Comparative Effect of Amino Functionality on the Performance of Isostructural Mixed‐Ligand MOFs towards Multifunctional Catalytic Application
Bhavesh Parmar, Parth Patel, Gopala Ram Bhadu, Eringathodi Suresh
Abstract
Abstract Two isostructural MOFs {[Cd( BDC )( L )] ⋅ CH 3 OH} n ( 1 ) and {[Cd(NH 2 ‐ BDC )( L )] ⋅ CH 3 OH} n ( 1‐NH 2 ) involving Cd metal center and different dicarboxylate ligands (1,4‐benzenedicarboxylate ( BDC ) in 1 and 2‐amino‐1,4‐benzenedicarboxylate (NH 2 ‐ BDC ) in 1‐NH 2 ) and a common amide functionalized N‐donor ligand ((E)‐N′‐(pyridin‐3‐ylmethylene)nicotinohydrazide ( L )) has been synthesized in bulk by diverse routes with phase‐purity. The MOFs were characterized by spectroscopic methods such as FT‐IR, elemental, TGA analysis, PXRD, and SXRD analysis. Amide functionality of L in 1 and both amide/‐NH 2 functional groups attached to the ligands in 1‐NH 2 of the interpenetrated isostructural 3D framework has been found to be catalytically active basic site towards multiple organic transformations. Both 1 and 1‐NH 2 showed good catalytic activity towards both CO 2 ‐epoxide cycloaddition and Biginelli reaction. A comparative study of the catalytic activity of 1 and 1‐NH 2 for cycloaddition and Biginelli reaction revealed that the amine‐functionalized framework 1‐NH 2 showed better catalytic performance than 1 due to the existence of additional amino site. Presence of accessible functionally decorated Lewis basic ‐NH 2 and amide sites on BDC and N‐donor ligands of 1‐NH 2 synergistically activate the substrate making this framework interesting and efficient heterogeneous base catalyst. Excellent product yield under moderate conditions with reusability is the highlight in both catalytic reactions.