Multiple heating rate kinetic parameters, thermal, X-ray diffraction studies of newly synthesized octahedral copper complexes based on bromo-coumarins along with their antioxidant, anti-tubercular and antimicrobial activity evaluation

2012 ◽  
Vol 96 ◽  
pp. 468-479 ◽  
Author(s):  
Ketan S. Patel ◽  
Jiten C. Patel ◽  
Hitesh R. Dholariya ◽  
Kanuprasad D. Patel
Keyword(s):  
Antimicrobial Activity ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Copper Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Activity Evaluation

scholarly journals Copper(II) Complexes of 2-(Methylthiomethyl)anilines: Spectral and Structural Properties and In Vitro Antimicrobial Activity

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Temitope E. Olalekan ◽  
Denzil R. Beukes ◽  
Bernardus Van Brecht ◽  
Gareth M. Watkins
Keyword(s):  
Antimicrobial Activity ◽  
Electronic Spectra ◽  
Copper Complexes ◽  
Structural Formula ◽  
Bidentate Ligand ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Elemental Analyses

Copper(II) complexes of 2-(methylthiomethyl)anilines (1a–1f) have been obtained and characterized by elemental analyses, IR, electronic spectra, conductivity, and X-ray crystallography. The complexes (2a–2f) have the structural formula [CuCl2L] with the bidentate ligand coordinating through sulfur and nitrogen. The single crystal X-ray diffraction data reveal that the copper complex (2f) has a tetragonally distorted octahedral structure with long Cu–Cl equatorial bonds. Magnetic susceptibility measurements indicate the availability of one unpaired electron in the complexes and the conductivity measurements in DMF show their behaviour as nonelectrolytes. The solid reflectance spectra and the electronic spectra of the complexes in DMSO were determined. The ligands and their copper complexes were screened for in vitro antimicrobial activity against S. aureus, B. subtilis, E. coli, and C. albicans. The methoxysubstituted complex (2c) showed more promising antibacterial activity against S. aureus and B. subtilis than other compounds at the concentration tested.

Synthesis of Nanocomposites of V2OO5©Selenium Nanoparticles and Multiwalled Carbon Nanotubes for Antimicrobial Activity

2021 ◽  
Vol 21 (11) ◽  
pp. 5673-5680
Author(s):  
Muthukrishnan Francklin Philips ◽  
Jothirathinam Thangarathinam ◽  
Jayakumar Princy ◽  
Cyril Arockiaraj Crispin Tina ◽  
Cyril Arockiaraj Crispin Tina ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Antimicrobial Activity ◽  
Multiwalled Carbon Nanotubes ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Functionalized Multiwalled Carbon Nanotubes ◽  
Uv Visible ◽  
Micro Organisms

The authors report the preparation of the nanocomposite comprising of vanadium pentoxide (V2O5) and selenium (Se) nanoparticles and functionalized multiwalled carbon nanotubes (MWCNTs) (V2O5@Se NPs/MWCNTs). Since Se NPs possesses extraordinary physicochemical properties including larger surface area with higher adsorption capacity, V2O5 NPs were adsorbed onto Se NPs surface through physisorption process (designated as V2O5@Se NPs). The nanocomposite synthesized hydrothermally was evaluated for its antimicrobial activity. The morphology and microstructure of the nanocomposite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, respectively. Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectroscopy (UV-Vis) were employed to analyze the spectral properties of nanocomposite. The microbicidal efficacy of nanocomposite was tested against Gram-negative (G-)ZGram-positive (G+) bacteria and fungus. This is the first report on the synthesis of V2O5@Se NPs/MWCNTs nanocomposites by chemical method that showed microbicidal effect on micro-organisms. The thiol (-SH) units facilitates the enrichment of V2O5@Se NPs onto MWCNTs surface. Ultimately, it reflects on the significant antimicrobial activity of V2O5@Se NPs/MWCNTs.

scholarly journals Copper(II) and Zinc(II) Complexes Derived from N,N’-Bis(4-bromosalicylidene)propane-1,3-diamine: Syntheses, Crystal Structures and Antimicrobial Activity

