scholarly journals Syntheses, Crystal Structures, and Antibacterial Activity of New Tetranuclear Zinc(II) Complexes with Schiff Base Ligands

2021 ◽  
Vol 68 (3) ◽  
pp. 638-644
Author(s):  
Heng-Yu Qian

Two new tetranuclear zinc(II) complexes, [Zn4(L1)2(μ2-η1:η1-CH3COO)4(μ1,1-N3)2] (1) and [Zn4(L2)4(CH3CH2OH) (H2O)] (2), where L1 and L2 are the deprotonated forms of 4-fluoro-2-((pyridin-2-ylmethylimino)methyl)phenol (HL1) and 4-fluoro-2-((2-(hydroxymethyl)phenylimino)methyl)phenol (H2L2), have been synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy, and single crystal X-ray diffraction. X-ray crystal structural study indicated that the distances between the adjacent Zn atoms are 3.160(1)–3.353(1) Å in 1 and 3.005(1)–3.168(1) Å in 2. All zinc atoms in 1 are pentacoordinated in trigonal bipyramidal geometry, and those in 2 are in square pyramidal and octahedral geometry. The complexes and the Schiff bases were assayed for antibacterial activities against three Gram-positive bacterial strains (B. subtilis, S. aureus, and St. faecalis) and three Gram-negative bacterial strains (E. coli, P. aeruginosa, and E. cloacae) by MTT method.

2021 ◽  
Vol 68 (3) ◽  
pp. 700-708
Author(s):  
Heng-Yu Qian

Two new polynuclear zinc complexes [Zn2Br2(L1)2] (1) and [Zn(μ1,5-dca)L2]n (2), and two new mononuclear cobalt(III) complexes [CoL1N3(Brsal)] (3) and [CoL2(HL2)] (4), where L1 = 5-bromo-2-(((2-dimethylamino)ethyl)imino)methyl)phenolate, L2 = 5-bromo-2-(((2-hydroxyethyl)imino)methyl)phenolate, dca = dicyanoamide, Brsal = 5-bromo-2-formylphenolate, have been synthesized and characterized. The complexes were characterized by elemental analyses, IR, UVVis spectra, molar conductivity, and single crystal X-ray diffraction. X-ray analysis indicates that the Zn atoms in complex 1 are in distorted square pyramidal coordination, the Zn atoms in complex 2 are in distorted trigonal bipyramidal coordination, and the Co atoms in complexes 3 and 4 are in octahedral coordination. The molecules of the complexes are stacked through π···π interactions and hydrogen bonds. The complexes were assayed for antibacterial activities against three Gram-positive bacterial strains (B. subtilis, S. aureus, and St. faecalis) and three Gram-negative bacterial strains (E. coli, P. aeruginosa, and E. cloacae) by MTT method.


2020 ◽  
Vol 67 (4) ◽  
pp. 1155-1162
Author(s):  
Fu-Ming Wang ◽  
Li-Jie Li ◽  
Guo-Wei Zang ◽  
Tong-Tong Deng ◽  
Zhong-Lu You

A new copper(II) complex [Cu(L1)(NCS)(CH3OH)] (1) and a new zinc(II) complex [ZnCl2(HL2)] · CH3OH (2), derived from 4-bromo-N’-(pyridin-2-ylmethylene)benzohydrazide (HL1) and 4-methoxy-N’-(pyridin-2-ylmethylene)benzohydrazide (HL2), were prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction. The hydrazone HL1 coordinates to the Cu atom in enolate form, while the hydrazone HL2 coordinates to the Zn atom in carbonyl form. Single crystal structural analyses indicate that the hydrazones coordinate to the metal atoms through the pyridine N, imino N, and enolate/carbonyl O atoms. The Cu atom in complex 1 is in square pyramidal coordination, and the Zn atom in complex 2 is in trigonal-bipyramidal coordination. The inhibitory effects of the complexes on Jack bean urease were studied, which show that the copper complex has strong activity on urease.


