In situ synthesis of Eu(Tp)3 complex inside the pores of mesoporous silica nanoparticles

A route for europium (III) tris-pyrazolyl borate complex [Eu(Tp)3] formation inside the pores of mesoporous silica nanoparticles (MSNs) has been established to yield a highly luminescent nanostructured hybrid. Two different in situ chemical precipitation techniques have been explored for the nanoencapsulation of the Eu3+ complex [Eu(Tp)3] inside the pore channels of mesoporous silica nanoparticles, by varying the sequence order of precursor impregnation. In the first method, the Eu salt is introduced into the pores by wet impregnation and removal of the solvent, followed by wet impregnation of the ligand. In the second approach, the addition sequence is reversed. The importance of the addition sequence was demonstrated by the successful formation of the europium (III) tris-pyrazolyl borate complex in the pore network by following the first approach. The observed pyrazol-1-yl borate (Tp) to Eu3+ intramolecular energy transfer, i.e., the antenna effect, verified the formation of the complex. Photoluminescence spectroscopy, X-ray diffraction, N2 adsorption, FTIR spectroscopy, and TEM were used to characterize the material.