Tetranuclear pyrophosphate-bridged Cu(II) complex with 2,2′-dipyridylamine: Crystal structure, spectroscopy and magnetism

Use of pyrophosphate, 2,2′-dipyridylamine (hdpa) with Cu(NO3)2 · 3H2O has enabled to synthesize a novel tetranuclear copper(II) complex, [Cu4(hdpa)4(μ-P2O7)2] · 11H2O 1, which was characterized by single crystal X-ray diffraction, IR, ESR spectrum, and variable-temperature magnetic susceptibilities (4.2–300 K). Extensive π–π stackings and H-bonding water clusters resulting from 11 free water molecules join Cu4 units to make a 3D network. According to the molecular structure, the experimental data were fitted to the expressions derived from the Hamiltonian H=-2J12S^1S^2-2J13(S^1S^3+S^2S^4)-2J14(S^1S^4+S^2S^4) showing dominant antiferromagnetic behaviors.

Graphical abstractUse of pyrophosphate, 2,2′-dipyridylamine with Cu(NO3)2 · 3H2O has enabled the synthesis of two copper(II) complexes, tetranuclear [Cu4(hdpa)4(μ-P2O7)2] · 11H2O with extensive π–π stackings and H-bonding water clusters and polymer single-helical structure [Cu(hdpa)(HPO4)]n, under different reaction conditions; magnetic studies reveal that the tetranuclear one has dominant antiferromagnetic behavior.Figure optionsDownload full-size imageDownload as PowerPoint slide