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The acidic hydrogen‐tethered allylic carbonates were successfully applied in phosphine catalysis. Their (4+2) annulation reaction with sulfamate‐derived cyclic imines under phosphine catalysis worked well to produce tetrahydropyridine‐fused heterocyclic compounds in high yields. A moderate ee was obtained in the initial screening. The zwitterionic intermediate produced through in‐situ deprotonation functioned as a four‐membered synthon. [ABSTRACT FROM AUTHOR]

As a result of reactions of nucleophilic addition of tertiary phosphines to pulegone in the presence of hydrochloric acid, quaternary phosphonium salts were obtained. Structure of the obtained compounds was established using a complex of spectral methods. Antibacterial and antifungal properties were determined for some phosphonium salts. [ABSTRACT FROM AUTHOR]

The novel core–shell type polymeric supports with accessible phosphorus groups were synthesised in the search for new reactive materials designed for the synthesis of functional resins. Amberlite XAD-4 adsorbent was impregnated with tri octyl phosphine oxides (Cyanex 921), which were then polymerized in the polymer carrier structure. The syntheses were evaluated by capturing FT-IR spectra, SEM micrographs, and analysing the sorption process. Batch studies were conducted to study the influence of some factors like pH, contact time, the metal ions concentration, and temperature on sorption efficiency of La (III) ions. The results showed that the optimum conditions were at pH equal to 0.5 and an equilibrium contact time of 30 min. According to the results of the sorption data analysis, the pseudo-second-order and Langmuir models were better fitted than the other estimated models. The sorption capacity of La (III) ions into impregnated resin as adsorbent martial was 54.25 mg g−1. The results revealed that the used adsorbent has been used successfully as a promising material for the elimination and recovery of La ions from the aqueous solutions. The impregnated resin exhibits a high chemical stability, reusability and fast equilibration. Further, the above procedure has been successfully employed for the application of real sample. [ABSTRACT FROM AUTHOR]

Tertiary bicyclic phosphines derived from (R)-(+)-limonene provided efficient palladium catalysts for Heck cross-coupling reactions. Overall, high yields of the desired aryl alkenes products were obtained for cross-coupling of sterically and electronically diverse substrates. The efficiency of the catalysts was further demonstrated in the synthesis of commercial ketones, such as raspberry ketone and its derivatives. [ABSTRACT FROM AUTHOR]

Trialkyl and triaryl phosphines are important classes of ligands in the field of catalysis and materials research. The wide usability of these low-valent phosphines has led to the design and development of new synthesis routes for a variety of phosphines. In the present work, we report the synthesis and characterization of some mixed arylalkyl tertiary phosphines via the Grignard approach. A new asymmetric phosphine is characterized extensively by multi-spectroscopic techniques. IR and UV–Vis spectra of some selected compounds are also compared and discussed. Density functional theory (DFT)-calculated results support the formation of the new compounds. [ABSTRACT FROM AUTHOR]

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We report a phosphine-directed ruthenium-catalyzed C8-selective alkylation of naphthalenes with alkenes. This protocol provides straightforward access to a large library of electron-rich C8-alkyl substituent 1-naphthphosphines, which outperformed common commercial phosphines and their precursors in the Pd-catalyzed Suzuki–Miyaura coupling of aryl bromides with alkylboronic acid. [ABSTRACT FROM AUTHOR]

A novel synthesis of diphenyl(2-thienyl)phosphine, along with its' oxide, sulfide and selenide derivatives, is reported here. These phosphines have been characterized by NMR, IR, MS and X-Ray crystallography. The phosphine oxide derivative was reacted with a selection of lanthanide(III) nitrates and triflates, LnX3, to give the resultant metal–ligand complexes. These complexes have also been characterized by NMR, IR, MS and X-Ray crystallography. Single crystal X-Ray diffraction data shows a difference in metal–ligand complex stoichiometry and stereochemistry depending on the counteranion (nitrate vs. triflate). The [Ln(Ar3P＝O)3(NO3)3] ligand–nitrate complexes are nine-coordinate to the metal in the solid state (bidentate nitrate), featuring a 1 : 3 lanthanide–ligand ratio and bear an overall octahedral arrangement of the six, coordinated ligands. Our [Ln(Ar3P＝O)3(NO3)3] ligand–nitrate complexes gave three examples of fac-stereochemistry, where mer-stereochemistry is almost universally observed in the literature of highly related [Ln(Ar3P＝O)3(NO3)3] complexes. For the Tb complexes, two different arrangements of the ligands around the metal were observed in the solid state for [Tb(Ar3P＝O)3(NO3)3] and [Tb(Ar3P＝O)4(OTf)2] [OTf]. [Tb(Ar3P＝O)3(NO3)3] is strictly nine-coordinate, ligand mer-stereochemistry in the solid state, and [Tb(Ar3P＝O)4(OTf)2] [OTf] is strictly octahedral, six-coordinate, with a square-planar stereochemical arrangement of the phosphine oxide ligands around the metal. [ABSTRACT FROM AUTHOR]

The reactivity of the Au(I) fluorido complex [Au(F)(SPhos)] (SPhos=dicyclohexyl(2',6'‐dimethoxy[1,1'‐biphenyl]‐2‐yl)phosphine) (1) towards several alkynes was studied. The formation of fluorovinyl species by formal insertion of the alkyne in the metal‐fluorine bond was observed. Addition of HCl to vinyl complexes resulted in protodeauration and elimination of the hydrofluorinated alkynes. Treatment of 1 with the terminal alkyne 1‐hexyne resulted in clean formation of the alkynyl complex [Au(C≡CC4H9)(SPhos)] (15), whereas with an excess alkyne hydrofluorination was also observed. Various Au(I) phosphine complexes including 1 were then compared in their ability to catalyze hydrofluorination reactions of 1‐phenyl‐1‐propyne with Et3N ⋅ 3HF as HF source. Model reactions suggested a reaction mechanism, which imparts a pre‐coordination of an alkyne to a cationic gold center followed by nucleophilic addition of a fluoride. Mechanistic investigations included reactivity studies at [Au(SPhos)][B(C6F5)4)] (17), which was treated with 4‐phenyl‐3‐butyn‐2‐one and TMAF (TMAF=tetramethylammonium fluoride). The reaction led to the formation of the complex [Au(CH3C(O)C=C(F)Ph)(SPhos)] (13), but not the fluorido complex 1. [ABSTRACT FROM AUTHOR]

