Synthesis and structural characterization of mordant yellow 10-pillared magnesium–aluminum layered double hydroxides

Mordant yellow 10-pillared magnesium–aluminum layered double hydroxide (MY10-LDH) is prepared by anion exchange method. The intercalated structures and the chemical compositions of MY10-LDH are characterized by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. The experimental data prove that MY10 anion is successfully intercalated into the interlayer space of the LDHs. XRD patterns indicate that the MY10-LDH has the special intercalated structure of LDHs with an interlayer distance of 1.58 nm. IR spectra show that the product has the characteristic absorption bands of azo form of MY10 anion, as well as the Mg–O and Al–O vibrations of LDH layers. Furthermore, the microscopic structure of MY10-LDH is investigated by the quantum chemical method. The stable geometries of MY10 and MY10-LDH model molecules are optimized by using density functional theory of quantum chemistry at the level of B3LYP/6-31G(d,p). Through comparing the molecular size of MY10 anion in MY10-LDH with the interlayer distance of MY10-LDH from XRD data, it is determined that the MY10 anions are inclined arranging in the interlayer space of LDHs, because the gallery height is less than the size of MY10 anion.