Search

The Mitsunobu reaction is one the most widely known reactions in the organic chemistry canon. Despite its fame, some aspects of the mechanism remain poorly understood, 55 years after its initial discovery. This short review collates the findings of several publications focused on the mechanism of the Mitsunobu reaction, highlighting both the current state of knowledge and the remaining missing pieces.

Preformed Ni(0) complexes are rarely used as precatalysts in cross-coupling reactions, although they can incorporate catalytically active nickel directly into the reaction. In this work, we focus on the preparation and the catalytic application of low-coordinate Ni(0) complexes supported by bulky monophosphine ligands in C–S cross-coupling reactions. We have prepared two families of Ni(0) complexes, bis-phosphine aducts of the type [Ni(PR2Ar′)2] (Ar′ = m-terphenyl group) and monophosphine derivatives of the type [Ni(PR2Ar′)(DVDS)] (DVDS = divinyltetramethyldisiloxane). DFT calculations were used to account for the atypical bent structures displayed by the bis-phosphine Ni(0) complexes. Monophosphine-Ni(0) complexes display catalytic activity superior to bis-phosphine Ni(0) adducts, which suggests that the former facilitate the generation of highly reactive monoligated PNi(0) species. Furthermore, the reactivity of monophosphine-Ni(0) precatalysts outperform that observed with Ni(II) precatalysts with the same phosphine ligands, supporting a more facile activation step to the same catalytic species. This enhanced reactivity allows for the use of lower catalyst loadings (1–5 mol%) and for carrying out the challenging coupling between aryl chlorides and alkylthiols. [ABSTRACT FROM AUTHOR]

The papaya mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae), poses a serious threat to global trade and is classified as a quarantine pest in some countries. Phosphine (PH3) is considered an alternative to methyl bromide for postharvest control of P. marginatus. However, reports addressing the impact of PH3 treatment to control P. marginatus on succulent plants are lacking. This study aims to investigate the effects of PH3 fumigation alone and in combination with ethyl formate (EF) on insecticidal activity across all developmental stages of P. marginatus and its influence on the quality of plant products. Tolerance tests showed that among all developmental stages, the egg stage of P. marginatus is the most tolerant to PH3 treatment. A concentration of 1 g m–3 PH3 for 8 h exposure at 25 °C achieved a 99.9968% (Probit-9) mortality rate for the eggs. Additionally, we examined the synergistic effects of combining EF with PH3. Combined fumigation with 0.5 g m–3 PH3 and 2 g m–3 EF for 8 h at 25 °C did not adversely affect the lifespan and quality of three succulent plant species, achieving an effective dose of 0.99991. These findings suggest that PH3 fumigation, with or without EF, are effective treatments for postharvest control of P. marginatus in succulent plants. Graphical Abstract [ABSTRACT FROM AUTHOR]

[(L1)Au(µ-H)2MCp2][BF4] complexes (M = Mo and W) featuring cavity-shaped tris-2-(4,4'-di-tert-butylbi-phenylyl)phosphine (L1) have been isolated. The tungsten derivative showed a remarkably fast reactivity in photolytic hydride transfer to generate the mononuclear gold hydride (L1)AuH. Both bimetallic adducts trap Ag+ cations, forming unprecedented {Au(µ-H)M(µ-H)Ag} trimetallic assemblies with destabilized Au-M interactions. [ABSTRACT FROM AUTHOR]

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Spain and co-rapporteur Member State Germany for the pesticide active substance phosphine are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative uses of phosphine as a post-harvest indoor insecticide to control insects infesting stored grains (barley, oat, rye, wheat), cacao and coffee beans, tree nuts and oilseeds and dried fruit via gassing application (gas-tight rooms/container). The reliable end points, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified. [ABSTRACT FROM AUTHOR]

In this paper, the clean high yielding, synthesis, and structure of the tetraphosphine ligand, 1,1′,2,2′-tetrakis-(di-isopropyl-phosphino)ferrocene, (tdipf), is described. In addition, improved synthesis methods for 1,1′,2,2′-tetrakis(diphenylphosphino)ferrocene, (tppf), and 2,2′-bis-(diphenylphosphino)-1,1′-dibromoferrocene are also reported, and the synthetic method is generalised to include the synthesis of 3,3′-bis-(diphenylphosphino)-1,1′,2,2′-tetrabromoferrocene. The related ligands 2,2′-bis-(iso-propylphosphino)-1,1′-bis-diphenylphosphinoferrocene (diprdppf) and 2,2′-bis-(di-isopropylphosphino)-dibromoferrocene have also been prepared and characterised. The crystal structure of the square planar bimetallic nickel (II) dichloride of tdipf is also described, together with a brief NMR study investigating the synthesis of this and related metal complexes. The crystal structures of the palladium and platinum dichloride complexes of 2,2′-bis-(di-isopropylphosphino)-1,1′-dibromoferrocene, bpdbf, are also discussed in the context of comparison with previously known crystal structures in the same general family. A general discussion on the synthetic methodology is given, along with indications for future research that other researchers might explore. [ABSTRACT FROM AUTHOR]

