Crystal structure and characterization of a novel layered copper-lithium phosphonate with antiferromagnetic intrachain Cu(II)···Cu(II) interactions

Novel metal phosphonate [CuLi(PPA)] [H₃PPA=3-phosphonopropionic acid] was synthesized hydrothermally and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. It crystallizes in the space group C2/c, with cell parameters a=21.617(2) Å, b=4.9269(2) Å, c=14.342(1) Å, β=132.3(2)°, and Z=8. Its framework is built up from a main trimer, acting as a secondary building unit (SBU), which is formed by vertex-shared between two (LiO₄) and one (Cu(1)O₄) polyhedra. These units repeat along b-axis forming infinite inorganic chains, these chains are in turn cross-linked by corner sharing with (Cu(2)O₄) polyhedra to produce inorganic layers lying in the bc-plane. The neighboring layers are connected through the PPA ligand, leading to a 3D pillared-layered structure. The topological analysis reveals that the compound exhibits 3,4,10-c net. Finally, magnetic susceptibility measurement of this compound over the temperature range of 2–300 K reveals the occurrence of weak antiferromagnetic intrachain interactions. - Graphical abstract: Hydrothermal synthesis and structural characterization of a novel lithium-copper phosphonate, formulated as [CuLi(PPA)] (H₃PPA=3-phosphonopropionic acid), have been reported. This compound has a 3D pillared-layered structure with 3,4,10-c net topology. The magnetic susceptibility data over the temperature range of 2–300 K reveals the occurrence of weak antiferromagnetic interactions. - Highlights: • Novel metal phosphonate, [CuLi(PPA)] (1), has been synthesized and characterized. • Compound 1 has a 3D pillared-layered structure with 3,4,10-c net topology. • Magnetic susceptibility data reveals the occurrence of weak antiferromagnetic interactions.