Synthesis, Characterization, and Photophysical Properties of Materials Obtained by Co-intercalation of Chromophores into Layered Double Hydroxides

A pair of chromophores with donor-acceptor properties, coumarin-3-carboxylic acid (3-CCA) and 9-anthracene carboxylic acid (9-ACA), have been successfully intercalated into the layered double hydroxide (LDH), [Zn_0.66Al_0.34(OH)₂](CO₃)_0.17·0.33H₂O by an ion-exchange method. The obtained co-intercalation compounds were characterized by X-ray diffraction, FTIR spectral, thermogravimetry techniques and chemical composition. The guest molecular sizes and structures were investigated utilizing an ab initio (HF/6-31G) method by G98w. These anions were steadily arranged between the metal hydroxide layers by their carboxylate functional groups interacting with the layer plane. The photophysical properties of the obtained compounds were studied by UV-Vis absorption and fluorescence spectroscopy. These results indicate that the confinement of the pair of chromophores, 3-CCA and 9-ACA, within the interlayer region of the host is in favor of guest-host interaction and guest-guest interaction, and that the pair of chromophores, 3-CCA and 9-ACA can give rise to energy transfer processes because of the characteristics of their excited states.