Reactions of Na2PdCl4 with two equivalents of 5-(p-tolyl)-1,3,4-oxadiazole-2-thiol (MoxSH), afford complex of the type [Pd(MoxS)2] (1). Further reaction with equivalent mole of diphosphine ligand {Ph2P(CH2)nPPh2} (where n = 1 dppm, 2 dppe, 3 dppp, 4 dppb, (CH2)n = dppf) or two equivalents of triphenyl phosphine or triphenyl phosphine sulfide affords mixed-ligand complexes of the type [Pd(MoxS)2(Ph2P(CH2)nPPh2)] (2-6), [Pd(MoxS)2(PPh3)2] (7) and [Pd(MoxS)2(SPPh3)2](8). The prepared complexes were characterized using different physical and spectroscopic methods. The results indicated that the MoxS ligand behave as coordinate in a anion monodentate fashion sulfur atom to give a square planer around the metal ion. Preliminary anti-bacterial activity has been assessed against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis bacteria. The prepared complexes show good activity in compared with standard drug. [Pd(MoxS)2(dppf)] (6) displays good activity (18, 22 and 20 mm) against certain tested microbes Escherichia coli, Staphylococcus aureus and Bacillus subtilis, respectively. [ABSTRACT FROM AUTHOR]

In this work, we unveil a novel synthesis of bench stable Ni (II) complexes supported by tetradentate Schiff‐base ligands and the complexes were devoid of any phosphine or phosphine‐based ligand. These Ni‐complexes were successfully applied for the dehydrogenation of secondary alcohols for ketone and ketazine syntheses. Secondary alcohols with different functional groups were well tolerated during catalytic cycle. Moreover, we successfully extended this protocol for the synthesis of biologically significant ketones and ketazines. On the basis of various control experiments, probable reaction pathway was proposed, and an acceptorless alcohol dehydrogenation mechanism was suggested. [ABSTRACT FROM AUTHOR]

A novel one-pot three-steps process has been developed, including phosphine-catalyzed Rauhut–Currier reaction of γ-alkyl allenoates, Diels–Alder reaction with di- tert -butyl azodicarboxylate, followed by deprotection of Boc group to prepare tetra-substituted 1,6-dihydropyridazines in good yields. The 1,6-dihydropyridazines were easily converted to pyridazine derivatives via oxidative aromatization by DDQ. [ABSTRACT FROM AUTHOR]

In this study, we explore 1,4,2‐dioxazol‐5‐one as an alternative reagent to acyl azides in the Staudinger reaction, providing a safe and efficient method for synthesizing N‐acyliminophosphoranes under metal‐free conditions. This approach involves a heat‐promoted nucleophilic attack of phosphines on 1,4,2‐dioxazol‐5‐ones, followed by the extrusion of CO2 gas, resulting in the formation of the P−N coupling product. The synthetic utility of this metal‐free imidization of phosphine was demonstrated through a gram‐scale reaction and its suitability for subsequent transformations. Density functional theory (DFT) calculations were employed to elucidate the overall reaction pathway leading to the formation of N‐acyliminophosphoranes. [ABSTRACT FROM AUTHOR]

In the Morita‐Baylis‐Hillman (MBH) reaction, a nucleophile undergoes β‐addition to activated alkenes or alkynes, forming reactive intermediates for subsequent carbon‐carbon or carbon‐hetero bond formation. By using a π‐conjugated acceptor, however, an unprecedented reactivity of 1,3‐enynoates and indane‐1,3‐diones was uncovered in the presence of phosphines. When indan‐1,3‐diones were used, γ‐addition of phosphines to 1,3‐enynoates was observed for the first time; moderate to good yields were obtained for 14 substances containing the prominent spirocyclopropane scaffold with 100 % retention of (Z)‐alkene. When 2‐methyl‐indan‐1,3‐diones were used, di(tri)‐substituted furans were produced through the δ‐addition pathway, with 20 substances and a yield of up to 88 % being achieved. Control experiments and density functional theory calculations were conducted to obtain insights into the unconventional γ‐addition reaction pathway. [ABSTRACT FROM AUTHOR]

Unusual open‐chain tetradentate NHC‐phosphine pre‐ligand [Ph2PCH(Ph)ImCH2ImC(H)PhPPh2](BF4)2 was prepared in a good yield by metal‐mediated approach starting from Mn(I) complex [Cp(CO)2Mn(η2‐Ph2P=C(H)Ph)](BF4) and bis(imidazole) derivative ImCH2Im. Its reaction with Pd(OAc)2 afforded dicationic Pd(II) complex of bis(NHC)bis(phosphine) ligand adopting κ4PĈĈP coordination mode as a mixture of two diastereomers. The deprotonation of the C(H)Ph ligand bridge in the latter using KN(SiMe3)2 as base provided stable complex exhibiting unconventional phosphonium ylide moiety, whereas all attempts to detect the corresponding bis(ylide) derivative failed. [ABSTRACT FROM AUTHOR]

