Synthesis, Structural and Biological Studies of Some Metal Complexes derived from Tridentate Pyrazole-based Ligand

Abstract

The new derivatives of heterocyclic resulting, studying spectral Cobalt(II), Nickel(II), Copper(II), and Cadmium (II) with new tridentate ligand namely [3-(1-acetyl-4-[4- (dimethylamino)phenyl]-1H-pyrazol-3-yl)-4-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one] which was formed by the (E)-3-(3-(4-(dimethylamino) phenyl)acryloyl)-4-hydroxy-6-methyl- 2H-pyran-2-one with excess of hydrazine monohydrate in glacial acetic acid. NMR, FTIR, MS spectra as well as the elemental analyses, identified the new ligand and TLC was carried out to confirm their structures. The Cobalt (II), Nickel (II), Copper (II) and Cadmium (II) were precipitated by direct reactions of their chlorides with the solution of the ligand in 2:1 molar ratios. All complexes have been identified on the basis of the preliminary analysis, infrared, ultraviolet spectra of the visible moments of magnetic conductivity measurements were conducted for radiation conclude the octahedral geometry around Cobalt (II), Copper (II), and Nickel (II). The Cadmium (II) complex was investigated as tetrahedral in 1:1 ratio. The biological activity of the ligand and its metal complexes in DMSO against some bacterial strains (Staphylococcus aureus, Bacillus subtilis, Escherichia coli and P. aeruginosa). Effected of the syntheses of HL ligand, [Co(L)2] and [Cu(L)2] complexes were studied on Acetylcholinesterase (AChE) in healthy human serum. Results indicated that all of the compounds displayed moderate and selective AChE inhibitory activity. The complexes of [Cu(L)2] and [Co(L)2] showed inhibition constant in the range (Ki: 8.333×10-4, 3.159×10–12, 2.5×10-6, 3.333×10-4 M respectively) higher than HL ligand (1.1×10-4, 1.964×10–12 respectively) M for AChE.