Extraktion von Lanthaniden mittels Thenoyltrifluoraceton, 2. Mitt.

Zusammenfassung Die Verteilung von Nd(NO₃)₃, Sm(NO₃)₃ Gd(NO₃)₃, und Tu(NO₃)₃ ^* zwischen einer wäßrigen Lösung mit Ionenstärke 0,1 und einer 0,2M-Benzollösung des 2-Thenoyltrifluoracetons wurde untersucht. Es wurde festgestellt, daß mit steigender Atomnummer des extrahierten Elements auch die Extraktions-Gleichgewichtskonstante zunimmt. Die funktionelle Abhängigkeit des Logarithmus dieser Konstante vom Potential des Metallions könnte mit erster Näherung als linear angenommen werden; daher kann Thenoyltrifluoraceton zur Trennung der Lanthanide benutzt werden.

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The distribution of Nd(NO₃)₃, Sm(NO₃)₃, Gd(NO₃)₃ and Tu(NO₃)₃ between an aqueous solution with an ionic strength of 0,1 and a 0,2M-benzene solution of 2-thenoyltrifluoroacetone has been investigated. It was found that with the growing atomic number of the extracted element, the extraction equilibrium constant is also increased. The functional dependence of the logarithm of this constant from the potential of the metal ion could with first approximation be assumed as linear. On the basis of these investigations, thenoyltrifluoracetone can be used for separating the lanthanides.

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Mit 2 Abbildungen     

Near infrared study of aqueous lanthanide perchlorates

The near infrared spectra of water in aqueous solutions of La(ClO₄)₃, Pr(ClO₄)₃, Nd(ClO₄)₃, Gd(ClO₄)₃, Er(ClO₄)₃, Yb(ClO₄)₃, Lu(ClO₄)₃, and NaClO₄ have been measured in the concentration range from 0.3 to 2.5 mol-dm^–3, at 25°C. The relative contents of free OH groups in the 1.0, 1.6, and 2.2M solutions have been calculated from extinction coefficients for water at 1160 nm. They increase with increasing salt concentration and are greater in solutions of the lighter lanthanide perchlorates at any fixed molarity. The results are discussed in terms of the stoichiometry and structure of hydrated cations of trivalent lanthanides.     

Synthesis and magnetic properties of copper (II)-lanthanoid (III) binuclear complexes with N,N′-bis(3-aminopropyl) oxamido ligand

Six novel μ-oxamido binuclear complexes, namely Cu(axpn)Ln(L)₂(ClO₄)₃ (Ln: Eu, Gd, Tb, Nd, Ho, Er), where oxpn is N,N'-bis(3-aminopropyl) oxamido, L denotes 5-nitro,10-phenanthroline (abbreviated as NO₂-phen), have been synthesized and characterised. The magnetic susceptibility of complexes Cu(oxpn)Gd(NO₂-phen)2(ClO₄)₃.2H₂O was measured over the 4–300 K and the observed data were successfully simulated by equation based on spin Hamiltonian operator (H = -2J₁ · S₂), giving the exchange integral J(Cu-Gd)=-1.62 cm^?1. This indicates a weak antiferromagnetic interaction between the Cu(II) and Gd(III) ions.     

Complexes of lanthanide perchlorates with 4-N-(2′-hydroxy-1′-naphthylidene)aminoantipyrine

Lanthanide perchlorate complexes with 4-N-(2′-hydroxy-1′-naphthylidene) aminoantipyrine [HNAAP(HL)] of types [Ln(L)₂ClO₄] (where Ln = La, Pr, Nd or Sm) and [Ln(HL)₄](ClO₄)₃ (where Ln = Gd, Tb, Dy, Ho or Y) have been synthesized and characterized. HNAAP acts as a monovalent terdentate ligand in the complexes of the lighter lanthanides and as a neutral bidentate ligand in the complexes of the heavier lanthanides. The perchlorate group is coordinated only in the complexes of the lighter lanthanides.     

Thermodynamics of ternary salts in dioxane—water mixtures from conductance measurements

Studies of electrolytic conductance in dioxane—water mixtures of varying dioxane content were initiated in 1978 [1]. In the present communication, an attempt has been made to evaluate the thermodynamic function ΔG⁰_t for the transfer of Mg(ClO₄)⁺, Mg(NO₃)⁺, BaCl⁺, BaBr⁺, Ba(ClO₄⁺, Ba(NO₃)⁺, SrCl⁺, Sr(NO₃)⁺, CaCl⁺ and Ca(NO₃)⁺ from water to dioxane—water media, which would give some information regarding ionic solvation.     

