Search

Lead‐free tin halide perovskites, particularly Cs2SnBr6, are gaining significant attention for their potential in optoelectronic applications. In this study, we investigate the material's electrical and vibrational properties under varying illumination conditions, providing novel insights into the impact of light on its conduction mechanisms. Cs2SnBr6 was synthesized via liquid‐phase and solid‐state reactions, and we report comprehensive analyses of its impedance, AC conductivity, and dielectric properties over a wide frequency range. Notably, our results reveal that light‐induced photogenerated charge carriers enhance conductivity, which is well explained by the overlapping large‐polaron tunneling (OLPT) model, while in darkness, the material follows the correlated barrier hopping (CBH) model. Moreover, Raman spectroscopy highlights structural changes, including a slight shortening of Sn–Br bond distances under illumination, which influences the vibrational frequencies and intensities. These findings emphasize the crucial role of illumination in tuning the electrical and dielectric responses of Cs2SnBr6, thus demonstrating its considerable promise for future optoelectronic applications, such as solar cells and photodetectors. [ABSTRACT FROM AUTHOR]

In the current work, chloro(meso-tetrakis(phenyl)porphyrin) manganese(III) [Mn(TPP)Cl] was synthesized following two steps: the preparation of meso-tetraphenylporphyrin (H⁠2TPP) and the insertion of manganese into the free porphyrin H2TPP. The compounds were characterized using SEM, FT-IR, UV, TGA/DTA, and XRD analyses. Manganese(III) meso-porphyrins exhibited hyper-type electronic spectra with a half-vacant metal orbital with symmetry, such as [dπ:dxz and dyz]. The thermal behavior of [Mn(TPP)(Cl)] changed (three-step degradation process) compared to the initial H2TPP (one-step degradation process), confirming the insertion of manganese into the core of the free porphyrin H2TPP. Furthermore, [Mn(TPP)Cl] was used to degrade calmagite (an azo dye) using H2O2 as an oxidant. The effects of dye concentration, reaction time, H2O2 dose, and temperature were investigated. The azo dye solution was completely degraded in the presence of [Mn(TPP)(Cl)]/H2O2 at pH = 6, temperature = 20 °C, C0 = 30 mg/L, and H2O2 = 40 mL/L. The computed low activation energy (Ea = 10.55 Kj/mol) demonstrated the efficiency of the proposed catalytic system for the azo dye degradation. Overall, based on the synthesis process and the excellent catalytic results, the prepared [Mn(TPP)Cl] could be used as an effective catalyst for the treatment of calmagite-contaminated effluents. [ABSTRACT FROM AUTHOR]

Ligno-cellulosic biomasses had been recognized for their potential use to produce chemicals and biomaterials. The current study focused on the use of a new cellulosic Robinia Pseudoacacia fiber and extracted lignin as adsorbents for methylene blue (a cationic dye). The biomaterials were analyzed using FT-IR spectroscopy, SEM, XRD, and TGA-DTA techniques. The surface of Robinia fibers was rough and porous. The crystallinity index (CrI) value for Robinia fibers was found to be 32%. The ability of the studied samples to remove methylene blue from water was assessed under the variation of time, pH, dye concentration, temperature, and NaCl concentration. The maximum adsorption capacity of methylene blue reached 191 mg/g for Robinia fibers and it achieved 22 mg/g for the extracted lignin (T = 20 °C, pH = 6, and time = 90 min). The adsorption data complied with the pseudo second-order kinetic model and both Langmuir and Freundlich isotherms. Based on these findings, the process suggested the occurrence of many physicochemical interactions between methylene blue molecules and the studied biomaterials. The adsorption mechanism was exothermic, non-spontaneous, and it was described by the decrease of the disorder. Adsorption results proved that Robinia fiber was an attractive candidate for the removal of cationic dyes from water. A low-cost and abundant Robinia Pseudoacacia fiber and its extracted lignin are characterized and further studied as adsorbents for cationic dyes under the change of the experimental conditions. [ABSTRACT FROM AUTHOR]

In this investigation, Pergularia tomentosa leaves were used as a promising source of bioproducts for the reduction of copper sulfate into copper oxide nanoparticles. The prepared nanoparticles were characterized using Fourier-transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), and Thermogravimetric analysis (TGA). FI-IR showed the presence of hydroxyl, ester, and aromatic groups, which are characteristics of phenolics and other bioproducts. SEM features exhibited spherical and agglomerated particles. In EDX data, the peak at 1 Kev, is an index of metallic nanoparticles of copper. The signals related to C and O peaks indicated the presence of phytochemicals in the studied extract. The synthesized copper oxide nanoparticles had a face-centered cubic structure. The size of the nanoparticles varied from 1.7 to 15.2 nm. The adsorption capacity of methylene blue using copper oxide nanoparticles reached 93.2 mg/g (pH = 6, T = 22 °C, adsorbent dose = 0.0125 g). Additionally, methylene blue solution was completely decolorized after 2 min of reaction (pH = 6, 0.0057 mg NaBH4, C0 = 10 mg/L, catalyst = 0.005 g). NOVELTY STATEMENT In this study, Pergularia tomentosa leaves were used, for the first time, as a biomaterial rich in bioproducts for the reduction of copper sulfate into copper oxide nanoparticles. The prepared particles act as promising materials for the decolorization of contaminated water via both adsorption and degradation processes. [ABSTRACT FROM AUTHOR]

