Structural studies and biological evaluation of Co (II), Ni (II) and Cu (II) complexes of carbohydrazone derived from ethyl acetoacetate in addition to crystallographic description of La (III) or Sm (III) catalytic activity abnormal product

New carbohydrazone ligand derived from the condensation of carbohydrazide and ethyl acetoacetate, diethyl 3,3′‐(carbonylbis (hydrazin‐2‐yl‐1‐ylidene))(3E,3′E)‐dibutyrate (H₄EBC), and its divalent Co, Ni and Cu chelates have been isolated and characterized utilizing convenient methods. ¹H‐NMR spectrum of H₄EBC revealed the abundance of the enol isomer in solution, which was the opposite to what was shown by the solid IR. This was supported by comparing the theoretical IR of both keto and enol forms. In [Ni(H₄EBC)Cl₂(H₂O)]·2H₂O, H₄EBC acts as a neutral NON tridentate ligand via the (C=O)_carbonyl oxygen atom besides the two (C=N)_azomethine nitrogen atoms, while in [Co(H₄EBC)Cl₂(2H₂O)]·2H₂O, H₄EBC behaves as a neutral NN bidentate ligand through the two azomethine groups. Magnetic measurements inherent to their electronic spectra show that both Ni (II) and Co (II) chelates have octahedron coordination frameworks. On the other hand, the ligand behaves as a binegative tetradentate in [Cu₂(H₄EBC)Cl₂]·H₂O via the deprotonated (C=O)_carbonyl groups of the ethyl acetoacetate framework and the two (C=N)_azomethine groups. In the latter complex, the carbonyl group of the carbohydrazide moiety is converted to hydroxyl group. Cu (II) complex has a tetrahedral geometry according to ESR and electronic spectral data. The reaction of H₄EBC with SmCl₃·6H₂O or LnCl₃·7H₂O gave single crystals of abnormal product (C₁₆H₁₆N₄O₄). The packing diagram of this crystal has a chain structure. The photoluminescence spectra of [Cu ₂ (H ₄ EBC)Cl ₂ ]·H ₂ O , [Co(H ₄ EBC)Cl ₂ (H ₂ O) ₂ ]·2H ₂ O and [Ni(H ₄ EBC)Cl ₂ (H ₂ O)]·2H ₂ O display emission broad‐bands at 342, 321 and 337 nm, respectively. The microbial behavior of the synthesized moieties was investigated against various bacterial and fungal strains. [Cu₂(H₄EBC)Cl₂]·H₂O complex shows the same activity as ampicillin towards Escherichia coli and Staphylococcus aureus with inhibition zones of 26 and 22 mm, respectively. Antioxidant activity is determined using bleomycin‐dependent DNA damage assay besides erythrocyte hemolysis. Finally, in vitro cytotoxic activities against two different cell lines have been examined.     

Synthesis,spectroscopic, DFT,biological studies and molecular docking of oxovanadium (IV), copper (II) and iron (III) complexes of a new hydrazone derived from heterocyclic hydrazide

A new Schiff base hydrazone (Z)‐2‐(2‐aminothiazol‐4‐yl)‐N′‐(2‐hydroxy‐3‐methoxybenzylidene) acetohydrazide (H₂L) and its chelates [VO (HL)₂]·5H₂O, [Cu (HL)Cl(H₂O)]·2H₂O and [Fe(L)Cl(H₂O)₂]·3H₂O have been isolated and characterized using different physico‐chemical methods, for example infrared (IR), electron paramagnetic resonance (EPR), thermogravimetric analysis and DTG in the solid state, and ¹H‐NMR, ¹³C‐NMR and UV in solution. Magnetic and UV–visible measurements proposed that the coordination environments are square pyramidal, tetrahedral and octahedral geometries for oxovanadium (IV), Cu (II) and Fe (III), respectively. The ligand acts as mono‐negative NO towards oxovanadium (IV) and Cu (II) ions, and bi‐negative ONO for Fe (III) ion. The geometries of the ligand and its complexes were performed using Gaussian 9 program with density functional theory. The EPR spectral data of oxovanadium (IV) and Cu (II) chelates confirmed the mentioned geometries. The molecular modeling was done, and illustrated bond lengths, bond angles, molecular electrostatic potential, Mulliken atomic charges and chemical reactivity for the inspected compounds. Theoretical IR and ¹H‐NMR of the free ligand were calculated. Furthermore, thermodynamic and kinetic parameters for thermal decomposition steps were studied. Docking study of H₂L was applied against the proteins of both bacterial strains Staphylococcus aureus and Escherichia coli, as well as the protein of xanthine oxidase as antioxidant agent by Schrödinger suite program utilizing XP glide protocol. Furthermore, antimicrobial, antioxidant and DNA‐binding activities of the compounds have been carried out.     

