Search Results (559)

The asymmetric [3+2] cycloaddition of azomethine ylides generated from the corresponding imino ester-to-trans-β-nitrostyrene catalysis by chiral aziridine-containing phosphines and phosphine oxides is described. Of the sixteen stereoisomers that could be formed as a result of the title reaction, three were formed, two of which were obtained in an enantiomerically enriched or pure form, and one in a racemic form. One of the products underwent epimerization under basic reaction conditions. Full article

The relationship between the structure of bis (2,4,4-trimethylpentyl) phosphinic acid (BTPA), diethyl phosphinic acid (DEPA), and diphenyl phosphinic acid (DPPA) on the flotation performance of malachite was investigated. Through a series of flotation experiments, density functional theory (DFT) calculations, and surface analysis methods, we aimed to deeply understand the microscopic mechanism of the interactions between these collectors and the malachite surface. The experimental results showed that BTPA exhibited excellent selectivity and flotation performance for malachite in the pH range of 5.0–11.0, significantly better than DEPA and DPPA. Surface analysis evidence from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) further confirmed the chemical adsorption characteristics of BTPA on the malachite surface. DFT calculations revealed that the adsorption capacity of BTPA on the malachite surface exceeds that of DEPA and DPPA. Electron transfer analysis, especially through frontier molecular orbital theory, differential charge density, PDOS, and COHP analysis, indicated that the charge transfer process from the s orbitals of oxygen atoms in the collectors to the d orbitals of copper atoms on the mineral surface is the decisive factor for the adsorption strength. Full article

Lithium-ion portable batteries (LiPBs) contain valuable elements such as cobalt (Co), nickel (Ni), copper (Cu), lithium (Li) and manganese (Mn), which can be recovered through solid–liquid extraction using choline chloride-based Deep Eutectic Solvents (DESs) and bi-functional ionic liquids (ILs). This study was carried out to investigate the extraction of metals from solid powder, black mass (BM), obtained from LiPBs, with various solvents used: six choline chloride-based DESs in combination with organic acids: lactic acid (1:2, DES 1), malonic acid (1:1, DES 2), succinic acid (1:1, DES 3), glutaric acid (1:1, DES 4) and citric acid (1:1, DES 5 and 2:1, DES 6). Various additives, such as didecyldimethylammonium chloride (DDACl) surfactant, hydrogen peroxide (H₂O₂), trichloroisocyanuric acid (TCCA), sodium dichloroisocyanurate (NaDCC), pentapotassium bis(peroxymonosulphate) bis(sulphate) (PHM), (glycine + H₂O₂) or (glutaric acid + H₂O₂) were used. The best efficiency of metal extraction was obtained with the mixture of {DES 2 + 15 g of glycine + H₂O₂} in two-stage extraction at pH = 3, T = 333 K, 2 h. In order to obtain better extraction efficiency towards Co, Ni, Li and Mn (100%) and for Cu (75%), the addition of glycine was used. The obtained extraction results using choline chloride-based DESs were compared with those obtained with three bi-functional ILs: didecyldimethylammonium bis(2,4,4-trimethylpentyl) phosphinate, [N_10,10,1,1][Cyanex272], didecyldimethylammonium bis(2-ethylhexyl) phosphate, [N_10,10,1,1][D2EHPA], and trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate, [P_6,6,6,14][Cyanex272]/toluene. The results of the extraction of all metal ions with these bi-functional ILs were only at the level of 35–50 wt%. The content of metal ions in aqueous and stripped organic solutions was determined by ICP-OES. In this work, we propose an alternative and highly efficient concept for the extraction of valuable metals from BM of LiPBs using DESs and ILs at low temperatures instead of acid leaching at high temperatures. Full article

Phosphine (PH₃) has been widely used as a fumigant in food storage, but increasing PH₃ resistance in major pests makes finding alternative fumigants urgent. Methyl benzoate (MBe), a volatile organic compound regarded to be a food-safe natural product, has recently demonstrated significant toxicity against a variety of insect pests. This study is the first evaluation of the fumigation toxicity of three benzoate compounds, MBe, vinyl benzoate, and ethyl benzoate, against PH₃-susceptible and PH₃-resistant strains of Rhyzopertha dominica and Sitophilus oryzae. All strains were exposed to the compounds at concentrations up to 20 µL/1.5 L air for 24 h. Compared to vinyl benzoate and ethyl benzoate, MBe induced higher mortality rates in all strains at all concentrations. When food was made available, the lethal median concentration for MBe was 10–17-fold higher than when tested without food. Moreover, no significant differences were observed between the responses of the PH₃-susceptible and PH₃-resistant strains to the compounds. Notably, S. oryzae was more susceptible to MBe. In laboratory settings, MBe successfully controlled PH₃-resistant strains of R. dominica and S. oryzae, making it a viable option for PH₃-resistance management. Thus, MBe might be suitable for food security programs as an environmentally benign alternative fumigant. Full article