To better understand the stability of isolable primary phosphine oxides, new members of this family were synthesized through the oxidation of the corresponding phosphines. Specifically, the previously reported air‐stable primary phosphines (R)‐2‐phosphanyl‐2'‐methoxy‐1,1'‐binaphthyl, 9,10‐dihydro‐9,10‐etheno‐anthracen‐9‐yl phosphine, and 3‐phosphino‐2‐naphthol were treated with hydrogen peroxide or meta‐chloroperoxybenzoic acid to yield the new primary phosphine oxides. The compounds were characterized using NMR, MS, EA, and X‐ray crystallography. The oxides were further investigated in thermal disproportionation, and studied as ligands in half‐sandwich Ru(II) complexes bearing an auxiliary η6‐p‐cymene ligand. [ABSTRACT FROM AUTHOR]

The conventional synthetic approach to transition metal pincer complexes calls for the preparation of the tridentate pincer (pro)ligand first, with subsequent introduction of the transition metal center as the last step. This work demonstrates that the alternative synthetic logic, where the central main group element is introduced last, can be applicable to a number of PEP pincer complexes (E=B, Al, Si, P) derived from phosphinophenols and phosphinopyrroles. This approach obviates the need to isolate well‐behaved propincer precursors, and instead relies on the formation of phosphine‐metal adducts first, whose nature determines the stoichiometry of the needed main group reagent to complete the synthesis. [ABSTRACT FROM AUTHOR]

We report a one-pot synthesis of aryl carboxylic acids utilizing HCOOH as a CO surrogate with low Pd-catalyst loading. This operationally simple and scalable method does not require use of a high-pressure reactor, two-chamber reaction vessel, phosphine ligand, or base and proceeds in a relatively short amount of time at ambient temperature. Notably, halides, including iodo and bromo groups, and nitro groups remain intact under these mild reaction conditions. This methodology has been successfully applied to synthesizing 13C-labeled aryl carboxylic acids with satisfactory yields. [ABSTRACT FROM AUTHOR]

Catalysis by the colloidal suspension of nanoparticles has attracted considerable attention in recent years as it may combine interesting features: (i) the possibility of using inorganic catalysts, such as those of transition metal nanoparticles; (ii) the opportunity of adding well-designed ligands, as in homogeneous catalysis, to tune the activity and selectivity of a given reaction. However, it is critical to delineate operating conditions (e.g., stoichiometry of the ligand versus the number of active surface sites) for which the catalyst surface does not get poisoned by a very large number of coordinating species.Originating from molecular catalysis, a frustrated Lewis pair (FLP) is a compound containing a strong Lewis acid and a strong Lewis base that are prevented from forming an adduct. The FLPs represent a major advance over the past 20 years for the catalytic activation of small molecules (H2, CO, CO2, etc.) under mild conditions. More recently, a similar interaction on the surface of inorganic compounds has enabled hydrogenation to be carried out under milder conditions than those in conventional processes. These surface FLPs are emerging as promising materials in heterogeneous catalysis, but they remain underdeveloped in the field of transition metal nanoparticles.Here, we propose and illustrate the design of metal nanoparticles in colloidal suspension as Lewis acid partners of a “NanoFLP”, that is, a frustrated Lewis pair in which one partner is the nanoparticle surface and the other is a molecular Lewis base. This concept was explored for the hydrogenation of alkynes such as phenylacetylene. However, to this date, no direct proof for the occurrence of an FLP has been provided on the examples that we developed. We discuss possible interpretations of the experimental data and ways of clarifying the mechanism involved.

Phosphine plays an important role in chemistry, materials science, physics, agriculture and other fields, and is widely used in semiconductor, plastic industry and storage fumigation. In order to systematically sort out the research hotspots of phosphine and deeply understand the research trends in the field of agriculture, this paper has utilized the Web of Science Core Collection database and employed CiteSpace for bibliometric analysis from dimensions such as annual publication output, keywords, authors, and institutions. The results showed that the publication output on phosphine research generally exhibited an upward trend, with research mainly concentrated in fields like chemistry and materials science. In the agricultural field, the United States, Australia, China, Greece, and Brazil occupy leading positions. In addition, attention should be focused on ' Journal of Stored Products Research ', ' Journal of Economic Entomology ' and ' Pest Management Science ' to keep up with the latest research trends in this field. In terms of research hotspots, current efforts are primarily centered on optimizing phosphine fumigation methods and investigating mechanisms of phosphine resistance. The application of RNAi technology in phosphine research may become one of the frontier hotspots in the future. This bibliometric study has emphasized elucidating the research dynamics of phosphine in the agricultural field, providing a systematic analysis of current research that can be utilized by industry professionals and researchers interested in this domain.

