Organic Phosphine Research Articles

Water-soluble neutral octahedral chalcogenide tungsten and molybdenum {M6Q8} clusters with P(C2H4CONH2)3 ligand

Developing the chemistry of octahedral chalcogenide molybdenum and tungsten cluster complexes in the context of applications in biology and medicine, in this work a series of water-soluble neutral cluster complexes [{M6Q8}(P(C2H4CONH2)3)6] (M = Mo, W; Q = S, Se) have been obtained by simultaneous replacement of inner and terminal halide ligands in [{M6I8}I6]2− with chalcogenide and organic phosphine ligands and characterized by single-crystal X-ray diffraction analysis, 1H and 31P NMR spectroscopies, elemental analysis, and UV–vis spectroscopy. The amide groups of the organic ligands, on the one hand, contribute to the solubility of the resulting clusters in water and, on the other hand, are able to form an extensive network of hydrogen bonds, leading to the crystallization of the complexes from aqueous solutions. Despite this fact, the complexes have sufficient solubility and stability in aqueous solutions, which made it possible to demonstrate their low cytotoxicity on Hep-2 cells (IC50 were not reached even at concentration up to 4 mM). The resulting clusters are among the most biocompatible of the octahedral clusters studied to date and are the starting point for the development of a new family of X-ray contrast agents.

Modulating the carbon chain length of organic phosphine for the selective Au(I) recovery from a copper-ammonia-thiosulfate leaching solution

The selective recovery of gold ions from gold leaching solutions limits the industrial application of the copper-ammonia (Cu2+–NH3)-thiosulfate system. Here, the influence of the carbon chain length of organic phosphines on the selective recovery of gold ions was studied, and an extractant (trihexylphosphine, THP) that is suitable for the selective recovery of gold ions from a Cu2+–NH3-thiosulfate leaching solution was screened. The selectivity of organic phosphines with different carbon chain lengths for gold ions was C8 = C6 > C4 > C3 > C2, and when the number of carbon atoms in a single carbon chain was at least six, the selective recovery of gold ions from the Cu2+–NH3-thiosulfate solution was realized. THP completely recovered low concentration gold ions (6.73 mg/L) in the Cu2+–NH3-thiosulfate gold leaching solution regardless of the pH. The mechanism of gold ion extraction into the organic phase mainly involved ligand exchange between THP and [Au(S2O3)2]3−. Job’s method and density functional theory calculations confirmed that the composition ratio of the complex formed by THP and Au was 2:1 at the practical and theoretical levels, respectively. Finally, Multiwfn and VMD were used to visually predict the possible reaction sites in THP. This study provides an exact method for the selective recovery of gold ions from thiosulfate-based gold leaching solutions, which will promote the development of thiosulfate-based gold leaching systems

Production and Characterization of Flame Retardant Leather Waste Filled Thermoplastic Polyurethane.

Discovering new applications for discarded materials, such as leather waste (LW), has proven to be an effective approach to an ecofriendly and sustainable production. The manufacture of halogen-free flame retardant LW containing thermoplastic polyurethane (TPU)-based samples containing an organic phosphinate (OP)-based flame retardant additive would represent an advance in this area. The effects of LW and OP levels on the thermal, flame retardant, and tensile properties of the samples using thermal gravimetric analysis (TGA), limiting oxygen index (LOI), vertical UL-94 (UL-94 V), mass loss calorimetry, and tensile tests have been assessed. OP is highly effective in LW-filled TPU. The highest UL-94 V rating of V0, LOI value of 31.4%, the lowest peak heat release rate (93 ± 3 kW/m2), and total heat evolved (49 ± 2 MJ/m2) values are obtained with the use of 20 wt % OP. OP is primarily promoted through the creation of a compact intumescent residue structure in the condensed phase. LW exhibits an adjuvant effect by producing nonflammable gases in the gas phase and raising the residual yield in the condensed phase. The most remarkable effect of the LW presence is observed in fire performance index (FPI) and fire growth rate (FIGRA) values. The highest FPI value of 0.49 sm2/kW and the lowest FIGRA value of 0.91 kW/m2s are observed with the use of 20 wt % LW.

