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

Tahir

Journal of Coordination Chemistry

et al. 2014

Five zinc(II) complexes, [Zn(L 1 ) 2 ] (1), [Zn(L 1 ) 2 (phen)H 2 O]·H 2 O (2), [Zn(L 1 ) 2 (bipy)] (3), [Zn(L 2 ) 2 ] (4), and [Zn(L 2 ) 2 (phen)] (5) (where L 1 = 4-nitrophenylacetate, L 2 = phenylacetate, phen = 1,10-phenanthroline and bipy = 2,2′-bipyridine), have been synthesized and characterized by elemental analysis, FT-IR, and multinuclear NMR. Complexes 2, 3, and 4 have been confirmed by single-crystal X-ray diffraction. In 2 and 3, zinc is bonded monodentate to two carboxylates exhibiting distorted trigonal bipyramidal and tetrahedral geometries, respectively, whereas in 4, the carboxylates are bridging bidentate in distorted tetrahedral geometry. The complexes have been screened for electroand biological activities, including DNA interaction and enzyme inhibition studies. The effect of concentration of 1-5 on the activity of enzyme, alkaline phosphatase, showed that an increase in concentration of complex decreased the activity of the enzyme. Electrochemical behavior of HL 1 , 2, and 3 was investigated by cyclic voltammetry and it was observed that ligand-centered electroactivity exhibits a proportionate change on complexation. The UV-visible spectroscopic and viscometric data indicate electrostatic and groove binding of the complexes with DNA. The binding constant and Gibb's free energy values indicate the feasibility of the complex-DNA interaction and show potent biological activity of the complexes.

mentioning

confidence: 63%

Synthesis, characterization, crystal structures, enzyme inhibition, DNA binding, and electrochemical studies of zinc(II) complexes

Tahir

Journal of Coordination Chemistry

et al. 2014

“…The measured and calculated FT‐IR spectra of the ligand HL 4 and its complex, C4 , are given in Figures a and b, and a and b, respectively. In HL 1 spectrum, ν(O–H) and ν(N–H) vibration frequencies appear separately at 3325 and 3245 cm −1 , respectively, because of weak intramolecular hydrogen bonding . In HL 2 –HL 5 spectra, the characteristic 𝑣(O–H) and 𝑣(N–H) vibration frequencies of the ligands exhibit only a single strong band at ~3300 cm −1 , probably due to double intramolecular hydrogen bonding between the phenoxyl hydrogen atom and one of the C = N nitrogen atoms.…”

Section: Resultsmentioning

confidence: 99%

“…In HL 2 and HL 4 , the bands at 1058 and 1097 cm −1 correspond to the stretching vibrations of C‐Cl, respectively. The sharp or medium bands in the ligands and their complexes in the range of 675–864 cm −1 are due to the out‐of‐plane deformation bands for the aromatic C–H . In the spectra of free ligands, there is a band at about 1298 cm −1 , which is assigned to 𝑣(C–O) of the phenolic group.…”

Section: Resultsmentioning

confidence: 99%

“…In HL 1 spectrum, ν(O-H) and ν(N-H) vibration frequencies appear separately at 3325 and 3245 cm −1 , respectively, because of weak intramolecular hydrogen bonding. [26] In HL 2 -HL 5 spectra, the characteristic v(O-H) and v(N-H) vibration frequencies of the ligands exhibit only a single strong band at~3300 cm −1 , probably due to double intramolecular hydrogen bonding between the phenoxyl hydrogen atom and one of the C = N nitrogen atoms. The corresponding peak in the theoretical spectrum was calculated at~3253 cm −1 .…”

Section: Ft-ir Spectramentioning

confidence: 99%

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Synthesis and characterization of Ni(II) complexes bearing of 2‐(1H–benzimidazol‐2‐yl)‐phenol derivatives as highly active catalysts for ethylene oligomerization

Haghverdi

Tadjarodi

Bahri‐Laleh

et al. 2017

Applied Organom Chemis

Novel Ni(II) complexes of 2‐(1H–benzimidazol‐2‐yl)‐phenol derivatives (HLx: x = 1–5; C1–C5) have been synthesized and characterized. In the mononuclear complexes, the ligands were coordinated as bidentate, via one imine nitrogen and the phenolate oxygen atoms. The structures of the compounds were confirmed on the basis of FT‐IR, UV–Vis, 1H‐, 13C–NMR, inductively coupled plasma and elemental analyses (C, H and N). The purity of these compounds was ascertained by melting point (m.p.) and thin‐layer chromatography. The geometry optimization and vibrational frequency calculations of the compounds were performed using Gaussian 09 program with B3LYP/TZVP level of theory. All Ni(II) complexes were activated with diethylaluminum chloride (Et2AlCl), so that C2 showed the highest activity [6600 kg mol−1 (Ni) h−1], where the ligand contains a chlorine substituent. Oligomers obtained from the complexes consist mainly of dimer and trimer, and also exhibit high selectivity for linear 1‐butene and 1‐hexene. Both the steric and electronic effects of coordinative ligands affect the catalytic activity and the properties of the catalytic products.

“…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].…”

Section: Introductionmentioning

confidence: 99%

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

Gürbüz¹,

Tavman²,

Çınarli³

et al. 2016

ChemJMold

Self Cite

Abstract. 5,6-Dichloro/dimethyl-2-(2´,3´/2´,4´/2´,5´/3´,4´/3´,5´-dimethoxyphenyl)-1H-benzimidazoles were synthesized and characterized by using analytical data, FT-IR, FT-Raman, NMR, ESI-MS and fl uorescence spectroscopy. The optimized molecular geometry, zero point energy, dipole moment, ESE, band gap and charge distributions were calculated by Gaussian 09 using Density Functional Theory (DFT, RB3LYP) with 6-31++G(d,p) basis set. According to the calculations, the molecules have structures with various torsion angles between the benzimidazole and benzene rings from 9.7º to 47.8º. The calculated energy values with ZPE correction and DFT show that the methyl derivatives are more stable than the chloro forms. 3´,4´-Dimethoxy derivatives have higher decomposition points in comparison with the other compounds in series. The chlorine atoms of 5,6-dichloro-2-(2´,3´/2´,4´/2´,5´/3´,4´/3´,5´-dimethoxyphenyl)-1H-benzimidazoles are positively charged whereas the C5 and C6 carbon atoms are negatively charged due to the attached chlorine atoms, in virtue of the electron withdrawing characteristic of the imidazole part of the benzimidazole ring. Also, some calculated prominent bond lengths and bond angles were discussed.