Synthesis and Characterization of Silver and Palladium Complexes with Xanthene-Based N-Heterocyclic Carbene−Oxazoline Ligands

We synthesized xanthenes substituted with two different donor ligand units, N-heterocyclic carbene (NHC) and oxazoline, by the sequential coupling reaction. Silver complexes 15 and 19 were prepared by the reaction between the xanthene derivatives and Ag2O. Pd complexes 16 and 20 were also synthesized by the reaction of the corresponding silver complexes with Pd(PhCN)2Cl2. X-ray crystallographic analysis revealed that complexes 15-PF6, 16, and 20 adopted trans configurations, while the Ag atom of 15-Cl coordinated only to the NHC ligand.