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Phosphotungstic acid with a Keggin structure as an efficient, simple and green catalyst for the phosphinylation of secondary propargyl alcohols with phosphine oxides to afford γ-ketophosphine oxides with up to 88% isolated yield was developed using dimethyl carbonate as a green solvent. Diaryl- or alkylaryl-substituted propargyl alcohols, and diaryl or arylalkylphosphine oxides could tolerate the system, which reduced the catalyst dosage, and avoided the use of multi-components and toxic solvents. More interestingly, phosphotungstic acid exhibited the best activity when 0.58 moles of water were added per mole of HPWA, elevating the yield from 55% to 85%. An 18O labelled product was afforded using trace H218O instead of H2O, indicating the participation of water in the reaction. Besides, our work underscores the importance and effect of a small amount of water, acting to promote the transformation of secondary propargyl alcohols into enones, which should be the real intermediates of the reaction. A mechanism involving a carbocation, Meyer–Schuster rearrangement and Michael addition of enones was proposed. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) composed of a beta-diketone and phosphine oxides featuring different alkyl chain lengths were prepared and then employed as liquid-liquid extraction and dissolution media for the separation of iron, cobalt, neodymium, and dysprosium. In the dissolution the more sterically hindered DESs exhibited enhanced selectivity to neodymium, which was poorly separated using liquid-liquid extraction. The dissolution selectivity in less sterically hindered DESs could be controlled by the addition of organic acids with different alkyl chain lengths. [ABSTRACT FROM AUTHOR]

Carbon–phosphorus bond formation is of great importance in synthetic chemistry. A versatile strategy for the formation of carbon–phosphorus bonds involves the addition of phosphorus radicals to π-systems. However, the generation methods of phosphorus radicals are primarily restricted to homolytic cleavage of phosphorus–hydrogen bonds with excess peroxides or toxic metal salts as oxidants. Herein, we introduce a photoinduced palladium-catalyzed generation of phosphorus radicals using inexpensive and readily available Cl–phosphine oxides and Cl–phosphates as the phosphorus radical precursors. The key step for this strategy lies in the reductive activation of phosphorus–chloride bonds with the excited palladium complex under visible light irradiation. The involvement of phosphorus radicals has been evidenced by EPR spectroscopy and radical trapping experiments. Based on this strategy, both phosphinyl and phosphonyl groups could be regiospecifically incorporated into simple alkenes and heteroaromatic compounds via radical mediated carbon–phosphorus bond formation. Besides, carbon–phosphorus difunctionalization of alkenes was also achieved to afford phosphorylated oxindoles. [ABSTRACT FROM AUTHOR]

A silver-catalyzed chemoselective cascade nucleophilic addition of a P-centered anion to isocyanides and cyclization reaction was developed for the efficient and practical synthesis of a wide range of 2-phosphinoyl indole and indol-3-ol derivatives. Unlike the well-documented synthesis of phosphorus-functionalized heterocycles via a P-centered radical, an anionic reactivity profile of phosphine oxides is most likely involved in this domino transformation. [ABSTRACT FROM AUTHOR]

A rigid pentadentate chelating ligand (H2L) has been utilized to synthesize a series of octacoordinate mononuclear complexes, [Dy(L)(Ph3PO)(OOCR)] (where R = C6H5 (1), C(CH3)3 (2), CF3 (3)) and a dinuclear complex, [Dy2(L)2(Ph3PO)2{(OOC)2C6H4}] (4) based on the highly anisotropic Dy(III) ion. All the complexes were structurally characterized by single-crystal X-ray diffraction studies. The complexes were formed by the coordination action of the dianionic pentadentate ligand [L]2−, one phosphine oxide, and carboxylate ligands. DC and AC magnetic measurements were performed on 1–4. Complexes 1–4 show SMM behaviour, under zero DC field for 1 and 4, and under 500 Oe and 1000 Oe DC fields for 2 and 3 respectively, with thermally activated, Raman, and Raman and quantum tunnelling dominant relaxation mechanisms for 1 and 2, 3 and 4, respectively. [ABSTRACT FROM AUTHOR]

