Synthesis and characterization of Cu(II) complexes supported by a pyridylamide ligand

Abstract

In our effort to understand the impact of ligand platforms on the structure diversity and chemical properties of copper clusters, a tripod pyridylamide ligand H3tpmbc was used in this work. Two one-dimensional polymeric Cu(II) complexes [Cu(H3tpmbc)Cl2]n (1) and [Cu2(H3tpmbc)Cl4]n (2) were isolated and characterized. X-ray crystallography analysis showed that both structures have a similar one-dimensional backbone. The main structure difference of the two complexes is the presence of a second Cu(II) site in complex 2. Hirshfeld analysis revealed the presence of interesting C–H⋅⋅⋅π and π⋅⋅⋅π interaction networks in both complexes. Spectroscopic characterization of both complexes and [CuPyCl2] suggests the source of the color difference between the two polymers at the solid state. Computational studies based on the X-ray crystal structures were performed and the results provided a deeper understanding of the electronic structures of the Cu(II) site(s) in both complexes. Thermal gravimetric analysis (TGA) demonstrated that the two complexes have the similar thermal behavior, and this could be attributed to the similar one-dimensional backbone structure.