Electrochemical Growth of Sponge/Raspberry-Like Gold Nanoclusters at the Carbon Rod

For the first time, the positive carbon rod of zinc-carbon battery (battery carbon rod electrode, BCRE) was used as a new working electrode and its electrochemical behavior was compared with carbon paste and glassy carbon electrodes in KCl solution containing Fe(CN₆)^3–/4– ions as probe agent. Then, the sponge/raspberry-like Au nanoclusters (AuNCs) were synthesized on BCRE by one-step electrodeposition of HAuCl₄ in phosphate and nitrate buffer solution and the electrochemical properties of surfaces was investigated in probe media and sulfuric acid. This fabrication method was simple, facile and controllable, without any seed, template or surfactant.     

Synthesis,spectroscopic characterization,crystal structure determination and DFT calculations of [Au(Me<Subscript>2</Subscript>phen)Br<Subscript>2</Subscript>][AuBr<Subscript>2</Subscript>]

New mixed valence gold(III/I) salt containing two complexes [Au(Me₂phen)Br₂][AuBr₂] (1) was prepared from the reaction of AuBr₃ and 5,6-dimethyl-1,10-phenanthroline (Me₂phen) in a mixture of methanol and acetonitrile. Suitable crystals of 1 for X-ray diffraction measurement were obtained by slow evaporation of the resulted red solution at room temperature. This complex was characterized by spectral methods (IR, UV–Vis and ¹H NMR), elemental analysis and single-crystal X-ray diffraction. The X-ray structural analysis indicated that the asymmetric unit of 1 contains one [Au(Me₂phen)Br₂]⁺ cation and two half anions of [AuBr₂]^ˉ. Furthermore, the packing diagram of this complex, 3-D structure stabilized by intermolecular Au…Br and Au…π interactions and intermolecular C–H···Br hydrogen bonds. The experimental investigations on complex have been accompanied computationally by the density functional theory (DFT) and time-dependent DFT calculations. The nature of the Au–N bonds was investigated using quantum theory of atoms in molecules. Moreover, natural bond orbital analysis carried out to obtain hyper-conjugative interactions and electron delocalization on the complex.     

AJAC: Atomic data calculation tool in Python

In this work, new features and extensions of a currently used online atomic database management system are reported. A multiplatform flexible computation package is added to the present system, to allow the calculation of various atomic radiative and collisional processes, based on simplifying the use of some existing atomic codes adopted from the literature. The interaction between users and data is facilitated by a rather extensive Python graphical user interface working online and could be installed in personal computers of different classes. In particular, this study gives an overview of the use of one model of the package models (i.e., electron impact collisional excitation model). The accuracy of computing capability of the electron impact collisional excitation in the adopted model, which follows the distorted wave approximation approach, is enhanced by implementing the Dirac R-matrix approximation approach. The validity and utility of this approach are presented through a comparison of the current computed results with earlier available theoretical and experimental results. Finally, the source code is made available under the general public license and being distributed freely in the hope that it will be useful to a wide community of laboratory and astrophysical plasma diagnostics.     

Crystal structure of palladium(II) complex with 2,2′-dipyridylamine and 4-toluenesulfonyl-L-serine

The [Pd(dpa)(tsser)] complex (1) is prepared from the reaction of PdCl₂ and 2,2′-dipyridylamine (dpa) with 4-toluenesulfonyl-L-serine (tsserH₂). This complex is characterized by spectral methods (IR, UV-Vis, ¹H NMR, and luminescence), elemental analysis, thermal analysis (TG, DTA), and single crystal X-ray diffraction. X-ray structure determinations show that in this complex, Pd^II atoms are four-coordinated in a distorted square-planar configuration by two N atoms from a bidentate 2,2′-dipyridylamine ligand and one N atom and one O atom from a bidentate tsser^2– ligand.     

A new lanostane-type triterpene and sesquiterpene lactones from Vernonia leopoldii and their in vitro cytotoxicity

Investigation of the aerial parts of Vernonia leopoldii (Sch. Bip.) Vatke afforded a new lanostane-type triterpene along with known hirsutinolide-type sesquiterpene lactones and flavonoid glycosides, all are identified for the first time in this species. The new compound was identified as lanost-3β, 23S-dihydroxy-22(31)-ene. The structures of the isolated compounds were elucidated based on spectroscopic evidence. The hirsutinolides and the triterpene were evaluated for their cytotoxicity against four human cancer cell lines using MTT assay.     

Photodynamic Inactivation of <Emphasis Type="BoldItalic">E. coli</Emphasis> PTCC 1276 Using Light Emitting Diodes: Application of Rose Bengal and Methylene Blue as Two Simple Models

The lack of a comparative study about potential of high-power light emitting diodes (LEDs) for photodynamic inactivation (PDI) of pathogenic microorganisms has remained as a challenging issue for researchers. Therefore, the aim of this study is to fill this gap through introduction of an efficient model for in vitro PDI in an aqueous medium. For this purpose, two individual 30 mW/cm² irradiation systems were designed using suitable sets of green and red LEDs. At another work, Methylene blue (MB) and Rose bengal (RB) as two simple models in the range of 5–150 μM were used in order to compare PDI of E. coli PTCC 1276 using red and green LED systems. Our results showed that a first-order mathematical model has the strength to describe the temporal variation of survival curves. Based on our results, when concentration of photosensitizer increased, the rate of inactivation for RB increased while MB depicted a maximum rate value at 25 μM. In a comparative study, optimum inactivation of E. coli PTCC 1276 obtained during 2- and 10-min irradiation of the LED systems using RB and MB at 150 and 25 μM, respectively. With regard to lower value of inactivation time and higher rate of inactivation for RB, use of simultaneous green high-power LEDs and RB is proposed as an efficient approach for PDI of pathogenic bacteria in future industrial applications.     

