Fabrication of novel Fe (III), Co (II), Hg (II), and Pd (II) complexes based on water-soluble ligand (NaH2PH): structural characterization,cyclic voltammetric,powder X-ray diffraction,zeta potential,and biological studies

Sodium4-hydroxy-3-([2-picolinoylhydrazineylidene]methyl)benzenesulfonate (NaH₂PH) was synthesized as a novel water-soluble ligand, by the condensation of picolinohydrazide with sodium 3-formyl-4-hydroxybenzenesulfonate. The (NaH₂PH) ligand and its isolated Co (II), Fe (III), Hg (II), and Pd (II) complexes were analyzed by elemental analysis and characterized by spectroscopic (Fourier transform infrared spectroscopy, UV–visible, powder XRD, ¹H NMR,¹³C NMR, MS) and magnetic measurements. By comparing IR spectra of both ligand and the metal complexes, one can assume that the (NaH₂PH) ligand behaves as a bi-negative tetradentate (ONNO) in [Co (NaPH)(H₂O)₂].3H₂O, and a mono-negative tridentate (ONO) in [Fe (NaPH)Cl₂(H₂O)] complex, whereas in [Hg₂(NaPH)Cl₂(H₂O)] complex, (NaH₂PH) coordinates as a bi-negative pentadentate (ONNNO) ligand via deprotonated OH group of phenolic ring (C=N)_Py and (C=N*) coordinated to one of Hg (II) ion and the oxygen atom of enolic group and (C=N)_az group with the another Hg (II) ion. Moreover, (NaH₂PH) acts as bi-negative tridentate (ONO) ligand in [Pd (NaPH)(H₂O)].2H₂O complex. The geometries of complexes were suggested based on the UV–visible spectra, magnetic measurements and confirmed by applying discrete Fourier transform (DFT) optimization studies. The thermal fragmentation of both [Pd (NaPH)(H₂O)].2H₂O and [Co (NaPH)(H₂O)₂].3H₂O complexes was performed, and the kinetic and thermodynamic parameters were computed using the Coats–Redfern and Horowitz–Metzger methods. The redox behavior of divalent ions of cobalt and mercury were discussed by the cyclic voltammetry technique in the presence and absence of (NaH₂PH) ligand. Biological potencies of the ligand and its metal complexes were evaluated as antioxidants (ABTS and DPPH), anticancer, DNA, and antimicrobial (Staphylococcus aureus and Bacillus subtilis as Gram (+) bacteria, Escherichia coli and Pseudomonas aeruginosa as Gram (−) bacteria, and Candida albicans as fungi).     

Experimental Investigation of Pure Spinel Mn3O4 Properties Synthesized through Chemical Spray Pyrolysis for Future Gas Sensor Application

The semiconductor realization is a very significant stage in gas sensor application. Herein, the Mn₃O₄ semiconductor was deposited using chemical spray pyrolysis. The effect of deposition temperature on structural, vibrational optical and electrical Mn₃O₄ thin layers properties were investigated through: X-ray diffraction, Raman spectroscopy, UV-visible spectrophotometer, and two points electrometers respectively. The X-ray diffraction showed the appearance of spinel phase of tetragonal Mn₃O₄ with strong formation direction along (101) plan and without any secondary phase indicating the formation of pure Mn₃O₄. The Raman spectroscopy confirmed the results obtained in XRD and certified the high-quality formation of Mn₃O₄. In addition, the crystallinity improvement (the increase of crystallite size and the decrease of dislocation density) was caused by the increasing of deposition temperature from 350 °C to 450 °C. Optical properties such as transmittance, absorbance and band gap energy were extracted by UV-Visible spectrophotometer. Thus, low transmittance, high absorbance and small band gap energy were observed at the highest substrate temperature (450 °C). The electrical conductivity showed good values between 4.83 and 13.89 mS.cm⁻¹. These properties make Mn₃O₄ an appropriate material to be used as a sensitive layer in gas sensors applications.     

Temperature dependence of grain growth in zone-refined tin containing large additions of zinc in solid solution

Grain growth in zone-refined tin containing high concentrations > 0.05 < 0.40 wt% Zn in solid solution have been investigated in the temperature range 70–160°C. It has been found that increasing the zinc content by a factor of 8 decreased the rate of grain growth by ∼ 30% at all annealing temperatures, and this was attributed to small variations of grain boundary mobility. In addition, the increase of annealing temperature from 70 to 160°C resulted in the increase of grain growth by a factor of ∼ 50 at any given concentration, which shows that the rate of grain growth is not strongly influenced by increasing the zinc concentration. The energy activating the growth process was calculated for all concentrations investigated and had a nearly constant value of ∼ 1 eV. An empirical formula was proposed relating the rate of grain growth and the solute concentration.     

Crystal Structure of the Amine‐Carbonato‐Cobalt(III) Complex [Co(CO3)(L1)]ClO4 with Aminoalkyl Pendant‐Arm [12]eneN4, L1 = 9‐(3‐aminopropyl)‐1,5,9‐Triazacyclododecene

The crystal and molecular structure of the title complex [Co(CO3)(L1)]ClO4 was determined from X‐ray diffraction data using direct methods. The crystals are monoclinic, a = 13.588(4) Å, b = 9.049(3) Å, c = 15.569(6) Å, β = 114.75(2)°, Z = 4, V = 1738.5(10) ų, space group P21/n. The structure consists of isolated [Co(CO3)(C12H26N4)]+ complex cations, with distorted octahedral geometry and ClO4‐ counter anions. The results are discussed in relation to similar macrocycle and carbonato analogues.