Comparative analysis of refrigerant performance between LPG and R134a under subtropical climate

Journal of Thermal Analysis and Calorimetry - In this investigation, a series of experiments were conducted to explore the effects of liquefied petroleum gas (LPG) mixture of 60% propane and 40%...     

Divalent manganese,cobalt, copper and cadmium complexes of (Z)‐N‐benzoyl‐N′‐(1H‐1,2,4‐triazol‐3‐yl)carbamimidothioic acid: Preparation,characterization, computational and biological studies

In this work, (Z)‐N‐benzoyl‐N′‐(1H‐1,2,4‐triazol‐3‐yl)carbamimidothioic acid and its Mn(II), Co(II), Cu(II) and Cd(II) complexes were introduced for the first time. This carbonyl thiourea ligand was prepared by the reaction of 1H‐1,2,4‐triazol‐3‐amine with benzoyl isothiocyanate. The structural elucidation of these compounds was performed using elemental analysis and spectral and magnetic measurements. Octahedral structures of all complexes, except Cd(II) complex with a tetrahedral geometry, were confirmed by applying DFT structural optimization. The thermal decomposition behaviour of metal complexes of carbonyl thiourea ligand is discussed. The calculation of kinetic parameters for prepared complexes (E_a, A, ΔH*, ΔS* and ΔG*) of all thermal degradation stages has been evaluated using two comparable approaches. Antimicrobial and ABTS‐antioxidant studies indicated potent activity of Cd(II) complex compared with the other investigated compounds. The cytotoxic activity of the prepared compounds was investigated in vitro. The results indicated potent activity of Mn(II) complex against both HePG2 (liver carcinoma) and MCF‐7 (breast carcinoma) cancer cells.     

Preparation and Characterization of Poly Vinyl Alcohol/Poly Vinyl Pyrrolidone/Clay Based Nanocomposite by Gamma Irradiation

A series of PVA/PVP/clay nanocomposite were prepared by gamma irradiation with different clay contents of (0.15, 0.3, 1, 1.5, 3 and 5 wt%). The gelation content and swelling behavior were investigated. The morphology and structure of PVA/PVP/clay nanocomposite and dispersion of the clay nanoparticles in the polymeric matrix were examined by infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The introduction of clay into polymeric matrix was investigated by X-ray diffraction pattern (XRD) and Transmission electron microscope (TEM). It is observed that, the increase of the clay content causes a decrease in the swelling percent. The thermal stability studies confirmed that the introduction of clay lead to an increase in the thermal stability. The TEM results showed that the clay nanoparticles are interchelated or exfoliated in the polymeric matrix. Some desirable characteristics such as relatively good swelling and excellent barrier capability against microbe penetration suggested that PVA/PVP/clay nanocomposite can be a good candidate as a wound dressing.     

Quadrupole mass filter operation under the influence of magnetic field

This work demonstrates resolution enhancement of a quadrupole mass filter (QMF) under the influence of a static magnetic field. Generally, QMF resolution can be improved by increasing the number of rf cycles an ion experiences when passing through the mass filter. In order to improve the resolution, the dimensions of the QMF or the operating parameters need to be changed. However, geometric modifications to improve performance increase the manufacturing cost and usually the size of the instrument. By applying a magnetic field, a low‐cost, small footprint instrument with reduced power requirements can be realized. Significant improvement in QMF resolution was observed experimentally for certain magnetic field conditions, and these have been explained in terms of our theoretical model developed at the University of Liverpool. This model is capable of accurate simulation of spectra allowing the user to specify different values of mass spectrometer dimensions and applied input signals. The model predicts enhanced instrument resolution R>26 000 for a CO₂ and N₂ mixture with a 200‐mm long mass filter operating in stability zone 3 via application of an axial magnetic field. Copyright © 2013 John Wiley & Sons, Ltd.     

Mapping the Stability Diagram of a Quadrupole Mass Spectrometer with a Static Transverse Magnetic Field Applied

Previous experimental and theoretical work identified that the application of a static magnetic (B) field can improve the resolution of a quadrupole mass spectrometer (QMS) and this simple method of performance enhancement offers advantages for field deployment. Presented here are further data showing the effect of the transverse magnetic field upon the QMS performance. For the first time, the asymmetry in QMS operation with B _x and B _y is considered and explained in terms of operation in the fourth quadrant of the stability diagram. The results may be explained by considering the additional Lorentz force (v x B) experienced by the ion trajectories in each case. Using our numerical approach, we model not only the individual ion trajectories for a transverse B field applied in x and y but also the mass spectra and the effect of the magnetic field upon the stability diagram. Our theoretical findings, confirmed by experiment, show an improvement in resolution and ion transmission by application of magnetic field for certain operating conditions.