New complexes of lanthanide Ln(III), (Ln = La, Sm, Gd, Er) with Schiff bases derived from 2-furaldehyde and phenylenediamines

Some new Schiff bases derivates from 2-furaldehyde and phenylenediamines (L^1-3) and their complexes with lanthanum (La), samarium (Sm), gadolinium (Gd) and erbium (Er) have been synthesized. These complexes with general formula [Ln(L^1-3)₂(NO₃)₂]NO₃·nH₂O (Ln = La, Sm, Gd, Er) were characterized by elemental analysis, UV-Vis, FT-IR and fluorescence spectroscopy, molar conductivity and thermal analysis. The metallic ions were found to be eight coordinated. The emission spectra of these complexes indicate the typical luminescence characteristics of the Sm(III), La(III), Er(III) and Gd(III) ions.     

Transport behaviour of the lanthanide 152Eu(III), 153Gd(III) and 170Tm(III) and transplutonium element 254Es(III), 244Cm(III), 241Am(III), 249Cf(III) and 249Bk(III) ions in aqueous solutions at 298 K

Ionic self-diffusion coefficients (D) for trivalent radiotracers, lanthanide and actinide ions have been determined in concentrated aqueous solutions of supporting electrolytes of Gd(NO₃)₃–HNO₃ or Nd(ClO₃)₄–HClO₄ up to 1.5 mol L^?1 at 298.15 K and pH 2.50 by the open-end capillary method. The data obtained in large range of concentrations, allow to derive the limiting value D°, the validity of the Onsager limiting law and a more extended law. This study contributes to demonstrate similarities in transport and structure properties between 4f and 5f trivalent ions explained by a similar electronic configuration, ionic radius and hydration number. An empirical equation is suggested for predicting ionic hydration number with a good precision.     

The syntheses and magnetic properties of a series of heterospin [LnIIICuII 4] pentanuclear complexes

Twelve oxamide-bridged Ln(III)–Cu(II) heteropentanuclear complexes Ln[Cu(PMoxd)]₄(ClO₄)₃ · 5H₂O (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and PMoxd = the N,N′-Bi(α-pyridylmethyl)-oxamide dianion) and 12 oxamide-bridged Ln(III)–Cu(II) heteropentanuclear complexes with the formula of Ln[Cu(PEoxd)]₄(ClO₄)₃ · 5H₂O (PEoxd = the N,N′-Bi(α-pyridylethyl)-oxamide dianion) were synthesized and characterized. The magnetic properties of Gd[Cu(PMoxd)]₄(ClO₄)₃ · 5H₂O (7) and Gd[Cu(PEoxd)]₄(ClO₄)₃ · 2H₂O (19) show that there are ferromagnetic interactions between Gd(III) and Cu(II) in the complexes with J _Cu–Gd = 1.38 cm^?1 and J _Cu–Gd = 1.00 cm^?1, respectively. Fluorescent quenching phenomena for Eu[Cu(PMoxd)]₄(ClO₄)₃ · 5H₂O (6) and Tb[Cu(PMoxd)]₄(ClO₄)₃ · 5H₂O (8) were also observed.     

Synthesis, physico-chemical and thermal characteristics of seven and ten coordinated complexes of trivalent lanthanides derived from 4[N-(cinnamalidene)amino]antipyrine semicarbazone and diphenyl sulfoxide

In present studies a new series of twenty four complexes of seven and ten coordinated compounds derived from 4[Ncinnamalidene) amino]antipyrine semicarbazone (CAAPS) as primary ligand and diphenyl sulfoxide (DPSO) as secondary ligand has been reported. All the complexes have the general composition LnX_3.n(CAAPS).DPSO (Ln = La, Pr, Nd, Sm, Gd, Tb, Dy or Ho, X = NCS or ClO₄, n = 2, X = NO₃, n = 1). The compounds have been characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectra. Thermal characteristics were also reported. Based on the data appropriate structures are assigned for these complexes.     

Lanthanide perchlorate complexes of 4-cyano pyridine-N-oxide, 4-chloro 2-picoline-N-oxide and 4-dimethyl amino-2-picoline-N-oxide

Complexes of lanthanide perchlorates with 4-cyano pyridine-1-oxide, 4-chloro 2-picoline-1-oxide and 4-dimethyl-amino 2-picoline-1-oxide have been isolated for the first time and characterized by analysis, conductance, infrared, NMR and electronic spectra. The complexes of 4-cyano pyridine-1-oxides have the composition Ln(CyPO)₆(ClO₄)₃. 2H₂O (Ln=La, Sm, Dy and Ho); Ln(CyPO)₇ (ClO₄)₃. 2H₂O (Ln=Pr, Nd, Er and Yb); and Ln(CyPO)₅ (ClO₄)₃. 2H₂O (Ln=Gd and Tb). The complexes of 4-chloro 2-picoline-1-oxide analyse for the formulae Ln(CpicO)₆ (ClO₄)₃ (Ln=La, Pr, Nd and Ho); and Ln (CpicO)₅ (ClO₄)₃ (Ln=Er and Yb), and those of 4-dimethylamino 2-picoline-1-oxide for Ln(DMPicO)₆ (ClO₄)₃ (Ln=La and Nd); Ln(DMPicO)₇ (ClO₄)₃ (Ln=Gd, Er and Yb); and Ln(DMPicO)₈ (ClO₄)₃ (Ln=Dy and Ho).     

