The effect of cetyltrimethylammonium ion and type of smectites on the luminescence efficiency of bis(8-hydroxyquinoline)zinc(II) complex

A luminescence metal complex, bis(8-hydroxyquinoline)zinc(II) (Znq₂), was incorporated into the interlayer space of smectites (a natural montmorillonite and a synthetic saponite) by two different ways; colloidal processes via the in situ formation of bis(8-hydroxyquinoline)zinc(II) in cetyltrimethylammonium-smectites (CTA-smectites) and the adsorption of cetyltrimethylammonium coated bis(8-hydroxyquinoline)zinc(II) (Znq₂CTA) into hydrophilic smectites. The UV-Vis spectra confirmed the formation and the incorporation of bis(8-hydroxyquinoline)zinc(II) in the interlayer space of smectites. The photoluminescence bands of Znq₂CTA@montmorillonite and Znq₂@CTA-montmorillonite (498nm) were blue shifted in comparison with the weak emission bands of Znq₂CTA@saponite and Znq₂@CTA-saponite (510nm), indicating the formation of different nanostructures and/or packing of bis(8-hydroxyquinoline)zinc(II) in the two types of smectites. The state of the intercalated cetyltrimethylammonium ions also played a key role to the luminescence intensities of the products due to the concentration quenching and self-absorption.