CO2 conversion to value-added chemicals requires efficient catalytic CO2 reduction. Activation of CO2 using 14 phosphine–borane frustrated Lewis pair catalysts was done computationally using B3LYP-D3/6-31++G(d,p)/PCM/THF and M06-2X/6-311++G(d,p)/PCM/THF methods. We designed 14 catalysts, 12 of which exhibit better catalytic activity towards CO2 activation. Moreover, the catalytic mechanisms of compounds 12 and 4 were predicted, and they showed an efficient catalytic system for CO2 reduction to CO, HCHO and HCOOH. Catalysts 2, 3 and 4, with the same methylene linker, have activation energies of 20.5, 18.3 and 10.4 kcal/mol, respectively. This indicates that the catalytic activity of the compound is highly influenced by the ligand bound to borane and phosphine. Compound 4 with the CO2 activation energy of 10.4 kcal/mol is the most efficient catalyst for CO2 activation ever reported among phosphine–borane catalysts. The energy barriers for H2 activation with catalyst 12 (ΔG‡ = 26.6 kcal/mol) and 4 (ΔG‡ = 34.0 kcal/mol) are higher than the HCOOH releasing activation energy. The designed compounds will help to synthesise efficient metal-free phosphine–borane catalysts. Our results also indicate that phosphine–borane catalysts are promising candidates for CO2 reduction and direct hydrogenation. [ABSTRACT FROM AUTHOR]

Metallocenes are privileged backbones for synthesis and catalysis. However, the direct dehydrogenative C−H functionalization of unsymmetric metallocenes suffers from reactivity and selectivity issues. Herein, we report an electrochemically driven regioselective C−H phosphorylation of group 8 metallocenes. Mechanistic investigations indicate this dehydrogenative cross coupling occurs through an electrophilic radical substitution of the metallocene with a phosphoryl radical, facilitated by the metallocene itself. This work not only offers an efficient and divergent synthesis of phosphorylated metallocenes, but also provides a guide to interpret the reactivity and regioselectivity for the C−H functionalization of unsymmetric metallocenes. Metallocene-based phosphines are compounds with potential use in catalysis. Here, the authors report the electrochemical regioselective functionalization of group 8 metallocenes with phosphine oxides; over 60 examples of phosphorylated (benzo)ferrocenes and ruthenocenes can be accessed via this method without the need for a preinstalled directing group. [ABSTRACT FROM AUTHOR]

A phosphine‐catalyzed highly enantioselective and diastereoselective (up to 98 % ee and >20 : 1 dr) (3+2) annulation between vinylcyclopropanes and N‐tosylaldimines has been developed, which allows facile access to a range of highly functionalized chiral pyrrolidines. Notably, this method makes use of vinylcyclopropanes as a synthon for phosphine‐mediated asymmetric annulation reaction, which will offer new opportunities for potential applications of cyclopropanes substrates in phosphine‐catalyzed organic transformations. [ABSTRACT FROM AUTHOR]

Herein, we present the synthesis of new complexes based on ruthenium(II) (Ru(η6-p-cymene)Cl2PPh2CH2OH (RuPOH) and Ru(η6-p-cymene)Cl2P(p-OCH3Ph)2CH2OH (RuMPOH)) and iridium(III) (Ir(η5-Cp*)Cl2P(p-OCH3Ph)2CH2OH (IrMPOH) and Ir(η5-Cp*)Cl2PPh2CH2OH (IrPOH)) containing phosphine ligands with/without methoxy motifs on phenyl rings (P(p-OCH3Ph)2CH2OH (MPOH) and PPh2CH2OH (POH)). The complexes were characterized by mass spectrometry, NMR spectroscopy (1D: 1H, 13C{1H}, and 31P{1H} and 2D: HMQC, HMBC, and COSY NMR) and elemental analysis. All the complexes were structurally identified by single-crystal X-ray diffraction analysis. The Ru(II) and Ir(III) complexes have a typical piano-stool geometry with an η6-coordinated arene (RuII complexes) or η5-coordinated (IrIII compounds) and three additional sites of ligation occupied by two chloride ligands and the phosphine ligand. Oxidation of NADH to NAD+ with high efficiency was catalyzed by complexes containing P(p-OCH3Ph)2CH2OH (IrMPOH and RuMPOH). The catalytic property might have important future applications in biological and medical fields like production of reactive oxygen species (ROS). Furthermore, the redox activity of the complexes was confirmed by cyclic voltamperometry. Biochemical assays demonstrated the ability of Ir(III) and Ru(II) complexes to induce significant cytotoxicity in various cancer cell lines. Furthermore, we found that RuPOH and RuMPOH selectively inhibit the proliferation of skin cancer cells (WM266-4; IC50, after 24 h: av. 48.3 μM; after 72 h: av. 10.2 μM) while Ir(III) complexes were found to be moderate against prostate cancer cells (DU145). [ABSTRACT FROM AUTHOR]

In the pursuit of hydrophilic model fac-[Re(CO)3]+ complexes for (radio) pharmaceutical applications, six novel [2 + 1] mixed-ligand complexes of the general type fac-[Re(CO)3(bid)P] were synthesized and characterized, where bid is a bidentate ligand bearing either (N, O) or (S, S′) donor atom sets and P is the hydrophilic phosphine 1,3,5-triaza-7-phosphoadamantane (PTA) or its macrocyclic homologue 1,4,7-triaza-9-phosphatricyclo[5.3.2.1]tridecane (CAP). The (N, O) ligands used in this study were picolinic and quinaldic acid, while the (S, S′) ligand was diethyldithiocarbamate. The complexes were synthesized in generally high yields and purity and the characterization was performed by spectroscopic methods, IR, NMR, and elemental analysis. Detailed X-ray crystallographic study of molecular packing by using Hirshfeld analysis tools revealed a plethora of intermolecular interactions such as hydrogen bond, π⋯π, C-H⋯π, and carbonyl-carbonyl interactions. To our knowledge, the CAP complexes reported herein are the first example of [2 + 1] mixed-ligand fac-[Re(CO)3]+ complexes with CAP. The new complexes might have the potential to serve as platforms for the design of target-specific complexes with favorable pharmacokinetics. [ABSTRACT FROM AUTHOR]

