Computational investigations on structural and electronic properties of CuI nanoparticles immobilized on modified poly(styrene-co-maleic anhydride), leading to an unexpected but efficient catalyzed synthesis of 1,4-dihydropyridine via Hantzsch pyridine synthesis

Abstract

A quantitative description for the interaction of Cu(I) with poly(styrene-co-maleic anhydride) modified with 4-aminopyridine (denoted as CuI/SMI complex) is presented using density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) approaches. Topological analysis of electron density revealed the existence of effective interactions between Cu(I) ions and the nitrogen in the pyridine ring. Interestingly, the results also showed that there is considerable interaction between Cu(I) and the oxygen of the carbonyl motif in the SMI ligand. Thus, CuI/SMI was examined as a heterogeneous and recyclable catalyst in Hantzsch pyridine synthesis under solvent-free conditions, affording diverse 1,4-dihydropyridines (1,4-DHPs) in excellent yields with relatively short reaction times.