Additive manufacturing of flame retardant polyamide 12 with high mechanical properties from regenerated powder

PurposeThis paper aims to develop flame-retardant (FR) polyamide 12 (PA12) nanocomposite from regenerated powder via selective laser sintering (SLS), an additive manufacturing technique.Design/methodology/approachFirst, the morphology, processibility, thermal and mechanical properties of PA12 regenerated powder, consisting of 50 wt% new and 50 wt% recycled powder, as well as corresponding printed specimens, were evaluated to characterize the effects of previous SLS processing. Second, flame-retardant PA12 was developed by incorporating both single and binary halogen-free flame retardants into the regenerated powder.FindingsIt was found that the printed specimens from regenerated powder had much higher tensile and impact properties compared to specimens made from new powder, which is attributed to better particulate fusion and coalescence realized in higher temperature SLS printing. The effect of FRs on thermal, mechanical and flame retardant properties of the PA12 composites/nanocomposites was investigated systematically. It was found that the nanoclay, as a synergist, improved both flame-retardant and mechanical properties of PA12. UL94 standard rating of V-0 was achieved for the printed nanocomposite by incorporating 1 wt% nanoclay into 15 wt% phosphinates FR. Moreover, on average, the tensile and impact strength of the nanocomposite were increased by 26.13% and 17.09%, respectively, in XY, YZ and Z printing orientations as compared to the equivalent flame retardant composite with 20 wt% of the phosphinates FR.Originality/valueThis paper fulfills the need to develop flame retardant parts via SLS technology with waste feedstock. It also addresses the challenge of developing flame retardant materials without obviously compromising the mechanical properties by making use of the synergistic effect of nanoclay and organic phosphinates.

The immobilization of Sr(ll) and Co(ll) via magnetic easy-separation organophosphonate-hydroxyapatite hybrid nanoparticles

The magnetic Hexamethylene diamine tetramethylene phosphonic acid (HDTMP)-hydroxyapatite nanoparticles (HD-MHAP) were firstly prepared and applied for the immobilization of radioactive Sr2+ (Strontium ion) and Co2+ (Cobalt ion). The molar ratio of organic phosphine in HDTMP to total phosphorus was 10% (10HD-MHAP) and can also be easily separated from aqueous solution. At the equilibrium concentration of Sr2+ and Co2+ (200 mg/L), the adsorption capacity of MHAP and 10HD-MHAP on Co2+ was 28.4 mg/g and 172.3 mg/g, respectively and for Sr2+, the adsorption capacity was 54.9 mg/g and 320.7 mg/g. Additionally, the desorption percentage of Sr2+ (%) and Co2+ (%) was very low, which was 0.66 and 1.61, respectively. This is significant because the irreversible adsorption of HDTMP/Fe3O4/HAP composite for Sr2+ and Co2+ ensures the captured radionuclides will not be released back into the aquatic systems. Moreover, the affinity between HDTMP and HAP and the coordination of HDTMP and Sr2+ or Co2+ was probed by Multiwfn wavefunction analysis. The results indicated that the formation of a ternary surface complex of MHAP-HDTMP-M (Sr2+ or Co2+) was the key to the excellent immobilization performance of HD-MHAP composite for Sr2+ or Co2+.

A DFT study on MOFs with rhodium-coordinated organic phosphine linkers modified by functional groups for catalytic hydroformylation of 1-butene

The organic ligands containing different heteroatoms (N/O/P) to coordinate Rh-active metals were found active for the hydroformylation of 1-butene, and P-containing ligands were superior in catalytic activity and n/i selectivity. In this work, a model of MOF Rh-PCM-18 containing phosphine ligands, similar to the conventional rhodium-phosphine homogeneous catalyst, was constructed, then the phosphine ligands were modified by inserting functional groups to change the electronic properties of the ligands, which might improve the catalytic performance. Five different models were obtained and their structures and electronic properties were calculated. The adsorption energies of the reactant species and the reaction paths on these models were investigated. The results suggested that the enhancement of the electron-donating ability of the phosphine ligand increased the adsorption of CO and H and promoted the oxidative addition of H2 at the metal site, but caused a higher activation energy barrier of the first step. On the other hand, appropriate reduction in the electron-donating ability of the phosphine ligand weakened the adsorption of CO and H and led to a decrease in the energy barrier of the first two steps, which improved the catalytic performance. This work explored the influence of the electronic properties of organic phosphine ligands on the coordinated active metal catalyst for 1-butene hydroformylation, which provided a reference for the selection and modification of ligands when using MOFs to design heterogeneous catalysts for hydroformylation.

