A new mesoporous Ce–Mn-LDH-based Co-MOF nano-composite for the green synthesis of tetrazoloquinazolines

Abstract

Tannic acid (TA), as a plant polyphenol, has many active sites for chelation with metals, so TA-oligomers (TA-Olig) were used for the first time as ligands on the surface of Ce–Mn-LDH to prepare the layered double hydroxide-based metal–organic framework (Ce–Mn-LDH@CPTMS@TA-Olig@Co-MOF = E) nanocomposite. In this regard, a homogeneous water/ethanol solution was prepared by sol–gel method using polyethylene glycol and ammonia solution, and then TA was converted into a set of oligomers in the presence of formaldehyde. In the next step, Ce–Mn-LDH was prepared in a ratio of 1 : 4 of Ce to Mn, modified with 3-chloropropylmethoxysilane, functionalized by TA-Olig, and then cobalt salt was used to prepare E. Finally, the structure of E was determined by FT-IR, ICP, XRD, BET, EDX, SEM, SEM-mapping, TEM, and TGA-DTA techniques and used as a new and potent nanocatalyst for the synthesis of tetrazoloquinazolines a(1–12). One of the advantages of this nanocatalyst is the active surface to form products in a limited time in mild conditions with high efficiency and easy separation. Also, the catalytic activity is maintained even after four consecutive runs.