2021 ◽  
Vol 21 (11) ◽  
pp. 5784-5793
Author(s):  
K. Geetha ◽  
R. Udhayakumar

In this study, spinel NiCexFe2–XO4 (x = 0.0 - 0.5) nanoparticles (NPs) was synthesized by microwave combustion technique (MCT) utilizing the fuel of Aloe vera plant extract. The establishment of spinel cubic crystal structure was ensured by powder X-ray diffraction (PXRD) technique. The particles like nanostructured morphology were confirmed by high-resolution scanning electron microscope (HRSEM). Energy dispersive X-ray (EDX) studies confirmed the formation of spinel ferrite structure and ensured that no other elements were present. Magnetic parameters such as remanant magnetisation (Mr), coercivity (He) and saturation magnetization (Ms) were calculated from the magnetic hysteresis (M-H) loops, which exhibited ferromagnetic behaviour. The photocatalytic behavior was investigated by visible light treatment for the photocatalytic degradation (PCD) of rhodamine B (Rh-B) dye and the sample NiCe0.3Fe1.7O4 exhibits higher PCD efficiency (93.88%) than other compositions. The antibacterial activities of gram-positive S. aureus, B. subtilis, gramnegative K. pneumonia and E. coli have been investigated using undoped and Ce3+ substituted NiFe2O4 NPs and observed higher activity, which indicated that, they can be used in the bio-medical applications.


2020 ◽  
Author(s):  
Viktoria Leonhardt ◽  
Stefanie Fimmel ◽  
Ana-Maria Krause ◽  
Florian Beuerle

<div><div><div><p>A trigonal-bipyramidal covalent organic cage compound serves as an efficient host to form stable 1:1-complexes with C60 and C70. Fullerene encapsulation has been comprehensively studied by NMR and UV/Vis spectroscopy, mass spectrometry as well as single-crystal X-ray diffraction. Exohedral functionalization of encapsulated C60 via threefold Prato reaction revealed high selectivity for the symmetry-matched all-trans-3 addition pattern.</p></div></div></div>


2014 ◽  
Vol 2 (4) ◽  
pp. 510-515
Author(s):  
Hala Moustafa Ahmed

The present study mainly focuses of combined action of Nepali hog plum as well as citrate synthesized silver nanoparticles (AgNPs) and Amikacin, as an antibiotic. The synergistic actions of citrate stabilized silver nanoparticles (AgNPs with chem) were compared with that of Nepali hog plum Choerospondia saxillaris (Lapsi) synthesized silver nanoparticles (AgNPs with plant), together with action of antibiotic onselected bacterial strains of Salmonella typhi. The synthesized AgNPs were characterized through UV-Vis spectroscopy, Transmission electronmicroscopy and X-ray diffraction technique. The size of the synthesized silver nanoparticles was measured by Transmission Electron Microscope (TEM) and X-ray diffraction (XRD).DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11127 Int J Appl Sci Biotechnol, Vol. 2(4): 510-515 


2021 ◽  
Vol 68 (1) ◽  
pp. 102-108
Author(s):  
Yu-Mei Hao

A mononuclear copper(II) complex, [CuL] (1), and a phenolato-bridged trinuclear zinc(II) complex, [Zn3Cl2L2(DMF)2] (2), where L is the deprotonated form of N,N’-bis(4-bromosalicylidene)propane-1,3-diamine (H2L), have been prepared and characterized by elemental analyses, IR and UV-Vis spectroscopy, and single crystal X-ray diffraction. The Cu atom in complex 1 is in square planar coordination, while the terminal and central Zn atoms in complex 2 are in square pyramidal and octahedral coordination, respectively. The antibacterial activities of the complexes have been tested on the bacteria Staphylococcus aureus and Escherichia coli, and the yeast Candida parapsilosis.


