Tributylphosphine Oxide Research Articles

Complexes of phosphine oxides with substituted phenols: hydrogen bond characterization based on shifts of PO stretching bands.

In this work IR spectral characteristics of PO groups are used to evaluate the strength of OHO hydrogen bonds. Three phosphine oxides: triphenylphosphine oxide, tributylphosphine oxide and hexamethylphosphoramide are investigated as proton acceptors. The results of the experimental IR study and DFT calculation of 30 complexes formed by phosphine oxides with various substituted phenols or CF3CH2OH in CCl4 solution at room temperature are reported. We show that the PO vibrational frequency changes non-linearly upon hydrogen bond formation and strengthening and that the shift of the PO band could be used for the estimation of hydrogen bond strength in complexes with phosphine oxides. The accuracy of these estimations and the influence of solvation effects on the main characteristics of complexes are discussed.

High-Performance Blue Quasi-2D Perovskite Light-Emitting Diodes via Balanced Carrier Confinement and Transfer

HighlightsA new concept to optimize the passivating agents for the balance of the carrier confinement and transfer in blue quasi-2D perovskites.The moderate tributylphosphine oxide is introduced into the quasi-2D perovskites to simultaneously strengthen the carrier confinement for massive radiative recombination as well as promote efficient carrier transfer in the quasi-2D perovskites.High-efficient and stable blue PeLEDs are achieved with an external quantum efficiency of 11.5% and a very long operational stability of 41.1 min without any shift of the electroluminescence spectra.

4-Phosphoryl Pyrazolones for Highly Selective Lithium Separation from Alkali Metal Ions.

Effective receptors for the separation of Li+ from a mixture with other alkali metal ions under mild conditions remains an important challenge that could benefit from new approaches. In this study, it is demonstrated that the 4‐phosphoryl pyrazolones, HL 2‐HL 4, in the presence of the typical industrial organophosphorus co‐ligands tributylphosphine oxide (TBPO), tributylphosphate (TBP) and trioctylphosphine oxide (TOPO), are able to selectively recognise and extract lithium ions from aqueous solution. Structural investigations in solution as well as in the solid state reveal the existence of a series of multinuclear Li+ complexes that include dimers (TBPO, TBP) as well as rarely observed trimers (TOPO) and represent the first clear evidence for the synergistic role of the co‐ligands in the extraction process. Our findings are supported by detailed NMR, MS and extraction studies. Liquid‐liquid extraction in the presence of TOPO revealed an unprecedented high Li+ extraction efficiency (78 %) for HL 4 compared to the use of the industrially employed acylpyrazolone HL 1 (15 %) and benzoyl‐1,1,1‐trifluoroacetone (52 %) extractants. In addition, a high selectivity for Li+ over Na+, K+ and Cs+ under mild conditions (pH ∼8.2) confirms that HL 2‐HL 4 represent a new class of ligands that are very effective extractants for use in lithium separation.

Evaluating Halogen-Bond Strength as a Function of Molecular Structure Using Nuclear Magnetic Resonance Spectroscopy and Computational Analysis.

Halogen bonding (XB) is a highly directional, non-covalent intermolecular interaction between a molecule (XB donor) presenting a halogen with an electron-deficient region or sigma hole (σ-hole) and an electron-rich or Lewis-base molecule (XB acceptor). A systematic, experimental, and theoretical study of solution-phase XB strength as a function of the molecular structure for both XB donor and acceptor molecules is presented. The impact of specific structural features is assessed using 19F and 1H nuclear magnetic resonance (NMR) titrations to determine association constants, density functional theory calculations for interaction energies and bond lengths, as well as 19F-1H HOESY NMR measurements of intermolecular cross-relaxation between the interacting XB donor-acceptor adducts. For XB donor molecules (perfluoro-halogenated benzenes), results indicate the critical importance of iodine coupled with electron-withdrawing entities. Prominent structural components of XB acceptor molecules include a central atom working in conjunction with a Lewis-base atom to present high electron density directed at the σ-hole (e.g., tributylphosphine oxide). Additionally, larger surrounding aliphatic R groups (e.g., butyl and octyl) were found to significantly stabilize strong XB, particularly in solvents that promote the interaction. With a more thorough understanding of structure-optimized XB, one can envision harnessing XB interactions more strategically for specific design of optimal materials and chemical applications.

