Structural Characterization and Antimicrobial Activity of 2-(5-H/methyl-1H-benzimidazol-2-yl)-4-bromo/nitro-phenol Ligands and their Fe(NO3)3 Complexes

Abstract

2-(5-H/methyl-1H-benzimidazol-2-yl)-4-bromo/nitro-phenol (HL x :X=1-4) ligands and their iron(III) nitrate complexes have been synthesized and characterized. In all of the complexes, the ligands are bidentate, via one imine nitrogen atom and a phenolate oxygen atom. The coordination is completed with a bidentate nitrate anion, and a water molecule. Elemental analysis, molar conductivity, magnetic susceptibility, FT-Raman, FT-IR (mid i.r., far i.r.), UV-visible and as well as quantum chemical calculations performed with CACHE are in agreement with a 1:1 electrolyte structures that are mononuclear, and distorted 5-coordinate square pyramidal. The antimicrobial activities of free ligands, their hydrochloride salts and the complexes were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) toward nine bacteria, each with multiple, fresh clinical isolates, and the results are compared with those for penicillin-g, ampicillin, cefotaxime, vancomycine, oflaxacin and tetracycline. Antifungal activities were reported for Kluyveromyces fragilis, Rhodotorula rubra, Candida albicans, Hanseniaspora Guilliermondii and Debaryomyces hansenii yeasts, each with multiple isolates, and the results were referenced against nystatin, ketaconazole and clotrimazole antifungal agents. In most cases, the compounds tested showed broadspectrum (Gram + and Gram ) ) activities that were either more active or as potent as the references particularly as antifungal agents.

FT-Raman, FT-IR, NMR structural characterization and antimicrobial activities of 1,6-bis(benzimidazol-2-yl)-3,4-dithiahexane ligand and its Hg(II) halide complexes

“…In this expanding field, the interest towards transition metal complexes containing hetero-donor ligands has increased in order to obtain metal-based drugs either exhibiting a high biological activity together with a reduced toxicity or reduced biological activity for metal ion detoxification. In this respect, benzimidazole derivatives together with their transition metal complexes have been extensively investigated [9][10][11][12][13][14].…”

Investigation of Raman, FT-IR, EPR spectra and antimicrobial activity of 2-(5-H/Me/Cl-1H-benzimidazol-2-yl)-phenol ligands and their Fe(NO3)3 complexes

“…The electronic spectra of the complexes are of little help in the present case, since the d fi d transitions are masked by the strong charge-transfer bands. The complexes, have broad strong bands in the 400-550 nm region, may be caused by the combination of oxygen fi metal, nitrogen fi metal charge transfer (L fi Fe charge transfer) [8,25].…”

“…In this expanding field, the interest toward transition metal complexes containing hetero donor ligands has increased in order to obtain metal-based drugs exhibiting a high biological activity together with a reduced toxicity. In this respect, benzimidazole derivatives together with their transition metal complexes have been extensively investigated [7][8][9][10]. One of the most attractive features of these ligands in the field of biological investigation has been their structural similarities with the common nucleobases.…”

Synthesis and structural characterization of N-(2-{[(2E)-2-(2-hydroxybenzylidene)- hydrazinyl] carbonyl}-phenyl)benzamide (HL) and its Co(II), Fe(III), Cu(II) and Zn(II) complexes. X-ray crystal structure of HL

“…The experimental data of the Co(II) and Fe(III) complexes suggest us monodeprotonated structure in contradistinction to the Cu(II) and Zn(II) complexes. The dark color of the complexes, especially the Fe(III) and Co(II) complexes, shows that there are charge transfer transitions ligand to metal ions through phenolic oxygen atom, O→M [38,39].…”