Transition metal-catalyzed reactions of silacyclobutanes with a variety of π units have attracted much attention and become one of the most straightforward and efficient approaches to rapidly access structurally diverse organosilicon compounds. However, the reaction of silacyclobutanes with alkynes still suffers from some limitations: (1) internal alkynes remain challenging substrates; (2) expensive Pd- or Rh-based catalysts have been employed in all existing systems; (3) controlling chemodivergence has not yet been realized. Herein we realize Ni-catalyzed chemodivergent reactions of silacyclobutanes with alkynes. In comparison with the previous Pd or Rh catalytic systems, our Ni-catalytic system features: 1) complementary substrate scope; 2) ligand-controlled chemodivergence; 3) low cost. The ligand precisely dictates the pathway selectivity, leading to the divergent formation of (benzo)silacyclohexenes and allyl vinylsilanes. Moreover, we demonstrate that employment of a chiral phosphine ligand is capable of forming silicon-stereogenic allyl vinylsilanes in high yields and enantioselectivities. In addition, DFT calculation is performed to elucidate the origin of the switchable selectivities, which is mainly attributed to different ligand steric effects. Transition metal-catalyzed reactions of silacyclobutanes to access structurally diverse organosilicon compounds have attracted attention in recent years. Here, the authors show nickel-catalysed, ligand-controlled chemodivergent reactions of these compounds with alkynes to (benzo)silacyclohexenes and allyl vinylsilane. [ABSTRACT FROM AUTHOR]

Rhodium-catalyzed hydroaminomethylation of various vinyl arenes with anilines has been accomplished using water as an environmentally benign reaction media. This aqueous reaction is facilitated by the water-soluble diphosphine ligands derived from bis(2-(diphenylphosphaneyl)ethyl)amides. The methodology demonstrated a broad scope of substrates and accessed the N-(2-phenylpropyl)anilines in good yields (up to 94%) and high selectivities. Mechanistic studies with a series of competition experiments and isotope labeling revealed the imine hydrogenation reactivity of the catalysts. [ABSTRACT FROM AUTHOR]

Suzuki–Miyaura coupling (SMC) reactions are one of the most promising routes for carbon–carbon bond formation. It is believed that metal complexes, particularly palladium complexes, are the most effective catalysts for this purpose. However, the catalysis nature whether it is homogenous or heterogeneous is under debate. It is commonly believed that a homogenous catalysis pathway is responsible for the catalytic activity when the phosphine ligands are present in the structure due to the strong phosphorus‐metal interactions. In this study, Pd (II) complexes of phosphino‐benzaldoxime ligands were synthesized, characterized, and tested in SMC reactions. Interestingly, it was found that the catalytic activity increased by 11 times when the amount of catalyst was reduced by 10‐fold and increased by five times when the amount of catalyst was decreased by 100‐fold. The detailed analyses revealed that the palladium nanoparticles (NPs) are responsible for the catalytic activity which was formed in the reaction medium. A plausible mechanism was proposed for the formation of Pd NPs from palladium phosphino‐benzaldoxime complexes in the reaction medium. This study is expected to contribute to the debate over whether the catalytic activity of phosphine‐palladium complexes in SMC reactions results from a homogeneous or heterogeneous pathway. [ABSTRACT FROM AUTHOR]

Acyl phosphines (R2P–C(O)R) are the tertiary phosphorus compounds having a P–C(O) linkages. Though they are known historically, their literature is not exhaustive mainly due to the vulnerability of P–C(O) bonds toward nucleophilic substitution reactions. However, there is a renewed interest in the synthesis of acyl phosphines and di (acyl) phosphines, recently. Among the methods available for the synthesis, most involve nucleophilic substitutions at carbonyl carbon by phosphorus nucleophile as a customary step. The examples of phosphines possessing two acyl groups (R(O)C–RP–C(O)R) are found more frequently in the literature of late, and most of them are cyclic in nature. The transition‐metal complexes of acyl phosphines and di (acyl) phosphines are moderately explored in literature. However, their catalytic applications are meager. In the current review, the details of syntheses, reactivity, structural features, and catalytic activities of acyl phosphines and bis (acyl) phosphines reported in the last three decades are discussed. [ABSTRACT FROM AUTHOR]

The synthesis of bis(diphenylphosphino)ethane (dppe) and PMe3 mono-adducts [(dppe)BeCl2]n and [(PMe3)BeCl2]2 is described and their spectroscopic properties discussed. Hydrolysis of these two compounds and of the bis(diphenylphosphino)propane (dppp) adduct to BeCl2 gave [dppeH2][BeCl4], [Me3PH]n[Be4Cl9]n and [dpppH2][Be2Cl6], which have been isolated and structurally characterized by single crystal X-ray diffraction. The reactions of [(PMe3)BeCl2]2 with p-cresole gave [Me3PH]2[Be2Cl4(OC7H7)2]. This phenoxide together with [(Me3PO)2Be2Cl4], the oxidation product of [(PMe3)BeCl2]2, have also been structurally characterized. [ABSTRACT FROM AUTHOR]