Characterizing the Chemical Landscape in Commercial E-Cigarette Liquids and Aerosols by Liquid Chromatography-High-Resolution Mass Spectrometry.

The surge in electronic cigarette (e-cig) use in recent years has raised questions on chemical exposures that may result from vaping. Previous studies have focused on measuring known toxicants, particularly those present in traditional cigarettes, while fewer have investigated unknown compounds and transformation products formed during the vaping process in these diverse and constantly evolving products. The primary aim of this work was to apply liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and chemical fingerprinting techniques for the characterization of e-liquids and aerosols from a selection of popular e-cig products. We conducted nontarget and quantitative analyses of tobacco-flavored e-liquids and aerosols generated using four popular e-cig products: one disposable, two pod, and one tank/mod. Aerosols were collected using a condensation device and analyzed in solution alongside e-liquids by LC-HRMS. The number of compounds detected increased from e-liquids to aerosols in three of four commercial products, as did the proportion of condensed-hydrocarbon-like compounds, associated with combustion. Kendrick mass defect analysis suggested that some of the additional compounds detected in aerosols belonged to homologous series resulting from decomposition of high-molecular-weight compounds during vaping. Lipids in inhalable aerosols have been associated with severe respiratory effects, and lipid-like compounds were observed in aerosols as well as e-liquids analyzed. Six potentially hazardous additives and contaminants, including the industrial chemical tributylphosphine oxide and the stimulant caffeine, were identified and quantified in the e-cig liquids and aerosols analyzed. The obtained findings demonstrate the potential of nontarget LC-HRMS to identify previously unknown compounds and compound classes in e-cig liquids and aerosols, which is critical for the assessment of chemical exposures resulting from vaping.

Effect of organophosphorus ligands on supercritical extraction of neodymium from NdFeB magnet

Supercritical fluid extraction is receiving growing attention for the enhanced extraction and separation of metals. A metal must be charge neutral and coordinatively ready to dissolve in non-polar supercritical carbon dioxide (sc-CO2). This can be accomplished by bonding the metal with a combination of negative and neutral ligands. Here, we investigate the effect of four organophosphorus reagents including triethyl phosphate (TEP), tri-n-butyl phosphate (TBP), tributyl phosphine oxide (TBPO), and trioctyl phosphine oxide (TOPO), on the extraction of neodymium from a neodymium-iron-boron magnet in sc-CO2. The COSMO-vac model is used to predict the solubility of these reagents in sc-CO2 showing the order of TEP > TBPO ~ TBP > TOPO. The stoichiometry of Nd-ligand complexes is determined via UV-Vis spectroscopy, showing a 1:1 Nd–TEP, 1:3 Nd–TBP, 1:3 Nd-TBPO, and 1:4 Nd–TOPO complex chemistry. Highest neodymium extractions are achieved with TEP followed by TBP, TBPO, and TOPO, respectively. This is due to the increase in coordination number which results in more hydrophobic interactions between aliphatic functionalities, leading to larger micellar assemblies with lower solubility in sc-CO2, which result in lower extraction efficiency.

Towards a Stronger Halogen Bond Involving Astatine: Unexpected Adduct with Bu3PO Stabilized by Hydrogen Bonding

The halogen bond is a powerful tool for the molecular design and pushing the limits of its strength is of major interest. Bearing the most potent halogen-bond donor atom, astatine monoiodide (AtI) was recently successfully probed [Nat. Chem. 2018, 10, 428-434]. In this work, we continue the exploration of adducts between AtI and Lewis bases with the tributylphosphine oxide (Bu3 PO) ligand, revealing the unexpected experimental occurrence of two distinct chemical species with 1:1 and 2:1 stoichiometries. The 1:1 Bu3 PO⋅⋅⋅AtI complex is found to exhibit the strongest astatine-mediated halogen bond so far (with a formation constant of 10(4.24±0.35) ). Quantum chemical calculations unveil the intriguing nature of the 2:1 2Bu3 PO⋅⋅⋅AtI adduct, involving a halogen bond between AtI and one Bu3 PO molecular unit plus CH⋅⋅⋅O hydrogen bonds chelating the second Bu3 PO unit.

