Titanium tetrachloride incorporated crosslinked polystyrene copolymer as an efficient and recyclable polymeric Lewis acid catalyst for the synthesis of Β-amino carbonyl compounds at room temperature

An efficient and eco-friendly procedure for one-pot synthesis of β-amino carbonyl compounds by three-component reaction of aromatic aldehydes, acetophenone, and aromatic amines via a Mannich type reaction using a stable tightly bound complex, titanium tetrachloride incorporated crosslinked polystyrene copolymer (PS/TiCl₄), as a water tolerant, recoverable, and reusable polymeric Lewis acid catalyst in ethanol at room temperature is reported. The complex of the polystyrene and TiCl₄ provides a shelf-stable acidic, water tolerant material, and it is not easily hydrolyzed by water. Our findings thus show a novel and improved modification of the Mannich type reaction in terms of mild reaction conditions, clean reaction profiles, applicability to various substrates using a simple workup procedure which makes this reaction an interesting alternative to previously applied procedures. The recyclability of the catalyst makes this protocol environmentally benign.     

Efficient and Green Synthesis of 1,2-Disubstituted Benzimidazoles and Quinoxalines Using Br⊘nsted Acid Ionic Liquid, [(CH2)4SO3HMIM][HSO4], in Water at Room Temperature

1,2-Disubstituted benzimidazoles and quinoxalines have been synthesized in the presence of Br?nsted acid ionic liquid, [(CH₂)₄SO₃HMIM][HSO₄], in water at ambient temperature.     

Sulfur-Doped Binary Layered Metal Oxides Incorporated on Pomegranate Peel-Derived Activated Carbon for Removal of Heavy Metal Ions

In this study, a novel biomass adsorbent based on activated carbon incorporated with sulfur-based binary metal oxides layered nanoparticles (SML-AC), including sulfur (S₂), manganese (Mn), and tin (Sn) oxide synthesized via the solvothermal method. The newly synthesized SML-AC was studied using FTIR, FESEM, EDX, and BET to determine its functional groups, surface morphology, and elemental composition. Hence, the BET was performed with an appropriate specific surface area for raw AC (356 m²·g⁻¹) and modified AC-SML (195 m²·g⁻¹). To prepare water samples for ICP-OES analysis, the suggested nanocomposite was used as an efficient adsorbent to remove lead (Pb²⁺), cadmium (Cd²⁺), chromium (Cr³⁺), and vanadium (V⁵⁺) from oil-rich regions. As the chemical structure of metal ions is influenced by solution pH, this parameter was considered experimentally, and pH 4, dosage 50 mg, and time 120 min were found to be the best with high capacity for all adsorbates. At different experimental conditions, the AC-SML provided a satisfactory adsorption capacity of 37.03–90.09 mg·g⁻¹ for Cd²⁺, Pb²⁺, Cr^3+, and V⁵⁺ ions. The adsorption experiment was explored, and the method was fitted with the Langmuir model (R² = 0.99) as compared to the Freundlich model (R² = 0.91). The kinetic models and free energy (<0.45 KJ·mol⁻¹) parameters demonstrated that the adsorption rate is limited with pseudo-second order (R² = 0.99) under the physical adsorption mechanism, respectively. Finally, the study demonstrated that the AC-SML nanocomposite is recyclable at least five times in the continuous adsorption–desorption of metal ions.     

An unexpected tetracyclic product isolated during the synthesis of biscoumarins catalyzed by [MIM(CH2)4SO3H][HSO4]: Characterization and X-ray crystal structure of 7-(2-hydroxy-4-oxo-4H-chromen-3-yl)-6H,7H-chromeno[4,3-b]chromen-6-one

Under solvent-free conditions and in the presence of 3-methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate [MIM(CH₂)₄SO₃H][HSO₄], a Brønsted acidic ionic liquid, the reaction of aromatic aldehydes with 4-hydroxycoumarin has been investigated. A wide range of aromatic aldehydes easily undergoes condensation with 4-hydroxycoumarin to afford biscoumarins with good purity in excellent yields. However, reaction of 2-hydroxybenzaldehyde with 4-hydroxycoumarin gave, not the corresponding biscoumarin, but a tetracyclic compound, 7-(2-hydroxy-4-oxo-4H-chromen-3-yl)-6H,7H-chromeno[4,3-b]chromen-6-one, in high yield.     

Artifacts in magnetic resonance imaging after surgical resection of brain tumors

Background

Since the advent of magnetic resonance imaging, metal artifacts have posed an important diagnostic problem in different fields of medicine. However, this has not been systematically studied in patients undergoing surgery for brain tumors.

Objective

This study was planned to assess whether metal artifacts can occur in patients undergoing brain surgery without metallic implants.

Methods

Of 40 individuals who could be included because of having a pre- and postoperative MRI and a postoperative computed tomography (CT) scan or a conventional skull X-ray for the detection of metallic artifacts, 26 patients agreed to participate in this study and gave informed consent.

Results

Twenty-six subjects, 12 males and 14 females, with an age range of 12 to 54 years, were included in the study. Four patients were found to have gross metal particles in their postoperative brain CTs and were excluded. Of the remaining 22 subjects, 7 patients (31.8%) had metallic artifacts.