P‐stereogenic phosphines, renowned for their utility as ligands and catalysts, have been instrumental in the field of asymmetric catalysis. However, the catalytic asymmetric synthesis of chiral ligands possessing both axial and phosphine chirality remains a significant challenge. Here, we present the successful demonstration of a Cu‐catalyzed asymmetric C−P construction using in situ generated secondary phosphine and heteroaryl chloride. By introducing a chiral NHC ligand and an achiral diphosphine auxiliary ligand, we effectively alleviated the poisoning effect caused by phosphine(III) compounds and suppressed the nonenantioselective background reaction. The reaction exhibited excellent enantioselectivity, with up to 96 % ee, and good diastereoselectivity, with up to 14 : 1 dr, when employing less sterically hindered secondary phosphines. This particular substrate poses a significant challenge due to its strong poisoning effect in copper catalysis. [ABSTRACT FROM AUTHOR]

Chiral 2‐azetines and allenes are highly valuable structural units in natural products and useful chemicals. However, enantioselective synthesis of both 2‐azetines and allenes has been extremely challenging. Herein, we present asymmetric construction of chiral 2‐azetines (70–98 % yields and up to 96 % ee) through chiral phosphine‐catalyzed [2+2] annulation of yne‐enones with sulfamate‐derived cyclic imines. These 2‐azetines were easily transformed into chiral allenes upon treatment with Et3SiH, BF3 ⋅ Et2O and water at rt for 2 minutes. Based on the above transformations, a concise one‐pot synthetic procedure combining [2+2] annulation of yne‐enones and sulfamate‐derived cyclic imines under phosphine catalysis and sequential reduction/isomerization/ring‐opening reaction through Et3SiH, BF3 ⋅ Et2O and water was thus set up, providing axially chiral tetrasubstituted allenes in satisfactory yields and enantioselectivities (56–90 % yields and up to 91 % ee). [ABSTRACT FROM AUTHOR]

In order to replace the Pt catalyst which has several limitations that hampered the corresponding practical applications. A series of mesoporous carbons encapsulating CoP nano-particles and doped with P were prepared by a combination of solvent-evaporation-induced self-assembly (EISA) and carbonization. Phenolic-based resins and diammonium hydrogen phosphate as carbon and phosphorus precursors, respectively. Cobalt chloride hexahydrate (CoCl 2) was used as the cobalt precursor, which was also treated as the porogen. Based on characterization data, the porosity of the final sample depends on the amount of CoCl 2 added. which could further determine the electrocatalytic activity. When evaluated as the electrocatalysts towards hydrogen evolution reaction (HER), the as-received electrocatalysts exhibited outstanding electrocatalytic performance, including low overpotential, small Tafel slope, and good stability. • CoP NPs entrapped, P doped carbons are prepared via combination of EISA and carbonization. • The amounts of CoCl 2 determine the crystalline structures of final products. • Co1.00 PC-900 possesses excellent electrocatalytic performance towards HER. [ABSTRACT FROM AUTHOR]

A stable dialkylphosphinyl radical reacted with bromoboranes to afford the corresponding phosphinoboranes accompanied with a bromophosphine under neutral condition at room temperature. The obtained phosphinoboranes have almost planar structures and have an effective P–B dative π-bond. The formation of phosphinoboranes would proceed via coordination-induced bromine abstraction from bromoboranes as a pivotal step, which was supported by the computational study. [ABSTRACT FROM AUTHOR]

Convenient syntheses of organophosphorus analogs of α- and β-alanine containing functionalized phosphonous and phosphinic acid moieties based on readily available trimethylsilyl esters of trivalent phosphorus acids have been developed. Nucleophilic addition of bis(trimethylsiloxy)phosphine to trimethylsilyl acrylates or α-(acetylamino)-acrylates proceeds regioselectively to give [2-(trimethylsiloxycarbonyl)ethyl]phosphonites, the subsequent functionalization of which affords various derivatives of the target acids. The resulting compounds are of interest as promising biologically active substances and water-soluble ligands. [ABSTRACT FROM AUTHOR]

Nucleophilic phosphine-catalyzed annulations are recognized as practical and powerful tools for synthesizing various cyclic compounds. Phosphine acceptors play a key role in nucleophilic phosphine catalysis. The design and synthesis of new phosphine acceptors that are able to introduce new zwitterionic intermediates with new reactivities into phosphine-catalyzed annulations is highly desirable. We recently applied proton-shift principles in the design of new phosphine acceptors, and we synthesized several new acceptors. With the use of these acceptors, we have developed several novel phosphine-catalyzed annulation reactions. In this account, we present a brief introduction to the design and application of a series of acidic-hydrogen-tethered electron-deficient acceptors for phosphine-catalyzed annulation reactions, categorized according to the type of atom (N–H, O–H, C–H) to which the acidic hydrogen is bound. 1 Introduction 2 Phosphine Acceptors Tethered with an Acidic N–H Group 3 Phosphine Acceptors Tethered with an Acidic O–H Group 4 Phosphine Acceptors Tethered with an Acidic C–H Group 5 Conclusions [ABSTRACT FROM AUTHOR]