Structures of the oxidized states of some common biochemical reducing agents

Abstract The crystal structures of the oxidized states of three of the most common biochemical reducing agents have been determined, by crystallization from aqueous solution where possible: tris(2-carboxyethyl)phosphine oxide (TCEP oxide, 1), bis(2-hydroxyethyl) disulfide (2MESS, 3), and tributylphosphine oxide (Bu4PO, 4). In addition, a less disordered crystal structure of the reducing agent tris(2-carboxyethyl)phosphonium chloride (TCEP·HCl, 2) has been obtained. A greatly simplified method was found for synthesizing 1. An unusual method of obtaining X-ray quality crystals from hard-to-crystallize oily liquids is described, in which the oil is solidified to a glass by rapid cooling, allowed to warm to a supercooled liquid containing a few seed crystals, and finally crystallized just below its melting point. This method was successfully used to crystallize 3, a viscous oil at room temperature that had resisted all other methods of crystallization, for X-ray diffraction. An ab initio quantum chemical analysis of the conformers of 3 showed that the molecular geometry of this flexible molecule in the solid state was 320 kJ/mol higher than that of the lowest-energy conformer, underscoring the fact that the solid-state structure may not always yield the same molecular geometry as that of the minimum-energy conformer, especially for flexible molecules with strong intramolecular nonbonding interactions. The unusual NMR spectral characteristics of 4 are elucidated.

Synergism and Aggregation in Multi-Extractant Solvent Extraction Systems

ABSTRACT Several combinations of lipophilic extractants have been studied with the objective of investigating the synergistic behavior of metal ion extraction and its relation to reverse micelle formation. Combinations of acidic and neutral extracting reagents that have displayed synergic behavior in other studies were tested. While most of these either showed limited synergy or no correlation with water uptake under the conditions used here, two of the systems showed extraction synergy. These two extraction systems: 2-bromodecanoic acid with 2,2ʹ:6ʹ,2ʺ-terpyridine; and tributyl phosphine oxide with 2-thenoyltrifluoroacetone were modeled based on two different theoretical approaches: microemulsion-assisted extraction; or the formation of mixed complexes in the organic phase. Comparisons between the two models showed that in the case of bromodecanoic acid and terpyridine the approach of mixed complexes provided a somewhat better fit while the second system was not modeled well with either approach. Further work on the species present in the organic phase is needed to determine the role, if any, of aggregates in synergistic solvent extraction systems.

Investigation of strong photoluminescence and highly soluble Eu(III) complexes with phosphine oxides and β-diketonates

