Synthesis of 1,4-DHP-Based Bio-Active Molecules by a pH-Stable Lewis Acidic Ni-MOF Catalyst

The enhanced accessibility of active catalytic sites in 2D Metal-Organic Frameworks (MOFs) is promising for achieving superior catalytic performance. However, the achievement of abundant active catalytic sites along with excellent chemical stability onto a 2D MOF is a formidable challenge and of significant interest. Herein, we have strategically designed and developed a new Lewis-acidic 2D Ni-MOF: IITKGP-61 employing mixed ligand synthesis approach. Interestingly, MOF: IITKGP-61, even being a 2D framework maintained its superior crystallinity in liquid water for a month and across a wide range of aqueous pH solutions (2-12) due to the combined contribution from both thermodynamic and kinetic stability factors. With the abundant accessible open metal sites (two OMSs per formula unit), the developed framework was explored in the biologically important Hantzsch condensation reaction under the sustainable synthetic pathway. Good-to-excellent yields were achieved for a broad scope of substrates even with lower catalyst loading. Most importantly, to verify the practical utility, MOF: IITKGP-61 was employed for the synthesis of a biologically important 1,4-dihydropyridine molecule with antidiabetic properties in ethanol as green solvent with excellent yield. Utilization of a MOF catalyst in such a direction is scarce in the literature and thus demands extensive future research.