2021 ◽  
Vol 68 (1) ◽  
pp. 102-108
Author(s):  
Yu-Mei Hao
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Candida Parapsilosis ◽  
Antibacterial Activities ◽  
X Ray Diffraction ◽  
Deprotonated Form ◽  
X Ray ◽  
Square Planar ◽  
Vis Spectroscopy ◽  
Elemental Analyses

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.

scholarly journals Effects of Ultrasound on Zinc Oxide/Vermiculite/Chlorhexidine Nanocomposite Preparation and Their Antibacterial Activity

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1309 ◽  
Author(s):  
Karla Čech Barabaszová ◽  
Sylva Holešová ◽  
Kateřina Šulcová ◽  
Marianna Hundáková ◽  
Barbora Thomasová
Keyword(s):  
Antimicrobial Activity ◽  
Particle Size ◽  
Zinc Oxide ◽  
Antibacterial Activity ◽  
Ultrasonic Treatment ◽  
Nanocomposite Materials ◽  
Hybrid Nanocomposite ◽  
X Ray Diffraction ◽  
X Ray

Microbial infection and biofilm formation are both problems associated with medical implants and devices. In recent years, hybrid organic-inorganic nanocomposites based on clay minerals have attracted significant attention due to their application potential in the field of antimicrobial materials. Organic drug/metal oxide hybrids exhibit improved antimicrobial activity, and intercalating the above materials into the interlayer of clay endows a long-term and controlled-release behavior. Since antimicrobial activity is strongly related to the structure of the material, ultrasonic treatment appears to be a suitable method for the synthesis of these materials as it can well control particle size distribution and morphology. This study aims to prepare novel, structurally stable, and highly antimicrobial nanocomposites based on zinc oxide/vermiculite/chlorhexidine. The influence of ultrasonic treatment at different time intervals and under different intercalation conditions (ultrasonic action in a breaker or in a Roset’s vessel) on the structure, morphology, and particle size of prepared hybrid nanocomposite materials was evaluated by the following methods: scanning electron microscopy, X-ray diffraction, energy dispersive X-ray fluorescence spectroscopy, carbon phase analysis, Fourier transforms infrared spectroscopy, specific surface area measurement, particle size analysis, and Zeta potential analysis. Particle size analyses confirmed that the ultrasonic method contributes to the reduction of particle size, and to their homogenization/arrangement. Further, X-ray diffraction analysis confirmed that ultrasound intercalation in a beaker helps to more efficiently intercalate chlorhexidine dihydrochloride (CH) into the vermiculite interlayer space, while a Roset’s vessel contributed to the attachment of the CH molecules to the vermiculite surface. The antibacterial activity of hybrid nanocomposite materials was investigated on Gram negative (Escherichia coli, Pseudomonas aeruginosa) and Gram positive (Staphylococcus aureus, Enterococcus faecalis) bacterial strains by finding the minimum inhibitory concentration. All hybrid nanocomposite materials prepared by ultrasound methods showed high antimicrobial activity after 30 min, with a long-lasting effect and without being affected by the concentration of the antibacterial components zinc oxide (ZnO) and CH. The benefits of the samples prepared by ultrasonic methods are the rapid onset of an antimicrobial effect and its long-term duration.

A structural and carbon-nitrogen bond rotation study of N,N,N',N',2,2-hexamethylpropanediamide

1983 ◽  
Vol 36 (9) ◽  
pp. 1865 ◽  
Author(s):  
SF Lincoln ◽  
AM Hounslow ◽  
NJ Maeji ◽  
TW Hambley ◽  
MR Snow ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Kinetic Parameters ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Rotation ◽  
Nitrogen Bonds ◽  
Rotation Study ◽  
Nitrogen Bond