Several Eu(III) complexes with two phosphine oxide ligands and three β-diketonate ligands were prepared and their properties were investigated to realize strong photoluminescence and highly soluble Eu(III) complexes.Comparison of photoluminescence properties of Eu(III) (tfnb)3(TPPO)2 (5) (tfnb = 4,​4,​4-​trifluoro-​1-​(2-​naphthyl)​-​1,​3-​butanedionato and TPPO = triphenyl phosphine oxide), Eu(III)(tfpb)3(TPPO)2 (6) (tfpb = 4,4,4-trifluoro-1-phenyl-1,3-butanedionato), Eu(III) (hfnh)3(TPPO)2 (8) (hfnh = 4,4,5,5,6,6,6-heptafluoro-1-(2-naphthyl)-1,3-hexanedionato) and Eu(III)(tfdh)3(TPPO)2 (9) (tfdh = 6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedionato), which have the same phosphine oxide, reveals that photoluminescence intensities are in the descending order 8, 5, 6, 9. “hfnh” and “tfnb” are found to be preferable for molecular structures of β-diketonates.Next, effects of molecular structures of phosphine oxide- ligands on photoluminescence intensities of Eu(III) complexes were investigated.Comparison of photoluminescence spectra of Eu(III) (hfnh)3(TBPO)2 (7) (TBPO = tributyl phosphine oxide), Eu(III) (hfnh)3(TPPO)2 (8) and Eu(III) (hfnh)3(TPPO)(TBPO) (12), which have the same β-diketonate (hfnh), reveals that photoluminescence intensities are in the descending order 12, 7, 8. Likewise, comparison of photoluminescence spectra of Eu(III) (tfnb)3(TBPO)2 (3), Eu(III) (tfnb)3(TPPO)2 (5) and Eu(III) (tfnb)3(TPPO)(TOPO) (11), which have the same β-diketonate (tfnb), reveals that photoluminescence intensities are in the descending order 11, 5, 3.On the other hand, solubilities of Eu(III) (tfnb)3(TPPO)(TBPO) (11) and Eu(III) (hfnh)3(TPPO)(TBPO) (12) with two different phosphine oxides in 2,3-dihydrodecafluoropentane are much larger than those of other complexes.These results indicate that the optimum β-diketonate is “hfnh” and coordination of two different phosphine oxides with one Eu(III) ion has a remarkable effect in enlarging both photoluminescence intensity and solubility of Eu(III) complexes.Eu(III) complex 12 satisfies these conditions and quantum yield is very high (= 0.6). It is a promising candidate for many applications by virtue of its strong photoluminescence and high solubility.

Applicability of samarium(III) complexes for the role of luminescent molecular sensors for monitoring progress of photopolymerization processes and control of the thickness of polymer coatings

Applicability of 15 trivalent samarium complexes as novel luminescent probes for monitoring progress of photopolymerization processes or thickness of polymer coatings by the Fluorescence Probe Technique (FPT) was studied. Three groups of samarium(III) complexes were evaluated in cationic photopolymerization of triethylene glycol divinyl ether monomer (TEGDVE) and free-radical photopolymerization of trimethylolpropane triacrylate (TMPTA). The complexes were the derivatives of tris(4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate)samarium(III), tris(4,4,4-trifluoro-1-phenyl-1,3-butanedionate)samarium(III) and tris(4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedionate)samarium(III), which were further coordinated with auxiliary ligands, such as 1,10-phenanthroline, triphenylphosphine oxide, tributylphosphine oxide and trioctylphosphine oxide. It has been found that most of the complexes studied are sensitive enough to be used as luminescent probes for monitoring progress of cationic photopolymerization of vinyl ether monomers over entire range of monomer conversions. In the case of free-radical polymerization processes, the samarium(III) complexes are not sensitive enough to changes of microviscosity and/or micropolarity of the medium, so they cannot be used to monitor progress of the polymerization. However, high stability of luminescence intensity of some of these complexes under free-radical polymerization conditions makes them good candidates for application as thickness sensors for polymer coatings prepared by free-radical photopolymerization. A quantitative relationship between a coating thickness and the luminescence intensity of the samarium(III) probes has been derived and verified experimentally within a broad range of the thicknesses.

Extraction of Iron III with Tributylphosphine Oxide from Hydrochloric and Sulphuric Acid Solutions

Extraction of Iron III with Tributylphosphine Oxide from Hydrochloric and Sulphuric Acid Solutions

Dramatic Changes in the Solubilities of Ions Induced by Ligand Addition in Biphasic System D2O/DNO3//[C1C4im][Tf2N]: A Phenomenological Study.

