Calix[4]arene derivative functionalized lanthanide (Eu, Tb) SBA-15 mesoporous hybrids with covalent bonds: assembly, characterization and photoluminescence

Abstract

Three kinds of novel macrocylic calix[4]arene derivatives functionalized SBA-15 type of mesoporous hybrids (Calix-S15, Calix-NO₂-S15 and Calix-NH₂-S15) are synthesized by co-condensation of tetraethoxysilane (TEOS) and modified organic ligand (Calix-Si, Calix-NO₂-Si and Calix-NH₂-Si) in the presence of Pluronic P123 surfactant as a template. The structural preservation of these three parent materials is confirmed by FTIR spectra, ²⁹Si MAS NMR spectra, XRD pattern, and N₂adsorption-desorption measurements. The ternary mesoporous luminescent hybrids containing Ln³⁺ (Eu³⁺, Tb³⁺) complexes covalently attached to the functionalized ordered mesoporous SBA-15, which are designated as Ln(Calix-S15)phen, Ln(Calix-NO₂-S15)phen and Ln(Calix-NH₂-S15)phen, are obtained by introducing lanthanide ions and 1,10-phenanroline into the corresponding parent material via covalent bond assembling methods. XRD pattern, TEM and N₂adsorption-desorption measurements are employed to characterize the mesostrcture of the resulting lanthanide mesoporous hybrids. The photoluminescent behavior (luminescence, lifetime, quantum efficiency, and energy transfer) for these chemically bonded mesoporous hybrids is studied in detail. Also, their quantum efficiencies are determined, which indicates that the different mesoporous hybrid material systems derived from different functionalized calix[4]arene derivative bridges present different luminescence behavior.