Crystal and mol-ecular structures of di-chlorido-palladium(II) containing 2-methyl- or 2-phenyl-8-(diphenyphosphan-yl)quinoline.

The crystal structures of di-chlorido-palladium(II) complexes bearing 2-methyl- and 2-phenyl-8-(di-phenyl-phosphan-yl)quinoline, namely, di-chlorido-[8-(di-phenyl-phosphan-yl)-2-methyl-quinoline-κ ,]palladium(II), [PdCl(CHNP)] () and di-chlorido-[8-(di-phenyl-phosphan-yl)-2-phenyl-quinoline-κ ,]palladium(II), [PdCl(CHNP)] (), were analyzed and compared to that of the 8-(di-phenyl-phosphan-yl)quinoline (PQ) analogue (). In all three complexes, the phosphanyl-quinoline moiety acts as a bidentate -donating chelate ligand. In the PQ complex (), the Pd center has a typical planar coordination environment; however, both the methyl- and phenyl-substituted phosphanyl-quinoline (PQ and PQ, respectively) complexes () and () exhibit a considerable tetra-hedral distortion around the Pd center, as parameterized by the τ values of 0.1555 (4) and 0.1438 (4) for () and (), respectively. The steric inter-action from the substituted group introduced at the 2-position of the quinoline ring enforces the -positioned Cl ligand to be displaced from the ideal coordination plane. Also, the ideally planar phosphanyl-quinoline five-membered chelate ring shows a large bending deformation by the displacement of the Pd center from the quinoline plane. In addition, in the phenyl-substituted complex (), the coordinating quinolyl and the substituted phenyl rings are not co-planar to each other, having a dihedral angle of 33.08 (7)°. This twist conformation prohibits any inter-molecular π-π stacking inter-action between the quinoline planes, which is observed in the crystals of complexes () and ().