Group 4 Lewis acids are well-known catalysts and precursors for (non-aqueous) sol–gel chemistry. Titanium, zirconium and hafnium halides, and alkoxy halides are precursors for the controlled synthesis of nanocrystals, often in the presence of Lewis base. Here, we investigate the interaction of Lewis bases with the tetrahalides (MX4, X = Cl, Br) and metal alkoxy halides (MXx(OR)4−x, x = 1–3, R = OiPr, OtBu). The tetrahalides yield the expected Lewis acid–base adducts MX4L2 (L = tetrahydrofuran or phosphine oxide). The mixed alkoxy halides react with Lewis bases in a more complex way. 31P NMR spectroscopy reveals that excess of phosphine oxide yields predominantly the complexation product, while a (sub)stoichiometric amount of phosphine oxide causes disproportionation of the MXx(OR)4−x species into MXx+1(OR)3−x and MXx−1(OR)5−x. The combination of complexation and disproportionation yields an atypical Job plot. In the case of zirconium isopropoxy chlorides, we fitted the concentration of all observed species and extracted thermodynamic descriptors from the Job plot. The complexation equilibrium constant decreases in the series: ZrCl3(OiPr) > ZrCl2(OiPr)2 ≫; ZrCl(OiPr)3, while the disproportionation equilibrium constant follows the opposite trend. Using calculations at the DFT level of theory, we show that disproportionation is driven by the more energetically favorable Lewis acid–base complex formed with the more acidic species. We also gain more insight into the isomerism of the complexes. The disproportionation reaction turns out to be a general phenomenon, for titanium, zirconium and hafnium, for chlorides and bromides, and for isopropoxides and tert-butoxides. [ABSTRACT FROM AUTHOR]

A series of E＝P(V)-imine phosphine–imine ligands (Dipp-N＝C(CH3)–(CH2)–P＝E(Ph2)) (Dipp = 2,6-diisopropylphenyl, E = O, S, Se) and corresponding dimethyl aluminum and indium complexes were prepared and characterized using multi-nuclear NMR spectroscopy and SC-XRD. Solution-state 1H and 31P NMR spectroscopy indicate a mixture of isomers in solution (C6D6, CDCl3, and CD3CN). Solid state structures of both the imine and (E)-enamine isomers of the oxygen-based ligand have been observed. These three ligands (L) were then deprotonated with M(CH3)3 (M = Al or In), with methane loss forming a 6-membered ring via bidentate chelation ((κ2-L)M(CH3)2). The indium/oxide complex also crystallized as a 12-membered ring. [ABSTRACT FROM AUTHOR]

Photosensitizer design of luminescent terbium (Tb(III)) complexes with narrow bandwidths is important for advancing luminescent materials. In this study, we report an effective photosensitizer model in a thermally populated lowest excited triplet (T1) state during Tb(III) emission. The Tb(III) complex comprises a Tb(III) ion (serving as an emission center), hexafluoroacetylacetonates (acting as photosensitizer ligands), and bulky cyclohexyl group-attached phosphine-oxide-type ligands (functioning as an oxygen barrier system). Emission properties including emission and excitation spectra, ligand-excited emission quantum yields, and emission lifetimes were evaluated in the absence and presence of oxygen. Coordination geometry structures were determined through analysing single-crystal structures. The electronic structure based on 4f-orbitals was estimated from radiative rate constants and quantum chemical calculations. The bulky phosphine oxide ligand not only provides an oxygen barrier system but also induces an electronic structural modulation based on 4f-orbitals, allowing for effective photosensitized Tb(III) emission in a thermally populated ligand T1 state in air. [ABSTRACT FROM AUTHOR]

Epimers of the (1,10-phenanthroline-2,9-diyl)bis(ethyl(phenyl)phosphine oxide) (Et-Ph-BPPhen) ligand with two chiral centers (R,R/S,S and R,S) were synthesized. The configurational effects on the coordination ability and mechanism between these epimeric ligands and uranyl ions were thoroughly investigated. This work is helpful to reveal the effects of different conformations of epimeric ligands on their coordination properties. [ABSTRACT FROM AUTHOR]

Visible-light-induced C(sp²)--H phosphorylation of 2H-thiozoles/quinoxalines with H-phosphine oxides was achieved using an inorganic-ligand supported Mo oxide ([N(C4H9)4]2[Mo6O19]) as a hydrogen atom transfer (HAT) photocatalyst. The developed photo-driven C(sp²)--P bond formation protocol could furnish a wide range of products with excellent functional group tolerance in a water-based solvent at room temperature, without the addition of metals, bases, additives or external oxidants. A gram-scale reaction can occur in a low catalyst loading system. Moreover, the formulated photocatalyst showed excellent stability and reusability, and also exhibited satisfactory photo-reactivity under sunlight irradiation. The mechanistic investigations supported that the C(sp²)--P bond formation went through radical coupling or radical nucleophilic addition pathways. [ABSTRACT FROM AUTHOR]

A photocatalytic radical carbophosphorylation/cyclization of N-homoallyl aldehyde hydrazones with phosphine oxides was developed under metal-free conditions, achieving phosphorylated tetrahydropyridazines in yields up to 95%. Phosphorylated dihydropyrazoles were also constructed, by reacting N-allyl aldehyde hydrazones with phosphine oxides under the same conditions. [ABSTRACT FROM AUTHOR]

