Two New Schiff Base Ni Ii and Cu Ii Complexes: Synthesis and Structures

Li, Qingbin; Xue, Ling-Wei; Yang, Weishen; Zhao, Gan-Qing

doi:10.4067/s0717-97072013000300019

Cited by 8 publications

(6 citation statements)

References 13 publications

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“…The values obtained for Dq, B, β are in agreement with the experimental ones for Ni(II) octahedral complexes 22 . The magnetic moment value of Ni(II) complex is 3.12 BM indicating the presence of two unpaired electrons on Ni(II) ion and suggesting that this complex has an octahedral geometry 24,25 . (1) - (4) and (1′) -(8′) correspond to the peaks from Figure 1.…”

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confidence: 99%

Synthesis, Spectral Characterization and Thermal Behaviour of New Metal(ii) Complexes With Schiff Base Derived From Amoxicillin

Reiss

Samide

Ciobanu

et al. 2015

J. Chil. Chem. Soc.

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Metal complexes of Schiff base derived from different antibiotics are widely employed as biological active materials, especially as antibacterial agents. Two new metal (II) complexes with the Schiff, base (HL) derived from amoxicillin and salicylaldehyde were synthesized and investigated using elemental analysis, spectroscopic techniques (IR and UV-Vis), conductometric and magnetic measurements. The IR spectra illustrated a bidentate ligand which coordinates through phenolic oxygen atom and imino nitrogen atom from azomethine bond. UV-Vis spectrophotometry showed the characteristic adsorption bands corresponding to an octahedral geometry for both metal complexes. The general formula established from experimental data was found to be [ML 2 (H 2 O) 2 ] (M=Co(II) and Ni(II)). This composition was further confirmed by thermal analysis and their thermal stability in nitrogen atmosphere was investigated. Antibacterial study showed that the efficiency of metal complexes is higher than the one found for the free Schiff base ligand.

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confidence: 99%

Synthesis, Spectral Characterization and Thermal Behaviour of New Metal(ii) Complexes With Schiff Base Derived From Amoxicillin

Reiss

Samide

Ciobanu

et al. 2015

J. Chil. Chem. Soc.

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“…1 [29][30][31][32][33][34][35][36][37][38][39] In the Zn(II) complex 2b, the geometry at the Zn(II) center can be best described as a distorted tetrahedron in which two benzoxazole-2-chlorodifluoroacetonate (1b) ligands are placed in a similar disposition about the zinc center. [29][30][31] One coordination plane (N-O-Zn) in 2b is approximately perpendicular to the other with a dihedral angle of 89.2°.…”

Section: )mentioning

confidence: 99%

“…The Ni(II) complex 2e exhibits a distorted octahedral geometry, in which two 1a ligands are located in the equatorial plane, forming two stable six-membered rings with metal ion, and the axial sites are occupied by two coordinated water molecules. 33,34) In the Cu(II) complex 2f, the Cu(II) atom was coordinated by two N atoms and two O atoms from two 1a, forming a strictly square planar geometry (dihedral angle between two N-Cu-O planes: 0°). [35][36][37] In the Pd(II) complex 2g, the geometry at Pd(II) center was coordinated as nearly perfect square planar which are similar to that of the Cu(II) atom in 2f.…”

Section: )mentioning

confidence: 99%

Synthesis and Antimicrobial Activity of 2-Trifluoroacetonylbenzoxazole Ligands and Their Metal Complexes