The development of phosphine ligands continues to be essential for palladium‐catalyzed homogeneous carbonylation reactions, particularly in achieving high regioselectivity. In this study, a cyclosiloxane‐based multi‐dentate phosphine ligand, L1 (V4‐4Ph2P), characterized by its high thermal stability and oxidation resistance, was synthesized through the radical addition of secondary phosphines to the double bonds of tetravinyltetramethylcyclotetrasiloxane. L1 was then used in the Pd‐catalyzed alkoxycarbonylation of a variety of olefins, including terminal and internal alkenes, cyclic alkenes, aromatic terminal alkenes as well as tetra‐, tri‐ and 1,1‐disubstituted alkenes to afford the desired esters with moderate to good yields. As elucidated via DFT calculations and in situ IR spectroscopy, the optimum spatial chelation modes and high stability of Pd−H active species were responsible for the enhancement of catalytic efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Cereals, Oils & Foods is the property of Science & Technology of Cereals, Oils & Foods Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Self‐assembled peptides are used for diverse applications in the biomedical and technological fields. The morphology and function of the assembled systems are dictated by the peptide sequence and length. In this work, a supramolecular catalyst was obtained upon self‐assembly of the diphenylalanine peptide conjugated to a triphenylphosphine Au(I) complex in acetonitrile. The assembled molecules were characterized by spectroscopic techniques and by scanning electron microscopy. The activity of the catalyst was tested on two substrates in cyclization reactions. The morphology and the dimensions of the assembled systems vary depending on the presence of a carboxyl versus an amide C‐terminal end. The catalyst efficiently promotes intramolecular cyclization reactions. Results obtained encourage the use of self‐assembled peptides for the obtainment of new and efficient catalysts. [ABSTRACT FROM AUTHOR]

Seawater electrolysis is an economical hydrogen production method that necessitates corrosion-resistant and active catalysts. Non-noble metal-based high-entropy compounds emerge as promising catalysts for seawater electrolysis due to their ability to enhance stability and activity via compositional control and tuning. In this investigation, a high-entropy precursor with a fusiform microstructure was utilized to synthesize high-entropy phosphide (HEP) (FeCoNiMnCu)P x and high-entropy oxide (HEO) (FeCoNiMnCu)O x. It is found that phosphorization and oxidization transformed the morphologies of the (FeCoNiMnCu)P x and (FeCoNiMnCu)O x into a layered sphere-shaped microstructure. The unique morphology, high surface area and special hysteretic diffusion effect of high-entropy materials contributed to the exceptional performance of both (FeCoNiMnCu)P x and (FeCoNiMnCu)O x in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Remarkably, both catalysts exhibited excellent stability, running continuously for 160 h at current densities exceeding 100 mA cm−2, which offered the potential for efficient seawater electrolysis. [Display omitted] • (FeCoNiMnCu)P x and (FeCoNiMnCu)O x with layered sphere-shape structure are obtained. • Morphology remodeling from high entropy precursor to target catalysts are analyzed. • The rational nanosheet structure is found to improve stability of hydrogen production. • The catalysts maintain stability over 160 h at a current density exceeding 100 mA cm−2. [ABSTRACT FROM AUTHOR]

In order to mitigate the release of toxic phosphine from aluminum hypophosphite in twin-screw processing, montmorillonite–melamine cyanurate was prepared by three methods: (1) mechanical intercalation, (2) water intercalation and (3) in situ intercalation. The sheet spacing of montmorillonite was increased from 1.140 nm to 1.141 nm, 1.208 nm and 1.217 nm for these three methods, respectively, and scanning electron microscope (SEM) and transmission electron microscopy (TEM) proved that melamine cyanurate was successfully inserted into the montmorillonite sheets. The montmorillonite–melamine cyanurate from in situ intercalation can best inhibit the release of PH3 from aluminum hypophosphite, and the peaks of phosphine, mean values of phosphine and integral of phosphine were reduced by 81.9%, 72.1% and 72.2%, respectively. The mode of action of montmorillonite–melamine cyanuric inhibition of the emission of phosphine from aluminum hypophosphite can be attributed to the physical absorption of montmorillonite and the chemical bonding of melamine cyanurate. In addition, in situ intercalation can slightly improve flame retardancy, attributed to incomplete exfoliation of montmorillonite sheets. [ABSTRACT FROM AUTHOR]

