| Summary: | 碩士 === 中興大學 === 化學系所 === 95 === Synthetic and structural studies of Pd(II) and Ag(I) complexes of iminoyl-substituted N-heterocyclic carbine ligands. Reaction of 2a-c with Ag2O leads to the silver carbene complexes (C–N)AgBr (3a-c). Carbene transfer from Ag to Pd occurs when compounds 3a-c are treated with PdCl2 to yield bis(carbene) complexes (C–N)2PdCl2 (4a-c). The
molecular structures of the complexes 3c and 4b have been determined by X-ray diffraction studies, which revealed the palladium complex 4b had a trans square-planar geometry at their respective metal centers. In a trans coordination geometry, the two carbene ligands can have their two N(imidazole) substituents oriented in the same or in the opposite directions with respect to the coordination plane, denoted syn and anti for 4a-c. The in situ Pd(OAc)2-2a-c and complexes 4a-c were found to be
active catalysts for the Heck and Suzuki C-C coupling reactions, the less reactive aryl chloride substrates can also be used.
|
|---|