Magnetism of Metallic Molecular Crystals with Rare-Earth Complex Anions

Novel molecular metal salts comprising an organic donor 2,5-bis(1, 3-dithiol-2-ylidene)-1,3,4,6- tetrathiapentalene (BDT-TTP) and lanthanide nitrato complex anions [M(NO₃)_y]^−(y−3) were synthesized as the composition (BDT-TTP)_x[M(NO₃)_y]. Attempts on X-ray crystal structure analyses gave rise to a detection of two polymorphs. One of the polymorph, which had a composition of (BDT-TTP)₅[M(NO₃)₅] for M= Nd, Sm, Eu and Gd, was analyzed in detail. Five crystallographically independent BDT-TTP molecules were stacked face-to-face to form a pentad, which was jointed one after another by crystallographic inversion centers into a one-dimensional column. The calculated overlap integrals of the highest occupied molecular orbitals revealed that not only intracolumnar orbital overlaps but also transverse intermolecular interactions were important in the electronic band formation. Consequently, the system has two-dimensional Fermi surfaces that explain the stable metallic states. Magnetic measurements on the four salts, with M= Nd, Sm, Eu and Gd, showed Curie paramagnetic moments on rare-earth ions which were superimposed on the Pauli paramagnetism of metallic π electrons. Especially, the magnetic susceptibility of the isolated Eu³⁺ ion was written using Curie term and extremely large Van Vleck term.     

Magneto,spectral and thermal studies of lanthanide perchlorato complexes of 5,6-benzoquinoline

A new series of complexes of 5,6-benzoquinoline (Benzqn) with lanthanide perchlorates with the general composition Ln(ClO₄)₃·7Benzqn (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy or Ho) were synthesised and characterised by elemental analysis, conductance, molecular weight and infrared spectra. The thermal behaviour of these complexes have also been studied.     

Thermal decomposition of lanthanide(III) complexes of bis-(salicylaldehyde)-1,3-propylenediimine Schiff base ligand

The thermal decomposition of lanthanide complexes, with a general formula: [LnL(NO₃)₂](NO₃), where Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, and Er; and L = bis-(salicyladehyde)-1,3-propylenediimine Schiff base ligand, was studied by thermogravimetric (TG) and derivative thermogravimetric (DTG) techniques. The TG and DTG data indicated that all complexes are thermostable up to 398 K. The thermal decomposition of all Ln(III) complexes was a two-stage process and the final residues were Ln₂O₃ (Ln = La, Nd, Sm, Gd, Dy, Er), Tb₄O₇, and Pr₆ O₁₁. The activation energies of thermal decomposition of the complexes were calculated from analysis of the TG-DTG curves using the Kissinger, Friedman, and Flynn-Well-Ozawa methods.     

A conductance study of some cobalt(III) complexes in liquid ammonia

The electrical conductivity in liquid ammonia of Co(NH₃)₆(ClO₄)₃, Co(NH₃)₆(NO₃)₃, Co(NH₃)₅F(ClO₄)₂, Co(NH₃)₅F(NO₃)₂, and Co(NH₃)₅Cl(ClO₄)₂ has been measured between 2×10^?4 and 10^?2 M at temperatures varying from ?40 to ?75°C. In solutions more concentrated than 6×10^?4 M there is evidence that the only ionic species are univalent ions. The conductance data have been fitted to the Fuoss-Onsager-Skinner equation to give Λ₀ for the univalent complexes andK _A ¹ , the association constant of the uncharged complex ion pair. The quantities ΔH ^o and ΔS ^o were evaluated from the temperature dependence ofK _A ¹ . Walden products for the univalent complexes have been calculated and are discussed.     

Synthesis and characterization of some new Co(II) and Cd(II) macroacyclic Schiff-base complexes containing piperazine moiety

Three Cd(II) or Co(II) macroacyclic Schiff-base complexes [CoL¹Br]ClO₄ (1), [CdL²Cl]ClO₄ (2) and [CdL³(NO₃)]ClO₄ (3) were prepared by template condensation of 2-pyridinecarboxaldehyde and three different amines containing piperazine moiety, N,N′-bis(2-aminoethyl)piperazine, N,N′(2-aminoethyl)(3-aminopropyl)piperazine and N,N′-bis(3-aminopropyl)piperazine, in the presence of Co(II) or Cd(II) metal ions, respectively. All complexes have been studied with IR, FAB mass and microanalysis and for complex (3) by ¹H and ¹³C NMR spectra. One of these complexes, [CdL³(NO₃)]ClO₄ (3) has been characterized through X-ray crystallography. In complex (3), the Cd(II) ion is coordinated by the six nitrogen donor atoms from the ligand and by one oxygen atom from a monodentate nitrate ion in a N₆O environment.     

