Amide Functionalized Mesoporous MOF LOCOM‑1 as a Stable Highly Active Basic Catalyst for Knoevenagel Condensation Reaction

• Published in: ACS omega 2023-02, Vol.8 (7), p.6638-6649
• Main Authors: Afaq, Sheereen, Akram, Muhammad Usman, Malik, Wasif Mahmood Ahmed, Ismail, Muhammad, Ghafoor, Abdul, Ibrahim, Muhammad, Nisa, Mehr un, Ashiq, Muhammad Naeem, Verpoort, Francis, Chughtai, Adeel Hussain
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.2c07137

Acyl-amide is extensively used as functional group and is a superior contender for the design of MOFs with the guest accessible functional organic sites. A novel acyl-amide-containing tetracarboxylate ligand, bis­(3,5-dicarboxy-pheny1)­terephthalamide, has been successfully synthesized. The H4L linker has some fascinating attributes as follows: (i) four carboxylate moieties as the coordination sites confirm affluent coordination approaches to figure a diversity of structure; (ii) two acyl-amide groups as the guest interaction sites can engender guest molecules integrated into the MOF networks through H-bonding interfaces and have a possibility to act as functional organic sites for the condensation reaction. A mesoporous MOF ([Cu2(L)­(H2O)3]·4DMF·6H2O) has been prepared in order to produce the amide FOS within the MOF, which will work as guest accessible sites. The prepared MOF was characterized by CHN analysis, PXRD, FTIR spectroscopy, and SEM analysis. The MOF showed superior catalytic activity for Knoevenagel condensation. The catalytic system endures a broad variety of the functional groups and presents high to modest yields of aldehydes containing electron withdrawing groups (4-chloro, 4-fluoro, 4-nitro), offering a yield > 98 in less reaction time as compared to aldehydes with electron donationg groups (4-methyl). The amide decorated MOF (LOCOM-1-) as a heterogeneous catalyst can be simply recovered by centrifugation and recycled again without a flagrant loss of its catalytic efficiency.