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The paper describes the synthesis and biological evaluation of some new benzimidazole derivatives as potent clinical drugs that are useful in the treatment of some microbial infections and tumor inhibition. The starting compound 2-(bromomethyl)-1H-benzimidazole (1) was prepared, and hence underwent interesting functionalization reactions to afford several series of benzimidazole-5-(aryldiazenyl)thiazole derivatives: 3a–c, 7a–c, and 8a–c. The antibacterial activities of the synthesized compounds were evaluated by calculation of the inhibition zone diameter (mm) and the determination of minimum inhibitory concentration (µg/mL) against selected pathogenic bacteria Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria).Noticeable efficiency was found based on in vitro screening for their antioxidant activity and cytotoxicity effect against the human liver cancer cell line (HepG2) and human hepatocyte carcinoma cells at relatively high concentrations.

ABSTRACT. Creatinine biomolecule has three different coordination modes through the (exocyclic O(5) and ring N(1)), (imine N(2) and ring N(1)) or as monodentate ligand via exocyclic O(1)). The FTIR and electronic spectra of the synthesized manganese(II), iron(III), chromium(III), and cobalt(II) complexes consistent with the coordinated behavioral derived from the structural analyses. Thermogravimetric data agree with the stoichiometry and proposed formulas [Mn(C4H7N3O)2(Cl)2]4H2O, [Fe(C4H7N3O)2(Cl)2]Cl.6H2O, [Cr(C4H7N3O)2(Cl)2]Cl.6H2O, and [Co(C4H7N3O)2(Cl)2]6H2O. Four new transition metal complexes derived from the reaction of creatinine chelate and metal salt (MnCl2.4H2O, FeCl3.6H2O, CrCl3.6H2O, and CoCl2.6H2O), were prepared with 1:2 (metal: ligand) stoichiometry, isolated and well characterized by a different spectral and analytical techniques including FTIR, UV/Vis, magnetic susceptibility, molar conductance, elemental analysis, and TGA/DrTGA/DTA. The solid complexes were formed with the binding of the creatinine ligand through exocyclic O(5) and ring N(1) and presented as an octahedral geometry. In addition molecular docking calculations have been performed between complexes of manganese(II), iron(III), chromium(III) and cobalt(II) with creatinine biomolecule ligand with the Covid-19 protease (6LU7) to determine the best binding site and its inhibitory effect.                     KEY WORDS: Creatinine, Coordination, Transition metals, TGA/DTA, Octahedral geometry   Bull. Chem. Soc. Ethiop. 2021, 35(2), 399-412. DOI: https://dx.doi.org/10.4314/bcse.v35i2.13

New ligand containing 2-(2,4-dioxo-4-thiophen-2-yl-butyrylamino)-benzoic acid (HL) merged moiety was synthesized and characterized by FT-IR, elemental analyses, mass spectra and 1H-NMR spectral. In the present study, the attempts were carried to form complexes of HL ligand with some transition metal ions (MnII, CuII and CoII) of well-defined at the (1:1) ratio of the components in the dimethyl sulfoxide (DMSO) solvent. All complexes have been studied by FTIR spectra, elemental analyses, thermal analysis, molar conductivity, electronic spectra and magnetic moment. The HL ligand produced as a bidentate chelate with interactive metal ions. All the results suggested octahedral geometry to complexes and have the formulae [M(HL)(Cl)2(H2O)2].nH2O where M = Mn(II), Cu(II) and Co(II). The IR spectra of the complexes were assigned and compared with the data in literature. The kinetic and thermodynamic results such as E*, ΔH*, ΔS* and ΔG* were calculated based o the TGA/DTG curves using Coats and Redfern and Horowitz and Metzger approximation methods. Furthermore, the resultant complexes were evaluated for the anti-bacterial and anti-fungal potential.                     KEY WORDS: 2-(2,4-Dioxo-4-thiophen-2-yl-butyrylamino)-benzoic acid, Transition metal complexes, FTIR, TGA, Antimicrobial test   Bull. Chem. Soc. Ethiop. 2021, 35(1), 129-140. DOI: https://dx.doi.org/10.4314/bcse.v35i1.11