Photoactive Ternary Lanthanide-Centered Hybrids with Schiff-Base Functionalized Polysilsesquioxane Bridges and N-Heterocyclic Ligands

This work focuses on the synthesis of a series of silica‐based organic–inorganic hybrid materials, containing different Schiff‐base organic compounds, through a covalent self‐assembly process. We first prepared three functional molecular bridges that can both coordinate to lanthanide ions (Eu3+ and Tb3+) and form inorganic Si–O–Si networks with tetraethoxysilane (TEOS) from cohydrolysis and copolycondensation processes. Meanwhile, we selected N‐heterocyclic ligands [1,10‐phenanthroline (Phen) and 2,2′‐bipyridine (Bipy)] as the second ligands to act as the main energy donor to absorb abundant energy in the UV/Vis region and to transfer the energy to the corresponding lanthanide ions to sensitize their emission. The introduction of the second ligand can also take the place of the coordinated H2O and thus reduce the quenching effect of the OH group. Measurements of the photoluminescent properties of these materials show that the ternary lanthanide/inorganic/organic hybrids present stronger luminescent intensities and higher emission quantum efficiencies. The resulting amorphous materials exhibit regular, uniform microstructures and no phase separation occured since the organic and inorganic compounds were covalently linked through Si–O bonds through a self‐assembly process. This work focuses on the synthesis of a series of silica‐based organic–inorganic hybrid materials, containing different Schiff‐base organic compounds, through a covalent self‐assembly process. The resulting materials exhibit regular, uniform microstructures and the organic and inorganic compounds are covalently linked through Si–O bonds.