The solubilities of C1C4im(+) and Tf2N(-) in nitric aqueous phases have been measured for several ligand types and concentrations (0.04 M tributylphosphine oxide, 0.05 M N,N'-dimethyl-N,N'-dibutylmalonamide, 0.10 M 1-methyl-3-[4-(dibutylphosphinoyl)butyl]-3H-imidazol-1-ium bis(trifluoromethylsulphonyl)imidate, and 1.1 M N,N-dihexyloctanamide). The data evidence a significant difference between the solubilities of the cations and anions of the ionic liquid as a consequence of several ion-exchange and/or ion-pairing mechanisms involving all ions present in the system as well as the protonation/nitric-extraction ability of the ligand.

Phase behavior of simple tributylphosphine oxide (TBPO) and mixed gas (CO2, CH4 and CO2 + CH4) + TBPO semiclathrate hydrates

In this research, new experimental data of hydrate equilibrium conditions were measured for the following systems: tributylphosphine oxide (TBPO)+water; TBPO + CO2 +water; TBPO + CH4 +water; TBPO + CO2 +CH4 +water. The gas mixture CO2 + CH4 had a composition of 40 mol% of CO2 in order to simulate a typical biogas produced by an anaerobic digestion of agricultural waste. Differential scanning calorimetry (DSC) method was applied to measure the dissociation temperatures for each system. The dissociation enthalpy per mole of gas was estimated using Clausius-Clapeyron approximation. For the binary system, the mass fraction of TBPO in aqueous solution varied from 0.05 to 0.40 and the phase transition temperature varied from 278.1 K to 281.0 K. For the ternary systems the measurements were carried out for a mass fraction of TBPO varying from 0.05 to 0.30 in the gas pressure range of 1–3 MPa. The measured dissociation temperatures varied from 284.4 K to 292.5 K. The results showed that the presence of TBPO reduces the gas pressure for hydrate phase formation compared to the binary systems (gas + water). The higher dissociation temperature of TBPO/CH4 semi-clathrate, compared to TBPO/CO2 semi-clathrate, was confirmed. The phase behavior diagram of the binary and the ternary systems were also determined, which would be of interest to determine the operating conditions of potential industrial processes involving hydrate formation, such as gas storage or gas separation.

Optical properties of P3HT:tributylphosphine oxide-capped CdSe nanocomposites

The optical properties of nanocomposite layers prepared by incorporation of tributylphosphine oxide (TBPO)-capped CdSe nanocrystals (NCs) in a P3HT polymer matrix are studied using different nanocrystal concentrations. Reflection spectra analyzed through Kim oscillator model lead to the determination of optical constants such as refractive index n, extinction coefficient k, dielectric permittivity e and absorption coefficient α.Using the common Cauchy, Drude–Lorentz, Tauc and single-effective-oscillator theoretical models, we have determined the values of static refractive index n s and permittivity e s, plasma frequency $$\omega_{\text{p}}$$ , carrier density N, optical band gap E g and oscillator and dispersion energies E0 and E d, respectively. It is found that TBPO-capped CdSe NCs concentration affects the optoelectronic parameters of the nanocomposite thin films. Moreover, the disorder of this hybrid system is also studied by the determination of Urbach energy, which increases with TBPO-capped CdSe concentration.

Synergistic extraction of cerium(III)-oxinates in presence of tributyl phosphine oxide

Synergistic extraction of cerium(III)-oxinates in presence of tributyl phosphine oxide

The effect of tributylphosphate and tributyl phosphine oxide on hydrogen bonding interactions between water and the 1-ethyl-3-methylimidazolium cation in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

We have used attenuated total reflectance FTIR and NMR spectroscopies to study the hydrogen bonding interactions of tributylphosphate (TBP) and tributylphosphine oxide (TBPO) with the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][Tf2N]) in the presence and absence of water. Our results indicate that the addition of TBP or TBPO to a solution containing low concentrations of water in [EMIM][Tf2N] disrupts existing water–water hydrogen bonding interactions as well as those between water and the imidazolium ring protons. Significant shifts in the 1H NMR signal for imidazolium ring protons upon addition of TBP or TBPO suggest that terminal PO oxygen atoms engage in hydrogen bonding interactions with these protons. Results from 2H NMR, 17O NMR and ATR-FTIR spectra indicate that TBP and TBPO engage in hydrogen bonding interactions with water in the ionic liquid. Our results show that addition of water and TBP or TBPO can have a significant influence on [EMIM][Tf2N] hydrogen bonding interactions, and thus potentially affect the physical and chemical properties of this ionic liquid.

