Two-Dimensional Heteronuclear Coordination Polymers Constructed by Cyanide and 3-(2-Aminoethyl)pyridine Ligands

Two new heteronuclear (Ni/Cd and Pd/Cd) 2D coordination polymers formulated as namely {[Cd(μ-3aepy)2Ni(μ-CN)2(CN)2]⋅2H2O}n (1) and [Cd(3aepy)Pd(μ4-CN)4]n (2) (3aepy = 3-(2-aminoethyl)pyridine) were obtained and determined using different techniques (FT-IR and Raman spectroscopies, single crystal X-ray diffraction, elemental, SEM–EDX and thermal analyses). Single crystal X-ray study of the complexes revealed that the Ni(II) and Pd(II) ions are coordinated with four cyanide-carbon atoms in square planar geometries. The Cd(II) ions are bridged by 3aepy ligands to generate [Cd2(3aepy)2]2+ cation and adjacent cations are further linked to cyanide ligands from [Ni(μ-CN)4]2− anion, generating corrugated rectangular grid-like 2D sheets in 1. Whereas, the Cd(II) and Pd(II) ions are bridged by cyanide ligands, generating corrugated rectangular grid-like 2D sheets in 2. The Cd1 is possessed the distorted octahedral coordination geometry with six nitrogen atoms from two 3aepy and four cyanide ligands. The Cd2 is coordinated by four nitrogen atoms from cyanide ligands to form a square-planar geometry. Furthermore, the most remarkable properties of the complexes are the existence of the intermolecular C–H⋯M interactions between M(II) and hydrogen atoms of the 3aepy ligands (M(II) = Ni and Pd).