Synthesis, Crystal Structure, FT-IR and UV-Vis Spectra of Tetranuclear Copper (II) Complex with 4-methoxypyridine as Co-Ligand

A methanol solvate of the tetranuclear Cu(II) complex with 4-methoxypyridine (4-MOP) as co-ligand have been synthesized, [Cu₄OCl₆.(4-MOP)₄].CH₂OH, (4-MOP = 4-methoxypyridine) and characterized by IR, UV–Vis spectroscopy and single crystal X-ray diffraction. The complex exhibits a tetrahedral {Cu₄O} core, where four Cu(II) ions are bridged by six chloride ligands and further stabilized through coordination with 4-methoxypyridine ligands. Each copper center displays a distorted trigonal bipyramidal geometry. Intermolecular C–H···Cl and C–H···O hydrogen bonds interconnect the molecules, forming a three-dimensional supramolecular framework. Spectroscopic data, including UV-Vis and FT-IR, substantiate the formation of the Cu₄O cluster and align with the structural observations. These findings offer valuable insights into the coordination behavior and supramolecular organization of µ₄-oxo copper complexes, presenting a useful model for biomimetic systems and a potential foundation for applications in catalysis and material science.

Graphical Abstract

A rare example of a µ₄-oxo-bridged tetranuclear Cu(II) complex stabilized by 4-methoxypyridine ligands has been selectively synthesized and structurally characterized. This is among the few known Cu₄OCl₆ type architectures incorporating 4-MOP, revealing a well-defined {Cu₄O} core and a 3D supramolecular network through weak hydrogen bonding.