Influence of methyl group position in bipyridine ligand on structure and luminescence of related zinc(II) nitrate complexes

Three new zinc(II) complexes of [Zn(6-mbipy)(η²-NO₃)₂] (1), [Zn(6,6′-dmbipy)(η²-NO₃)₂] (2) and [Zn(5,5′-dmbipy)(η²–NO₃)(H₂O)₂](NO₃).H₂O (3) were prepared from the reaction of 6-methyl-2,2′-bipyridine (6-mbipy), 6,6′-dimethyl-2,2′-bipyridine (6,6′-dmbipy) and 5,5′-dimethyl-2,2′-bipyridine (5,5′-dmbipy) with Zn(NO₃)₂·4H₂O in methanol, respectively. These three complexes were thoroughly characterized by elemental analysis, thermal gravimetric analysis, differential thermal analysis, infrared, UV–Vis, ¹H NMR and ¹³C{¹H} NMR spectroscopy, and their structures have all been determined by the single-crystal X-ray diffraction. The luminescence spectra of the title complexes show that the intensity of their emission bands is stronger than the bands for the free ligands.     

Tetrakis [<Emphasis Type="Italic">N</Emphasis>-(2-pyridyl) sulfonamide] di palladium: synthesize,X-ray diffraction,antibacterial properties and as a novel binuclear Pd-complex for coupling reactions

The N-(2-pyridyl) 4-toluene sulfonamide as a free ligand (PTS) was prepared from the reaction of 2-amino pyridine and 4-toluenesulfonyl chloride in the presence of potassium hydroxide solution 1 M as a base and THF was used as a solvent. The complex tetrakis [N-(2-pyridyl) sulfonamide] di palladium (1) (Pd₂L₄) was also prepared from the reaction of PdCl₂(CH₃CN)₂ using (PTS) in the presence of NaOH 0.5 M and its application in Heck and Suzuki reactions. This complex consists of a binuclear unit consisting of four ligands linked to two palladium atoms via the nitrogen of pyridines ring and the nitrogen of sulfonamides. These compounds were confirmed by FT-IR and ¹H NMR spectroscopy. Moreover, the structure of the complex was studied by single-crystal X-ray diffraction method. The green crystal of Pd₂L₄ [L = N-(2-pyridyl) sulfonamide](1) was found to crystallize in the monoclinic space group C2/c with a = 18.2013(19), b = 19.7544(16), c = 17.2898(19) Å, β = 120.179(8) °; V = 5374.0(9) ų; Z = 4; the final R ₁ = 0.0894, wR ₂ = 0.1754 (or 5867 observed reflections and 318 variables). The Pd–Pd distance is 2.567(2) Å. In addition, PTS and Pd₂L₄ presented different antibacterial behaviors. The free ligand was active against Staphylococcus aureus and Escherichia coli, but the complex was inactive against them.     

Solution and solid-state studies of a new supramolecular proton transfer salt and its VO<Subscript>2</Subscript> complex constructed with chelidamic acid and 3,4-diaminopyridine

The proton transfer compound (Hdap)(chelH)·2H₂O (1) and its related anionic complex (Hdap) [VO₂(chel)] (2), where chelH₂ = 4-hydroxypyridine-2,6-dicarboxylic acid (chelidamic acid) and dap = 3,4-diaminopyridine, were synthesized and characterized by elemental analysis, spectroscopy (IR, UV–Vis), thermal (TG/DTG) analysis and single-crystal X-ray diffraction. Compound 1 resulted from proton transfer between chelH₂ and dap in aqueous solution. In 1, two carboxylic acids of chelH₂ were deprotonated and the protons transferred to the nitrogen atoms of one chelidamate anion and one dap moiety. Compound 2 resulted from complexation of 1 and vanadyl sulfate. In the crystal structure of 2, the metal ion is five coordinated by one tridentate ligand (chel)^2? and two O^2? anions, with (Hdap)⁺ as a counter cation. In both structures, a complicated hydrogen-bonding network accompanied with π–π, C–O···π and C–H···π stacking interactions leads to formation of a 3D supramolecular network. In the following, solution studies have been performed by means of pH potentiometric titrations method as a power technique. This method was used for determination of protonation constants of chelH₂ and dap in their probable protonated forms and for calculation of equilibrium constants for the chelH₂–dap proton transfer system and the stoichiometry and stability constants of binary and ternary complexes of this system with VO²⁺ ion in aqueous solution. The stoichiometries of the most complex species in solution were compared with the corresponding crystalline complexes in the solid state.     

The genus Machaerium (Fabaceae): taxonomy,phytochemistry, traditional uses and biological activities

Machaerium, in the family Fabaceae, predominantly is a genus of a Neotropical distribution of trees, shrubs, and lianas occurring from southern Mexico to Brazil and northern Argentina and as far as South America. Several Machaerium species are widely used in traditional medicine and are considered to have multiple medicinal properties. This review aims to provide up-to-date and comprehensive information on the taxonomy, phytochemistry, traditional uses and biological activities of plants in the genus Machaerium.