Preparation of cubane-1,4-dicarboxylate-Zn-Al layered double hydroxide nanohybrid: comparison of structural and optical properties between experimental and calculated results

In the present research, we report cubane-1,4-dicarboxylate anions (cuban-dc) assembled into a Zn2Al layered double hydroxide (LDH) inorganic host using the coprecipitation method, in which solutions of Zn(II) and Al(III) nitrate salts react with an alkaline solution of cubane-1,4-dicarboxylic acid. Powder X-ray diffraction, FTIR spectroscopy, elemental analyses, and thermal gravimetric analysis (TGA) were used to characterize the successful incorporation of the cubane-1,4-dicarboxylate anions into the interlayer space of LDH. Periodic density functional theory was employed to understand the structural and electronic properties of the cubane-dc-Zn2Al-LDH system. The quantum mechanics study was supported by periodic density functional theory (DFT) calculation which predicts appropriate values for structural and optical properties of cubane-dc-Zn2Al-LDH. Optical and structural theoretical results are in good agreement with the experimental results, which show that when cubane-1,4-dicarboxylate anions intercalate in Zn-Al-LDH, they cause a red shift and subsequently decrease the band gap energy in comparison with LDHs that contain small anions.