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

Abstract

2-(5-H/Me/Cl-1H-benzimidazol-2-yl)-phenol ligands form 1:1 electrolytes, 5-coordinate monometallic complexes with iron(III) nitrate. The geometry of the [Fe(L)(OH)(H 2 O) 2 ](NO 3 ) complexes was derived from theoretical calculation in DGauss/DFT level (DZVP basis set) on CACHE. In all of the complexes the ligands are bidentate, via one imine nitrogen atom and phenolate oxygen atom. The coordination is completed with a hydroxide ion, and two water molecules, adopting a distorted square pyramidal geometry. The structures of the compounds were confirmed on the basis of elemental analysis, molar conductivity, magnetic moment, FT-Raman, FT-IR (mid-IR, far-IR), EPR and u.v.-vis. The antimicrobial activities of the free ligands, their hydrochloride salts, and the complexes were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) dilution method, against nine bacteria and the results are compared with several known antibiotic agents. Antifungal activities were reported for Candida albicans, Kluyveromyces fragilis, Rhodotorula rubra, Debaryomyces hansenii, Hanseniaspora guilliermondii, and the results were referenced against nystatin, ketaconazole, and clotrimazole antifungal agents. In most cases, the compounds tested showed broad-spectrum (Gram + & Gram ) bacteria) activities that were either more active or as potent as the references.

Spectral characterization and antimicrobial activity of 2-(5-chloro/nitro-1H-benzimidazol-2-yl)-4-bromo/nitro-phenols and their zinc(II) complexes

“…3300 cm −1 in the IR spectra, caused by intramolecular hydrogen bonding between the phenoxyl hydrogen atom and C N nitrogen atom ( Table 2 and Fig. 2) [15,[28][29][30].…”

“…The other important benzimidazol derivatives, which are used as drugs, are thiabendazole [4,5], albendazole, mebendazole, flubendazole [6,7] astemizole [8] and fenbendazole [9]. In our previous studies, we found that various benzimidazolyl-phenol derivatives showed antimicrobial activity against several microorganisms [10][11][12][13][14][15].…”

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

“…According to the molar conductivity data, [32][33][34]. The room temperature magnetic moment value of Co(II) complex, 3.31 BM, lower than the spin-only value for high spin and higher than the spin-only value for low spin configurations.…”

Synthesis, Spectral and Theoretical Characterization of 5,6-Dichloro/Dimethyl-2-(2´,3´/2´,4´/2´,5´/3´,4´/3´,5´-Dimethoxyphenyl)-1H-Benzimidazoles

“…The high therapeutic properties of the related drugs have encouraged the medicinal chemists to synthesize a large number of novel chemotherapeutic agents [10][11][12]. They displayed many biological activities, such as: antiviral [13] and antitumoral [14]; antifungal and antimycotic [15]; antihistaminic and antiallergic [16]; antimicrobial [17][18][19][20] and antihelminthic activity [21]; all are unique characteristics known for benzimidazole derivatives [10]. These compounds are also extensively used in industrial processes as corrosion inhibitors for metal and alloy surfaces [22,23].…”