DUAL INTERLAYER DISTANCES IN SYNTHETIC SOLIDS OF INTERCALATED HYDROTALCITES WITH 9,10-ANTHRAQUINONE-2,6-DISULFONATE

Intercalation of 9,10-anthraquinone-2,6-disulfonate (AQ26) between layers of synthetic hydrotalcite is observed in powder X-ray diffraction (XRD) patterns, from which a pair of enhanced interlayer distances are obtained in separate solid samples of intercalated products, The dimensions of the interlayer distance and the guest anion size, which is estimated in a semi-empirical MO calculation, are compared. Being correlated with the AQ26:Al ratio in the intercalated products this duality is elucidated as a result of distinct conformations of the interlayer guest dianion which bridges adjacent layers of Mg and Al layered double hydroxides (Mg/Al-LDH). An absorption due to intercalation of the anthraquinone moiety appears in the visible region of the diffuse reflectance (DR) spectra of the products. The solid-state chemistry of the intercalated products is described on the basis of elemental analysis and X-ray photoelectron spectroscopy (XPS).