Search Results (647)

The antibacterial properties of Ag(I) coordination compounds are well documented; however, their effectiveness is highly dependent on the choice of appropriate ligands, and it is frequently hindered by their low water solubility and limited bioavailability. Herein, six new Ag(I) complexes incorporating the quinazolinone thioamide mqztH (=2-mercapto-4(3H)-quinazolinone) and phosphine co-ligands were synthesized and investigated for their antibacterial activity. In vitro activity assays against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacterial strains revealed that all complexes selectively inhibited S. aureus bacterial growth. Structure–activity relationship analysis showed that monodentate PPh₃ co-ligands play a key role in enhancing the antibacterial efficacy of their complexes. Notably, complex [AgCl(mqztH)(PPh₃)₂] (1) exhibited broad-spectrum activity, with IC₅₀ values of 4.2 ± 1.4 μg mL⁻¹ (4.9 μΜ) for S. aureus and 63 ± 1.9 μg mL⁻¹ (75 μΜ) for E. coli bacteria. To improve solubility and antibacterial activity, complex 1 was encapsulated in barium alginate (BaAlg) matrices to form hydrogel-based drug delivery formulations [1]@BaAlg. The synthesized formulations retained the bactericidal effect of the complex, achieving comparable activity at concentrations lower by an order of magnitude compared to complex 1 in free form. Combined with the demonstrated high biocompatibility of complex 1 toward L929 normal eukaryotic cells, as well as the biocompatible nature of the alginate matrix, these findings underscore the strong potential of the complex 1-loaded hydrogel formulations for further investigation and development as effective antibacterial drug platforms. Mechanistic studies confirmed the redox-active nature of complex 1 and its potential to inhibit the function of glutathione reductase (GR) and thioredoxin reductase (TrxR) at low concentrations, suggesting the interference with bacterial redox homeostasis as a relevant mechanism of bioactivity. Full article

With the increasing demand to scale the chip industry, attention is turning to the vital role that phosphanes and silanes play in semiconductor manufacturing processes such as chemical vapor deposition, plasma etching, and impurity doping. High-performance semiconductors often require a supply of ultra-pure gaseous phosphine (≥99.999%) to ensure the formation of defect-free thin-film structures with high integrity and strong functionality. In recent years, research on high-purity PH₃ synthesis methods has mainly focused on two pathways: the acidic route with fewer side reactions, high by-product economics, and higher exergy of high-purity PH₃, and the alkaline alternative with greater potential for practical application through lower reaction temperatures and a simpler reaction process. This paper presents the first comparative study and analysis on the preparation of ultra-high-purity PH₃ and its process energy consumption. Using Aspen and its related software, the energy consumption and cost issues are discussed, and the process heat exchange network is established and optimised. By combining Aspen Plus V14 with MATLAB 2023, an artificial neural network (ANN) prediction model is established, and the parameters of the distillation section equipment are optimised through the NSGA-II model to solve problems such as low product yield and large equipment exergy loss. After optimisation, it can be found that in terms of energy consumption and cost indicators, the acidic process has greater advantages in large-scale production of high-purity PH₃. The total energy consumption of the acidic process is 1.6 × 10⁸ kJ/h, which is only one-third that of the alkaline process, while the cost of the heat exchange equipment is approximately three-quarters that of the alkaline process. Through dual-objective optimisation, the exergy loss of the acidic distillation part can be reduced by 1714.1 kW, and the economic cost can be reduced by USD 3673. Therefore, from the perspective of energy usage and equipment manufacturing, the comprehensive analysis of the acidic process has more advantages than that of the alkaline process. Full article