Self-assembly reaction of Ln3+ and Ag+ ions with a multidentate N,O-donor ligand has been successfully applied to isolate the first examples of 4f-4d heterometallic coordination compounds based on a phosphine oxide linker. In particular, a series of one-dimension coordination polymers [LnAg(Py3PO)2(NO3)4]n (Ln = Sm, Eu, Tb, Dy) have been synthesized employing tris(2-pyridyl)phosphine oxide (Py3PO) as a bridging ligand. Coordination polymers exhibit good photostability and high thermal stability above 300 ℃. Their solid-state photoluminescence spectra represent a combination of emissions originating from the lanthanide f-f transitions and Ag+-involved charge transfer, resulting in the color-tunable luminescence depending on excitation light. [ABSTRACT FROM AUTHOR]

The adjustment of crystal symmetry and intramolecular magnetic coupling is of great importance for the construction of high-performance single-molecule magnets. By using an aggregation-induced-emission-active pyridine-carbohydrazone-based Schiff base ligand and phosphine oxides, four dinuclear and one one-dimensional DyIII-based complexes, [Dy2(TPE-pc)2(Bu3PO)2Cl2]·2CH3CN·2H2O (1), [Dy2(TPE-pc)2(Cy3PO)2Cl2] (2), [Dy2(TPE-pc)2(MePA)2Cl2]·2CH3OH (3), [Dy2(TPE-pc)2(Ph3PO)2Cl2]2 (4) and [Dy2(TPE-pc)2(DPPO)Cl2]n (5) (H2TPE-pc = (E)-N′-(2-hydroxy-5-(1,2,2-triphenylvinyl)benzylidene)picolinohydrazide, MePA = N-phenyl-N′,N′′-bis(morpholinyl) phosphoric triamide, DPPO = piperazine-1,4-diylbis(diphenyl phosphine oxide)), were isolated. All complexes are made up of an enol oxygen-bridged Dy2 unit, where DyIII ions possess a pentagonal bipyramidal geometry with pseudo D5h symmetry. Magnetic measurements reveal that intramolecular DyIII–DyIII couplings are ferromagnetic and all complexes display a significant slow magnetic relaxation phenomenon below 30 K under a zero dc field. Ab initio calculations indicate that the anisotropic magnetic axes of all DyIII ions are approximately perpendicular to the higher-order symmetric axes in all complexes, and that DyIII–DyIII magnetic couplings along the magnetic axes effectively suppress the ground state quantum tunneling effect of magnetization and promote the occurrence of slow magnetic relaxation. Raman relaxation prevails in all complexes. In addition, the H2TPE-pc ligand shows an aggregation-induced emission (AIE) effect; however, all complexes exhibit an aggregation-caused quenching (ACQ) phenomenon. [ABSTRACT FROM AUTHOR]

A series of four β-carbonylphosphine oxide compounds have been synthesized, and their complexes with the nitrate salts of Sm3+, Eu3+, Tb3+ and Dy3+ have been characterized in solution and in the solid state. Analysis of the complexes using IR and NMR suggests that metal-ligand binding occurs mainly through the phosphine oxide group of the ligand, with some involvement of the carbonyl group. All 16 complexes luminesce in solutions of acetonitrile, albeit with varying degrees of intensity. The highest quantum yield values obtained for this series are those where the ligand contains an aryl carbonyl group paired with an electron rich phosphine oxide group (29.8 and 11% for the Tb3+ and Eu3+ complexes, respectively). In contrast, the longest emission lifetime values were found for complexes where the ligand contains a bulky substituent on the carbonyl group paired with an electron rich phosphine oxide (1.86, 1.402, 0.045 ms for the Tb3+, Eu3+ and Sm3+ complexes, respectively). [ABSTRACT FROM AUTHOR]

Tertiary phosphines are ubiquitous in inorganic chemistry. They play important roles as ligands in coordination chemistry and catalysis. Furthermore, they act as surface acidity probes for oxide surfaces. However, only volatile phosphines, such as PH3 have been applied in this function so far. Here we demonstrate for the first time that the triaryl- and trialkylphosphines PPh3 and PCy3 with high melting points self-adsorb readily onto a silica surface even in the absence of a solvent. The self-adsorption takes place within days when both solid components are mixed and then left undisturbed. The phosphines form well-defined monolayers on the surface and the transition from monolayer to left-over polycrystalline phosphine is abrupt. Therefore, the maximal surface coverage with a monolayer can be easily determined. When the phosphines are adsorbed from solutions, the same maximal surface coverage is found. Solid-state NMR spectroscopy provides a unique analytical tool for studying the structure and dynamics of phosphines in different environments. 31P and 2H solid-state NMR measurements are successfully applied for characterizing the adsorption process and the mobilities of the adsorbed phosphines across the silica surface. Furthermore, using (Ph3P)2Ni(CO)2 as a representative, it is demonstrated that the silica surface has a hitherto unrecognized impact on immobilized and surface-residing catalysts because it competes for phosphine ligands coordinated to a metal center. This competition manifests as one more factor leading to the loss of phosphine ligands and ultimately leaching of immobilized metal complexes or nanoparticle formation. Besides the increase of fundamental knowledge about adsorption processes, the presented results have implications for chromatographic separations of metal complexes and for the lifetime of immobilized and other types of surface-residing catalysts. [ABSTRACT FROM AUTHOR]

