Extension of novel lanthanide luminescent mesoporous nanostructures to detect fluoride.

A novel polydentate type ligand derived from N(2),N(6)-bis(4,4-diethoxy-9-oxo-3-oxa-8,10-diaza-4-siladodecan-12-yl)pyridine-2,6-dicarboxamide (L) has been designed, and it played essential roles in the assembly of new organic-inorganic functional materials. First, its multiple amide groups would coordinate to lanthanide ions firmly and transfer the absorbed energy to both Eu(III) and Tb(III) simultaneously. Second, the hydrogen-bond donor units showed strong affinity to guest anion (F(-)). Third, the two silylated arms could induce the formation of sol-gel derived siloxane hybrid materials. Following this idea, two lanthanide luminescent amorphous particles (ASNs-Eu and ASNs-Tb) have been prepared for the recognition of fluoride ions. Further modification of the synthesis method and transformation to mesoporous network (MSNs-Eu and MSNs-Tb) led to much enhanced thermostabilities, larger specific surface area (from 78.5 to 515 m(2) g(-1) for Eu(III); 89.6 to 487 m(2) g(-1) for Tb(III)), and lower detection limits (2.5 × 10(-8) M for MSNs-Eu and 3.4 × 10(-8) M for MSNs-Tb) for the fluoride ion.