Differential capacitance and electrochemical impedance study of surfactant adsorption on polycrystalline Ni electrode

The adsorption of neutral organophosphorous compounds on a charged polycrystalline Ni electrode is studied by differential capacitance and impedance measurements in methanol solutions. Analysis of capacitance measurements reveals that tributylphosphine oxide, tri(n)octylphosphine oxide, and triphenylphosphine follow Langmuir adsorption isotherm. Saturation capacitance C sat, potential of maximum adsorption E max, limiting surface concentration Γ max, and standard Gibbs energy of adsorption ΔG max at E max are determined. The cathodic reduction of (NiOCH3)ads film formed on Ni surface at positive potentials, introducing a faradaic contribution in addition to the electrostatic charging of the interface, is supported by linear sweep voltammetric and impedance measurements. High values of electrode coverage and strong depression of faradaic currents are attained, indicating that these adsorbates may be suitable as corrosion inhibitors.

Extraction Mechanism and Selectivity of UO<sub>2</sub>(NO<sub>3</sub>)<sub>2</sub> in Tributylphosphine Oxide-Ionic Liquid System

The extraction of UO2(NO3)2 from aqueous solution was investigated using trioctylphosphine oxide (TOPO) and tributylphosphine oxide (TBPO) in ionic liquids (ILs) (CnmimNTf2, n=2, 4, 6, 8). A third phase was formed in the TOPO-C2mimNTf2 and TOPO-C4mimNTf2 extraction systems, whereas the extracted species of TBPO-CnmimNTf2 (n=2, 4, 6, 8) were well soluble in all ILs. The influence of the concentrations of the extractant, nitric acid, and salt on the extraction efficiency was also investigated. Adding HNO3 to the aqueous phase decreased the extraction efficiency. The effect of salt indicates the presence of a cation-exchange mechanism in the extraction. The addition of NO3 in the aqueous phase increased the extraction efficiency of U, which indicates that NO3 participates in the extraction. Selective extraction research indicates that TBPO-C4mimNTf2 exhibits good selectivity for U at low acid concentration despite the significant extraction efficiency on Zr at high acid concentration. After removing U, TBPO-C4mimNTf2 still showed high selectivity for Nd at low acid concentration. We also confirmed the difference of the extraction mechanisms among TBPO-CnmimNTf2 by quantitative measurement of NNO3 in ILs, electrospray ionization mass spectroscopy (ESI-MS), and UV spectroscopy. There are two extraction species (UO2(TBPO)3(NO3)

Acid catalytic function of mesopore walls generated by MFI zeolite desilication in comparison with external surfaces of MFI zeolite nanosheet

Mesopores with zeolite walls were generated through desilication of bulk crystals of MFI zeolite in a NaOH solution in the presence or absence of cetyltrimethylammonium surfactant, as reported in the literature. Catalytic functions of the Brønsted acid sites existing on the mesopore walls were evaluated in comparison with external surfaces of 2.5-nm thick MFI zeolite nanosheets, which were hydrothermally synthesized using a meso-micro dual structure-directing surfactant. Acid sites were characterized with respect to the strength and concentration by 31P NMR signals of adsorbed tributylphosphine oxide. Catalytic functions were evaluated for decalin cracking, and acetal formation of benzaldehyde with pentaerythritol. The result from desilication was quite sensitive to the particle diameters of the initial zeolite samples. In our best case of desilication, the mesopore walls exhibited similar catalytic activity for the acetal formation to the external surfaces of MFI nanosheets. In contrast to the condensation reaction occurring at mild or moderate acid sites, the result for decalin cracking requiring strong acid sites indicated that the desilicated zeolite corresponded to about 60% of the MFI nanosheets.