Fe(III) Complexes Based on Mono- and Bis-pyrazolyl-s-triazine Ligands: Synthesis,Molecular Structure,Hirshfeld, and Antimicrobial Evaluations

The self-assembly of iron(III) chloride with three pyrazolyl-s-triazine ligands, namely 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)-1,3,5-triazine (^PipBPT), 4-(4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl)morpholine (^MorphBPT), and 4,4’-(6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4-diyl)dimorpholine (^bisMorphPT) afforded [Fe(^PipBPT)Cl₂][FeCl₄] (1), [Fe(^MorphBPT)Cl₂][FeCl₄] (2), and [H(^bisMorphPT)][FeCl₄]. ^bisMorphPT.2H₂O (3), respectively, in good yield. In complexes 1 and 2, the Fe(III) is pentacoordinated with three Fe-N interactions from the pincer ligand and two coordinated chloride anions in the inner sphere, and FeCl₄¯ in the outer sphere. Complex 3 is comprised of one protonated ligand as cationic part, one FeCl₄¯ anion, and one neutral ^bisMorphPT molecule in addition to two crystallized water molecules. Analysis of molecular packing using Hirshfeld calculations indicated that H…H and Cl…H are the most important in the molecular packing. They comprised 40.1% and 37.4%, respectively in 1 and 32.4% and 37.8%, respectively in 2. Complex 1 exhibited the most bioactivity against the tested microbes while 3 had the lowest bioactivity. The ^bisMorphPT and ^MorphBPT were inactive towards the tested microbes while ^PipBPT was active. As a whole, the Fe(III) complexes have enhanced antibacterial and antifungal activities as compared to the free ligands.     

Manganese Accumulation in the Brain via Various Transporters and Its Neurotoxicity Mechanisms

Manganese (Mn) is an essential trace element, serving as a cofactor for several key enzymes, such as glutamine synthetase, arginase, pyruvate decarboxylase, and mitochondrial superoxide dismutase. However, its chronic overexposure can result in a neurological disorder referred to as manganism, presenting symptoms similar to those inherent to Parkinson’s disease. The pathological symptoms of Mn-induced toxicity are well-known, but the underlying mechanisms of Mn transport to the brain and cellular toxicity leading to Mn’s neurotoxicity are not completely understood. Mn’s levels in the brain are regulated by multiple transporters responsible for its uptake and efflux, and thus, dysregulation of these transporters may result in Mn accumulation in the brain, causing neurotoxicity. Its distribution and subcellular localization in the brain and associated subcellular toxicity mechanisms have also been extensively studied. This review highlights the presently known Mn transporters and their roles in Mn-induced neurotoxicity, as well as subsequent molecular and cellular dysregulation upon its intracellular uptakes, such as oxidative stress, neuroinflammation, disruption of neurotransmission, α-synuclein aggregation, and amyloidogenesis.     

Ti functionalized carbon and boron nitride chains: a promising material for hydrogen storage

The geometries, electronic structures, thermochemical properties, polarizabilities, and hyperpolarizabilities of high capacity hydrogen storage media consisting of alkali metal such as Li or transition metal as Ti, that is, functionalized at the end of C and BN chains have been investigated theoretically using density functional theory (DFT). Fundamental aspects such as interaction energy, natural bond orbital (NBO), charge transfer, energy gap, and the projected density of states (PDOS) are elucidated to analyze the adsorption properties of H₂ molecules. Our results revealed that H₂ is introduced sequentially on the Ti-C₇, Ti_(B)-B₄N₃, and Ti_(N)-B₃N₄ complexes and the H₂ uptake capacity are found to be 10.89, 10.80, and 10.58 wt%, respectively. Moreover, two Ti atoms can be adsorbed concomitantly to the ends of C₇, B₄N₃, and B₃N₄ chains where Ti sites can accommodate 16 H₂ molecules, with 8 per Ti center, leading to a storage capacity of up to 26.40, 26.28, and 25.94 wt%, respectively. In addition, two binding mechanisms contribute to the adsorption of hydrogen molecules: polarization of the H₂ under the electric field produced by the Ti–chain dipole and hybridization of the 3d orbitals of Ti with σ orbitals of H₂. These lead to the hydrogen binding energies within the range of 0.22–0.56 eV/H₂, open a prospect of a promising material system for hydrogen storage at ambient temperature. The large difference in charge transfer and interaction between the metal and chains is responsible for the large hyperpolarizability. Moreover, the C and BN chains can be stabilized effectively by C₂₀ fullerene termination and store 8 H₂ with an average binding energy of 0.22 eV/H₂. The hydrogen desorption energies and temperatures indicate that the Ti-C₇,Ti_(B)-B₄N₃, Ti_(N)-B₃N₄, Ti-C₇-Ti, Ti_(B)-B₄N₃-Ti_(B), Ti_(N)-B₃N₄-Ti_(N), Ti-C₇-C₂₀, Ti_(B)-B₄N₃-C₂₀, and Ti_(N)-B₃N₄-C20 complexes are easy to desorb H2 molecules.     