Aggregation‐Induced Emission in a Flexible Phosphine Oxide and its Zn(II) Complexes—A Simple Approach to Blue Luminescent Materials

AbstractEasily accessible blue‐emitting materials are in the focus of ongoing research, as they still lack the efficiency and lifetime of their red and green counterparts. The new multidentate phosphine oxide ligands and two respective ZnCl2 complexes presented here combine a straightforward synthesis with high yields and show interesting luminescent properties. The free ligand exhibits blue luminescence in the crystalline state, but not in amorphous films or diluted solution. In contrast, the Zn(II) complexes shows intense blue luminescence in the crystalline state as well as in amorphous thin films and in solution. Fluorescence lifetime imaging microscopy measurements show luminescence lifetimes of 3–6 ns indicative of fluorescence. By combining the experimental data with quantum chemical calculations, we propose a model where the conformation of the molecule is restricted, either via the crystal environment, aggregation, or the steric fixation by the coordinating central atom, blocking the nonradiative relaxation from the excited into the ground electronic state. However, this nonradiative relaxation is still possible in the gas phase via elongation of a PC bond. These results may provide a general mechanism to explain the luminescence properties in a whole class of organic phosphine oxides.

A Novel Fluorescent Sensor Based on Aptamer and qPCR for Determination of Glyphosate in Tap Water.

Glyphosate (GLYP) is a broad-spectrum, nonselective, organic phosphine postemergence herbicide registered for many food and nonfood fields. Herein, we developed a biosensor (Mbs@dsDNA) based on carboxylated modified magnetic beads incubated with NH2-polyA and then hybridized with polyT-glyphosate aptamer and complementary DNA. Afterwards, a quantitative detection method based on qPCR was established. When the glyphosate aptamer on Mbs@dsDNA specifically recognizes glyphosate, complementary DNA is released and then enters the qPCR signal amplification process. The linear range of the method was 0.6 μmol/L−30 mmol/L and the detection limit was set at 0.6 μmol/L. The recoveries in tap water ranged from 103.4 to 104.9% and the relative standard deviations (RSDs) were <1%. The aptamer proposed in this study has good potential for recognizing glyphosate. The detection method combined with qPCR might have good application prospects in detecting and supervising other pesticide residues.

Recent Advances in Visible-Light-Induced Organic Phosphine- Promoted Deoxygenative Functionalization Reactions

Recent Advances in Visible-Light-Induced Organic Phosphine- Promoted Deoxygenative Functionalization Reactions

Pd nanoparticles embedded into MOF‑808: An efficient and reusable catalyst for Sonogashira and Heck cross-coupling reactions

In this work, the Pd@MOF-808 composite was prepared to effectively catalyze the Sonogashira and Heck reactions without the presence of organic phosphine ligands. The results showed that the developed catalyst provided an environment-friendly reaction condition for these two reactions with the existence of a variety of functional groups and substrates. In addition, the Pd@MOF-808 catalyst could be easily recovered and reused for up to 5 times with less deterioration of catalytic performance.

Removal of organic phosphonate HEDP by Eu-MOF/GO composite membrane

The efficient removal of organic phosphonate 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) from reverse osmosis brine concentrate was investigated by coupling adsorption and membrane separation. The prepared adsorbent of europium-metal organic framework (Eu-MOF) has an adsorption capacity of 37.31 mg-P/g for organic phosphine, which is the highest reported so far. Eu-MOF and graphene oxide (GO) were mixed and deposited on a supporter polyethersulfone by vacuum filtration to form Eu-MOF/GO composite membrane. The micro-space channels between the Eu-MOF straw-sheaf crystals and intrinsic nanosized pores in the Eu-MOFs served as separation membrane adsorbent with both high selectivity and high flux. The composite membrane could achieve a 100% rejection rate of HEDP from the simulated RO concentrate solution at pH 5–8, and the flux was more than six times that of a pure GO membrane. The increase in the interlayer spacing of GO nanosheets adjusted by Eu-MOF would enhance the permeation flux of the composite membrane. Most importantly, the Eu-MOF with the most probable pore size of 3.371 nm, embedded in the composite membrane, also increased permeation flux and at the same time enhanced the adsorption capacity of HEDP molecules. The separation mechanism of the composite membrane was mainly ligand exchange and hydrogen bonding. The trade-off effect between permeation flux and selectivity was overcome by the prepared composite membrane. This work provides a new strategy for designing composite membranes with adsorption function and such composite membrane can serve as a promising material for removing organic phosphonates from water.