In this report, two diiron ethane-1,2-dithiolate carbonyl complexes with bridging 1,3-bis(diphenylphosphino)propane (dppp) or tris(3-fluorophenyl)phosphine have been synthesized and characterized. Treatment of complex [Fe2(CO)6(µ-SCH2CH2S)] (1) with a diphosphine ligand dppp or a monophosphine ligand tris(3-fluorophenyl)phosphine using Me3NO·2H2O as the decarbonylating reagent afforded the corresponding derivatives [{Fe2(CO)5(µ-SCH2CH2S)}2(Ph2PCH2CH2CH2PPh2)] (2) and [Fe2(CO)5(µ-SCH2CH2S){P(3-C6H4F)3}] (3) in 82% and 92% yields, respectively. Complexes 2 and 3 have been characterized by elemental analysis, IR, NMR spectroscopy, as well as confirmed by single crystal X-ray diffraction analysis. Moreover, the electrochemistry of these complexes were studied by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Addition of 2-aminobenzothiazole (abt) and substituted derivatives to Hg(OAc)2 leads to the high yield formation of ortho-cyano-aminothiophenolate (ocap) complexes [Hg{SC6H3XN(C≡N)}]n (X = H, Me, Cl, Br, NO2) resulting from dehydrogenation and C–S bond cleavage. The reaction appears to be unique to Hg(OAc)2 and with HgCl2 the product [HgCl2(abt)]n contains an intact abt ligand, but reacts with acetate to afford the ocap complex [Hg{SC6H4N(C≡N)}]n. Binding of abt to Hg(II) has previously been probed in molecular structures of [Hg(sac)2(abt)L] (L = MeOH, DMSO) and these have been reexamined to understand the perturbation of abt upon coordination. When the reaction of abt and Hg(OAc)2 was carried out at low temperatures the intermediate [Hg(κ2-OAc)(EtOH)(μ-HNCNSC6H4)]2 was isolated resulting from a single ligand deprotonation thus allowing a mechanism for ring-opening to be proposed. Reactions of [Hg{SC6H3XN(C≡N)}]n with mono- and bidentate phosphines have been studied, affording a series of complexes in which the ocap ligands adopt four different binding modes in the solid state, as shown by a number of crystallographic studies. In all, the ligand chelates to a single mercury centre but spans to the second via either: (i) a simple S,N-chelate, (ii) coordination through nitrogen of the C≡N group, (iii) the sulfur acting as a thiolate-bridge, (iv) both thiolate bridging and cyanide coordination. With PPh3 two different binding modes are seen in complexes [Hg{SC6H3XN(C≡N)}(PPh3)]2 being dependant upon the nature of the arene-substituent, while addition of excess PPh3 affords mononuclear [Hg{SC6H3XN(C≡N)}(PPh3)2]. With dppm, binuclear [Hg{SC6H3XN(C≡N)}(κ1-dppm)]2 result in which the diphosphine binds in a monodentate fashion. With the more flexible diphosphines, dppe and dppb, coordination polymers [Hg{SC6H3XN(C≡N)}(κ1,κ1-diphosphine)]n result in which ocap binds in a simple chelate fashion. Somewhat unexpectedly, with dppp, binuclear complexes [Hg2{SC6H3XN(C≡N)}2(μ,κ1,κ1-dppp)] result in which two diphosphines bridge the Hg2 centre, while with dppf mononuclear chelates are proposed to result. Thus, the simple and high-yielding ring-opening of 2-aminobenzothiazole and substituted derivatives by mercuric acetate provides ready access to a range of novel ortho-cyano-aminothiophenolate complexes, being shown to be a highly versatile ligand that can adopt a number of different coordination modes. [ABSTRACT FROM AUTHOR]

We here found that while Meldrum's acid as the reactive warhead allows for the attachment of a single chemical modification on aldehyde-containing proteins, pyrazolone derivatives in combination with a phosphine nucleophile enable protein dual site-specific conjugation with the same or distinct moieties. These reactions are efficient and convergent under biocompatible conditions and allow access to protein bioconjugates with superior stability, homogeneity and flexibility. Our work expands the repertoire of bioconjugation chemistries and offers opportunities to construct bioconjugates with defined structure that have potential for medical and biomaterial applications. [ABSTRACT FROM AUTHOR]

Atomically precise gold clusters are highly desirable due to their well‐defined structure which allows the study of structure–property relationships. In addition, they have potential in technological applications such as nanoscale catalysis. The structural, chemical, electronic, and optical properties of ligated gold clusters are strongly defined by the metal–ligand interaction and type of ligands. This critical feature renders gold–phosphine clusters unique and distinct from other ligand‐protected gold clusters. The use of multidentate phosphines enables preparation of varying core sizes and exotic structures beyond regular polyhedrons. Weak gold–phosphorous (Au–P) bonding is advantageous for ligand exchange and removal for specific applications, such as catalysis, without agglomeration. The aim of this review is to provide a unified view of gold–phosphine clusters and to present an in‐depth discussion on recent advances and key developments for these clusters. This review features the unique chemistry, structural, electronic, and optical properties of gold–phosphine clusters. Advanced characterization techniques, including synchrotron‐based spectroscopy, have unraveled substantial effects of Au–P interaction on the composition‐, structure‐, and size‐dependent properties. State‐of‐the‐art theoretical calculations that reveal insights into experimental findings are also discussed. Finally, a discussion of the application of gold–phosphine clusters in catalysis is presented. [ABSTRACT FROM AUTHOR]

Neutral zinc complexes supported by H[PNNO], a diaminophenolate ligand bearing a pendant phosphine group, were synthesized and characterized. The phosphine arm adopts two different configurations in solution and prevents aggregation. The monomeric zinc hydride complex is stable at elevated temperatures up to 125 °C and reacts readily with CO2 to afford a zinc formate complex. The zinc hydride is active for CO2 hydrosilylation at atmospheric CO2 pressure and is selective for CO2 reduction to the silyl-formate product. [ABSTRACT FROM AUTHOR]

A chiral bis‐hosphine ligand bearing two pyridyl crown ethers was complexed with primary ammonium salts of different absolute configuration to form supramolecular chiral catalysts, which were successfully applied in the Rh‐catalyzed asymmetric hydrogenation of α‐dehydroamino acid esters and Ir‐catalyzed asymmetric hydrogenation of quinoxalines. By comparison with the non‐assembled catalysts, the complexation between the chiral catalysts and primary ammoniums obviously improved enantioselectivities. Up to 11 % enhancement in ee values in asymmetric hydrogenation of α‐dehydroamino acid esters and 30 % enhancement in ee values in asymmetric hydrogenation of quinoxalines were achieved. [ABSTRACT FROM AUTHOR]

