Extraction of heterometal ruthenium(II) complexes by diphenyl(dibutylcarbamoylmethyl)phosphine oxide from nitrate-nitrite solutions

The synergistic extraction of [RuNO(NO₂)₄OH]^2? by diphenyl(dibutylcarbamoylmethyl)phosphine oxide (L) in the presence of nonprecious metal cations (M²⁺) is studied; the extraction occurs on the account of the formation of heterometal complexes [RuNO(NO₂)₄OHML_m] (M = Zn, Cu, Co, Ni) due to the addition of M²⁺ to ruthenium through the oxygen atoms of the OH and NO₂ groups and the bidentate coordination of L to M²⁺. The extraction constants for Ru/M complexes and ML_n(NO₃)₂ are determined. The variation in the extraction constants with changing M (Co, Zn, Cu > Ni) does not agree with the Irwing-Williams row, unlike the extraction with monodentate PO-containing extractants (Zn > Cu > Co > Ni). The feasibility of ruthenium extraction in the form of Ru/M complexes from complex nitrate-nitrite solutions is demonstrated.     

Complexation and extraction of non-ferrous metals by calix[n]arene phosphine oxides

The extraction of non-ferrous metal (M²⁺) nitrates by the calix[4,6]arenes (L), bearing four or six phosphine oxide donor groups at the upper or at the lower rim, was quantitatively described in the form of [M_n(NO₃)_2nL] (n = 1, 2) complexes. The extraction constants (Zn²⁺ > Cu²⁺ > Co²⁺ > Ni²⁺) for the both types of L coincide with Irving-Williams sequence. Calix[4]arenes, phosphorylated at the lower (narrow) rim, provide better stability of ML complexes because of the best spatial fitting of M²⁺ by the donor groups. For the upper (wide) rim phosphorylated calix[4]arenes M₂L and ML₂ complexes are more stable. Unusual zwitterionic [Co₂(NO₃)₄L] complex of the lower rim tetraphosphorylated calix[4]arene 1 was determined by X-ray structural analysis.     

Selective reduction of allenyl(diphenyl)phosphine oxides to allyl(diphenyl)phosphine oxides

The reduction of allenyl(diphenyl)phosphine oxides with HSiCl₃ or LiAlH₄ selectively afforded the corresponding allyl(diphenyl)phosphine oxides. 3-Methylbut-2-en-1-yl(diphenyl)phosphine oxide reacted with AlCl₃ to give a mixture of 4,4-dimethyl-1-phenyl-1,2,3,4-tetrahydro-λ⁵-phosphinoline 1-oxide and 4,4-dimethyl-1-phenyl-1,4-dihydro-λ⁵-phosphinoline 1-oxide.     

Comparative Investigation into the Complexation and Extraction Properties of Tridentate and Tetradentate Phosphine Oxide-Functionalized 1,10-Phenanthroline Ligands toward Lanthanides and Actinides

Two new phosphine oxide-functionalized 1,10-phenanthroline ligands, tetradentate 2,9-bis(butylphenylphosphine oxide)-1,10-phenanthroline (BuPh-BPPhen, L¹ ) and tridentate 2-(butylphenylphosphine oxide)-1,10-phenanthroline (BuPh-MPPhen, L² ), were synthesized and studied comparatively for their coordination with trivalent actinides and lanthanides. The complexation mechanisms of these two ligands toward trivalent f-block elements were thoroughly elucidated by NMR spectroscopy, UV/vis spectrophotometry, fluorescence spectrometry, single-crystal X-ray diffraction, solvent extraction, and theoretical calculation methods. NMR titration results demonstrated that 1 : 1 and 1 : 2 (metal to ligand) lanthanides complexes formed for L¹ , whereas 1 : 1, 1 : 2 and 1 : 3 lanthanide complexes formed for L² in methanol. The formation of these species was validated by fluorescence spectrometry, and the corresponding stability constants for the complexes of Nd^III with L¹ and L² were determined by using UV/vis spectrophotometry. Structures of the 10-coordinated 1 : 1-type complexes of Eu L¹ (NO₃)₃ and [Eu L² (NO₃)₃(H₂O)] Et₂O in the solid state were characterized by X-ray crystallography. In solvent-extraction experiments, L¹ exhibited extremely strong extraction ability for both Am^III and Eu^III, whereas L² showed nearly no extraction toward Am^III or Eu^III due to its high hydrophilicity. Finally, the structures and bonding natures of the complex species formed between Am^III/Eu^III and L¹/L² were analyzed in DFT calculations.     