In the present work, we report the antibacterial activity of silver nanoparticles (AgNP) coated with the surfactants para‐amino‐N‐((1‐decylpyridin‐1‐ium bromide)‐4‐yl) benzamide and para‐amino‐N‐((1‐dodecylpyridin‐1‐ium bromide)‐4‐yl) benzamide (P10 and P12, respectively). P10 and P12‐coated AgNP were stable, as confirmed by ultraviolet–visible spectrophotometry, transmission electron microscopy, and other surface activity parameters. Both P10 and P12 and the coated AgNP formulations were investigated for their activity against sulfate reducing bacteria (SRB). Overall, our results showed the importance of coating AgNP with surfactants (P10 and P12) in the design and development of new biocides against SRB. [ABSTRACT FROM AUTHOR]

Summary: Despite the interesting structure of the generic thiacalix[4]arene containing four coordinating sulfur atoms bridging four phenolic units, there are only a few reported examples of thiacalixarene-based coordination complexes that are used as electrocatalysts. Herein, we report electrocatalytic hydrogen evolution reaction (HER) by a thiacalix[4]arene-based copper(II) complex (1). As expected, two reduction waves were appeared (-0.48 V and-1.30 V vs Ag/AgCl) for Cu2+/Cu+ and Cu+/Cu reduction couples. The HER by proton reduction occurs at-1.03 V with a shift of 0.27 V compared to the second peak potential at-1.30 V. The increase in the number of acetic acid equivalents, from 0 to 17.5 with a frequency of 2.5 eq, was accompanied by an increase in the peak current that reached a maximum value of 183 µA for 15 equivalents of acetic acid. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, [Sb(C44H28N4)Cl2][SbCl6], consists of one half of an anti-mony(V) tetra-phenyl-porphyrin complex cation and one half of an hexa-chlorido-anti-monate(V) anion. In the complex cation, the Sb(V) atom lies on an inversion center and is octa-hedrally coordinated by four N atoms from a macrocyclic tetra-phenyl-porphyrinate ligand and two chloride ions. The complex cation has approximately a planar core with a maximum deviation of 0.018 (5) Å from the porphyrin mean plane. The average Sb-N distance is 2.062 (11) Å, while the Sb-Cl distance is 2.355 (1) Å. The Sb(V) atom of the anion is also located on an inversion center. The [SbCl6](-) octa-hedron exhibits rhombic distortion characterized by the Sb-Cl bond lengths [2.311 (3), 2.374 (2) and 2.393 (4) Å]. In the crystal, the cations and anions are linked C-H⋯ Cl hydrogen bonds, forming a layer parallel to (211).

The asymmetric unit of the title complex, [Sb(C(44)H(28)N(4))Cl(2)][Sb(2)Cl(8)](0.5)·CH(2)Cl(2), is composed of a Sb(V) complex cation wherein the Sb atom is hexa-coordinated by four N atoms of the pyrrole rings of the tetra-phenyl-porphyrinate (TPP) ligands and two chloride ions, a half di-μ-chlorido-bis-[trichloridoanti-monate(III)] counter-anion and a dichloro-methane solvent mol-ecule. In the cation, the average Sb-N distance is 2.066 (2) Å, while the Sb-Cl distances are 2.3410 (11) and 2.3639 (12) Å. The central unit of the cation, SbN(4)C(20), is far from being planar, with deviations of atoms from the least-squares plane ranging from -0.110 (4) to 0.124 (4) Å. The Sb-Cl distances in the anion, which is located about an inversion center, lie in the wide range 2.3715 (13)-2.7489 (13) Å, the longest distances being between the Sb and bridging Cl atoms. The crystal structure is stabilized by inter-molecular C-H⋯Cl inter-actions involving the cations, the anions and the solvent mol-ecules. The solvent mol-ecule is disordered over two orientations in a 0.901 (13):0.099 (13) ratio.

In the title dinuclear Nb(V) compound, [Nb(2)(C(44)H(28)N(4))(2)O(3)], each Nb atom is seven-coordinated with three bridging O atoms and four N atoms from a chelating tetra-phenyl-porphyrinate anion. The Nb-O bond lengths range from 1.757 (6) to 2.331 (6) Å, and the average (niobium-pyrrole N atom) distance is 2.239 Å. In the dinuclear mol-ecule, the Nb⋯Nb separation is 2.8200 (8) Å, and the dihedral angle between the two porphyrinate mean planes is 5.4 (1)°. Weak inter-molecular C-H⋯π inter-actions are present in the crystal structure.