nickel(0) complexes [(4)Ni(eta(2):eta(2)-cod)] and [(5)(2)Ni-2(mu, eta(2): eta(2)-cod)]. (C) 2020 Elsevier B.V. All rights reserved.