The widespread use of phosphine ligand libraries is frequently hampered by the challenges associated with their modular preparation. Here, we report a protocol that appends arenes to arylphosphines to access a series of biaryl monophosphines via rhodium-catalyzed P(III)-directed ortho C–H activation, enabling unprecedented one-fold, two-fold, and three-fold direct arylation. Our experimental and theoretical findings reveal a mechanism involving oxidative addition of aryl bromides to the Rh catalyst, further ortho C–H metalation via a four-membered cyclometalated ring. Given the ready availability of substrates, our approach opens the door to developing more general methods for the construction of phosphine ligands. The widespread use of biaryl monophosphines is frequently hampered by the challenges associated with their modular preparation. Here, the authors report a protocol that appends arenes to arylphosphines to access a series of these compounds via rhodium-catalysed P(III)- directed ortho C–H activation, enabling one-fold, two-fold, and threefold direct arylation. [ABSTRACT FROM AUTHOR]

In the present manuscript, we reported the facile, low cost, and phosphine-free synthesis of indium selenide (InSe) quantum dots (QDs) via one-pot synthesis route. The particle size analysis revealed the average particle size of InSe QDs as ~ 13 nm. Optical properties of InSe QDs were investigated using photoluminescence (PL) and UV absorption analysis. InSe QDs exhibited an excitation wavelength of 370 nm with two major absorption peaks at ~ 405 and 432 nm. Characteristic energy band gap of the QD was evaluated as 2.2 eV from Tauc plot. Time-resolved photoluminescence (TRPL) witnessed the 6.41 ns recombination time for the InSe QDs. Formation of uniform spherical particle with size ranging from 2 to 4 nm is evident from transmission electron microscopy (TEM). XRD pattern of as-synthesized InSe QD was found in the close agreement with standard tetragonal chalcopyrite structure. Finally, the sensing film was fabricated using a spin-coating method and is further employed as a LPG gas and humidity sensor. Sensor response for the LPG gas was found as 4.41 with response and recovery times calculated as 7.5 and 6.3 s, whereas for the humidity the average sensitivity of the sensing film is calculated as 8.89 MΩ/% RH with response and recovery times 5.3 and 13.2 s. [ABSTRACT FROM AUTHOR]

We report an organocatalytic trans hydroboration of 3-substituted-propiolonitriles. In the presence of catalytic amounts of tributylphosphine and pinacolborane, regioselective hydroboration of the internal triple bond proceeded in a stereoselective fashion under mild conditions to afford the corresponding (E)-1,2-vinylcyanoborane derivatives. The mechanism is proposed to occur through a 1,2-phosphine addition instead of a canonical 1,4-conjugate addition pathway. [ABSTRACT FROM AUTHOR]

The treatment of nuclear spent fuels, especially the separation of minor actinides, is an imperative task for the healthy development of the nuclear industry. Up to now, it still remains a worldwide challenge to separate trivalent An3+ from Ln3+ because of their similar chemical properties. Therefore, investigating the mechanism behind the selective extraction of An3+ by theoretical methods is necessary. In this work, three phosphine oxide ligands with the same side structures but different bridging frameworks, Ph2PyPO, Ph2BipyPO and Ph2PhenPO, were investigated theoretically, and compared with each other using relativistic density functional theory. The results of QTAIM and MBO suggest that the Am--N bonds in the studied complexes have more covalent character than those in the Eu--N bonds, whereas the PDOS analysis indicates that more overlap exists between Am-5f and the Ph2PyPO's N-2p orbital than between Am-5f and Ph2BipyPO's N-2p, and Am-5f and Ph2PhenPO's N-2p orbital. However, the studied ligands all possess stronger affinities towards Am3+ than Eu3+, which partly results in the Am3+ selectivity towards Eu3+ in these three ligands. The calculated reaction free energy can reproduce the Am/Eu separation ability difference of three ligands well. This work offers some useful information for An/Ln separation of phosphine oxide ligands, and may help to design more efficient An3+/Ln3+ separation ligands. [ABSTRACT FROM AUTHOR]

Trivalent-phosphorus-containing molecules are widely used in fields ranging from catalysis to materials science. Efficient catalytic methods for their modifications, providing straightforward access to novel hybrid structures with superior catalytic activities, are highly desired to facilitate reaction improvement or discovery. We have recently developed new methods for synthesizing polyfunctional phosphines by C–C cross-couplings through rhodium-catalyzed C–H bond activation. These methods use a native P(III) atom as a directing group, and can be used in regioselective late-stage functionalization of phosphine ligands. Interestingly, some of the modified phosphines outperform their parents in Pd-catalyzed cross-coupling reactions. 1 Introduction 2 Early Examples of Transition-Metal-Catalyzed P(III)-Directed C–H Bond Activation/Functionalizations 3 Synthesis of Polyfunctional Biarylphosphines by Late-Stage Alkylation: Application in Carboxylation Reactions 4 Synthesis of Polyfunctional Biarylphosphines by Late-Stage Alkenylation: Application in Amidation Reactions 5 Conclusion [ABSTRACT FROM AUTHOR]

The known boranes (R(Me3Si)N)2BF (R=Me3Si 1, tBu 2, C6F53, o‐tol 4, Mes 5, Dipp 6) and borinium salts (R(Me3Si)N)2B][B(C6F5)4] (R=Me3Si 7, tBu 8) are prepared and fully characterized. Compound 7 is shown to react with phosphines to generate [R3PSiMe3]+ and [R3PH]+ (R=Me, tBu). Efforts to generate related borinium cations via fluoride abstraction from (R(Me3Si)N)2BF (R=C6F53, o‐tol 4, Mes 5) gave complex mixtures suggesting multiple reaction pathways. However for R=Dipp 6, the species [(μ‐F)(SiMe2N(Dipp))2BMe][B(C6F5)4] was isolated as the major product, indicating methyl abstraction from silicon and F/Me exchange on boron. These observations together with state‐of‐the‐art DFT mechanistic studies reveal that the trimethylsilyl‐substituents do not behave as ancillary subsitutents but rather act as sources of proton, SiMe3 and methyl groups. [ABSTRACT FROM AUTHOR]

