Síntese, caracterização e estudo fotofísico de hidróxidos lamelares de európio (iii) contendo íons SB3+ com potenciais aplicações biomédicas

Abstract

Layered rare earth hydroxides (LReHs) represent a family of inorganic materials with positive charge, characterized by anion exchange, exfoliation, electrical, magnetic, and optical properties, which have garnered interest in various fields of materials science. The strategy of introducing mixed Eu3+/Sb3+ metals can synergistically enhance luminescence by promoting interactions between these metallic centers within the host material. This study focuses on the synthesis of layered europium hydroxides containing Sb3+ (LEu1-xSbxH-Cl (x = 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30)) via the hydrothermal method. X-ray diffraction (XRD) analysis confirmed that the obtained layered europium hydroxide (LEuH-Cl) and layered europium hydroxides containing Sb3+ (LEu1-xSbxH-Cl) structures are similar to the layered iterbium hydroxide (LYbH-Cl) standard, exhibiting a high degree of crystallinity, although compounds with x > 20% showed a reduction in crystallite size and crystallinity due to increased concentrations of Sb3+ in the host lamella. Energy-dispersive X-ray spectroscopy (EDX) revealed the quasi-quantitative presence of europium, chlorine, and antimony, while HG-AFS quantified the actual amount of antimony in the obtained compounds. Scanning electron microscopy (SEM) showed morphology alterations from quasi-hexahedral to spherical. Fourier transform infrared spectroscopy (FT-IR) spectra exhibited bands corresponding to oscillation modes (MO) and hydroxyl groups (-OH) in wave intervals of 473-600 cm-1 and 3500–3750 cm-1 , respectively. Thermogravimetric analysis (TGA) revealed mass loss events and greater stability in compounds containing antimony. UV-visible diffuse reflectance spectroscopy (DRS) indicated Sb3+ transitions as the antimony content increased, and photoluminescence studies demonstrated energy transfer from Sb3+ to Eu3+, enhancing Eu3+ photoluminescence. Finally, cytotoxicity and cell viability assays demonstrated that the materials are harmless and biocompatible, suggesting their applicability in both physicochemical and biological and biomedical fields.