Currently, developing efficient and cost-effective electrocatalysts for hydrogen evolution reaction (HER) is an enormously grand challenge. Herein, an N-doped carbon-encapsulated CoNiP (CoNiP-NC) is successfully prepared using a dual-chelate (ZIF-67@EDTA-Ni2+) precursor by a simple method. Benefiting from the synergistic effects among the redistributed charges, the rich porous structure, and the different chemical states of doped N in the CoNiP-NC, the optimized CoNiP-NC-600 shows an excellent electrocatalytic performance toward HER with an overpotential of 104.2 mV and a small Tafel slope of 71.4 mV/dec to derive a current density of 10 mA/cm2 in 0.5 M H 2 SO 4 solution. Moreover, due to the N-doped carbon shell protection, CoNiP-NC-600 exhibits considerably enhanced stability under the harsh conditions of a 60-h reaction. Density functional theory (DFT) calculations reveal that the optimized CoNiP-NC-600 not only enhances the adsorption of H 2 O but also decreases the desorption of formed H 2 , essentially promoting the catalytic activity. It is believed that our developed method provides an effective and feasible route for constructing bimetallic phosphide electrocatalysts for hydrogen production. [Display omitted] • N-doped carbon-encapsulated CoNiP (CoNiP-NC) is prepared using dual chelates. • CoNiP-NC exhibits excellent HER performance in 0.5 M H 2 SO 4 solution. • Optimized CoNiP-NC needs a small overpotential of 104.2 mV to derive 10 mA/cm2. [ABSTRACT FROM AUTHOR]

While remarkable progress has been made in the development of peptide medicines, many problems related to peptide synthesis remain unresolved. Previously, we reported electrochemical peptide synthesis using a phosphine as a potentially recyclable coupling reagent. However, there was room for improvement from the point of view of reaction efficiency, especially in the carboxylic acid activation step and the peptide bond formation step. To overcome these challenges, we searched for the optimal phosphine. Among phosphines with various electronic properties, we found that electron‐rich triaryl phosphines improved the reaction efficiency. Consequently, we successfully performed electrochemical peptide synthesis on sterically hindered and valuable amino acids. We also synthesized oligopeptides that were challenging with our previous method. Finally, we examined the effect of substituents on the phosphine cations, and gained some insights into reactivity, which will aid researchers designing reactions involving phosphine cations. [ABSTRACT FROM AUTHOR]

We have developed a phosphine catalyzed asymmetric [3+2] cyclization of 3-oxetanone derived MBH carbonates with activated methyleneoxindole, to construct oxetane dispirooxindole skeletons. Diastereodivergent synthesis was realized via the control of the phosphine catalyst. The (−)-DIOP provides the syn diastereoisomers, while the spiro phosphine (R)-SITCP achieves the anti-epimers. [ABSTRACT FROM AUTHOR]

Simple Summary: This study explores the prevalence of phosphine resistance in stored-grain insects. The research, conducted in Greece, examined 53 key insect species and used two assessment protocols, namely, dose–response and CORESTA, to estimate phosphine resistance. The results showed that 13.3% of field populations were resistant, and mortality rates increased with higher phosphine concentrations. According to the dose–response protocol, 37.7% of field populations were found to be resistant, while all populations were susceptible according to the CORESTA protocol. The observed resistance patterns differ from those reported in other regions. The study emphasizes the importance of tailored fumigation strategies considering insect species' susceptibility to phosphine and recommends best management practices and rotational strategies to develop effective resistance management plans. The results offer valuable insights into the dynamic landscape of phosphine resistance in stored-product insects and suggest potential avenues for further research and control measures. Post-harvest losses due to insect infestation and spoilage by bacteria and molds pose significant challenges to global cereal production. This study investigates the prevalence of resistance to phosphine, a commonly used grain protection agent, in stored-grain insects. The research, conducted in various storage facilities across Greece, examined 53 populations of key stored-product insect species. Two assessment protocols, namely, dose–response (at 50–1000 ppm for 3 days exposure) and CORESTA (at 300 ppm for 6 days), were used herein to estimate phosphine resistance. The results showed that 13.3% of field populations were resistant, and mortality rates increased with higher phosphine concentrations. Specifically, according to the dose–response protocol, among the 53 field populations, 37.7% were found to be resistant to phosphine, namely, two populations of O. surinamensis, one of S. oryzae, seven of T. confusum, one of C. ferrugineus, one of T. castaneum, and all populations of R. dominica, whereas, according to the CORESTA protocol, all populations were found to be susceptible to phosphine. The observed resistance patterns differ from those reported in other regions of the world. The study highlights the importance of tailored fumigation strategies, considering insect species varying susceptibility to phosphine. It recommends the use of best management practices and rotational strategies, such as combining phosphine with other methods, to develop effective resistance management plans. The results provide valuable insights into the dynamic landscape of phosphine resistance in stored-product insects and suggest potential avenues for further research and control measures. [ABSTRACT FROM AUTHOR]