Watanabe

Sekiya

Tamai

et al. 2018

CHEMICAL & PHARMACEUTICAL BULLETIN

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Key words antibacterial activity; fluorinated benzoxazole; metal complex; trifluoroacetylBacterial infection remains a serious threat to human lives due to rapid development of resistance to the existing antibiotics. In order to prevent this major medical problem, the discovery of new types of antimicrobial agents is a very important but challenging task.1,2) Transition metal complexes have received great attention because many drugs such as antibiotics and quinolone antibiotics possess better pharmaceutical properties when they are in the form of metal complexes. 3-7)Benzoxazole heterocycle system is an important pharmacophore and privileged structure in the medicinal chemistry. 8-10)Its derivatives and particularly, 2-substituted benzoxazoles exert various biological activities such as antimicrobial, antiviral, antifungal, and anticancer. [11][12][13][14][15] In previous studies, we have identified 2-trifluoroacetonylbenzoxazole (1a) with in vitro antimicrobial activity against Helicobacter pylori and Escherichia coli (Ec) from our compound library of trifluoromethyl ketones obtained by our developed reactions. 16,17) The heteroaryl-substituted alkenol systems such as 1a are known to chelate some metal ions such as aluminum 18) and to form a stable six-membered metal complexes in a bidentate mode, where the complexes were reinforced by a positive inductive effect of the heterocyclic moiety and a negative inductive effect of the CF 3 groups. [19][20][21][22][23] In the light of these knowledge, three 2-fluoroacetonylbenzoxazole ligands 1a-c and their new Zn(II) complexes 2a-c have been synthesized in order to check how the metal ion binding may influence their antibacterial activity (Chart 1). In addition, syntheses of new metal [Mg(II), Ni(II), Cu(II), Pd(II), and Ag(I)] complexes 2d-h from 1a have been also described ( Table 1). The structures of six metal complexes 2b and 2d-h were determined by single-crystal X-ray diffraction analyses. In vitro antimicrobial activities of the ligands 1a-c and their metal complexes 2a-h were investigated against six Gram-positive (G(+)) and six Gram-negative (G(−)) bacteria and the results were compared with those of silver nitrate and appropriate antibiotics such as Kanamycin, Gentamicin, Norfloxacin, and/or Linezolid. The most potent Ag(I) complex 2h is bacteriostatic, disrupts membrane integrity observed by scanning electron microscopy (SEM) and is less likely to develop resistance development against Pseudomonas aeruginosa (Pa). Results and DiscussionChemistry First, three benzoxazole ligands 1a-c and their new Zn(II) complexes 2a-c have been prepared in order to investigate the relationship of the ligands and their Zn(II) complexes with their antibacterial activities.Our synthetic protocol to obtain the ligand 1a consists of a trifluoroacetylation of 2-methylbenzoxazole with trifluoroacetic anhydride (TFAA) in the presence of pyridine 24) (Chart 1). The Zn(II) complex 2a was prepared by the reaction of 1a with zinc dust in MeCN in 78% yield, consisting of 1a with zinc(...

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“…The Schiff bases coordinate to the metal ions through the phenolate O and imine N atoms. 16 A series of macrocycle compounds of Cu(II), Co(II), Ni(II), and Zn(II) prepared through the template condensation reaction of ethylene diamine and acetonyl acetone have been reported. 17 These complexes have proved good antibacterial activity against some pathogenic bacteria.…”

Section: Introductionmentioning

confidence: 99%

SYNTHESIS, CHARACTERIZATION, THEORETICAL AND BIOLOGICAL STUDIES OF A NEW MACROCYCLE SCHIFF BASE WHITH Co(II), Ni(II), Cu(II) AND Zn(II) COMPLEXES

Soleimani

Taheri

Sargolzaei

2017

J. Chil. Chem. Soc.

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A new macrocycle Schiff base, by the reaction between benzene-1,2-diamine and 3-bromo-pentane-2,4-dione, is introduced and a series of its complexes with Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized. FTIR, 1 H and 13 C NMR, and TGA, also biological activities of all complexes and the electronic spectral data have been investigated. The results show that there are no water molecules, also that macrocycle Schiff base is bonded to the metal ions through nitrogen atoms of four azomethine groups via an octahedral arrangement containing N4 tetra-dentate donor sites on planar and two Cl atoms occupying the other two opposed sites. The corresponding Cu(II) and Zn(II) complexes showed good antibacterial and antifungal activities. The molecular geometry, frontier molecular orbitals and Mulliken atomic charge of the compounds are investigated theoretically using DFT method.

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Two New Schiff Base Ni Ii and Cu Ii Complexes: Synthesis and Structures

Abstract: (1) is in an octahedral coordination, and the Cu atom in (2) is in a square planar coordination.

Cited by 8 publications

References 13 publications

Synthesis, Spectral Characterization and Thermal Behaviour of New Metal(ii) Complexes With Schiff Base Derived From Amoxicillin

Synthesis, Spectral Characterization and Thermal Behaviour of New Metal(ii) Complexes With Schiff Base Derived From Amoxicillin

Synthesis and Antimicrobial Activity of 2-Trifluoroacetonylbenzoxazole Ligands and Their Metal Complexes

SYNTHESIS, CHARACTERIZATION, THEORETICAL AND BIOLOGICAL STUDIES OF A NEW MACROCYCLE SCHIFF BASE WHITH Co(II), Ni(II), Cu(II) AND Zn(II) COMPLEXES

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