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 H-1, C-13 and Al-27 NMR in solution, and the coordination status of the aluminum atom in the complexes were determined by Al-27 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. (C) 2010 Elsevier Inc. All rights reserved.