Understanding the extraction mechanism,radiolytic stability and stripping behavior of thorium by ionic liquid based solvent systems: evidence of ‘ion-exchange’ and ‘solvation’ mechanism

The extraction efficiency for thorium followed the trend: Cyanex-923 > Cyanex-272 > DHOA > TBP. In case of TBP and DHOA the extraction proceeded via ‘solvation mechanism’ through Th(NO₃)₄·2L, while for Cyanex-923 and Cyanex-272 it proceeded via ‘ion exchange’ mechanism through (Th(NO₃)₂·2L)²⁺. The extraction process followed slower kinetics while change in Gibb’s energy revealed the spontaneity of the process. These ionic liquid based systems were found to be radiolytically stable, highly efficient and selective for Th. Oxalic acid was found to be suitable for almost quantitative stripping of Th from extracted ionic liquid phase.     

Comparison of calix[n]arenes phosphorylated in the upper and lower rims as applied to extraction of nitrosoruthenium nitrite species

Compared were dialkylcalix[4]phosphine oxides (L) having PO groups in the opposing rims as regards the extraction of [RuNO(NO₂)₄(OH)]²⁻, nonprecious metals (M²⁺), and Ru/M heterometallic complexes of their base. The extraction constants for the ion association {(Na⁺)₂(LH₂O) _r [RuNO(NO₂)₄(OH)]²⁻ and the degree of aggregation of L were calculated. The destruction of (LH₂O) _r upon metal extraction was verified IR-spectroscopically. The stoichiometry was determined and extraction constants were calculated for mono- and binuclear complexes [M _m L _n (NO₃)_2m ] and mononuclear Ru/M species [RuNO(NO₂)₄(OH)ML _n ]. Nonprecious metals form mononuclear ML complexes in the lower rim. The size of the upper rim is responsible for the addition of a second metal nitrate molecule or addition to L or the addition of a second L molecule to the metal. Ru/M complexes with all L are present in an organic phase as two mononuclear species, ML and ML₂. Rationale is given to the selection of extraction systems for recovery of ruthenium from nitrated nitric acid solutions selectively or together with actinides and lanthanides in the form of Ru/M complexes.     

Extraction of plutonium from acidic media using various phosphine oxides

Extraction, loading and stripping studies of Pu(IV) have been carried out using three phosphine oxides namely Cyanex^Ò-923 (cyn-923), Cyanex^Ò-925 (cyn-925) and TOPO in dodecane from nitric acid medium. All the three phosphine oxides have shown very high extraction of Pu. The order of extraction for Pu by these compounds is cyn-923 > TOPO - cyn-925. Loading of Pu (30.0 mg/l) in 3.0M HNO₃ was carried out using 5% solution of each of the phosphine oxides in dodecane. It was found that even at an organic to aqueous phase ratio of 1:10, the loading of Pu is >96%. From the loaded organic phase, Pu could be almost quantitatively stripped using 0.1 or 0.5M oxalic acid. The extraction of Pu(IV) with cyn-925 has also been carried out from HCl, HNO₃ or HClO₄ (0.5 to 9.1M). The species extracted into the cyn-925/dodecane phase from 3.0M HNO₃ or HCl media was found to be Pu(L)₄ ^.2 cyn-925 where L = NO₃ ^– or Cl^–. Similar species were observed to be formed when dodecane was replaced by xylene, chlorobenzene or o-dichlorobenzene.     

Electrolytical enrichment for liquid scintillation determinations of low tritium samples: A revised methodology

The determination of carbon, hydrogen, nitrogen, fluorine, chlorine and sulphur contents for characterization of plutonium complexes with organic ligands have been standardized and glove box adopted. Various plutonium(IV) mono- and di-carboxylates, plutonium(IV) chelates with pyrazolones, UO ₂ ⁺⁺ and PuO ₂ ⁺⁺ complexes having pyrazolones as chelating agent and sulfoxides, amides and phosphine oxide ligands as oxodonors; uranium carbides and uranium nitrides and several potential organic extractants for actinides were analyzed satisfactorily. All these methods set up in double module glove box train are extremely useful for a low budget radioactive laboratory engaged in research in solid actinide complexes.     

