Synthesis, DFT calculations and catalytic activity in the Biginelli reaction of two hydrazone Cu(II) complexes

In this work, two Cu(II) complexes containing ۵-amino-۱-R-۱H-benzimidazol-۴-yl)(۴-chloro)phenylmethanone hydrazones ligands were synthesized and their spectral characterization, DFT calculations, and catalytic activity were reported. New heterocyclic hydrazone ligands were prepared by the reaction of o-amino-ketones with hydrazine hydrate in high yield. Structural assignments of new compounds were based on their microanalytical and spectral data and formula [Cu(L)۲(H۲O)۲](SO۴) was suggested for complexes. Moreover, to gain a further insight into the geometry of synthesized complexes, the DFT calculations were carried out at the B۳LYP/۶-۳۱۱+G(d,p) level of theory. The catalytic activity of Cu(II) complexes as heterogeneous catalysts were also investigated in the synthesis of biologically active compound ۳,۴-dihydropyrimidin-۲(۱H)-one C۵ ester, via classical Biginelli reaction followed by trans-esterification reaction. The results confirmed that the current method formed the products at the lower reaction time and high yields, which might as a result of the enhanced reactivity of the reactants on the surface sites of Cu(II) complexes.

کلیدواژه ها:

Cu(II) complex ، amino-benzimidazol-hydrazone ligand ، DFT ، Biginelli reaction ، Catalyst stability