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Glassy samples from the undoped ternary system Na2O–ZnO–P2O5 in combination with other samples from the same system doped with variable amounts of MoO3 (0.25, 0.5, or 1 gm/batch) were successfully melted under ordinary, oxidizing, or reducing conditions followed by annealing. Fourier transform infrared spectrophotometric measurements in combination with optical absorption spectra were recorded before and after doping with variable concentrations of MoO3 in multiple melting media both as prepared or after being subjected to (8 Mrad) gamma irradiation dose. The studied spectral properties of the glasses were correlated with variations with the existing valence state of the Mo ions and the effects of gamma irradiation on the optical spectra and IR vibrational bands together with the role of the condition of melting the batches. The optical spectra of the glasses reveal pronounced UV and visible bands due to trace iron (Fe3+) ions as impurities or the sharing of the low valence states of the added molybdenum ions. The FTIR peaks show condensed spectra of phosphate groups (Q2, Q3), and the effects of dopant are limited because of low percent. Gamma irradiation causes distinct variations in the undoped spectra, but the MoO3-doped glasses show some shielding behavior. [ABSTRACT FROM AUTHOR]

In this work, a photoelectrochemical (PEC) aptasensor for detecting kanamycin (KAN) was designed based on an aptamer modified Bi/BiOBr/titania nanorod array (TiO2 NRA). Bi/BiOBr was loaded onto the TiO2 NRA via a one-pot solvothermal method using glucose as a reductant. The p–n heterojunction structure constructed from chrysanthemums like BiOBr and the TiO2 NRA improves the electron transfer rate. Combined with metal Bi with the surface plasmon resonance (SPR) effect, it further increases the absorption range of visible light and enhances the light response performance of the PEC aptasensor. The KAN aptamer is fixed to the Bi/BiOBr/TiO2 NRA photoelectric material through the C＝N structure. Once the aptamer precisely captures KAN molecules, photocurrent changes are generated to realize the detection of KAN. The designed PEC aptasensor shows good detection performance in the linear response range of 1 pM–200 nM, and the detection limit is 0.7 pM (S/N = 3). The aptasensor was applied to the determination of KAN in milk with satisfactory results. [ABSTRACT FROM AUTHOR]

Two zinc(II) complexes, DBZ and DBZH4, that have (ZnN3S2) cores and differ in the bridging mode of the ligating backbone, effectively bind to BSA. The binding affinity varies as DBZ > DBZH4 and depends on the ligand structure. At low concentrations, both complexes exhibit dynamic quenching, whereas at higher concentrations they exhibit mixed (static and dynamic) quenching. The energy transfer mechanism from the BSA singlet excited state to DBZ and DBZH4, is highly likely according to steady-state fluorescence and time-correlated singlet photon counting. Molecular docking was used to support the mode of interaction of the complexes with BSA and showed that DBZ had more energy for binding. Furthermore, antibacterial testing revealed that both complexes were active but to a lesser extent than chloramphenicol. In comparison to DBZH4, DBZ has higher antibacterial activity, which is consistent with the binding constants, molecular docking, and particle size of adducts. These findings may have an impact on biomedicine. [ABSTRACT FROM AUTHOR]

The biologically relevant alkylations of the thiolate ligands in tripod zinc thiolates by methyl iodide were studied kinetically. This was undertaken to elucidate the factors that affect the rate of alkylation by varying the donor sets of the tripods, the nature of thiolates, and the steric requirements of tripod.

A new complex, [Ni(Tren)(Barb)(H2O)](Barb)(Barb-H)·2H2O (NiC) {Tren = tris(2-aminoethyl)amine and Barb = 5,5-diethlybarbiturate}, has been synthesized and characterized. The nickel(II) complex was grafted to g-C3N4, forming NiC@g-C3N4. The obtained NiC complex and its hybrid material NiC@g-C3N4 were characterized by FT-IR, TGA-DSC, UV–vis, SEM-EDX, and XRD. Single crystal X-ray crystallography shows that NiC exhibits NiN5O octahedral geometry. The results also show that the complex molecules are connected via N–H⋅⋅⋅⋅O hydrogen bonds. The complex NiC and NiC@g-C3N4 show oxidative stress effects on in vivo experiments. They also showed an increase in tissue damage markers that are represented by increase in tissue levels of malondialdehyde (MDA) in brain, liver, kidney and heart. Both materials showed inhibitory activity for examined antioxidants such as glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione (GSH) and glutathione reductase (GSH-R). The destructive effects were clearer for the NiC@g-C3N4 composite in liver, brain and kidney, respectively. The grafting of NiC complex in g-C3N4 is responsible for improving the catalytic activity of the compound, due to the synergistic effect of both components and facile recovery, as well recycling of the catalyst. The immobilization of the synthesized nickel(I) complex [Ni(Tren)(Barb)(H2O)](Barb)(Barb-H)•2H2O (NiC) to the graphitic carbon nitride (g-C3N4) as electron rich surface, forming the hybrid material NiC@g-C3N4, which provides both the benefits i.e improved catalytic activity owing to the synergistic effect of both components and facile recovery, recycling of the catalyst. [ABSTRACT FROM AUTHOR]

Summary: A new bipyridine‐containing manganese (II) complex, namely [(BPy)2MnCl2]·0.5H2O (MnC), was synthesized and characterized. Spectral and X‐ray structural features revealed that MnC has an octahedral environment around Mn(II). Graphene oxide (GO) was noncovalently functionalized with the MnC. MnC‐ and (MnC/GO)‐modified glassy carbon (GC) interfaces with different loading densities (0.2, 0.4, 0.8, and 1.0 mg cm−2) were tested as electrocatalysts for efficient generation of H2 in 0.1 M KOH solution. The GC‐MnC catalysts exhibited high electrocatalytic activity for the HER, which enhances upon increasing the catalyst's loading density. The GC‐MnC catalyst's HER activity, at any tested loading density, was found to further increase upon supporting MnC on GO. The best performing electrocatalyst, namely GC‐(MnC/GO) with a loading density of 1.0 mg cm−2, exhibited high HER catalytic activity with a low onset potential value of −22 mV vs. reference hydrogen electrode (RHE) and a high exchange current density of 0.75 mA cm−2. It delivered a current density of 10 mA cm−2 at an overpotential value of 119 mV. In addition, it recorded a Tafel slope value of −114 mV dec−1. These HER electrochemical kinetic parameters approached those measured here for the commercial Pt/C under the same operating conditions (−10 mV vs. RHE, 0.88 mA cm−2, 113 mV dec−1, and 110 mV to yield a current density of 10 mA cm−2) and also comparable to the most active molecular electrocatalysts for H2 generation from aqueous alkaline electrolytes published in the literature. The long‐term stability of the best performing electrocatalyst, namely GC‐MnC (1.0 mg cm−2)/GO, was evaluated using cyclic voltammetry (repetitive cycling up to 5000 cycles) and chronoamperometry (48 hours) techniques, and the obtained results revealed its promising stability. A plausible mechanism for the interaction of MnC with GO was proposed based on density functional theory (DFT) calculations. DFT calculations confirmed the catalytic role of the supporting material (GO) on the fabricated metal complex in catalyzing the HER. [ABSTRACT FROM AUTHOR]