Cyclization of diketones to pyridazine and furan derivatives

Condensation of (±)-2,3-bis(3,4-dimethoxybenzoyl)butane-1,4-dione 1 with different hydrazine bases afforded the corresponding pyridazines 2 and 3 . Refluxing the diketone 1 with methanolic hydrogen chloride yielded the corresponding 3,4-dimethylfuran derivative 5 . Reaction of acetonylacetone 6 with p-sulfamylphenylhydrazine afforded the corresponding 3,6-dimethyl-1H-pyridazine derivative 7 . Reaction of 7 with the appropriate isocyanate and isothiocyanate yielded the corresponding benzenesulfonylurea 8 and thiourea 9 derivatives respectively. The structures of the compounds synthesized were affirmed by microanalyses and spectral studies.     

Biochemical and Functional Characterization of Kidney Bean Protein Alcalase-Hydrolysates and Their Preservative Action on Stored Chicken Meat

A new preservation approach is presented in this article to prolong the lifetime of raw chicken meat and enhance its quality at 4 °C via coating with highly soluble kidney bean protein hydrolysate. The hydrolysates of the black, red, and white kidney protein (BKH, RKH, and WKH) were obtained after 30 min enzymatic hydrolysis with Alcalase (E/S ratio of 1:100, hydrolysis degree 25–29%). The different phaseolin subunits (8S) appeared in SDS-PAGE in 35–45 kD molecular weight range while vicilin appeared in the molecular weight range of 55–75 kD. The kidney bean protein hydrolysates have considerable antioxidant activity as evidenced by the DPPH-scavenging activity and β-carotine-linolenic assay, as well as antimicrobial activity evaluated by disc diffusion assay. BKH followed by RKH (800 µg/mL) significantly (p ≤ 0.05) scavenged 95, 91% of DPPH and inhibited 82–88% of linoleic oxidation. The three studied hydrolysates significantly inhibited the growth of bacteria, yeast, and fungi, where BKH was the most performing. Kidney bean protein hydrolysates could shield the chicken meat because of their amphoteric nature and many functional properties (water and oil-absorbing capacity and foaming stability). The quality of chicken meat was assessed by tracing the fluctuations in the chemical parameters (pH, met-myoglobin, lipid oxidation, and TVBN), bacterial load (total bacterial count, and psychrophilic count), color parameters and sensorial traits during cold preservation (4 °C). The hydrolysates (800 µg/g) significantly p ≤ 0.05 reduced the increment in meat pH and TVBN values, inhibited 59–70% of lipid oxidation as compared to control during 30 days of cold storage via eliminating 50% of bacterial load and maintained secured storage for 30 days. RKH and WKH significantly (p ≤ 0.05) enhanced L*, a* values, thus augmented the meat whiteness and redness, while, BKH increased b* values, declining all color parameters during meat storage. RKH and WKH (800 µg/g) (p ≤ 0.05) maintained 50–71% and 69–75% of meat color and odor, respectively, increased the meat juiciness after 30 days of cold storage. BKH, RKH and WKH can be safely incorporated into novel foods.     