Organophosphine‐Sandwiched Copper Iodide Cluster Enables Charge Trapping

AbstractHerein, we report a feasible molecular design of the binuclear clusters featuring the n‐p‐n heterojunction of biligand‐sandwiched inorganic units, which can be used as the effective charge trapper in ambipolar transistor memories with the large memory windows and the energy‐saving operation. We found that the hole confinement on the p‐type inorganic units is enhanced by spatial electronic anisotropy provided by the peripheral n‐type organic phosphine ligands. The steric hindrance of the coordination sites, the insulating effect of the carbon‐phosphorous single bonds and the parallel dual‐ligand coordination mode jointly elongate the interunit distances to nanometer scale and restrain the intramolecular electronic communications, leading to the tunable and reliable charge trapping. Our results show that the spatial effect is crucial to further amplifying the electronic differences between organic and inorganic units for function enhancement.

Organophosphine-Sandwiched Copper Iodide Cluster Enables Charge Trapping.

Herein, we report a feasible molecular design of the binuclear clusters featuring the n-p-n heterojunction of biligand-sandwiched inorganic units, which can be used as the effective charge trapper in ambipolar transistor memories with the large memory windows and the energy-saving operation. We found that the hole confinement on the p-type inorganic units is enhanced by spatial electronic anisotropy provided by the peripheral n-type organic phosphine ligands. The steric hindrance of the coordination sites, the insulating effect of the carbon-phosphorous single bonds and the parallel dual-ligand coordination mode jointly elongate the interunit distances to nanometer scale and restrain the intramolecular electronic communications, leading to the tunable and reliable charge trapping. Our results show that the spatial effect is crucial to further amplifying the electronic differences between organic and inorganic units for function enhancement.

Investigation of Hydrophosphorylation Reaction of Pentacoordinate Hydrospirophosphorane and Electron‐Deficient Alkenes Catalyzed by Organic Phosphine

AbstractPR3 efficiently catalyzes the addition of H‐spirophosphorane to electron‐deficient alkenes to give the spirophosphoranes with a pentacoordinate P−C bond in moderate to excellent yields. This practical procedure was conducted by using PR3 as an organocatalyst, which avoided the use of an additional base, traditional heating, and metal reagents. The investigation of the reaction mechanism showed that the zwitterion intermediate served as the base to further catalyze hydrospirophosphorane. Then the spirophosphoranide formed as a nucleophile attacked electron‐deficient alkene to give the addition products. This reaction is a first and simple hydrophosphorylation reaction of alkenes to construct pentacoordinate P−C bond under organocatalysis

Sensing Organophosphorus Compounds with SWCNT Films.

Promising electrical properties of single-walled carbon nanotubes (SWCNTs) open a spectrum of applications for this material. As the SWCNT electronic characteristics respond well to the presence of various analytes, this makes them highly sensitive sensors. In this contribution, selected organophosphorus compounds were detected by studying their impact on the electronic properties of the nanocarbon network. The goal was to untangle the n-doping mechanism behind the beneficial effect of organic phosphine derivatives on the electrical conductivity of SWCNT networks. The highest sensitivity was obtained in the case of the application of 1,6-Bis(diphenylphoshpino)hexane. Consequently, free-standing SWCNT films experienced a four-fold improvement to the electrical conductivity from 272 ± 21 to 1010 ± 44 S/cm and an order of magnitude increase in the power factor. This was ascribed to the beneficial action of electron-rich phenyl moieties linked with a long alkyl chain, making the dopant interact well with SWCNTs.

Selective and Efficient Olefin Epoxidation by Robust Magnetic Mo Nanocatalysts

Iron oxide magnetic nanoparticles were synthesized with different sizes (11 and 30 nm). Subsequently they were shelled with a silica layer allowing grafting of an organic phosphine ligand that coordinated to the [MoI2(CO)3] organometallic core. The silica layer was prepared by the Stöber method using either mechanical (both 11 and 30 nm nanoparticles) or ultrasound (30 nm only) stirring. The latter nanoparticles once coated with silica were obtained with less aggregation, which was beneficial for the final material holding the organometallic moiety. The Mo loadings were found to be 0.20, 0.18, and 0.34 mmolMo·g−1 for MNP30-Si-phos-Mo,MNP11-Si-phos-Mo, and MNP30-Sius-phos-Mo, respectively, with the ligand-to-metal ratio reaching 4.6, 4.8, and 3.2, by the same order, confirming coordination of the Mo moieties to two phos ligands. Structural characterization obtained from powder X-ray diffraction (XRD), scanning electron microscopy (SEM)/ transmission electron microscopy (TEM) analysis, and Fourier-transform infrared (FTIR) spectroscopy data confirmed the successful synthesis of all nanomaterials. Olefin epoxidation of several substrates catalyzed by these organometallic nano-hybrid materials using tert-butyl hydroperoxide (tbhp) as oxidant, achieved very good results. Extensive testing of the catalysts showed that they are highly active, selective, recyclable, and efficient concerning oxidant consumption.

