Solid-state intercalation of 8-Hydroxyquinoline into Li(I)-, Zn(II)- and Mn(II)-montmorillonites

Formation of three fluorescent complexes, Li(I)-, Zn(II)- and Mn(II)-8-hydroxyquinoline complexes (Mq_n), was investigated in the interlayer spaces of montmorillonites by solid-solid reactions between homoionic (Li(I), Zn(II) and Mn(II)) montmorillonites and neat 8-hydroxyquinoline at room temperature. The intercalation of 8-hydroxyquinoline molecules into the interlayer spaces of Li(I)-, Zn(II)- and Mn(II)-montmorillonites was confirmed by powder XRD, FT-IR, TG-DTA and chemical analysis. The in-situ complex formation was proved by FT-IR, UV-vis, and photoluminescence spectroscopies. The absorption and luminescence bands of the complexes shifted slightly compared to the corresponding neat complexes, suggesting the different microstructures including molecular packing of the complexes in the interlayer spaces of montmorillonites as a result of host-guest interactions.