Organophosphorus compounds containing hydrolytically and metabolically stable C(sp3)– and C(sp2)–P bonds are widely used as reagents, ligands, pesticides, herbicides, flame retardants, surface modifiers, and antiviral and anticancer drugs. These applications rely on efficient C(sp3)– and C(sp2)–P bond-forming reactions. However, currently available C(sp2)–P cross-coupling protocols require high catalyst loadings and temperatures, as well as environmentally unsustainable and harmful organic solvents (e.g., N,N-dimethylformamide, DMF). Herein, we disclose a conceptually novel strategy for performing multimetallic Pd/Ni- and dual-ligand Pd-catalyzed C(sp2)–P cross-coupling reactions in aqueous micelles under mild and environmentally friendly conditions. Micellar catalysis in water enables C(sp2)–P cross-coupling while avoiding environmentally unsustainable organic solvents, thereby reducing organic waste generation. Such micellar C(sp2)–P cross-coupling reactions tolerate various functional groups and provide access to structurally diverse (hetero)aryl (thio)phosphonates, phosphinates and phosphine oxides using inexpensive commercial materials and catalysts. Moreover, C(sp2)–P cross-coupling reactions of medically relevant substrates and drugs under late-stage functionalization settings and multistep one-pot processes highlight the potential applications of this experimental paradigm. [ABSTRACT FROM AUTHOR]

A deep eutectic solvent (DES) containing choline chloride (ChCl) and urea (1 : 2) was introduced as an efficient, cost-effective, reusable, and environmentally benign medium for the metal-free synthesis of α-aminophosphine oxide/phosphonate derivatives from one-pot, three-component hydrophosphorylation reactions of aldehydes, amines, and diphenylphosphine oxides/diethylphosphite. Here ChCl–urea (1 : 2) DES played a dual role, namely that of a solvent as well as an efficient catalyst. Using this protocol, diverse α-aminophosphorous derivatives were obtained in excellent yields after short duration, with decent functional group tolerance. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Chemical Communications," published by The Royal Society of Chemistry. It provides information about the articles and contributors featured in the issue, aiming to connect the world with the chemical sciences. The document also includes contact information for queries and subscriptions. Additionally, it offers instructions for authors who wish to submit material for publication, guidelines for reproducing published contributions, and copyright information and permissions required for reproducing the publication. Lastly, the document includes a list of recent communications published in the journal. [Extracted from the article]

P-Stereomutation of phosphine oxides is extremely slow. We show that it is catalysed by chlorophosphonium salts (CPS) which can directly be formed in the system in situ. The racemization of phosphine oxides at ambient conditions catalysed by 1 mol% of CPS takes 1–2 hours and can be arrested by additon of a primary alcohol. The process probably proceeds via the development of oxodiphosphonium P–O–P species. [ABSTRACT FROM AUTHOR]

Herein, we report a photocatalyzed radical difunctionalization of acetylene for the rapid synthesis of C2-linked phosphine compounds. The reaction was initiated by addition of a phosphinoyl radical, followed by two cascade transformations. One involves a double addition for the formation of DPPE-dioxide analogues and in the other the intermediate vinylphosphine oxide is intercepted by a radical formed from an oxoheterocycle. This method features metal-free and mild conditions (rt, 1 atm acetylene), 100% atom economy and easy operation. Furthermore, the reaction can be robustly performed on a decagram scale. [ABSTRACT FROM AUTHOR]