The luminescent properties of Au(I) and Pt(II) compounds are commonly tuned by exploiting the alkynyl ligand with varying electron density. Herein, we describe the synthesis of three new emissive transition metal compounds, ^tbpyPt(C₂pym)₂, Ph₃PAuC₂pym, and Cy₃PAuC₂pym (where HC₂pym = 2-ethynylpyrimidine), verified by ¹H-NMR, EA, and a single-crystal X-ray diffraction analysis. The ^tbpyPt(C₂pym)₂ complex crystallized as an Et₂O solvate in the orthorhombic space group Pbca with Z = 24 with three unique Pt(II) species within the unit cell. The Cy₃PAuC₂pym species crystallizes in a monoclinic space group with one unique complex in the asymmetric unit. Changing the identity of the phosphine from Cy₃P to Ph₃P influences interactions within the unit cell. Ph₃PAuC₂pym, which also crystalizes in a monoclinic space group, has an aurophilic bonding interaction Au–Au distance of 3.0722(2) Å, which is not present in crystalline Cy₃PAuC₂pym. Regarding optical properties, the use of an electron-deficient heterocycle provides an alternate approach to blue-shifting the emission of Pt(II) transition metals’ compounds, where the aryl moiety is made more electron-deficient by exploiting nitrogen within this moiety instead of the typical strategy of decorating the aryl ring with electron withdrawing substituents (e.g., fluorines). This is indicated by the blue-shift in emission that occurs in ^tbpyPt(C₂pym)₂ (λ_max, emission = 512 nm) compared to the previously reported ^tbpyPt(C₂2-py)₂ (where HC₂2-py = 2-ethynylpyridine) complex (λ_max, emission = 520 nm). Full article

3,4-disubstituted maleimides find wide applications in various pharmacologically active compounds. This study presents a highly effective approach for synthesizing derivatives of 3,4-disubstituted maleimides through the direct isomerization of α-succinimide-substituted allenoates, followed by a cascade γ′-addition and aryl imines using PR₃ as a catalyst. The resulting series of 3,4-disubstituted maleimides exhibited excellent stereoselectivities, achieving yields of up to 86%. To our knowledge, the phosphine-mediated γ′-addition reaction of allenoates is seldom reported. Full article

Recycling spent lithium-ion batteries (LIBs) is crucial to prevent environmental pollution and recover valuable metals. Traditional methods for recycling spent LIBs include hydrometallurgy and pyrometallurgy. Among these methods, solvent extraction can selectively extract valuable metals in spent LIB leachate. Meanwhile, spent LIBs that underwent pyrometallurgical treatment generate a so-called ‘black alloy’ of Ni, Co, Cu, and so on. These elements in the black alloy need to be separated by solvent extraction and there have been few studies on extracting valuable metals from black alloy. Therefore, it is necessary to examine the extraction behavior of elements in black alloy and optimize the solvent extraction process to recover valuable metals. In this paper, four types of organic extractants are used to extract metals from simulated black alloy leachate: di-(2ethylhexyl) phosphoric acid (D2EHPA), bis-(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A), and neodecanoic acid (Versatic acid 10). Based on the pH isotherms, D2EHPA would be the most reasonable for Mn extraction and impurity removal. Cyanex 272 would be more suitable for Co separation than PC88A, and Versatic acid 10 is preferred for Cu extraction over other metals. In conclusion, the optimal combination of extractants is suggested for the recovery of valuable metals. Full article

