Fluorescence Properties Change of Lanthanide Coordination Polymers Dispersed in Mesoporous SBA-15 by Energy Transition Process

Four lanthanide coordination polymers, {[Ln(HPDA)(PDA)(H₂O)₂]·4H₂O} _n (Ln?=?Sm (1), Eu (2), Tb (3)) and {[Sm₃(H₂PDA)₂(HPDA)₂(PDA) (OH)₅(H₂O)₃]·2dta·4H₂O} _n (4) (H₂PDA?=?pyridine-2,6-dicarboxylic acid, dta?=?diethyl amine), have been synthesized under hydrothermal conditions and were characterized by elemental analysis, IR spectrometer, and single-crystal X-ray crystallography. In the complexes 1–3, the 1D chains are assembled into 2D layer by hydrogen bonds formed between the carboxyl groups, and were further assembled into 3D framework by hydrogen bonds and π–π stacking interactions. In complex 4, each Sm³⁺ ion connected to the neighboring Sm³⁺ ion through bridging carboxyl oxygen atoms, and then give rise to a new 2D layered open-framework structure. The 3D supramolecular structure of 4 is constructed through hydrogen-bonding and π–π stacking interactions between adjacent metal–organic polymeric coordination chains. Complexes 1–3 were dispersed in mesoporous materials SBA-15 in DMF solution (denoted as ML-SBA-15, ML?=?1, 2, 3), which were characterized by XRD, IR, and fluorescence spectra. Compared to the complexes 1–3, the photoluminescence efficiency of hybrid material was improved by the energy transition between mesoporous materials and the complexes. The complexes encapsulated in mesoporous materials SBA-15 exhibited stronger luminescence intensity and longer fluorescence lifetime.