Phosphine oxides and arsine oxides feature highly polarized pnictoryl groups (Pn+–O−/Pn = O; Pn = P, As) and react as Brønsted bases through O-centered lone pairs. We recently reported the first example of a monomeric stibine oxide, Dipp3SbO (Dipp = diisopropylphenyl), allowing periodic trends in pnictoryl bonding to be extended to antimony for the first time. Computational studies suggest that, as the pnictogen atom becomes heavier, delocalization of electron density from the O-centered lone pairs to the Pn–C σ* orbitals is attenuated, destabilizing the lone pairs and increasing the donor capacity of the pnictine oxide. Herein, we assess the Brønsted basicity of a series of monomeric pnictine oxides (Dipp3PnO; Pn = P, As, and Sb). Stoichiometric reactivity between Dipp3PnO and a series of acids demonstrates the greatly enhanced ability of Dipp3SbO to accept protons relative to the lighter congeners, consistent with theoretical isodesmic reaction enthalpies and proton affinities. 1H NMR spectrometric titrations allow for the pKaH,MeCN determination of Dipp3AsO and Dipp3SbO, revealing a 106-fold increase in Brønsted basicity from Dipp3AsO to Dipp3SbO. The increased basicity can be exploited in catalysis; Dipp3SbO exhibits dramatically increased catalytic efficiency in the Brønsted base-catalyzed transesterification between p-nitrophenyl acetate and 2,2,2-trifluoroethanol. Our results unambiguously confirm the drastic increase in Brønsted basicity from Dipp3PO < Dipp3AsO < Dipp3SbO, a direct consequence of the variation in the electronic structure of the pnictoryl bond as the pnictogen atom increases in atomic number. [ABSTRACT FROM AUTHOR]

The distinctive fluorine effects on "on-water" chemistry have remained less explored. In this work, an "on-water" reaction of β-trifluoromethylated enones with phosphine oxides was developed for the preparation of highly functionalized gem-difluorodienes with excellent Z-selectivity. The reaction occurred through a well-designed tandem phospha-Brook rearrangement and defluorination sequence under transition-metal-free conditions in water solution, which efficiently overcame some competitive side reactions, such as hydrodefluorination, 1,4-nucleophilic addition, and phosphorylation. The success was attributed to favorable H-bonding interactions at the water–organic phase boundary which could activate the substrates and enhance the reaction selectivity. [ABSTRACT FROM AUTHOR]

We report herein on the nickel-catalyzed methylation of arylphosphines using AlMe3via the cleavage of unactivated C(aryl)–P bonds. This reaction allows for the direct, catalytic substitution of an aryl group on a phosphorus center with a methyl group. This catalytic methylation can proceed, when phosphine oxides and sulfides are used as a substrate. [ABSTRACT FROM AUTHOR]

We report herein on the nickel-catalyzed methylation of arylphosphines using AlMe3via the cleavage of unactivated C(aryl)–P bonds. This reaction allows for the direct, catalytic substitution of an aryl group on a phosphorus center with a methyl group. This catalytic methylation can proceed, when phosphine oxides and sulfides are used as a substrate. [ABSTRACT FROM AUTHOR]

The two triple-armed species tris(2-carboxyethyl)nitromethane (H3tcenm) and tris(2-carboxyethyl)phosphine (H3tcep) have been used to synthesize seven uranyl ion complexes under (solvo)-hydrothermal conditions and in the presence of various structure-directing cations. The three carboxylate groups chelate three different cations and the nitro group is uncoordinated in [H2NMe2][UO2(tcenm)]·3H2O (1), [C(NH2)3][UO2(tcenm)]·0.5H2O (2) and [PPh3Me][UO2(tcenm)] (3), which crystallize as diperiodic coordination polymers with the hcb topology and minor variations in shape depending on the counterion. The two isomorphous complexes [UO2(tcenm)M(bipy)2][UO2(tcenm)]·3H2O, with M = Ni (4) or Cu (5) and bipy = 2,2′-bipyridine, display the same arrangement, with a M(bipy)22+ group bridging two adjoining carboxylate donors in one uranyl equatorial plane. [(UO2)2(tcenm)2Cu(R,S-Me6cyclam)]·2H2O (6), where R,S-Me6cyclam = 7(R),14(S)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, is the only triperiodic framework in the series, with the tcs topology resulting from CuII pillaring diperiodic, uranyl-based sql networks. H3tcep is oxidized in situ to give the phosphine oxide H3tcepo, which is partially deprotonated in [UO2(Htcepo)] (7); the phosphine oxide and the two carboxylate groups are coordinated, and the diperiodic, three-dimensional network formed has the point symbol {66} and the vertex symbol 62·62·63·66·64·64, with the rings involved in Hopf links formation. Only complexes 3 and 7 are significantly emissive in the solid state, with photoluminescence quantum yields of 9%, and the emission maxima positions are in agreement with the number of uranyl equatorial donors. [ABSTRACT FROM AUTHOR]

