Synthesis, Characterization, and Biological Activity of Mixed Ligand Complexes from 8-Hydroxyquinoline and New Ligand for β-Enaminone

[4-Chloro-5- (N-(5,5-dimethyl- 3-oxocyclohex-1-en-1-yl) sulfamoyl)-2- ((furan-2-ylmethyl) amino) benzoic acid] is the ligand[H2L1]. [H2L1] was synthesized and identified using Fourier transform infrared (FT-IR), 1H, 13C-NMR, CHN, mass spectra, and UV-Vis spectroscopy methods. To detect mixed ligand complexes, analytical and spectroscopic approaches such as micro-analysis, conductance, UV-visible, magnetic susceptibility, and FT-IR spectra were utilized. Its mixed ligand complexes [M(L1) (Q)Cl2] and complexes [Pd(L1) (Q)] and [Pt(L1) (Q)Cl2]; [H2L1] = β-enaminone ligand =L1 and Q= 8-Hydroxyquinoline = L2]. The results showed that the complexes were synthesized utilizing the molar ratio M: L1:L2 (1:1:1). For the metal complexes Co(II), Ni(II), Cd(II), and Pt(IIII), a six-coordinate octahedral geometry was proposed, whereas the Pd(II) complex was square planar. By Using the agar well diffusion method, the ligands and complexes were evaluated for antibacterial activity against Staphylococcus aureus and Escherichia coli. The studies demonstrate that the ligand and its complexes have variable activity against the bacterial types. Some of the complexes had an effect on affected bacteria, while others had less inhibitory action than the ligand. Also, the produced ligand and its metal complexes have been tested for fungi (Candida albicans); the complexes exhibited suppressing activity against fungi compared to the ligand prepared from them.