(2,2′-biquinoline-κ2N,N′)dichloropalladium(II), -copper(II) and -zinc(II)

In the three title complexes, namely (2,2'-biquinoline-kappa(2)N, N') dichloropalladium(II), [PdCl2(C18H12N2)], (I), and the corresponding copper(II), [CuCl2(C18H12N2)], (II), and zinc(II) complexes, [ZnCl2(C18H12N2)], (III), each metal atom is four-coordinate and bonded by two N atoms of a 2,2'-biquinoline molecule and two Cl atoms. The Pd-II atom has a distorted cis-square-planar coordination geometry, whereas the Cu-II and Zn-II atoms both have a distorted tetrahedral geometry. The dihedral angles between the N - M - N and Cl - M - Cl planes are 14.53 ( 13), 65.42 ( 15) and 85.19 ( 9)degrees for ( I), ( II) and ( III), respectively. The structure of ( II) has twofold imposed symmetry.