Background/Objectives: The mechanisms of action of phosphine are diverse and include neurotoxicity, metabolic inhibition, and oxidative stress; however, its efficacy at low temperatures is unclear. Methods: Comparative metabolomics is suitable for investigating the response of the spotted-wing fly Drosophila suzukii to exposure toward a combination of cold stimuli and fumigant PH3. Results: Under this combined exposure, 52 metabolites exhibiting significant differences in stress were identified and their physiological roles were analyzed in the Drosophila metabolic pathway. Most metabolites were involved in amino acids, TCA cycle, and nucleic acids. In addition, the alteration levels of cell membrane lipids, such as glycerophospholipids, sphingolipids, and glycerolipids, clearly showed changes in the combined treatment compared to PH3 and low temperatures alone. Aconitic acid, a component of the TCA cycle, was completely inhibited by the combined treatment. Conclusions: These results suggest that treatment-specific indicators could be useful biomarkers to indicate the synergistic effects of PH3 and low temperature on energy metabolism. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Taiwan Agricultural Research is the property of Taiwan Agricultural Research Institute, Council of Agriculture, Executive Yuan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Trivalent phosphine catalysis is mostly utilized to activate the carbon‐carbon multiple bonds to form carbanion intermediate species and is highly sensitive to certain variables. Random manual multi‐variables are critical for understanding the batch disabled regeneration of trivalent phosphine chemistry. We need the artificial intelligence‐based system which can change the variable based on previously conducted failed experiment. Herein, we report an auto‐optimized electro‐micro‐flow reactor platform for the in‐situ reduction of stable P(V) oxide to sensitive P(III) and further utilized the method for Corey‐Fuchs reaction. [ABSTRACT FROM AUTHOR]

The Wittig reaction is renowned as exceptionally versatile method for converting a diversity of aldehydes and ketones into alkenes. Recently, strategies for chiral phosphine catalysis under PIII/PV=O redox cycling emerged to render this venerable transformation stereoselective. Herein, we describe that phosphine redox catalysis enables the enantioselective synthesis of pertinent biaryl atropisomers by means of a stereocontrolled arene‐forming Wittig reaction. Key to the process is the release of an endogenous base from readily accessible tert‐butyloxycarbonylated Morita–Baylis–Hillman adducts triggered by catalyst intramolecularization, permitting mild phosphine redox catalysis for atroposelective Wittig reactions. By this strategy, a broad diversity of biaryl atropisomers is obtained with up to 94 : 6 enantioselectivity. [ABSTRACT FROM AUTHOR]

Boraadamantanes are a privileged class of caged group 13 compounds having a trigonal pyramidal (non-VSEPR) ground-state. The Lewis acid–base chemistry of this type of compound is underdeveloped when compared to acyclic derivatives. This report provides the first examples of bifunctional boraadamantanes with an appended phosphine moiety (also the first boraadamantanes having a phosphorus–boron bond). Using this scaffold, boraadamantane coordination compounds are accessed for the first time. [ABSTRACT FROM AUTHOR]

The development of efficient and stable non-precious bifunctional electrocatalysts is of great significance, but it remains a great challenge. Herein, we have constructed Co/CoP@NC heterojunction catalyst loaded with Co and CoP particles on a nitrogen-doped carbon (NC) substrate using the pyrolysis-oxidation-phosphating strategy. The synergistic effect of Co and CoP particles on the NC substrate increases the active specific surface area, accelerates the charge transfer rate, and improves the intrinsic activities of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The Co/CoP@NC catalyst exhibits superior HER and OER performance. Specifically, the overpotentials required for Co/CoP@NC to reach the current density of 10 mA cm−2 are 142 and 186 mV for HER and OER, respectively. This study provides new insights into the design and synthesis of efficient and stable Co-based heterostructure catalysts. [Display omitted] • Co/CoP@NC is prepared by the pyrolysis-oxidation-phosphating strategy. • Co/CoP@NC has a larger specific surface area and faster charge transfer. • The OER performance of Co/CoP@NC is better than commercial Ir/C at 10 mA cm−2. • Only 1.67 V is needed for Co/CoP@NC to drive 10 mA cm−2 for overall water splitting. [ABSTRACT FROM AUTHOR]