The molecular structure of N,N,N',N',2,2-hexamethylpropanediamide has been determined in the solid state by X-ray diffraction methods. The structure of Me2NCOCMe2CONMe2 may be broadly described as two planar Me2NCO entities intersecting at the tetrahedral -CMe2- site. The angle between the normals to the two Me2NCO planes is 104.6�, and the two oxygen atoms are disposed outwards from the molecule and away from each other. Proton (270-MHz) n.m.r. studies yield k(320 K) 32.0 � 3.2 s-1, ΔH‡ 69.5 � 0.4 kJ mol-1 and ΔS‡ 0.6 � 1.1 J K-1 mol-1 for rotation of the N-methyl groups about the carbon-nitrogen bonds in CD3NO2 solution. Similar magnitudes for the kinetic parameters characterizing this process are obtained in CDCl3, and CD3CN solutions.

scholarly journals Novel hollow titanium dioxide nanospheres with antimicrobial activity against resistant bacteria

2019 ◽  
Vol 10 ◽  
pp. 1716-1725 ◽  
Author(s):  
Carol López de Dicastillo ◽  
Cristian Patiño ◽  
María José Galotto ◽  
Yesseny Vásquez-Martínez ◽  
Claudia Torrent ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Titanium Dioxide ◽  
Superior Performance ◽  
Spherical Particles ◽  
Resistant Bacteria ◽  
Global Public Health ◽  
Hollow Nanospheres ◽  
X Ray Diffraction ◽  
Calcination Process ◽  
X Ray

The search for and synthesis of new antimicrobial nanostructures is important to reduce microbial incidence that induces infectious diseases and to aid in the antibiotic resistance crisis, which are two of the most pressing issues in global public health. In this work, novel, hollow, calcined titanium dioxide nanospheres (CSTiO2) were successfully synthesized for the first time through the combination of electrospinning and atomic layer deposition techniques. Poly(vinylpyrrolidone) (PVP) electrosprayed spherical particles were double-coated with alumina and titanium dioxide, and after a calcination process, hollow nanospheres were obtained with a radius of approximately 345 nm and shell thickness of 17 nm. The structural characterization was performed using electron microscopy, and X-ray diffraction and small-angle X-ray diffraction evidenced an anatase titanium dioxide crystalline structure. Thermogravimetric analysis and Fourier-transform infrared spectroscopy studies demonstrated the absence of polymer residue after the calcination process. The antimicrobial properties of the developed CSTiO2 hollow nanospheres were evaluated against different bacteria, including resistant E. coli and S. aureus strains, and when compared to commercial TiO2 nanoparticles, CSTiO2 nanospheres exhibited superior performance. In addition, the positive effect of UV irradiation on the antimicrobial activity was demonstrated.

scholarly journals Evaluation of Hydrogen Yield Evolution in Gaseous Fraction and Biochar Structure Resulting from Walnut Shells Pyrolysis

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6359
Author(s):  
Elena David
Keyword(s):  
Heating Rate ◽  
Pyrolysis Temperature ◽  
Walnut Shell ◽  
Hydrogen Yield ◽  
X Ray Diffraction ◽  
Fast Heating ◽  
X Ray ◽  
Walnut Shells ◽  
Water Vapors ◽  
Gaseous Fraction

Conversion experiments of wet and dry walnut shells were performed, the influence of moisture content on the hydrogen yield in the gas fraction was estimated and the resulted biochar structure was presented. Measurements of the biochar structures were performed using X-ray diffraction and scanning electron microscopy methods. The results demonstrate that heating rate played a key role in the pyrolysis process and influenced the biochar structure. Under fast heating rate, the interactions between the water vapors released and other intermediate products, such as biochar was enhanced and consequently more hydrogen was generated. It could also be observed that both biochar samples, obtained from wet and dry walnut shells, had an approximately smooth surface and are different from the rough surface of the raw walnut shell, but there are not obvious differences in shape and pores structure between the two biochar samples. The increasing of the biochar surface area versus pyrolysis temperature is due tothe formation of micropores in structure. The biochar shows a surface morphology in the form of particles with rough, compact and porous structure. In addition the biochar structure confirmed that directly pyrolysis of wet walnut shells without predried treatment has enhanced the hydrogen content in the gas fraction.

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