The surface morphology of perovskite films significantly influences the performance of perovskite light-emitting diodes (PeLEDs). However, the thin perovskite thickness (~10 nm) results in low surface coverage on the substrate, limiting the improvement of photoelectric performance. Here, we propose a molecular additive strategy that employs pentafluorophenyl diphenylphosphinate (FDPP) molecules as additives. P=O and Pentafluorophenyl (5F) on FDPP can coordinate with Pb²⁺ to slow the crystallization process of perovskite and enhance surface coverage. Moreover, FDPP reduces the defect density of perovskite and enhances the crystalline quality. The maximum brightness, power efficiency (PE), and external quantum efficiency (EQE) of the optimal device reached 24,230 cd m⁻², 82.73 lm W⁻¹, and 21.06%, respectively. The device maintains an EQE of 19.79% at 1000 cd m⁻² and the stability is further enhanced. This study further extends the applicability of P=O-based additives. Full article

The direct copolymerization of ethylene with polar monomers to produce functional polyolefins continues to be highly appealing due to its simple operation process and controllable product microstructure. Low-cost nickel catalysts have been extensively utilized in academia for the synthesis of polar polyethylenes. However, the development of high-temperature copolymerization catalysts suitable for industrial production conditions remains a significant challenge. Classified by the resultant copolymers, this review provides a comprehensive summary of the research progress in nickel complex catalyzed ethylene-polar monomer copolymerization at elevated temperatures in the past five years. The polymerization results of ethylene–methyl acrylate copolymers, ethylene-tert–butyl acrylate copolymers, ethylene–other fundamental polar monomer copolymers, and ethylene–special polar monomer copolymers are thoroughly summarized. The involved nickel catalysts include the phosphine-phenolate type, bisphosphine-monoxide type, phosphine-carbonyl type, phosphine-benzenamine type, and the phosphine-enolate type. The effective modulation of catalytic activity, molecular weight, molecular weight distribution, melting point, and polar monomer incorporation ratio by these catalysts is concluded and discussed. It reveals that the optimization of the catalyst system is mainly achieved through the methods of catalyst structure rational design, extra additive introduction, and single-site catalyst heterogenization. As a result, some outstanding catalysts are capable of producing polar polyethylenes that closely resemble commercial products. To achieve industrialization, it is essential to further emphasize the fundamental science of high-temperature copolymerization systems and the application performance of resultant polar polyethylenes. Full article

In this paper, an interesting γ′-carbon 1,6-conjugate addition for phosphine-catalyzed α-succinimide substituted allenoates has been disclosed. A wide array of substrates was found to participate in the reaction, resulting in the production of diverse 4-diarylmethylated 3,4-disubstituted maleimides with satisfactory to outstanding yields. Furthermore, a plausible mechanism for the reaction was proposed by the investigators. Full article

Human abdominal aortic aneurysms (AAAs) are characterized by increased activity of matrix metalloproteinases (MMP), including MMP-12, alongside macrophage accumulation and elastin degradation, in conjunction with superimposed atherosclerosis. Previous genetic ablation studies have proposed contradictory roles for MMP-12 in AAA development. In this study, we aimed to elucidate if pharmacological inhibition of MMP-12 activity with a phosphinic peptide inhibitor protects from AAA formation and progression in angiotensin (Ang) II-infused Apoe^−/− mice. Complimentary studies were conducted in a human ex vivo model of early aneurysm development. Administration of an MMP-12 inhibitor (RXP470.1) protected hypercholesterolemia Apoe^−/− mice from Ang II-induced AAA formation and rupture-related death, associated with diminished medial thinning and elastin fragmentation alongside increased collagen deposition. Proteomic analyses confirmed a beneficial effect of MMP-12 inhibition on extracellular matrix remodeling proteins combined with inflammatory pathways. Furthermore, RXP470.1 treatment of mice with pre-existing AAAs exerted beneficial effects as observed through suppressed aortic dilation and rupture, medial thinning, and elastin destruction. Our findings indicate that pharmacological inhibition of MMP-12 activity retards AAA progression and improves survival in mice providing proof-of-concept evidence to motivate translational work for MMP-12 inhibitor therapy in humans. Full article