2021 ◽  
Vol 68 (3) ◽  
pp. 567-574
Author(s):  
Guo-Xu He ◽  
Ling-Wei Xue

A series of three new hydrazone compounds derived from the condensation reactions of 4-dimethylaminobenzohydrazide with 4-dimethylaminobenzaldehyde, 2-chloro-5-nitrobenzaldehyde and 3-methoxybenzaldehyde, respectively, were prepared. The compounds were characterized by elemental analysis, infrared and UV-vis spectra, HRMS, 1H NMR and 13C NMR spectra, and single crystal X-ray diffraction. Crystals of the compounds are stabilized by hydrogen bonds. The compounds were assayed for antibacterial (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescence and Staphylococcus aureus) and antifungal (Aspergillus niger and Candida albicans) activities by MTT method. The results indicated that compound 2 is an effective antibacterial material.


Author(s):  
Thanuja B ◽  
Charles Kanagam

Objective: The objective of this work to evaluate the antimicrobial activities of synthesized 22’dichlorohydrobenzoin (22’CD) a new organic crystal.Methods: 22’CD a new organic crystal was grown by vapor diffusion method. Single crystals of 22’CD have been subjected to X-ray diffraction analysis to estimate the lattice parameters and the space group. The molecular structure was confirmed using Fourier transform infrared and nuclear magnetic resonance (NMR) spectral analyses. Optical behavior and thermal stability of the crystal were determined using UV-Vis spectroscopy and thermogravimetry-differential thermal analysis curves. In the present study, antimicrobial activity of 22’CD was evaluated against Escherichia coli and Bacillus subtilis was evaluated by agar well diffusion method.Results: Antibacterial activity of 22’CD was analyzed with ciprofloxacin and miconazole standard and tested against E. coli, Pseudomonas aeruginosa, Salmonella paratyphi, Klebsiella pneumonia’s, Staphylococcus aureus, Streptococcus progenies, and B. subtilis.Conclusion: The 22’CD was found to be effective against E. coli and B. subtitles.


Author(s):  
M Karthikeyan ◽  
A Jafar Ahamed ◽  
P Vijaya Kumar

The present investigation, the successful preparation of pure ZnO (Z1) NPs and SrBa dual doped ZnO (Z2) NPs by chemical co-precipitation technique without use of any capping agent. The structural and morphological properties of Z1 and Z2 NPs were analyzed using X-ray diffraction (XRD) studies, Field emission scanning electron microscopy (FESEM), Elemental analysis (EDAX), Fourier transform infrared spectroscopy (FTIR). An optical property was studied by UV–Vis spectroscopy and Photoluminescence (PL) spectra. The antimicrobial activity of Z1 and Z2 NPs has been investigated against Staphylococcus aureus and Klebsiella pneumoniae bacterial strains. It has been interestingly observed that Z2 NPs has enhanced the inhibitory activity than that of Z1 NPs against S. aureus and more efficiently than the K. pneumoniae bacterial strain.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Anju Arya ◽  
Khushbu Gupta ◽  
Tejpal Singh Chundawat ◽  
Dipti Vaya

The spread of infectious diseases and the increase in the drug resistance among microbes has forced the researchers to synthesize biologically active nanoparticles. Improvement of the ecofriendly procedure for the synthesis of nanoparticles is growing day-by-day in the field of nanobiotechnology. In the present study, we use the extract of green alga Botryococcus braunii for the synthesis of copper and silver nanoparticles. The characterization of copper and silver nanoparticles was carried out by using UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron spectroscopy (SEM). FTIR measurements showed all functional groups having control over reduction and stabilization of the nanoparticles. The X-ray diffraction pattern revealed that the particles were crystalline in nature with a face-centred cubic (FCC) geometry. SEM micrographs have shown the morphology of biogenically synthesized metal nanoparticles. Furthermore, these biosynthesized nanoparticles were found to be highly toxic against two Gram-negative bacterial strains Pseudomonas aeruginosa (MTCC 441) and Escherichia coli (MTCC 442), two Gram-positive bacterial strains Klebsiella pneumoniae (MTCC 109) and Staphylococcus aureus (MTCC 96), and a fungal strain Fusarium oxysporum (MTCC 2087). The zone of inhibition was measured by the agar well plate method, and furthermore, minimum inhibitory concentration was determined by the broth dilution assay.


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