Reinforced MOF/polymer composite based on a copper metal-organic framework supported on nanoporous hyper cross-linked polycalix[4]resorcinarene for the preparation of phthalazine and 4H-pyran heterocycles

Abstract

The present study has aimed to prepare a novel MOF/polymer composite called PC4RA@PrSi-CA/Cu-MOF to take benefit from the advantages of both Cu-based metal-organic framework (Cu-MOF) and porous polymer based on Cis-calix[4]resorcinarene (PC4RA). Various processes, including preparation of a 3D network of polycalix, modification of polycalix with (3-aminopropyl)trimethoxysilan (APTMS) and citric anhydride (CA), and functionalization of the modified polymer with Cu-MOF nanostructure, respectively, were used for synthesizing MOF/polymer composite. Next, the characterization and confirmation of the polymer-supported Cu-MOF were analyzed using FT-IR, EDS-Mapping, STA, PXRD, FE-SEM, and TEM techniques. In the continuation, two types of heterocycles, including phthalazines and 4H-pyrans, were synthesized to reveal the efficiency of the PC4RA@PrSi-CA/Cu-MOF nanocomposite. The catalyst showed a reasonable performance by providing a satisfactory yield of the desired products (90–99 %) during a short time (8–20 min) under mild and green conditions (50 °C in H2O). Furthermore, the structure of the heterocycles was validated using FT-IR, 1H/13C NMR. Then, the catalyst was successively reused ten times in the model reaction and studied using FT-IR, EDX, TEM, and elemental mapping analyses to demonstrate the catalyst stability in recoverability. According to the results, this heterogenized catalyst can recover several times without a notable drop in stability and activity.