Synthesis, Structure, and Properties of a Polymer Complex of Copper(II) With Maleic Acid

A new polymeric copper(II) complex with maleic acid, used as a dicarboxylate ligand, were synthesized Na₂[Cu(C₄H₂O₄)₂]·xH₂O. The resulting complex was characterized by elemental analysis, infrared and UV–visible spectroscopy, and X-ray crystallography. Spectroscopic data indicate that the maleinate ion coordinates in a chelating bidentate mode, creating a distorted octahedral coordination environment around Cu(II). X-ray crystallography confirmed the formulation Na₂[Cu(C₄H₂O₄)₂]·xH₂O and revealed that the central Cu²⁺ ion is in a distorted octahedral geometry. The maleinate ion acts as a bidentate chelator, coordinating through two carboxylate oxygens to form a stable five-membered ring. Two water molecules complete the coordination sphere of the Cu center, yielding a [Cu(C₄H₂O₄)(H₂O)₂]⁻ unit This study extends our understanding of the coordination behavior of π-conjugated dicarboxylic acids with transition-metal ions. Molecular docking studies demonstrated that the polymeric copper(II)–maleic acid complex exhibited strong binding affinity toward B-DNA (1BNA), with a binding energy of − 10.2 kcal/mol and multiple stable hydrogen bond interactions.