Two new covalent organic frameworks (COFs) were synthesized from 4,4′,4′′,4′′′‐(pyrene‐1,3,6,8‐tetrayl)tetraaniline and 2,5‐dimethoxyterephthalaldehyde (Py‐DMTA‐COF) or 2′,5′‐dimethoxy‐[1,1′:4′,1′′‐terphenyl]‐4,4′′‐dicarbaldehyde (Py‐DMTPDA‐COF) under solvothermal conditions. These two COFs were further facilely developed as efficient photocatalytic platforms for the synthesis of thiophosphinates. Py‐DMTA‐COF exhibited better photocatalytic activity, broad substrate applicability, and excellent recycling capacity for the preparation of thiophosphinates from P(O)H compounds and thiols compared to Py‐DMTPDA‐COF. This methodology was further extended to the seamless gram‐scale production of target phosphorothioate derivatives. The results demonstrate that COFs can provide a robust platform for developing metal‐free, base‐free, highly efficient, and reusable heterogeneous photocatalysts for organic transformations. [ABSTRACT FROM AUTHOR]

The synthesis of two new 1,2,3-triazole appended monophosphines [P(Ph){(o-C6H4)(1,2,3-N3C(Ph)CH}2] (1) and [P(Ph){o-C6H4(CCH)(1,2,3-N3-Ph)}2] (2) and their RuII complexes is described. The reactions of 1 and 2 with [Ru(PPh3)3Cl2] in a 1 : 1 molar ratio produced cationic complexes 3 and 4, respectively. Both the complexes showed very high catalytic activity towards transfer hydrogenation, nitro reduction, and α-alkylation reactions and afforded the corresponding products in good to excellent yields. The free energy of β-hydride elimination from the respective Ru-alkoxide intermediates, a key mechanistic step common to all the three catalytic pathways, was calculated to be close to ergoneutral by density functional theory-based calculations, which is posited to rationalize the catalytic activity of 3. The reduction of aromatic nitro compounds was found to be highly chemoselective and produced the corresponding amines as major products even in the presence of a carbonyl group. The triazolyl–N2 coordinated RuII–NPN complex 3 showed better catalytic activity compared to the triazolyl–N3 coordinated complex 4. [ABSTRACT FROM AUTHOR]

A series of chromium‐halide, ‐nitride, and ‐dinitrogen complexes bearing carbene‐ and phosphine‐based PCP‐type pincer ligands has been newly prepared, and some of them are found to work as effective catalysts to reduce dinitrogen under atmospheric pressure, whereby up to 11.60 equiv. of ammonia and 2.52 equiv. of hydrazine (16.6 equiv. of fixed N atom) are produced based on the chromium atom. To the best of our knowledge, this is the first successful example of chromium‐catalyzed conversion of dinitrogen to ammonia and hydrazine under mild reaction conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flexible hydroformylation of olefins using a cyclic monofluorophosphite ligand. • On-demand, in-flow aldehyde regioselectivity tuning from 90% linear to 75% branched. • Hydroformylation of 1-octene with a turnover frequency >75,000 mol ald.mol Rh−1.h−1. • Selective tuning of the ligand to metal coordination on-the-fly. • In-flow mechanistic studies of rhodium-catalyzed hydroformylation of 1-octene. Tuning aldehyde regioselectivity via homogeneous hydroformylation of olefins using the same catalyst system remains a challenge. Here, we present flexible rhodium (Rh)-catalyzed hydroformylation of 1-octene and propylene with a bulky cyclic monofluorophosphite ligand L. Hydroformylation of 1-octene with Rh/ L catalyst achieves, for the first time , turnover frequencies exceeding 75,000 mol ald.mol Rh−1.h−1 (at 30% conversion) in segmented flow, while enabling access to an unmatched tunable aldehyde branching (0.06 < linear/branched < 15) with the same ligand L. Our mechanistic studies demonstrate that L provides a viable alternative to traditional bidentate phosphine/phosphite ligands for high activity with the added benefit of tunable selectivity. The unique high flexibility feature of L over traditional linear- or branched-selective ligands allows for on-demand tuning from 90% linear to 75% branched aldehyde in a continuous flow reactor without the need for ligand/catalyst alteration. Furthermore, when starting from the internal olefins, Rh/ L catalyst achieves high regioselectivity (>90%) toward the two positional aldehyde isomers. The high turnover frequencies obtained with L in flow will enhance the economics of the production of aldehydes and their isotopically labeled analogues by significantly reducing the reaction time, thereby enabling better utilization of the increasingly expensive Rh catalyst and minimizing the need for catalyst/ligand separation and recycle. [ABSTRACT FROM AUTHOR]

An efficient palladium-manganese system for the Markovnikov selective alkoxycarbonylation reaction of aromatic and aliphatic alkenes was developed. [Display omitted] • A general and efficient palladium-manganese system for the Markovnikov selective alkoxycarbonylation reaction of alkenes. • By using the carbazole-derived phosphine ligand containing bipyridine moiety, various aromatic and aliphatic olefins were transformed into the corresponding esters in good yields with moderate to high branched selectivity. • Preliminary mechanistic studies reveal the respective contribution of palladium and manganese centers to achieve highly branch-selective alkoxycarbonylations. Carbazole derived phosphine ligands containing pyridine moiety were designed and prepared. It allows the challenging Pd-catalyzed Markovnikov-selective alkoxycarbonylation of aliphatic alkenes to give the branched ester products (28 examples; 51–97% branch selectivity). Preliminary mechanistic studies support that the bridging bromide between Pd and Mn centers is crucial for the enhancement of regioselectivity. [ABSTRACT FROM AUTHOR]

