Synthesis, structure, Hirshfeld surface, DFT and in silico studies of 4-[(E)-(2, 5-dimethoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (DMAP) and its metal complexes

The synthesis of the Schiff base ligand 4-[(E)-(2,5-dimethoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (DMAP) and its Co(II) and Ni(II) complexes is reported. The ligand and complexes were characterized by NMR, ESI-MS and IR techniques. The XRD data showed that the compound crystallized in the orthorhombic crystal system with the P212121 space group. The molecular structure of the ligand shows the phenyl-pyrazole and di-methoxyphenyl group on alternate sides of the azomethine functionality. The Cu(II) and Co(II) complexes of the ligand were obtained by the reaction of a 2:1 mol ratio of the ligand and the metal salts respectively. Evidence from U·V–vis, IR and ESI-mass spectral analysis of the complexes suggest the formation of bidentate tetrahedral complexes. Drug activity relationship of the synthesized ligand and complexes were evaluated and DMAP showed significant binding affinity upon interaction with 4KW5 (antitubercular drug target) and 1REV (antiviral drug target). DMAPCo and DMAPCu showed positive interactions with the bacterial agents that were used. Hirshfeld surface analysis was employed to estimate the strength of the intermolecular non-covalent interactions in the ligand.