Lanthanide-centered covalently bonded hybrids through sulfide linkage: Molecular assembly, physical characterization, and photoluminescence

A series of novel photoactive lanthanide (europium, terbium, dysprosium, samarium) hybrid materials with organic parts covalently bonded to inorganic parts via sulfide linkage have been assembled by the sol-gel process. The organic parts as molecular bridge are obtained from the functionalized thiosalicylic acids by five silane crosslinking reagents, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-(triethoxysilyl)propylisocyanate. The intramolecular energy transfer process between lanthanide ions and the molecular bridges took place within these molecular-based hybrids and especially the quantum efficiency of europium hybrids were determined, suggesting that the hybrid material systems derived from different molecular bridges present different luminescence efficiencies.