Formation of mono(8-hydroxyquinoline) lithium(I) complex in smectites by solid–solid reactions

Lithium quinolate including mono(8-hydroxyquinoline) lithium(I) complex (Liq) formed in the interlayer spaces of two smectites via solid–solid reactions and in situ complex formation by reacting Li-smectites (Li(I)-synthetic saponite and Li(I)-montmorillonite) with 8-hydroxyquinoline at room temperature. The incorporation of 8-hydroxyquinoline into Li(I)-smectites was proved by powder X-ray diffraction, infrared spectroscopy, thermal and elemental (CHN) analysis. UV–vis absorption and photoluminescence spectra indicated that 8-hydroxyquinoline ligand formed Liq chelate in the interlayer spaces of smectites. The higher luminescence intensity of the Liq complex in synthetic saponite confirmed the very low content of quenching impurities such as iron in the synthetic saponite. The variation of the photoluminescence bands supported the difference in molecular packing and/or crystal structure of the complex formed in the interlayer spaces of smectites.