Ameliorating the Adverse Effects of Tomato mosaic tobamovirus Infecting Tomato Plants in Egypt by Boosting Immunity in Tomato Plants Using Zinc Oxide Nanoparticles

Tomato mosaic virus (ToMV) is one of the economically damageable Tobamovirus infecting the tomato in Egypt that has caused significant losses. It is therefore of great interest to trigger systemic resistance to ToMV. In this endeavor, we aimed to explore the capacity of ZnO-NPs (zinc oxide nanoparticles) to trigger tomato plant resistance against ToMV. Effects of ZnO-NPs on tomato (Solanum lycopersicum L.) growth indices and antioxidant defense system activity under ToMV stress were investigated. Noticeably that treatment with ZnO-NPs showed remarkably increased growth indices, photosynthetic attributes, and enzymatic and non-enzymatic antioxidants compared to the challenge control. Interestingly, oxidative damage caused by ToMV was reduced by reducing malondialdehyde, H₂O₂, and O₂ levels. Overall, ZnO-NPs offer a safe and economic antiviral agent against ToMV.     

Benzimidazole condensed ring systems. 1. Syntheses and biological investigations of some substituted pyrido[1,2-a]benzimidazoles

The synthesis of some substituted 3-hydroxy-1-oxo-1H,5H-pyrido[1,2-a]benzimidazole-4-carbonitriles and 4-ethyl carboxylates 3 and their 0- and N-dialkyl derivatives 5,6 is described. 3-Ethoxy-5-ethyl-2-phenyl-1H,5H-pyrido[1,2-a]benzimidazol-1-one 7 was obtained during the course of ethylating the parent ester 3t with triethyl phosphate. Chlorination of 3 with phosphorus oxychloride afforded the corresponding 1,3-dichloropyrido[1,2-a]benzimidazoles 8 which were converted to a variety of azido, amino, morpholino and methoxy derivatives of the system. The synthesis of the indolopyridobenzimidazole 15 is also described. Two compounds exhibited in vitro antibacterial activity. Many compounds were screened for antileukemic, antimicrobial, herbicidal and plant antifungal potencies but were inactive.     

Synthesis of a Novel Unexpected Cu(II)–Thiazolidine Complex—X-ray Structure,Hirshfeld Surface Analysis,and Biological Studies

An unexpected trinuclear Cu(II)–thiazolidine complex has been synthesized by mixing CuCl₂·2H₂O with the Schiff base ligand, 1-(((4,5-dihydrothiazol-2-yl)ethylidene)hydrazono)methyl)phenol L, in ethanol. Unexpectedly, the reaction proceeded via the hydrolysis of the Schiff base L, followed by cyclization to afford 3-methyl-5,6-dihydrothiazolo[3,2-c][1,2,3]triazole (L^a), then complexation with the Cu(II) salt, forming the trinuclear [Cu₃(L^a)₄(Cl)₆] complex. The complex was characterized by means of FTIR spectra, elemental analysis, and X-ray crystallography. In the trinuclear [Cu₃(L^a)₄(Cl)₆] complex, there are two crystallographically independent hexa- and penta-coordinated Cu(II) sites, where the thiazolidine ligand L^a units act as a monodentate ligand and a linker between the Cu(II) centers. The crystal packing of the [Cu₃(L^a)₄(Cl)₆] complex is primarily affected by the weak non-covalent C-H∙∙∙Cl interactions. In accordance with Hirshfeld surface analysis, the Cl∙∙∙H, H∙∙∙H, S∙∙∙H, and N∙∙∙H percentages are 31.9%, 27.2%, 13.5%, and 9.9%, respectively. X-ray photoelectron spectroscopy confirmed the oxidation state of copper as Cu(II), as well as the presence of two different coordination environments around copper centers. The complex showed interesting antibacterial activity against the Gram-positive bacteria S. subtilis, with MIC = 9.7 µg/mL compared to MIC = 4.8 µg/mL for the control, gentamycin. Moreover, the Cu(II) complex showed an equal MIC (312.5 µg/mL) against C. albicans compared to ketoconazole. It also exhibits a very promising inhibitory activity against colon carcinoma (IC₅₀ = 3.75 ± 0.43 µg/mL).     

Chemistry of Phosphorus Ylides. Part 40. Synthesis of Pyrazoles by the [3 + 2] Cycloaddition of Diazo Compounds with Wittig Reagents as Antimicrobial Compounds

A comparative study between the reactions of active phosphacumulenes and stabilized phosphonium ylides on some diazo compounds have been performed. A number of substituted phosphanylidene spiro pyrazoles have been synthesized from the reaction of the active phosphacumulenes and the diazo derivatives. On the other hand, treatment of the diazo substrates with the stabilized phosphonium ylides led to the formation of the corresponding ylidenes and diazenyl phosphanylidenes. The antimicrobial activities for the new compounds are also reported.