Sulfonated bis(4-methyl benzoate) phenylphosphine oxide (sBMPO) was synthesized by the sulfonation and esterification of bis(4-methylbenzoate)phenylphosphine oxide (BMPO). A series of high-molecular-weight sulfonated polybenzimidazoles (sPBI-PO) was also prepared via the random co-polycondensation of sBMPO, BMPO, and 3,3′-diaminobenzidine. The solubility was improved by incorporating a high concentration of phenylphosphine oxide units with pendant benzene groups in the polymers due to the remodeling of an irregular arrangement of polymer main chains. The sPBI-PO polymers showed excellent mechanical properties and thermal stability. The prepared sPBI-PO membranes displayed suitable water uptake and excellent dimensional stability in a very narrow range of 7.4–9.5% because of the good water retention ability of the phenylphosphine oxide units. With increasing sulfonation degree, the hydrophilic/hydrophobic nanophase separation morphology of sPBI-PO became more obvious, as shown by AFM phase images. The sPBI-PO membranes exhibited relatively low proton conductivity due to the strong acid–base interaction between the sulfonated group and the benzimidazole ring. However, after doping with phosphoric acid, the proton conductivity of the sPBI-PO90-PA membrane was 27.62 mS cm−1, which was 3.89 times higher than that of the undoped sPBI-PO90 membrane (7.1 mS cm−1) at 80 °C and 100% RH. Hence, these sPBI-PO polymers are highly promising matrix materials for PEMs. [ABSTRACT FROM AUTHOR]

We report the synthesis of a new palladium complex (1a) bearing two different P-donors, di(1-adamantyl)phosphinous acid and triphenylphosphine. A heteroleptic complex with a phosphinous acid ligand has rarely been reported. With phenyl bromide and di-p-tolylphosphine oxide as reagents, PPh3-stabilised 1a was proved to be a noteworthy Pd(II) precatalyst for carbon-phosphorus bond formation. 1a-catalysed Hirao coupling could be efficiently made in environmentally benign ethanol. Reacting for 10 to 120 minutes, aryl bromides equipped with electron-donating or electron-withdrawing groups were successfully catalysed. Nucleophile-sensitive 2-bromopyridine, 2-bromothiophene, and 4-bromobenzonitrile were applicable in toluene/ethylene glycol (EG) (9/1). 1a-catalyzed Hirao coupling was successfully applied to the synthesis of a host material in an organic light-emitting diode (OLED) and precursor of biarylphosphines. A mechanistic study regarding how plausible Pd(0) active species are generated was jointly investigated by means of DFT calculation, ESI mass spectroscopy, and experiment. Interestingly, we demonstrated a proof of concept that bulky di(1-adamantyl)phosphine oxide is a useful preligand and less bulky di-p-tolylphosphine oxide is the substrate in the Hirao coupling. [ABSTRACT FROM AUTHOR]

We report the synthesis of [(L)DyIII(Cy3PO)2]·[BPh4] (1-Dy) (where H2L = 2,6-diacetylpyridine bis-benzoylhydrazone and Cy = cyclohexyl) which crystallized in the triclinic, P1¯ space group. The local geometry around Dy(III) in 1-Dy was found to be pentagonal bipyramidal (pseudo-D5h). The AC magnetic susceptibility measurements performed on 1-Dy and on its diluted 1-Y(Dy) samples showed a typical single-molecule magnet signature revealed by the appearance of AC-frequency dependent out-of-phase susceptibility signals in the absence of a static magnetic field. The out-of-phase AC susceptibility signals were well resolved on the application of a small magnetic field (HDC = 500 Oe) and yielded an energy barrier for magnetization flipping of Ueff/kB = 50 K for the diluted derivative. The magnetic studies on 1-Dy and 1-Y(Dy) and data analysis further confirm that Raman and QTM under-barrier magnetic relaxations play a crucial role in lowering Ueff despite the almost axial nature of the Dy(III) ion in 1-Dy. We have rationalized these observations through detailed ab initio calculations performed on the X-ray crystal structure of 1-Dy. [ABSTRACT FROM AUTHOR]

Inspired by the diverse bioactivities of α-amino phosphine oxides, an efficient strategy for the synthesis of less researched α-(hydroxyamino)diarylphosphine oxides has been developed and their antitumor activities are explored. Under water as a solvent and catalyst-free conditions, the addition of nitrones and diphenylphosphine oxide occurs smoothly to afford α-(hydroxyamino) diarylphosphine oxides in high yields. This reaction features a wide substrate scope, facile starting materials, atom economy, and easy purification. Moreover, the biological evaluation revealed that two synthesized derivatives 5e and 5f could serve as interesting anti-cancer agents for further development. [ABSTRACT FROM AUTHOR]