Aromaticity tuning of biaryl monophosphines can significantly impact their catalytic performance. Biaryl monophosphines constitute a crucial class of compounds due to their potential as ligand precursors in asymmetric Pd-catalyzed cross-coupling and some other catalytic reactions. In this study, we investigate the tuning of aromaticity within a series of selected biaryl monophosphine derivatives exhibiting diverse steric and electronic properties. XRD structures and Hirshfeld surface analyses were complemented by DFT calculations. Aromaticity indices, such as geometric HOMA, HOMER, and magnetic NICS, were evaluated and correlated with ligand properties. NICS(1)zz was the most sensitive to aromaticity changes. The results showed that among the ring-activating substituents, methoxy groups were more beneficial than hydroxy ones. The hydroxy groups not only modulated the aromaticity but also induced unfavorable conformational changes of the catalyst precursors through strong inter- and intramolecular hydrogen bonding. The spatial arrangement of the P atom adjacent to the aryl ring system confers catalytic advantages by promoting the assembly of coordination compounds (catalysts) in which Pd—C bond formation occurs, yielding C,P-chelated five-membered palladacyclic structures. The hydroxy substituents blocked access to the P atom, thereby hindering catalytic performance. The studies show that even subtle changes in the monophosphine biaryl scaffold, especially aromaticity tuning should be carefully evaluated during the rational design of new efficient catalysts. The studied compounds were evaluated for their biological activity against three Gram-positive and four Gram-negative bacteria as model microorganisms. The research was supplemented by in vitro cytotoxicity evaluation. Full article

Although transition metal catalysts have been used extensively for the polymerization of hydrocarbon monomers, several cationic aluminum catalysts have been also known to promote polymerization of ethylene and 1,3-butadiene. Transition-metal catalyzed polymerization generally proceeds via coordination and insertion of the monomer on one metal center. In contrast, in ethylene polymerization using aluminum catalysts, a bimolecular chain growth mechanism, including the reaction between neutral aluminum species and the monomer activated by cationic aluminum species, is proposed. Although previously reported aluminum catalysts are based on a monoaluminum complex, a dialuminum complex is expected to catalyze the polymerization more efficiently, considering the proposed mechanism. In this work, we found that a combination of diphosphines and MAO promotes polymerization of ethylene and 1,3-butadiene. The 1,4-bis(diphenylphosphino)butane (DPPB)/methylaluminoxane (MAO) system showed a much higher activity toward ethylene polymerization than other monophosphine or diphosphine/MAO systems. NMR analysis of a mixture of diphosphine and MAO indicates the formation of cationic dialuminum species in the presence of DPPB, whereas the formation of cationic monoaluminum species occurs in the presence of other diphosphines. The 2,2′-bis(diphenylphosphino)-1,1′-biphenyl (BIPHEP)/MAO system promoted 1,3-butadiene polymerization to give polybutadiene having a cis-1,4 selectivity of up to 93.8%. Full article

Previously unobserved (carbamoyl)disulfanyl chlorides were prepared by (i) addition of limiting aromatic secondary amine to (chlorocarbonyl)disulfanyl chloride; (ii) Harris reactions of sulfur dichloride with appropriate O-alkyl N-methyl-N-arylthiocarbamates; and (iii) regiospecific chlorolysis of bis(N-methyl-N-arylcarbamoyl)disulfanes. The newly synthesized unstable species were observed in situ by ¹H NMR and were trapped with alkenes, thiocarbamates, and thiols using methods precedented by the chemistry of analogous (carbamoyl)sulfenyl chlorides. Furthermore, each of the trapped products was synthesized by an alternate route, reinforcing conclusions about their structures. While (N-methyl-N-phenylcarbamoyl)disulfanyl chloride was unstable and decomposed quickly or cyclized intramolecularly, introduction of the N,2,6-trimethylphenyl moiety led to significantly improved stability. As part of this study, an interesting, unexpectedly stable 1,2,4-dithiazinone was discovered and its structure was established by X-ray crystallography. The new heterocycle, with its twisted out-of-plane disulfide bond in a six-membered ring, readily donated a sulfur atom to triphenylphosphine; this reaction resulted in the formation of triphenylphosphine sulfide, along with the corresponding highly stable heterocycle in which the single sulfur that remains is part of a planar five-membered ring, fused to a co-planar aryl moiety. Full article

