A one-dimensional copper(II) coordination polymer incorporating succinate and N,N-diethylethylenediamine ligands: crystallographic analysis, vibrational and surface features, and DFT analysis

Abstract

Transition metal atoms can be bridged by aliphatic dicarboxylate ligands to produce chains, layers and frameworks. The reaction of copper sulfate with succinic acid (H₂succ) and N,N-diethylethylenediamine (deed) in basic solution produces the complex catena-poly[[[(N,N-diethylethylenediamine-κ²N,N')copper(II)]-μ-succinato-κ²O¹:O⁴] tetrahydrate], {[Cu(C₄H₄O₄)(C₆H₁₆N₂)]·4H₂O}_n or {[Cu(succ)(deed)]·4H₂O}_n. Each carboxylate group of the succinate ligand coordinates to a Cu^II atom in a monodentate fashion, giving rise to a square-planar coordination environment. The succinate ligands bridge the Cu^II centres to form one-dimensional polymeric chains. Hydrogen bonds between the ligands and water molecules link these chains into sheets that lie in the ab plane. Density functional theory (DFT) calculations were used to support the experimental data. From these calculations, a good linear correlation was observed between the experimental and theoretically predicted structural and spectroscopic parameters (R² ∼ 0.97).

Keywords: DFT; Hirshfeld surface; N,N-diethylethylenediamine; copper(II); crystal structure; one-dimensional coordination polymer; succinic acid; vibrational analysis; water cluster.