During the synthesis of phosphabetaines and phosphonium salts that are good catalysts and antimicrobial agents, the formation of triphenylphosphine oxide was observed. A new synthesis method for phosphonium salts based on tertiary phosphines and substituted acrylic acids was suggested. In vitro antibacterial and antimycotic activity was determined in comparison to standard agents. [ABSTRACT FROM AUTHOR]

Four new dinuclear iridium(I) complexes were synthesized from the di(N-heterocyclic carbene) ligand precursors 1,1′-methylene-bis(3-benzyl-imidazolium)dichloride and 1,1′-methylene-bis(3-(2,4,6-trimethylbenzyl)imidazolium)dichloride. The complexes were fully characterized by spectroscopic methods, HR-MS (ESI) spectrometry, furthermore, the structure of complexes 1 and 2 were determined by single-crystal X-ray diffraction. Complexes 3a and 3b which have sulfonated triphenylphosphine ligands, were successfully used under mild conditions as catalysts in reduction reaction of ketones via hydrogen transfer from aqueous 2-propanol, and for hydrogenation of alkynes in aqueous-organic biphasic systems. [ABSTRACT FROM AUTHOR]

The CAL-B-mediated kinetic resolution of racemic 2-hydroxymethylphenyl-(methyl)phenylphosphine and its P-BH3 analogue gave, via their enantioselective monoacetylation, the corresponding monoacetates and unreacted substrates in moderate yields and with indeterminate enantiomeric excess, depending on the solvent applied. The P-BH3 analogues were transformed into 2-aminomethyl derivatives via O-tosyl or O-mesyl intermediates, which will be checked as tridentate catalyst/ligands in asymmetric synthesis. [ABSTRACT FROM AUTHOR]

A heterogeneous single-site catalyst Pd@MOF-808 was successfully synthesized by water-based, green synthesis procedure. The catalytic experiments exhibited the Pd@MOF-808 promoted efficiently the Suzuki–Miyaura coupling reaction without the assistance of organic phosphine ligands at atmospheric pressure conditions. The catalyst also could be applied in the gram-scale synthesis of industrially anti-inflanmatory analgestic Fenbufen. [ABSTRACT FROM AUTHOR]

[Display omitted] • [HFe(CO) 4 ]− is a versatile and powerful metal hydride. • It reacts readily with chloro phosphines. • [HFe(CO) 4 ]− is able to produce low coordinated phosphorus complexes. • Diphosphenes, phospha-alkenes, phospho-alllenes, and phosphide complexes have been obtained. The reaction of [X][Hfe(CO) 4 ] (X = mainly PPh 4 , but also NEt 4 , K and Ph 3 PNPPh 3) with chlorophosphines for the synthesis of low coordinated phosphorus complexes is reviewed. Diphosphene (P P), phospha-alkene (P C<), phospha-allene (P C C<), and phosphide (>P) iron complexes have been in particular obtained, and characterized by 31P NMR, and by X-ray diffraction in several cases. [ABSTRACT FROM AUTHOR]

Herein, we report the integration of simple linear regressions with gold(I) catalysis to interrogate the influence of phosphine structure on metal-catalyzed organic transformations. We demonstrate that observed product ratios in [4 + 3]/[4 + 2] cycloisomerization processes are influenced by both steric and electronic properties of the phosphine, which can be represented by the Au-Cl distance. In contrast, the observed selectivity of a similar [2 + 3]/[2 + 2] cycloisomerization is governed by L/B1, a steric parameter. Using this correlation, we were able to accurately predict the selectivity of a previously untested, Buchwald-type ligand to enhance selectivity for the same transformation. This ligand found further utility in increasing the selectivity of a previously reported gold-catalyzed cycloisomerization/arylation of 1,6-enynes by ~1 kcal/mol.

• Platinum complexes with cyclometalated carbene and metallocene bisphosphine ligands were prepared. • The compounds were characterized by spectroscopic methods and cyclic voltammetry. • Structures of two representatives were determined by X-ray diffraction analysis. • DFT calculations were used to described the bonding situation in these componds. Four cycloplatinated complexes of the type [Pt(C^C*){M(η5-C 5 H 4 PPh 2) 2 -κ2 P,P '}][PF 6 ] n (M = Fe, n = 1; M = Co, n = 2), where C^C* is 2-(3-methylimidazol-2- ylidene-1-yl-κC2)phenyl-κC1 and similar cyclometalated ligands bearing an additional aromatic ring and phenyl substituents at the imidazol-2-ylidene unit, were prepared and structurally characterized by spectroscopic methods (NMR and ESI MS), elemental analysis, cyclic voltammetry and DFT calculations. Experimental structural parameters and DFT calculations consistently indicate differentiation of the Pt-bound phosphine groups due to unlike trans influence of the phenyl and carbene donor moieties at the cyclometalated ligand in these compounds [Display omitted] [ABSTRACT FROM AUTHOR]

• A multidonor amidophosphine ligand was prepared using an alternative route. • The ligand reacts with group 10 metal dichloride precursors to produce P,N,N-chelate complexes. • Spontaneous HCl elimination occurs during the complexation. • Terminal chloride ligand can be replaced for a phosphine. • The complexes were fully characterized and possess similar molecular structures. The multidonor amidophosphine 2-Ph 2 PC 6 H 4 NHC(O)C 5 H 4 N, where C 5 H 4 N is a 2-pyridyl substituent, reacted with the synthetic equivalents of group 10 metal dichlorides, viz. [NiCl 2 (dme)], [PdCl 2 (MeCN) 2 ] or [PtCl 2 (cod)] (dme = 1,2-dimethoxyethane, cod = cycloocta-1,5-diene), to produce neutral bis-chelate complexes [MCl(Ph 2 PC 6 H 4 NC(O)C 5 H 4 N-κ3 P,N,N ′)] (M = Ni, Pd, and Pt). During the complexation reaction, spontaneous HCl elimination occurred, possibly as the result of overall structural stabilization by the deprotonation of the amide nitrogen, which is brought toward the metal centers by initial P,N(pyridine)-coordination of the amidophosphine ligand. Subsequent reaction of 3 as the representative with AgClO 4 and triphenylphosphine produced the cationic bis(phosphine) complex [Pd(PPh 3)(Ph 2 PC 6 H 4 NC(O)C 5 H 4 N-κ3 P,N,N ′)]ClO 4 (5), which converted back to parent chloride complex in the presence of chloride ions. All complexes were fully characterized using NMR and IR spectroscopy, mass spectrometry, and elemental analysis. X-ray diffraction analysis for 2, 3, 4 ·½ CH 2 Cl 2 and 5 ·Me 2 CO revealed that compounds 2 – 4 exhibit similar coordination geometry, which is rather marginally affected upon replacement of the chloride for a bulkier phosphine ligand. [Display omitted] [ABSTRACT FROM AUTHOR]

