A comprehensive study on the synthesisand X-ray characterization of new dimeric palladium(II) complexes of phosphoniumylides

A new series of palladium (II) complexes having α-keto stabilized phosphoniumylides as ligands with general formula [Pd(μ-X)(PPh3CHC(O)C6H4R)]2 [X = Cl, R=m-OCH3 (1), R=p-NO2 (2), X = Br, R=m-OCH3 (3), R=p-NO2 (4)] was prepared. All complexes were characterized by FT-IR and multinuclear (1H, 13C, and 31P) NMR spectroscopic techniques. Also, a single crystals X-ray diffraction study was executed for compounds 1 and 3, which revealed a dimeric square-planar geometry around Pd(II) ions for these complexes. Based on the spectroscopic and crystallographic results, it was found that the phosphoniumylides have coordinated to palladium(II) centers through the coordinatively active ylidic carbon atom and ortho-carbon atom of PPh3 phenyl ring (ortho-palladation) [1,2].