A series of mononuclear and binuclear lanthanideIII complexes with formulae [Dy(Cy3PO)(tmhd)3] (1), [Dy2(dppeO2)(tmhd)6] (2) and [Ln2(dppeO2)(acac)6(H2O)2] (3, Ln = Dy, 4, Ln = Gd, 5, Ln = Eu, 6, Ln = Tb) (Cy3PO = tricyclohexyl phosphine oxide, tmhd = 2,2,6,6-tetramethyl-3,5-heptane dionate, acac = acetylacetone, dppeO2 = 1,2-bis(diphenylphosphino)ethane dioxide) constructed using β-diketonate combined with mono- and bi-phosphine oxide ligands were structurally, optically and magnetically characterized. The easy to modify backbone of monodentate phosphine oxide and bidentate β-diketonate enables them to modulate local coordination geometries around lanthanide ions by means of an electronic effect and/or steric hindrance of substituents on the terminal of these ligands and consequently optimize the corresponding optical and magnetic properties. In this vein, a series of Dy containing single-molecule magnets (SMMs) were constructed, in which complex 3 possessed a relatively higher local geometry symmetry (D4d) and displayed a significantly slow magnetic relaxation behavior at a hysteresis temperature of 3 K. In addition, the Gd congener complex 4 showed a pronounced magnetocaloric effect (MCE) with a –ΔS maxm value of 20.4 J kg−1 K−1, and more strikingly, a field induced SMM behavior was observed in 4 despite the isotropic nature of GdIII ions. Also of note is that the suitable triple state energy of ligands matches well with the excited states of EuIII, TbIII and DyIII ions, which led to the corresponding characteristic metal-centered luminescence emission. In this work, the deliberately selected β-diketonate and phosphine oxide combined with different lanthanide ions led to a series of multifunctional materials with SMM, luminescence and MCE properties. [ABSTRACT FROM AUTHOR]

Chemoselective annulations of phosphoryl carbenes generated from diazo(aryl)methyl(diaryl)phosphine oxides with pyridinium 1,4-zwitterionic thiolates were performed under microwave irradiation, affording 1-diarylphosphoryl-1H-benzo[c]thiopyran derivatives via [3+3] annulation and indolizine derivatives via ([1+5]-1) annulation with P-Cope elimination as the key step. The annuloselectivity was controlled by the steric hindrance of pyridiniums in pyridinium 1,4-zwitterionic thiolates. [ABSTRACT FROM AUTHOR]

An efficient organocatalyzed enantioselective hydrophosphinylation of indole-derived vinylogous imines generated in situ from sulfonyl indoles has been developed. Using quinine-derived bifunctional thiourea as the catalyst, a wide range of structurally diverse chiral 3-(1-diphenylphosphoryl-arylmethyl)indoles were obtained with good to excellent results (up to 99% yield and 99% ee). This method represents the first example of the catalytic asymmetric Michael addition of phosphine oxides to vinylogous imine intermediates. [ABSTRACT FROM AUTHOR]

In today's world, water pollution is a serious problem. Dye adsorption and photocatalytic degradation are effective methods to deal with water pollution. The key to dealing with water pollution is to find suitable adsorbents and catalysts. We synthesized a series of rare earth complexes containing [PMo12O40]3− and a P＝O ligand, [REL4](PMo12O40)·nCH3CN (RE = La for 1, Ce for 2, Pr for 3, Sm for 4, Eu for 5, Gd for 6, and Tb for 7; n1,2,3,5,6 = 2 and n4,7 = 0; L = tetraethyl ethylenediphosphonate), and [REL3(H2O)](PMo12O40)·CH3CN (RE = Tm for 8, Yb for 9, and Y for 10). Complexes 1–7 are all eight-coordinated mononuclear structures centered on lanthanide ions, [PMo12O40]3− anions and solvent molecules are not coordinated with metal ions, while complexes 8–10 are seven-coordinated mononuclear structures. These mononuclear structures eventually form complicated 3D supramolecular structures through hydrogen bond weak interactions. These complexes have good adsorption properties for rhodamine B (RhB) and can degrade methylene blue (MB) under UV irradiation. Furthermore, terahertz time-domain spectroscopy (THz-TDS) is used to characterize the structures of complexes and ligands, which will provide useful information for building bridges between THz spectra and the structures of complexes in coordination chemistry. [ABSTRACT FROM AUTHOR]

Lysine–covalently modified graphene oxide (GO-Lys) was prepared by an innovative procedure. Lysine brushes promote enhanced adsorption of bisphenol A, benzophenone-4 and carbamazepine contaminants from tap water, with a removal capacity beyond the state of the art. [ABSTRACT FROM AUTHOR]

