Europium(III) Complex Probing Distribution of Functions Grafted using Molecular Stencil Patterning in 2D Hexagonal Mesostructured Porous Silica

The "molecular stencil patterning" technique has been used to optimize at high coverage the distribution of aminopropylsilyl tethers (APS) grafted into the nanochannels of a mesostructured MCM-41 type porous silica. To probe this distribution, the APS functions are first derivatized via a Schiff reaction with a 5-substituted 1,10-phenanthroline possessing an aldehyde side arm, and second, reacted with europium(III) ions used as a analytical marker. The integrity of the porous structure has been checked using XRD and N2 adsorption-desorption profiles, whereas the molecular nature of the grafted Eu complex was characterized using 13C NMR, FT-IR, reflectance UV-visible, and luminescence spectroscopies. EDX-TEM measurements at the 1.5 x 1.5 nm resolution scale reveal a rather homogeneous distribution of Eu and, therefore, of APS tethers for several micrometers inside the fibers.