The activation of carbon dioxide by transition metal complexes is a fundamental process in catalysis and carbon capture. In this study, density functional theory (DFT) calculations, combined with Quantum Theory of Atoms in Molecules (QTAIM) and Natural Orbitals for Chemical Valency (NOCV) analyses, were employed to investigate the bonding characteristics and electronic structure of Fe(0)–, Pd(0)–, and Pt(0)–phosphine complexes with CO₂. The Fe(0) complexes exhibited the strongest CO₂ activation, characterized by substantial C=O bond elongation, significant charge transfer, and strong $\pi$-backdonation. In contrast, Pd(0) complexes showed minimal CO₂ activation, while Pt(0) complexes displayed intermediate behavior. The electronic effects of phosphine ligands were also analyzed, revealing that electron-donating phosphines enhance CO₂ activation, whereas electron-withdrawing phosphines weaken metal–CO₂ interactions. These findings provide key insights into the design of transition-metal-based catalysts for CO₂ conversion and utilization. Full article

Background/Objectives: Lyotropic liquid crystalline nanoparticles are promising drug delivery nanocarriers, exhibiting significant technological advantages, such as their extended internal morphology. In this study, cationic non-lamellar lyotropic–lipidic liquid crystalline nanoparticles were formulated by phytantriol lipid. Methods: The poly(2-(dimethylamino)ethyl methacrylate)-b-poly(lauryl methacrylate) block copolymer carrying tri-phenyl-phosphine cations (TPP-QPDMAEMA-b-PLMA), was employed as a stabilizer co-assisted by other polymeric guests. The exact qualitative and quantitative formulation of the systems was investigated. Their physicochemical profile was depicted from a variety of light scattering techniques, while their microenvironmental parameters were determined by fluorescence spectroscopy using adequate probe molecules. The effect of environmental conditions was monitored, confirming stimuli-responsiveness properties. Their morphology was illustrated by cryo-TEM, revealing expanded internal assemblies. Resveratrol was incorporated into the nanoparticles and the entrapment efficiency was calculated. Results: Their properties were found to be dependent on the formulation characteristics, such as the lipid used, as well as the architecture of the polymeric stabilizer, also being found to be stealth toward proteins, exhibiting stimuli responsiveness and high entrapment efficiency. Conclusions: The studied liquid crystalline nanoparticles, being stimuli-responsive, with high cationic potential, high loading capacity and showing intriguing 3D structures, are suitable for pharmaceutical applications. Full article

This study explores the application of phosphonium-based ionic liquids (ILs) for the efficient separation of valeric acid (VA) through reactive liquid–liquid extraction. Two hydrophobic quaternary phosphine ILs, trihexyl(tetradecyl)phosphonium decanoate (C103) and trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate (C104), were evaluated in combination with heptane as a diluent. Extraction efficiency was experimentally determined at different levels of extraction process factors in terms of aqueous phase pH (3–6), IL concentration (0–120 g/L), and process temperature (25–60 °C). For each IL, extraction efficiency was predicted using a response surface regression model, and the process factors were optimized based on the desirability function approach. Both ILs effectively extracted VA, with optimal mean values of extraction efficiency of 98.61% for C103 and 99.24% for C104 under optimal conditions (pH of 3.8 and 4, respectively, IL concentration of 60 g/L, and temperature of 25 °C). Mechanistic analysis revealed that VA extraction occurs through the formation of IL-acid complexes, involving hydrogen bonding between the non-dissociated acid and the IL anion. Depending on the extractant concentration, 1:1 and 2:1 acid-to-IL stoichiometric ratios were observed. These findings highlight the potential of phosphonium-based ILs, particularly in a heptane-diluted system, as high-performance extractants for carboxylic acid separation. Full article

The research presented in this manuscript aimed to conduct complex studies on epoxy composites filled with modified biowaste. This work discusses the entire process: first, the preparation and analysis of oak waste flour used as an additive to epoxy materials based on Epidian 6; then, obtaining and characterizing epoxy composites containing 5 wt.% of biowaste; and finally, the determination of the influence of wood filler and modification performed using selected ionic liquids (tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)amide (IL-1), tetradecyltrihexylphosphonium bis(2,4,4-trimethylpentyl)phosphinate (IL-2), and 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide) (IL-3)) on the susceptibility of epoxy composite to the enzymatic degradation. The enzymatic degradation was performed for four weeks using the lipase enzymes (Porcine Pancreas and Rhizopus Oryzae). The epoxy composition EP6-WF_IL-2, containing 5 wt.% of wood flour modified with IL-2, was characterized by the best mechanical parameters in terms of bending strength and flexural modulus (65.64 MPa and 1855.3 MPa, respectively). During enzymatic biodegradation, the lowest susceptibility to enzymatic degradation, regardless of the incubation conditions, was observed in samples of EP6-WF_IL-3 epoxy composition containing wood flour modified with methyltrioctylammonium bis(trifluoromethylsulfonyl)imide. Full article