Magnesium hydroxide, as a green inorganic flame-retardancy additive, has been widely used in polymer flame retardancy. However, magnesium hydroxide is difficult to disperse with epoxy resin (EP), and its flame-retardancy performance is poor, so it is difficult to use in flame-retardant epoxy resin. In this study, an efficient magnesium hydroxide-based flame retardant (MH@PPAC) was prepared by surface modification of 2-(diphenyl phosphine) benzoic acid (PPAC) using a simple method. The effect of MH@PPAC on the flame-retardancy properties for epoxy resins was investigated, and the flame-retardancy mechanism was studied. The results show that 5 wt% MH@PPAC can increase the limiting oxygen index for EP from 24.1% to 38.9%, achieving a V-0 rating. At the same time, compared to EP, the peak heat release rate, peak smoke production rate, total smoke production rate, and peak CO generation rate for EP/5 wt% MH@PPAC composite material decreased by 53%, 45%, 51.85%, and 53.13% respectively. The cooperative effect for PPAC and MH promotes the formation of a continuous and dense char layer during the combustion process for the EP-blend material, significantly reducing the exchange for heat and combustible gases, and effectively hindering the combustion process. Additionally, the surface modification of PPAC enhances the dispersion of MH in the EP matrix, endowing EP with superior mechanical properties that meet practical application requirements, thereby expanding the application scope for flame-retardant EP-blend materials. Full article

Osteosarcoma malignancy currently represents a major health problem; therefore, the need for new therapy approaches is of great interest. In this regard, the current study aims to evaluate the anti-neoplastic potential of a newly developed phosphinic acid derivative (2-carboxyethylphenylphosphinic acid) and, subsequently, to outline its pharmaco-toxicological profile by employing two different in vitro human cell cultures (keratinocytes—HaCaT—and osteosarcoma SAOS-2 cells), employing different techniques (MTT assay, cell morphology assessment, LDH assay, Hoechst staining and RT-PCR). Additionally, the results obtained are compared with three commercially available phosphorus-containing compounds (P1, P2, P3). The results recorded for the newly developed compound (P4) revealed good biocompatibility (cell viability of 77%) when concentrations up to 5 mM were used on HaCaT cells for 24 h. Also, the HaCaT cultures showed no significant morphological alterations or gene modulation, thus achieving a biosafety profile even superior to some of the commercial products tested herein. Moreover, in terms of anti-osteosarcoma activity, 2-carboxyethylphenylphosphinic acid expressed promising activity on SAOS-2 monolayers, the cells showing viability of only 55%, as well as apoptosis features and important gene expression modulation, especially Bid downregulation. Therefore, the newly developed compound should be considered a promising candidate for further in vitro and in vivo research related to osteosarcoma therapy. Full article

A family of silver(I) and copper(I) complexes containing carboxylate ligands were prepared from the corresponding carboxylic acids and Ag₂O. The compounds were characterized by various spectroscopic methods and X-ray diffraction. In the solid state, the silver(I) salts are coordination polymers based on dinuclear silver species with bridging carboxylate ligands. The reaction of these silver salts with Ph₃P gives four-coordinate, tetrahedral bis(phosphine) complexes. Analogous copper(I) bis(phosphine) compounds were prepared by the reduction of copper(II) carboxylates with Ph₃P. Decomposition temperatures and thermal decomposition products were studied by TGA/DSC measurements. The metal compounds decomposed cleanly to their respective metals (silver or copper) at temperatures ranging from 206 to 338 °C. Full article

Zirconium is recognized as one of the main impurities of the rare earth element scandium during purification. It presents significant challenges due to its similar chemical properties, making separating it difficult. This study used trialkyl phosphine oxide (TRPO) as a functional ligand, and the effects of carrier type and acidity on adsorption performance were first investigated. Among these, the novel extraction resin SiO₂-P as a carrier for TRPO demonstrated more prominent separation performance in 0.2 M H₂SO₄ and 5 M HCl solutions. The kinetic and isotherm data were consistent with the pseudo-secondary kinetics and Langmuir model, respectively, and the adsorption process could be regarded as homogeneous monolayer adsorption subject to the dual effects of chemisorption and internal diffusion. In addition, thermodynamic analysis showed that the adsorption process of zirconium under the experimental conditions was a spontaneous endothermic process. Combined with the results of SEM-EDS, FT-IR, and XPS analyses, scandium and zirconium were successfully adsorbed by the resin and uniformly distributed on its surface, and the greater affinity of the P=O groups on the resin for zirconium was the critical factor contributing to the separation of scandium and zirconium. Finally, scandium and zirconium in sulfuric acid and hydrochloric acid media were extracted and separated by column experiments, and the purity of scandium could reach 99.8% and 99.99%, respectively. Full article