Newly designed and synthesized heterobimetallic [Cu^II–Dy^III] salamo-like complex: structural characterization, DFT calculation, and fluorescent property

A heterobimetallic 3d–4f complex [Cu(L)Dy(NO₃)₃] based on a symmetric salamo-like ligand (H₂L) was synthesized and characterized by elemental analyses, IR, UV-Vis spectroscopy, and single-crystal X-ray diffraction. The complex crystallized in the monoclinic, space group P 2₁/c, included one tetra-coordinated Cu(II) atom (Cu1), one deca-coordinated Dy(III) atom (Dy1), one completely deprotonated (L)²⁻ unit, and three nitrate groups involved in coordination. Cu1 adopted a planar quadrilateral configuration, and Dy1 formed a slightly distorted double-cap square antiprism geometry. The complex finally formed an infinite 2D and 3D supramolecular structure via the intermolecular hydrogen bonds and π–π interactions. Due to the paramagnetism of Cu²⁺ ions, the complex showed fluorescence quenching. The electronic structure and stability of the complex were proved by density functional theory (DFT) calculation.