Conclusion

Our study showed that simple bone drilling or chiseling during surgical manipulation of skull bones may result in separation of very tiny metal particles which can remain in the surgical site and cause artifacts in postoperative MRIs. This finding appeared to be independent of factors such as age, sex, tumor/incision site, tumor size, pathologic tumor type, total radiation dose, operation–MRI time interval and sequence of MRI.     

BN Nanotube Serving as a Gas Chemical Sensor for N<Subscript>2</Subscript>O by Parallel Electric Field

Density functional theory calculations were performed to understand the electronic properties of C₂₄, B₁₂N₁₂, B₁₂P₁₂, and (6, 0) BNNT interacted with N₂O molecule in the presence and absence of an external electric field using the B3LYP method and 6-31G** basis set. The adsorption of N₂O from O-side on the surface of (6, 0) BNNT has high sensitivity in comparison with B₁₂N₁₂ nano-cage. The adsorption energy of N₂O (O-side) on the sidewalls of B₁₂N₁₂ and BNNT in the presence of an electric field are ?21.01 and ?15.48 kJ mol^?1, respectively. Our results suggest that in the presence of an electric field, the B₁₂N₁₂ nano-cage is the more energetically notable upon the N₂O adsorption than (6, 0) BNNT, C₂₄, and B₁₂P₁₂. Whereas, our results indicate that the electronic property of BNNT is more sensitive to N₂O molecule at the presence of an electric field than B₁₂N₁₂ nano-cage. It is anticipated that BNNT could be a favorable gas sensor for the detection of N₂O molecule.     

Sequential charge separation in two axially linked phenothiazine-aluminum(III) porphyrin-fullerene triads

New supramolecular triads (PTZpy→AlPor-C(60), TPTZpy→AlPor-C(60)), containing aluminum(III) porphyrin (AlPor), fullerene (C(60)), and phenothiazine (phenothiazine = PTZ, 2-methylthiophenothaizine = TPTZ) have been constructed. In these triads the fullerene and phenothiazine units are bound axially to opposite faces of the porphyrin plane via covalent and coordination bonds, respectively. The ground- and excited-state properties of the triads and reference dyads are studied using steady-state and time-resolved spectroscopic techniques. The time-resolved data show that photoexcitation results in charge separation from the excited singlet state of the porphyrin to the C(60) unit, generating (Donor)py→AlPor(?+)-C(60)(?-), Donor = PTZ and TPTZ. A subsequent hole shift from the porphyrin to phenothiazine generates the charge-separated state (Donor)(?+)py→AlPor-C(60)(?-). The lifetime of the charge separation exhibits a modest increase from 39 ns in the absence of the donor to 100 ns in PTZpy→AlPor-C(60) and 83 ns in TPTZpy→AlPor-C(60). These lifetimes are discussed in terms of the electronic coupling between phenothiazine, the porphyrin, and C(60).     

无溶剂条件下碳基固体酸催化一锅法合成酰胺烷基萘酚(英文)

An efficient, environmentally friendly procedure for the synthesis of amidoalkyl naphthols through the one‐pot, three‐component reaction of β‐naphthol, aryl aldehydes, and acetamide in the presence of a carbon‐based solid acid under thermal solvent‐free conditions is described. The beneficial fea-tures of this new synthetic approach include short reaction time, high yields, clean reaction profiles, and a simple work‐up procedure. Furthermore, the catalyst can be readily recycled and reused four times without obvious significant loss of activity. The structure of the catalyst was confirmed by Fourier transform infrared spectroscopy, N2 adsorption/desorption analysis, and X‐ray diffraction.     

Green synthesis of silver nanoparticles from aqueous extract of Ziziphora clinopodioides Lam and evaluation of their bio-activities under in vitro and in vivo conditions

The purpose of this experiment was the green synthesis of silver nanoparticles from aqueous extracts of Ziziphora clinopodioides Lam (AgNPs@Ziziphora) and assessment of their cytotoxicity, antioxidant, antibacterial, antifungal, and cutaneous wound-healing effects. These nanoparticles were characterized using ultraviolet–visible spectroscopy (UV–Vis), X-ray diffraction (XRD), field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDX), atomic force microscopy (AFM), and transmission electron microscopy (TEM). UV–Vis, TEM, and FESEM analyses indicated that the size of Ag nanoparticles (AgNPs) depended on Z. clinopodioides and AgNO₃ concentrations. In vitro biological experiments indicated that AgNPs@Ziziphora has excellent antioxidant potential against DPPH, antifungal effects against Candida guilliermondii, Candida krusei, Candida glabrata, and Candida albicans, and antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Streptococcus pneumonia, Salmonella typhimurium, Pseudomonas aeruginosa, and Escherichia coli O157:H7. Also, these nanoparticles did not exhibit cytotoxicity property against human umbilical vein endothelial cells (HUVECs). An in vivo biological test revealed that AgNPs@Ziziphora ointment significantly (p ≤ 0.01) increased the levels of wound contracture, blood vessels, hydroxyl proline, hexuronic acid, hexosamine, fibrocytes, fibroblasts, and fibrocyte/fibroblast ratio and significantly (p ≤ 0.01) decreased the wound area, and levels of total cells, neutrophils, and lymphocytes than other groups in rats. The results of UV–Vis, XRD, FESEM-EDX, AFM, and TEM confirmed that the aqueous extract of Z. clinopodioides can be used to produce silver nanoparticles with significant antioxidant, antimicrobial, and cutaneous wound-healing properties without any cytotoxicity.