Highly luminescent and stable CsPbBr3 perovskite quantum dots modified by phosphine ligands

All-inorganic cesium lead halide perovskite quantum dots (QDs) have been a promising candidate for optoelectronic devices in recent years, such as light-emitting diodes, photodetectors and solar cells, owing to their superb optoelectronic properties. Still, the stability issue of nanocrystals is a bottleneck for their practical application. Herein, we report a facile method for the synthesis of a series of phosphine ligand modified CsPbBr3 QDs with high PL intensity. By introducing organic phosphine ligands, the tolerance of CsPbBr3 QDs to ethanol, water and UV light was dramatically improved. Moreover, the phosphine ligand modified QD films deposited on the glass subtracts exhibit superior PL intensity and optical stability to those of pristine QD based films.

Eco-Friendly and Highly Efficient Enzyme-Based Wool Shrinkproofing Finishing by Multiple Padding Techniques.

Wool fibers usually need shrinkproofing finishing. The enzyme process is an eco-friendly technology but the traditional exhaustion treatment usually takes excessive time. This study developed a novel multiple padding shrinkproofing process of wool with Savinase 16L and an organic phosphine compound {[HO(CH2)n]3P, n ∈ (1, 10)}. SEM and XPS analyses were employed to compare the wool treated respectively by exhaustion and by padding to reveal the effect of multiple padding. The results showed that treated wool fiber achieved the requirement of machine-washable (area shrinkage less than 8% according to standard TM 31 5 × 5A) in 2.5 min by the padding process. The padding process can control the adsorbance of enzyme on wool, which makes treatment more uniform and avoids strong damage of the wool. Also, the removal efficiency of the disulfide bond was about 15 times as much as in the exhaustion treatment in 2.5 min. The average catalytic rate of the padding process was 14 times faster than the exhaustion process, and the process time (2.5 min) decreased by 32.5 min compared with the exhaustion process (35 min). Multiple padding techniques can achieve continuous production and replace the environmentally harmful chlorination process. Our results provide the underlying insights needed to guide the research of the enzyme process application.

The Role of Nanobubbles in the Precipitation and Recovery of Organic-Phosphine-Containing Beneficiation Wastewater.

Dissolved air flotation (DAF) is broadly applied in wastewater treatment, especially for the recovery of organic pollution with low concentration. However, the mechanism of interaction between nanoscale gas bubbles and nanoparticles in the process of DAF remains unclear. Here, we investigated the role of nanobubbles in the precipitation of styryl phosphoric acid (SPA)-Pb particles and recovering organic phosphine containined in beneficiation wastewater by UV-vis (ultraviolet-visible) spectra, microflotation tests, nanoparticle tracking analysis, dynamic light scattering, and atomic force microscopy measurements. As suggested from the results, nanobubbles can inhibit the crystallization of SPA-Pb precipitation, which makes the sediment flotation recovery below 20%. After the precipitation crystallization is completed, nanobubbles can flocculate precipitated particles, which can promote the flotation recovery of precipitated particles to 90%. On the basis of the results, we proposed a model to explain the different roles of nanobubbles in the process of precipitation and flotation of SPA-Pb particles. This study will be helpful to understand the interaction between nanobubbles and nanoparticles in the application of flotation.

Theoretical study of adsorption of organic phosphines on transition metal surfaces

ABSTRACTThe adsorption properties of organic phosphines on transition metal (TM) surfaces (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au) have been studied to explore the possibility of building novel heterogeneous chiral catalytic systems based on organic phosphines. Preferred adsorption sites, adsorption energies and surface electronic structures of a selected set of typical organic phosphines adsorbed on TM surfaces are calculated with density-functional theory to obtain a systematic understanding on the nature of adsorption interactions. All organic phosphines considered are found to chemically adsorb on these TM surfaces with the atop site as the most preferred one, and the TM–P bond is formed via the lone-pair electrons of the P atom and the directly contacted TM atom. These findings imply that it is indeed possible to build heterogeneous chiral catalytic systems based on organic phosphines adsorbed on TM surfaces, which, however, requires a careful design of molecular structure of organic phosphines.