Studies on highly regio- and stereoselective fluorohydroxylation reaction of 3-aryl-1,2-allenyl phosphine oxides with Selectfluor

The fluorohydroxylation of allenyl phosphine oxides with Selectfluor in commercial MeCN without prior treatment or a mixed solvent of anhydrous MeCN (refluxed over CaH₂ and distilled before use) and 7.0 equiv of H₂O or MeNO₂/H₂O=10/1 afforded 2-fluoro-3-hydroxy-1(E)-alkenyl diphenyl phosphine oxides in moderate yields with very high regio- and stereoselectivities. The E-stereoselectivity is believed to be controlled by the phosphine oxide functionality. In the reaction of 3-(4-methoxyphenyl)-1,2-propadienyl diphenyl phosphine oxide, further fluorination on the electron-rich phenyl ring was also observed.     

Studies on highly regio- and stereoselective selenohydroxylation reaction of 1,2-allenyl phosphine oxides with PhSeCl

The selenohydroxylation of readily available 1,2-allenyl phosphine oxides with PhSeCl in MeCN/H₂O afforded 3-hydroxy-2-phenylselanyl-1(E)-alkenyl diphenyl phosphine oxides in good yields with very high regio- and stereoselectivities including the high efficiency of the axial chirality transfer. The E-stereoselectivity is believed to be determined by the neighboring group participation effect of the diphenyl phosphine oxide functionality.     

Disclosing Interfaces of ZnO Nanocrystals Using Dynamic Nuclear Polarization: Sol‐Gel versus Organometallic Approach

The unambiguous characterization of the coordination chemistry of nanocrystal surfaces produced by wet‐chemical synthesis presently remains highly challenging. Here, zinc oxide nanocrystals (ZnO NCs) coated by monoanionic diphenyl phosphate (DPP) ligands were derived by a sol‐gel process and a one‐pot self‐supporting organometallic (OSSOM) procedure. Atomic‐scale characterization through dynamic nuclear polarization (DNP‐)enhanced solid‐state NMR (ssNMR) spectroscopy has notably enabled resolving their vastly different surface‐ligand interfaces. For the OSSOM‐derived NCs, DPP moieties form stable and strongly‐anchored μ₂‐ and μ₃‐bridging‐ligand pairs that are resistant to competitive ligand exchange. The sol‐gel‐derived NCs contain a wide variety of coordination modes of DPP ligands and a ligand exchange process takes place between DPP and glycerol molecules. This highlights the power of DNP‐enhanced ssNMR for detailed NC surface analysis and of the OSSOM approach for the preparation of ZnO NCs.     

Assay of reducing sugars in beverages, wines, honey and marmalades using potentiometric stripping analysis (PSA)

Summary A simple, rapid and non-destructive method for the detection and determination of phosphines and phosphine oxides in solution by ¹H and ³¹P NMR spectroscopy is proposed. Diphenylphosphine (DPP) and diphenylphosphine oxide (DPPO) mixtures in C₆D₆ chosen as model system were studied in wide ranges of concentration (10^–2 to 4 mol/l). The detection of DPP and DPPO in solution by ¹H NMR was based on the presence of two doublets (hydrogen directly bonded to phosphorus, H_P) originating from P-H and P(O)H groups with one bond coupling constant ¹J_PH of 216.08 and 476.12 Hz. ³¹P NMR signals at –40.07 and +18.26 ppm additionally proved the presence of DPP and DPPO in solution. A linear dependence of the measured H_P and ortho-proton integral intensity on the concentration of DPP and DPPO was found. The content of DPP and DPPO evaluated by ³¹P without adding Cr(acac)₃ and by ¹H NMR agreed with the quoted amounts within 1 to 3%.Under Indo-Polish cultural exchange programme, temporarily at Silesian University     