Phosphanylidenephosphoranes of the type R–P(PR′3), also known as phospha-Wittig reagents, can be utilized in a variety of bond activation reactions exploiting their phosphinidenoid reactivity. Herein, we thoroughly show that a facile PMe3 for H2O exchange gives access to various primary phosphine oxides of the general formula RP(H)2O (R = Mes*, MesTer, DipTer) and the molecular structure of DipTerP(O)H2 was determined. However, phosphanylidenephosphoranes are described to be highly nucleophilic as well. We show that the attachment of main group Lewis acids such as GaCl3 and GaI3 to R–P(PMe3) yielded the highly sensitive, yet stable coordination compounds [(RPGaX3)PMe3] (R = Mes*, DipTer) or [(RPPMe3)2GaCl2]GaCl4 (R = MesTer). In contrast to the free phosphanylidenephosphoranes, these species reacted differently with H2O, which was demonstrated for [(Mes*PPMe3)GaI3]. Here the formation of the phosphino-phosphonium cation [Mes*P(H)PMe3]+ and different anions was observed with combined NMR spectroscopic and SC-XRD (SC-XRD = single crystal X-ray diffraction analysis) studies. This work demonstrates that the ambiphilic character of phosphanylidenephosphoranes can be utilized to manipulate the reactivity of R–P(PMe3) towards water, giving primary phosphine oxides, whereas the Lewis acid adducts [(RPGaX3)PMe3] gave phosphino-phosphonium species. [ABSTRACT FROM AUTHOR]

Metal–organic layers (MOLs), a category of two-dimensional materials, have attracted wide interest due to their molecular tunability and the ease of surface modification. Herein, we reported the synthesis and structural determination of a free-standing MOL, {[Hf6O8H4(HCOO)2(H2O·OH)4]3[Hf12O16H8(HCOO)6.8(H2O·OH)11.2](TPO)8}n, constructed from Hf6-oxo and Hf12-oxo clusters as secondary building units (SBUs) and the tris(4-carboxylphenyl)phosphine oxide (TPO) ligand. We establish a structure model of this new MOL based on the combined information from different characterization methods. [ABSTRACT FROM AUTHOR]

Using triphenylphosphine oxide (OPPh3) or tetraethyl ethylenebisphosphonate (L) as a ligand and phosphomolybdic acid hydrate as an anion template, six new lanthanide complexes [Nd(OPPh3)4(H2O)3](PMo12O40)·4CH3CN (1a), [Ln(OPPh3)4(H2O)3](PMo12O40)·4C2H5OH (2a–4a) (Ln = Dy, Ho, Er), [NdL4](PMo12O40)·CH3CN (1b), and [ErL3(H2O)](PMo12O40)·CH3CN (4b) were synthesized. They were characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis and THz spectroscopy. Also, [LnL3(H2O)](PMo12O40)·CH3CN (2b, 3b) (Ln = Dy, Ho) have been published previously and they are cited in this paper for comparison. Complexes 1a–4a and 2b–4b are all seven-coordination mononuclear structures centered on lanthanide ions, while complex 1b is of eight-coordination. These mononuclear structures eventually form complicated supramolecular structures through hydrogen bonding, Mo–O⋯π or C–H⋯π weak interactions. The photocatalytic experiments show that the photocatalytic degradation removal rates of methylene blue are 94.93–99.55% for 1a–4a, 1b and 4b, and they have good stability and can be recycled, so they can be used as catalysts to degrade dye molecules in sewage. Due to the similar structures of complexes 1a–4a, 1b and 4b, they have almost the same THz absorption spectra with different absorption intensities, which may be attributed to the difference in the number of weak interactions. So THz spectroscopy can be used as a sensitive way to distinguish and determine small differences between lanthanide–organic complexes. In summary, the structures, photocatalytic properties, adsorption and terahertz spectra of a series of lanthanide complexes based on phosphine oxide ligands and Keggin type polyoxometalates were studied in this paper. [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 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]

Group 11 metal complexes with their ability to form metallophilic interations are widely pursued to develop multifunctional luminescent materials. Heteronuclear coinage metal complexes are promising candidates to tune electronic and optical properties which are not readily accessed by their homometallic congeners. In this review, we present the concept of orthogonal ligands which are rationally designed to access heteronuclear coinage metal complexes and studied in terms of their photophysical properties. Bifunctional ligands containing soft and hard donor atoms have the potential of providing different coordination modes to selectively synthesise heterobimetallic complexes in a predictable manner. This review deals with ligand sets composed of pyridine, bipyridine- or iminopyridine-substituted NHCs featuring C–N coordination modes, phosphine-based N-heterocycles and amidinate ligand scaffolds comprising of P–N functionalities and mixed phosphine–phosphine oxide with P–O donor sites. Therefore, the scope of this perspective is the discussion of heteronuclear coinage metal complexes supported by recently developed bifunctional ligands in terms of their synthesis, coordination geometries and tunability of optical properties when compared to their homometallic analogues. [ABSTRACT FROM AUTHOR]