Photofunctional terbium centered inorganic/organic hybrid material with the functionalized 5-dihydroxybenzoate linkage

In this study, silica-based organic-inorganic hybrids were prepared using sol-gel methods. A new kind of monomer (DHBA-TESPI) was derived by modifying the double hydroxyl groups of 3, 5-dihydroxybenzoic acid (DHBA) with 3-(triethoxysilyl)-propyl isocyanate (TESPI) through the addition reaction. Then, the obtained compound and tetraethoxysilane (TEOS) were used as the inorganic and organic counterparts respectively. Coordination reaction between Tb3+ and the carboxylic groups of the monomer happen simultaneously. IR, NMR, UV/Vis absorption, low-temperature phosphorescence spectroscopy and fluorescence spectroscopy were used to characterize the hybrids. The final materials exhibited strong green-colored fluorescence (Tb3+), which can be explained by the intramolecular energy transfer caused by coordination of the organic counterpart. The spectroscopic data also revealed that the triplet state energy of the organic ligand matches the emissive energy level of Tb3+.