Novel organic–inorganic hybrid soft xerogels with lanthanide complexes through an ionic liquid linkage

Abstract

This paper provides the strategy to prepare luminescent sandwich structured hybrid materials [Ln(L)₄]⁻IM⁺–Al/Ti (Ln = Eu, Sm; L = 2-thenoyltrifluoroacetonate (TTA); Ln = Tb, L = trifluoroacetylacetonate (TAA)) based on sol–gel derived hosts of Ti–O or Al–O networks. The ionic liquid compound 3-(2-carboxyethyl)-1-methylimidazolium bromide (IM⁺Br⁻) plays double roles of both connecting the lanthanide compounds with an ion exchange reaction and linking matrices through its carboxylic group. Subsequently, a series of hybrid soft materials of alumina and titania xerogels centered with lanthanide complexes are prepared via the hydrolysis and polycondensation of aluminum isopropoxide or tetrabutyl titanate. These hybrid soft xerogels are characterized under FTIR, XRD, UV-VIS diffuse reflection absorption spectra, SEM, TGA and especially luminescence spectroscopy. The results prove that it is an effective way to prepare [Ln(L)₄]⁻IM⁺–Al/Ti hybrid soft materials with favorable photoluminescent behaviors. It is noticeable that [Sm(TTA)₄]⁻IM⁺–Ti can render white light under broadband excitation for a certain content of Sm³⁺.