Phosphine resistance represents a major challenge for stored product protection worldwide. In this study, we evaluated populations of Oryzaephilus surinamensis, Rhyzopertha dominica, and Cryptolestes ferrugineus collected from different regions using three diagnostic protocols: (i) the FAO test (30 ppm for 20 h); (ii) a dose–response bioassay (50–1000 ppm for 3 d); (iii) the Phosphine Tolerance Test (3000 ppm for up to 270 min). Results indicated that while several O. surinamensis populations remained susceptible, all tested populations of R. dominica and C. ferrugineus were resistant. The three protocols produced comparable outcomes, supporting their reliability for diagnosing resistant populations. This is the first study to simultaneously compare three diagnostic approaches across multiple beetle species, providing the basis for a harmonized global diagnostic framework. These findings underscore the need for continued monitoring and highlight the importance of standardized tools for resistance management. Full article

S-Adenosyl-L-methionine (SAM) is a central cofactor in cellular methylation, donating methyl groups to a wide range of biological substrates. SAM analogues are promising tools for selective modulation of methyltransferase activity. Here, we investigated phosphorus-containing analogues of SAM and S-adenosyl-L-homocysteine (SAH), focusing on the H-phosphinic SAM analogue ((R,S)-SAM-P_H) with the HO(H)(O)P group replacing the carboxyl group of SAM. We examined the interaction of (R,S)-SAM-P_H with three representative methyltransferases: Dnmt1, responsible for maintenance of DNA methylation; Dnmt3a, which establishes de novo DNA methylation; and catechol-O-methyltransferase (COMT), which methylates protocatechuic aldehyde to yield vanillin and isovanillin. (R,S)-SAM-P_H is a methyl group donor for Dnmt3a and COMT, but not for Dnmt1, despite the high structural similarity of the Dnmt1 and Dnmt3a catalytic domains. These results demonstrate that targeted modification of the carboxyl group of SAM can yield analogues with specific activity towards various methyltransferases. The different recognition of (R,S)-SAM-P_H by Dnmt3a and Dnmt1 highlights its potential as a molecular probe for distinguishing de novo from maintenance DNA methylation. This work enriches our understanding of methyltransferase substrate specificity and provides a new tool for selective modulation of epigenetic processes. Full article

A pressing scientific task is the development of modern extractants that meet the increased requirements for efficiency and safety. In this work, a new three-component eutectic solvent based on bis(2,4,4-trimethylpentyl)phosphinic acid (BTMPPA), tributyl phosphate (TBP) and phenol was proposed. The formation of the eutectic solvent was confirmed by IR and ³¹P NMR spectroscopy. The temperature dependences of the main physical properties of the proposed eutectic solvent—the refractive index, density and viscosity—were determined. For the first time, the extraction properties of the eutectic solvent BTMPPA/TBP/phenol (1:1:2) were studied using the example of the extraction of metal ions from aqueous nitrate solutions. The extraction efficiencies of Pr, Nd and Dy in a single stage were 34, 38 and 81%, respectively. The extraction behaviour of Pr, Nd and Dy with the eutectic solvent BTMPPA/TBP/phenol was studied as a function of pH, salting-out agent concentration, component ratio in the eutectic mixture, phase volume ratio, etc. Nitric acid with a concentration of 0.5 mol/L was chosen as a stripping agent, and the chemical stability of the eutectic solvent BTMPPA/TBP/phenol during extraction–stripping cycles was evaluated. In summary, the proposed hydrophobic eutectic solvent has good physical characteristics and enables a more efficient recovery of rare-earth elements from nitrate solutions. Full article