Preparation and characterization of uranyl complexes with phosphonate ligands

The preparation, spectroscopic characterization and thermal stability of neutral complexes of uranyl ion, UO₂ ²⁺, with phosphonate ligands, such as diphenylphosphonic acid (DPhP), diphenyl phosphate (DPhPO) and phenylphosphonic acid (PhP) are described. The complexes were prepared by a reaction of hydrated uranyl nitrate with appropriate ligands in methanolic solution. The ligands studied and their uranyl complexes were characterized using thermogravimetric and elemental analyses, ESI-MS, IR and UV–Vis absorption and luminescence spectroscopy as well as luminescence lifetime measurements. Compositions of the products obtained dependent on the ligands used: DPhP and DPhPO form UO₂L₂ type of complexes, whereas PhP forms UO₂L complex. Based on TG and DTG curves a thermal stability of the complexes was determined. The complexes UO₂PhP·2H₂O and UO₂(DPhPO)₂ undergo one-step decomposition, while UO₂PhP · 2H₂O is decomposed in a two-step process. The thermal stability of anhydrous uranyl complexes increases in the series: DPhPO < PhP < DPhP. Obtained IR spectra indicate bonding of P–OH groups with uranyl ion. The main fluorescence emission bands and the lifetimes of these complexes were determined. The complex of DPhP shows a green uranyl luminescence, while the uranyl emission of the UO₂PhP and UO₂(DPhPO)₂ complexes is considerably weaker.     

Synthesis, crystal structures, and DNA-binding properties of zinc(II) and nickel(II) complexes with tris[2-(N-ethyl)benzimidazylmethyl]amine and cinnamate ligands

Tris[2-(N-ethyl)benzimidazylmethyl]amine (Etntb) and two of its complexes, [Zn(Etntb)(cinnamate)]NO₃·2DMF (1) and [Ni(Etntb)(cinnamate)·(H₂O)]NO₃ (2) have been synthesized and characterized by physico-chemical and spectroscopic methods. Single-crystal X-ray diffraction revealed that the complexes have different structures. In complex 1, the coordination sphere around Zn(II) is distorted trigonal bipyramidal, whereas the coordination sphere around Ni(II) is distorted octahedral in complex 2. The DNA-binding properties of the free ligand and its complexes have been investigated by electronic absorption, fluorescence, and viscosity measurements. The results suggest that the ligand and both complexes bind to DNA via an intercalative mode, and their binding affinity for DNA follows the order 1 > 2> ligand.     

Specifics of titanium tetrafluoride complexation with Ph<Subscript>2</Subscript>P(O)(CH<Subscript>2</Subscript>)<Subscript>2</Subscript>C(O)NMe<Subscript>2</Subscript>: The remarkable stability of the seven-membered chelate heterocycle TiOPCCCO and its conformational isomerism in solution

The composition and structure of the products of the reaction of titanium tetrafluoride with Ph₂P(O)(CH₂)₂C(O)NМе₂ (L), the simplest representative of diphenyl[2-(N,N-dialkylcarbamoyl)ethyl]phosphine oxides, in a СН₂Сl₂ have been studied by ¹⁹F and ³¹P NMR. It has been shown for the first time that functionalized phosphine oxides form stable seven-membered chelate heterocycles on complexes of d° transition metals. On the basis of NMR data, previously unknown conformational isomerism of the seven-membered TiOPCCCO heterocycle in solution has been proposed. A simple and rather efficient method of synthesis of the ligand (L) from commercially available reagents has been developed.     

Synthesis, spectroscopic, and thermal studies of some Hg(II) and Cd(II) coordination compounds of N,N-bis[(E)-3-(phenylprop)-2-enylidene]propanediamine

