Two dimensional cyano-bridged hetero-metallic coordination polymers containing metal⋅⋅⋅π interactions

•In the complexes, the adjacent 2D layers were connected by the μ-ampy bridging ligands.•M⋯π interaction forces have observed between the M ions and the pyridine rings.•In the formation of the complexes were effective hydrogen bonds.

Three cyano bridged hetero-metallic complexes of general formula, [Cu(NH3)2(μ-ampy)M(μ-CN)2(CN)2]n [ampy = 4-aminomethylpyridine, M = Ni(II) (1), Pd(II) (2) and Pt(II) (3)] have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal analyses and elemental analyses. The complexes crystallize in triclinic system with space group P-1. In all complexes, M(II) ions are coordinated by four cyano ligands, and four N atoms in the equatorial plane around the Cu atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the cyanide N atoms in the axial positions. In one-dimensional structures of all the complexes, [Cu(ampy)]2+ cations and [M(CN)4]2− anions are linked via bridging cyano ligands. The adjacent one-dimensional structures form a 2D network to connect by the μ-ampy bridging ligands. The 2D layers are further linked by metal⋯π and hydrogen bonding interactions to generate a three dimensional network.

Graphical abstractThe experimental study on complex 1 have revealed the great importance of the non-covalent Ni⋅⋅⋅π interactions between the Ni(II) ion and the 4-aminomethylpyridine ligand.Figure optionsDownload full-size imageDownload as PowerPoint slide