Two-dimensional decanuclear erbium wheel supported by mixed hemimellitate and 4-chlorobenzoate ligands

Abstract

Hydrothermal reaction of hemimellitic acid (H₃hma) and 4-chlorobenzoic acid (Hcba) with erbium oxide yielded a two-dimensional (2D) coordination polymer formulated as [Er₄(μ₃-OH)₄(hma)(cba)₅]_n·n(Hcba) (1). It is characterized by single crystal X-ray diffraction, powder XRD, infrared (IR) spectroscopy and thermogravimetric analysis (TGA). The compound possesses a centrosymmetric wheel-like core involving 10 Er(III) ions supported by two crystallographically identical hma ligands. Neighboring decanuclear [Er₁₀] wheels are connected to each other by edge-sharing two Er(III) ions along the a-axis and by μ₃-OH⁻ along the b-axis, generating a 2D layered erbium–organic network in the ab-plane. The organic moieties of the cba ligands point to the direction of the c-axis, forming a hydrophobic environment.