Three new palladium(II)-iminophosphine complexes, [Pd(L1)(Cl)2] C1, [Pd(L2)(Cl)2] C2 and [Pd(L3)(Cl)2] C3 have been synthesized and successfully characterized by using 1H-NMR, 13C-NMR, 31P-NMR, UV–Vis, FT-IR and magnetic susceptibility techniques. Catalytic activities of complexes towards Suzuki–Miyaura C–C coupling reactions between phenylboronic acid and several aryl halides were investigated under several reaction conditions (solvent, temperature, base, reaction time, and type of substrate). Under optimum conditions, achieving high yields of up to 99% was possible. When 1-bromo-4-nitrobenzene was used for complex C1, bromobenzene for complex C2, and bromobenzene for complex C3, product yields of 99, 99, and 98% were achieved, respectively. Three new palladium complexes bearing iminophosphine ligands was synthesized and successfully characterized. Catalytic activities of the synthesized complexes were investigated on Suzuki–Myaura type coupling reaction between phenylboronic acid and several aryl halides. All complexes exhibited good catalytic activities on C–C coupling reactions up to 99% product formations under mild conditions. [ABSTRACT FROM AUTHOR]

Catalysis has been at the forefront of the developments that has revolutionised synthesis and provided the impetus in the discovery of platform technologies for efficient C−C or C−X bond formation. Current environmental situation however, demands a change in strategy with catalysis being promoted more in solvents that are benign (Water) and for that the development of hydrophilic ligands (especially phosphines) is a necessity which could promote catalytic reactions in water, allow recyclability of the catalytic solutions and make it possible to isolate products using column‐free techniques that involve lesser usage of hazardous organic solvents. In this review, we therefore critically analyse such catalytic processes providing examples that do follow the above‐mentioned parameter. [ABSTRACT FROM AUTHOR]

Mixed-ligand complexes of Pd(II) and Pt(II) with 2H-benzo[e][1,3] oxazine-2,4(3H)-dione (HBzoxe), tertiary phosphines (dppe, dppp, dppf and Ph3P), 2,2′-bipyridine (Bipy) and 1,10-phenanthroline (Phen) have been synthesized and characterized by molar conductance measurements, elemental analysis, IR and NMR (1H, 13C and 31P) spectroscopy. In addition, the antimicrobial activity assay studies. The results showed that the HBzoxe ligand behaves as a bidentate chelation ligand through the O and N atoms in [M(Bzoxe)2] {MII = Pd(1) and Pt(2)} complexes, whereas it acts as monodentate ligand through the oxygen atom in complexes (3–14) to afford a square planner geometry around Pd(II) and Pt(II) for all of the complexes. All of the complexes were moderately active on all the bacteria tested (Staphylococcus aureus and Escherichia coli). Hirshfeld surface analysis was carried out to investigate the cooperative non-covalent supramolecular interactions within the various complexes. [ABSTRACT FROM AUTHOR]

Integrating chemical vapour deposition (CVD) diamond with GaN material for effective thermal management of the power electronic devices is critical. However, there are issues with CVD processing, like GaN substrate etching under normal CVD diamond growth conditions, which nowadays, is overcome by inserting an intermediate silicon nitride layer of very low thermal conductivity. Unfortunately, such a buffer layer is detrimental to proper heat dissipation. So, the direct growth of diamonds onto GaN substrates is still a relevant research topic. Here, we have used an innovative low-temperature growth process by linear antenna microwave plasma enhanced CVD to overcome such a problem. Other than the normal hydrogen gas CVD recipe, PH3 gas diluted with hydrogen (1,000 ppm in H2) was added as a doping gas precursor, to dope the diamond lattice with phosphorous atoms, by varying the substrate temperature from 400oC to 900oC. PH3 addition in the precursor gas recipe was found to etch the GaN substrate substantially. The phosphorous atom was found to be present on the surface of the diamond film from their corresponding X-ray photoelectron spectroscopy signal. Raman spectroscopy and scanning electron microscopy images do not reveal GaN substrate damage when pure hydrogen gas was used as a precursor without PH3 addition. However, there is a relative competition between the GaN substrate decomposition and CVD diamond growth rates when diluted PH3 gas was used in the precursor gas recipe. At a lower substrate temperature of 400oC, GaN etching was prevalent, but with a gradual increase in substrate temperature to 900ºC, diamond lateral growth was promoted inside the linear antenna CVD reactor, which partially protected the underneath GaN/sapphire heterostructures from decomposition under harsh plasma CVD conditions.

The molecular structure of tricarbonyl[η4-6-exo-(triphenylphosphino)cyclohepta-2,4-dien-1-one]iron(0) tetrafluoroborate dichloromethane hemisolvate, [Fe(C28H22O4)(CO)3]BF4·0.5CH2Cl2, as determined by single-crystal X-ray diffraction is reported. The two independent tricarbonyl[η4-6-exo-(triphenylphosphino)cyclohepta-2,4-dien-1-one] iron(0) cations and their corresponding anions form dimers, which constitute the asymmetric unit of the structure parallel to the (100) plane. Solid-state stability within that asymmetric unit as well as between neighboring dimeric units is afforded by C—H...O and C—H...F hydrogen bonds and C—H...π and Y—X...π (Y = B, C; X = F, O) interactions, which yield diperiodic sheets and a three-dimensional extended network.