Grafting aluminum(III) 8-hydroxyquinoline derivatives on MCM-41 mesoporous silica for tuning of the light emitting color.

Fluorescent materials (Q)(3-n)(2-BuO)(n)Al (Q = 8-hydroxyquinoline, 2-methyl-8-hydroxyquinoline and 5-chloro-8-hydroxyquinoline, n = 1 or n = 2) were prepared in toluene by reacting aluminum 2-butoxide with 8-hydroxyquinoline and its derivatives. The compounds were characterized by (1)H, (13)C and (27)Al NMR in solution, and the coordination status of the aluminum atom in the complexes were determined by (27)Al NMR chemical shifts. The compounds were grafted on mesoporous silica (MCM-41) at room temperature without isolation of the complexes. The prepared materials were characterized by elemental analysis, FT-IR spectroscopy, low-angle X-ray diffraction (XRD), thermal analysis (TGA/DSC) and N(2) adsorption and desorption measurements. The results showed that the characteristic mesoporous structure of MCM-41 after grafting aluminum complexes remains intact. The photoluminescence (PL) properties of (Q)(3-n)(2-BuO)(n-1)@Al-MCM-41 were investigated. The results revealed that the maximum wavelength is modulated by the MCM-41 guest.