• A Bis-(NHC)-P(II) complex supported on Fe 3 O 4 @SBA-15 catalyzed the carbonylation of haloarenes. • The reaction was performed under CO-free and phosphine-free conditions. • Benzoic acids were obtained in moderate to good yields. • The catalyst was easily separated from the reaction mixtures by a simple magnetic decantation. • The catalyst exhibited excellent recyclability with small deactivation over seven runs. In this work, our previously reported bis(NHC)-Pd(II) catalyst grafted on Fe 3 O 4 @SBA-15 has been successfully used as a phosphine-free heterogeneous magnetic catalyst in the CO-free carbonylation of aryl halides. It is shown that the immobilized Pd(II)-complex efficiently catalyzes the carbonylation of different aryl halides with HCOOH and DCC in the presence of Et 3 N as the base. Optimal reaction conditions were determined by screening various parameters such as solvent, HCOOH/DCC molar ratio, base, temperature, and catalyst dosage. The catalyst was magnetically retrievable and separated by an external magnet, washed, and re-used in the subsequent runs over seven catalytic cycles. The hot filtration experiment was conducted to determine the heterogeneous nature of the catalyst. [Display omitted] [ABSTRACT FROM AUTHOR]

A new type of phosphine covalent organic frameworks (P-COFs) has garnered interest because of their high specific surface area and good thermal stability. These microporous materials have potential applications in gas storage, separation, heterogeneous catalysis, and other fields. Here, we present a heterogeneous catalyst consisting of a phosphine-based COF supported by palladium salt (Pd(OAc) 2 /P-COF) for Suzuki-Miyaura coupling reactions. The electron-rich heteroatoms (P, N) can securely anchor the active component (Pd) within the walls of P–COF. This catalyst exhibits excellent catalytic activity and cyclic stability. The coupling yield of phenylboronic acid and chlorobenzene with low activity reaches 100 % at room temperature for 3 h. After five cycles, the coupling yield of bromobenzene and phenylboronic acid remains above 93 %. [Display omitted] • A P–COF with a high specific surface area and suitable pore size distribution was successfully synthesized. • The electron-rich heteroatoms (P, N) within P–COF cananchor the active component, creating dispersed and stable catalytic sites. • Pd(OAc) 2 /P–COF exhibits outstanding activity and stability, enabling the conversion of various aryl halides into high yields. [ABSTRACT FROM AUTHOR]

• New Cr(III) catalysts supported by the backbone-disubstituted PCCP ligands. • The Cr(III) catalysts for the selective ethylene trimerization and tetramerization. • The effect of ligand substitution on the catalytic performance has been evaluated. The effect of backbone-substituent of carbon-bridged diphosphine ligands of the type {Ph 2 PC(COOR)=C(COOR)PPh 2 } on the catalyst performance in ethylene oligomerization has been explored. The Cr precatalyst supported by the ligand {Ph 2 PC(COOMe)=C(COOMe)PPh 2 } (L1) achieved a high activity of 1800 kg/g Cr/h with a total selectivity of 90.8 % toward 1-hexene (77.3 %) and 1-octene (13.5 %) when activated with MMAO-3A. The catalytic system based on these ligands exhibited considerably high thermal stability, maintaining high activity even at 100 oC. [Display omitted] [ABSTRACT FROM AUTHOR]

Reduction of (Ph2PPrDI)FeBr 2 or (tBu2PPrDI)FeBr 2 under CO afforded the corresponding dicarbonyl compounds. Relative to the phosphine groups of Ph2PPrDI, the trialkylphosphine substituents of tBu2PPrDI are weaker π-acceptors, a feature that prevents substitution and formation of the respective monocarbonyl complex upon heating under vacuum. [Display omitted] A series of low-valent iron complexes that feature a phosphine-substituted α-diimine (DI) ligand have been synthesized. Reduction of (Ph2PPrDI)FeBr 2 with an excess of Na/Hg in the presence of carbon monoxide afforded the corresponding dicarbonyl complex, (Ph2PPrDI)Fe(CO) 2. Through multinuclear NMR and single crystal X-ray diffraction analysis, this complex was found to possess a 3-coordinate DI ligand. Upon heating for 10 days at 110 °C while applying intermittent vacuum, (Ph2PPrDI)Fe(CO) 2 was successfully converted to the corresponding monocarbonyl complex, (Ph2PPrDI)Fe(CO), which was found to feature a tetradentate chelate. Similar reactivity was explored using the analogous bis(tert -butyl)phosphine-substituted ligand, tBu2PPrDI. Addition of this chelate to FeBr 2 afforded (tBu2PPrDI)FeBr 2 , and subsequent reduction yielded (tBu2PPrDI)FeBr, which was found to possess a tridentate DI ligand by single crystal X-ray diffraction. Performing the reduction of (tBu2PPrDI)FeBr 2 in the presence of CO afforded the corresponding dicarbonyl complex, (tBu2PPrDI)Fe(CO) 2. Like aryl-substituted (Ph2PPrDI)Fe(CO) 2 , alkyl-substituted (tBu2PPrDI)Fe(CO) 2 was found to feature a pendant phosphine arm. However, heating (tBu2PPrDI)Fe(CO) 2 under vacuum did not allow for phosphine substitution and conversion to the corresponding monocarbonyl complex, highlighting the importance of phosphine π-acidity for substitution and the stabilization of low-valent iron. [ABSTRACT FROM AUTHOR]