Some new coordination compounds of cadmium(II) and mercury(II) with N,N-bis[(E)-3-(phenylprop)-2-enylidene]propanediamine (L) as a new bidentate Schiff base ligand with general formula MLX₂ (X = Cl^?, Br^?, I^?, SCN^?, and N₃ ^?) have been prepared. They were characterized by elemental analysis, FT-infrared (FT-IR) and Ultraviolet–Visible spectra, ¹H- and ¹³C-NMR spectra. The reasonable shifts of FT-IR and NMR spectral signals of the complexes with respect to the free ligand confirm well coordination of ligand and anions(X-) in inner sphere coordination mode. The thermal behavior of the complexes from room temperature to 800 °C shows weight loss by decomposition of the anions and ligand segments in the subsequent steps. The results showed that cadmium complexes have no water molecules (neither as lattice nor as coordinated water) and are decomposed in two temperature steps except about cadmium thiocyanate complex that is decomposed in three steps. Final residual contents of cadmium complexes are suggested to be cadmium oxide or sulfide. Mercury complexes were decomposed in three to four temperature steps. Mercury bromide and azide complexes leave out a little amount of mercury oxide in final, while mercury chloride, iodide, and thiocyanate complexes were found to be completely decomposed without any residual matter.     

Synthesis and Coordination Properties of Tripodal Ligand on the Triphenylphosphine Oxide Platform with Carbamoyl Side Arms

Abstract

A new tripodal O-donor ligand, tris(2-N,N-dibutylcarbamoylmethoxyphenyl)phosphine oxide (L), was synthesized. This potentially tetradentate ligand L exhibits variable denticity upon complexation with UO₂(NO₃)₂, Nd(NO₃)₃, and Lu(NO₃)₃. The complexes were studied by elemental analysis, IR, and ¹H, ¹³C, and ³¹P NMR spectroscopy.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables, and figures.]     

Extraction of heterometallic complexes of ruthenium and nonprecious metals by phosphorylmethylated calix[4]arenes from nitrate solutions

Synergetic extraction of [RuNO(NO₂)₄OH]^2? by calix[4]arene phosphine oxides (L) in the form of Ru/M heterometallic complexes was studied in the presence of nonprecious metals (M²⁺). The main extraction laws were recognized for [M(NO₃)₂L _n ] and [RuNO(NO₂)₄OH])ML _m ], where M²⁺ = Zn²⁺, Cu²⁺, Co²⁺, or Ni²⁺ and n, m = 1 or 2; extraction constants were determined for these metals. The variation row of the extraction constants with varying metal (Zn²⁺ > Cu²⁺ > Co²⁺ > Ni²⁺) coincides with the Irving-Williams row. Two or three PO groups of extractant L and the OH and NO₂ groups of the ruthenium anion are coordinated to the M²⁺ atom in Ru/M complexes. The conditions for generation of the Ru/Zn complex and its complete extraction were optimized as applied to the extraction of fission ruthenium from nitrated nitric acid and imitation solutions.     

Conformational analysis of 2-aminophenyl-, 2-aminobenzyl-, and 2-nitrobenzyl(diphenyl)phosphine oxides

The polarity and conformations of 2-aminophenyl-, 2-aminobenzyl-, and 2-nitrobenzyl(diphenyl)-phosphine oxides were studied by the dipole moment method, IR spectroscopy, and quantum chemical calculations. 2-Aminophenyl- and 2-aminobenzyl(diphenyl)phosphine oxides were found to exist preferentially as conformers with intramolecular hydrogen bond. 2-Nitrobenzyl(diphenyl)phosphine oxide is likely to be represented by equilibrium mixture of three conformers in which the phosphoryl and nitro groups are oriented syn or anti with respect to the \(PC_{sp^3 } C_{sp^2 } \) fragment.     

Adamantylcalixarenes with CMPO groups at the wide rim: synthesis and extraction of lanthanides and actinides

Starting from p-adamantylcalix[4]- and [6]arenes functionalized with carboxylic acid or ester groups at the adamantane nuclei, carbamoylmethylphosphine oxide (CMPO)-containing ligands of a novel type were synthesized. They were studied as extractants for a series of f-block elements including radioactive ¹⁵²Eu(III), ²⁴¹Am(III), ²³³U(VI), and ²³⁹Pu(IV). Tetrameric ligand 4b in which CMPO residues are connected to adamantane nuclei through methylene groups gave the best extraction results for lanthanides and actinides. For all the ligands the extraction efficiency does not decrease at higher nitric acid concentration. Although the discrimination between trivalent actinides and lanthanides is not good, all ligands are highly selective for thorium(IV) with the best separation factor achieved in the case of hexameric ligand 5 (D_Th/D_Ln>24).