A unique unit cell containing simultaneous doubly and triply copper(II) complexes bridging by 2,4-pyridine dicarboxylate: Synthesis, structural characterization and magnetic properties

The reaction of an aqueous solution containing Cu(ClO4)2, N,N,N′,N″,N″-pentamethylethylene-triamine (pmedien) and 2,4-pyridine dicarboxylic acid disodium salt (Na2.2,4-pydc) afforded {[Cu3(pmedien)3(μ-2,4-pydc)(H2O)2](ClO4)4,[Cu2(pmedien)2(μ-2,4-pydc)(H2O)](ClO4)2}∙4H2O (1). The complex was structurally and magnetically characterized. Single X-ray crystallography for 1 reveals the existence of two independent molecules in the unit cell in which the dinuclear and trinuclear Cu(II) centers are bridging by the 2,4-pyridine dicarboxylato ligands. Magnetic susceptibility measurements of the complex showed that the Cu(II) ions are antiferromagnetically weakly coupled (J = − 0.27 cm−1).

Graphical AbstractSingle X-ray crystallography for {[Cu3(Me5dien)3(μ-2,4-pydc)(H2O)2](ClO4)4,[Cu2(Me5dien)2(μ-2,4-pydc)(H2O)](ClO4)2}∙4H2O (1) reveals the existence of two independent molecules in the unit cell: dinuclear and trinuclear Cu(II) centers bridging by the 2,4-pyridine dicarboxylato ligands. The Cu(II) ions in the complex are antiferromagnetically weakly coupled.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch Highlights► Polynuclear Cu(II) complex containing di- and tri-nuclear entities. ► The Cu(II) centers are bridging by 2,4-pyridine dicarboxylato dianion. ► The complex exhibits very weak antiferromagnetic coupling.