Bio-based polymeric composites were prepared by dispersing different amounts of olive pit (OP) powder within an acrylate epoxidized soybean oil (AESO) photocurable resin using tetrahydrofurfuryl acrylate (THFA) as diluent and (2,4,6-trimethylbenzoyl), phosphine oxide (BAPO) as photo-initiator, and they were photocured by Vat Photopolymerization (VP) using a Liquid Crystal Display (LCD) 3D printer. Formulation viscosity was studied because of its important role in a VP process able to influence the printability of the final parts. Different 3D printed architectures were successfully realized with good resolution and accuracy, high level of detail, and flexibility. The effect of OP addition was investigated by thermal (TGA and DSC), morphological (SEM and PSD), viscoelastic (DMA), and mechanical (tensile testing) characterization. The filler led to an increase in the T_g, storage modulus, and tensile properties, underlining the stiffening effect induced by the OP particles onto the polymeric starting resin. This underlines the possibility to apply these bio-based composites in many application fields by valorizing agro-wastes, developing more sustainable materials, and taking advantages of VP 3D printing, such as low costs, minimal wastage, and customized geometry. Biocompatibility tests were also successfully carried out. The results clearly indicate that the AESO-based composites promote cell adhesion and viability. Full article

The reaction of the bulky ligand 1,2-bis-(di-tert-butylphosphinomethyl)benzene, 1 with [Ni(DME)Cl₂], 3, DME = 1,2-dimethoxyethane, at room temperature over extended periods, affords the new blue Zwitterionic complex [2-(C₆H₄-CH₂P(H)^tBu₂-1-(CH₂P^tBu₂NiCl₃)], 4, which contains a phosphonium group and an anionic nickel trichloride. This complex decomposes in alcohols such as methanol and the solution turns yellow. A discussion of the possible mechanism leading to the observed product is presented. Key to this is identification of the source of the phosphonium proton, which we speculated to arise from trace water in the initial nickel complex. To prove that trace water was present in [Ni(DME)Cl₂], a sample of this precursor was reacted under similar condition with anhydrous DMF alone. In addition to the known complex [Ni(DMF)₆)]²⁺[NiCl₄]²⁻, 5, we identified the trans-diaqua complex [Ni(Cl)₂(H₂O)₂(DMF)₂], 6, which proved the presence of trace water. Interestingly in dimethylformamide, [2-(C₆H₄-CH₂P(H)^tBu₂-1-(CH₂P^tBu₂NiCl₃)] exhibits thermochromic properties: an solution that is pale blue at ambient temperature reversibly changes colour to yellow upon cooling. This behaviour is specific to DMF and is related to the solvato-chromic behaviour exhibited by related DMF–nickel complexes. A discussion of the NMR spectra of compound 4 in a range of solvents is presented. The structures of the previously prepared molybdenum complex, [1,2-(C₆H₄-CH₂P^tBu₂)₂Mo(CO)₄] and the bis-(phosphine sulphide) of the ligand, [1,2-(C₆H₄-H₂P(S)^tBu₂)₂], 5, are described for structural comparative purposes. Full article

Phosphine (PH₃) is a fumigant often used to control insect pests, but its metabolic effects on insect physiology remain unclear. In this study, a comparative metabolomics analysis was performed to elucidate the physiological metabolic pathways affected by PH₃ exposure in Planococcus citri, and significant changes in the metabolic profiles induced by PH₃ treatment were identified. Principal component analysis and correlation analysis revealed different metabolic changes, and a total of 45 metabolites were identified and mapped to metabolic pathways using the KEGG database. PH₃ exposure inhibited energy metabolism by down-regulating riboflavin and flavin adenine dinucleotide, which are important cofactors in oxidative phosphorylation and reactive oxygen species generation. In addition, purine and pyrimidine metabolism, essential for nucleotide synthesis and cellular energy homeostasis, were also suppressed. Notably, lipid metabolism was significantly altered, and the juvenile hormone biosynthesis pathway was down-regulated. These results suggest that PH₃ inhibits electron transport chain activity, induces oxidative stress, and disrupts lipid homeostasis. This study enhances our understanding of the potential biomarkers of PH₃ exposure, the metabolic processes involved, and the resistance mechanisms that pests may develop in response to such exposure. Full article