Synthesis and study of RbSrR(MoO4)3 ternary molybdates (R = Nd, Sm, Eu, Gd) with scheelite-like structure

Phase relations in the subsolidus region of the Rb₂MoO₄-SrMoO₄-R₂(MoO₄)₃ systems (where R = Nd, Sm, Eu, Gd) were studied by IR spectroscopy, X-ray diffraction analysis, and differential thermal analysis. RbSrR(MoO₄)₃ ternary molybdates (where R = Nd, Sm, Eu, Gd) with scheelite-like structures belonging to the monoclinic crystal system (space group P21/n) were synthesized. Their unit cell parameters were determined; IR and Raman spectra were characterized.     

Synthesis and magnetic properties of novel copper(II)-lanthanoid(III) heterobinuclear oxamido bridged complexes

Summary Seven novel -oxamido hetero-metal binuclear complexes have been prepared and characterized, namely [Cu(oxae)-Ln(NO₂-phen)₂ (ClO₄)](ClO₄)₂, where oxae denotes the N,N-bis(2-aminoethyl)oxamido dianion, NO₂-phen denotes 5-nitro-1,10-phenanthroline and Ln is Nd, Eu, Gd, Tb, Dy, Ho or Er. The magnetic susceptibility of [Cu(oxae)Gd(NO₂-phen)₂(ClO₄)](ClO₄)₂ was measured over a 4–300 K temperature range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator = -2J ₁·₂, giving the exchange integral for Gd^III J _(Cu-Gd) = -1.52cm^-1. This indicated a weak antiferromagnetic interaction between the Cu^II and Cd^III ions.Visiting scholar: Qufu Normal University.Visiting scholar: Tianjin Second Medical College.     

4-Nitro and 4-chloro pyridine-N-oxide complexes of lanthanide perchlorates

Adducts of lanthanide perchlorates with 4-nitro and 4-chloro pyridine-Noxides (4-NPNO and 4-CPNO respectively) have been synthesised for the first time and characterised by analysis, electrolytic conductance, infrared, proton-NMR and electronic spectral data. The complexes are of the compositions Ln₂(NPNO)₁₅ (ClO₄)₆ (Ln = La, Pr, Nd and Gd), Tb(NPNO), (C1O₄)₆), Ln₂(NPNO)₁₃ (C1O₄)₆) (Ln = Dy, Ho, and Yb); Ln (CPNO)₈ (C10₄)₃) (Ln = La, Pr, Nd, Tb, Dy, Ho and Yb) and Ln(CPNO), (C1O₄)₃) (Ln = Sm and Gd). Conductivity and IR data provide evidence for the non-coordinated nature of the perchlorate groups. IR and NMR spectra suggest coordinationvia the oxygen of the N-oxide group. Electronic spectral shapes of the Nd⁺³ and Ho⁺³ complexes are interpreted in terms of eight-and seven-coordinate environments in the case of 4-NPNO complexes and eight-coordination in the case of 4-CPNO complexes. IR data indicate bridged structure in NPNO complexes of lanthanides other than Tb.     

Complexes of the Lighter Lanthanoid Nitrates with 15-crown-5 and 18-crown-6 ethers: Synthesis and characterization

Complexes of lanthanoid trinitrates Ln(NO₃)₃ with 15-crown-5 ether 1 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd) and with 18-crown-6 ether 2 (Ln = La, Ce, Pr, Nd) having a 1:1 stoichiometry as well as 4:3 complexes with 2 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd) have been synthesized and characterized. All the isolated complexes are solvent free. At 170–220° the 1:1 complexes of 2 are quantitatively transformed into 4:3 complexes. X-Ray powder diagrams of the neodymium complexes with 2 indicate that both the 1:1 and 4:3 complexes are genuine compounds. All the 1:1 complexes show a characteristic IR. absorption band at 875–880 cm^?1 absent from both the spectra of the free ligands and of the 4:3 complexes. The spectroscopic properties (IR. and electronic spectra, fluorescence lifetimes) of the complexes and the low magnetic moments of the Ln(III) ions in the complexes with Ln = Ce-Eu are indicative of a strong interaction between the lanthanoid ions and the crown ethers 1 and 2 .     

Copper(II)-lanthanoid(III)-copper(II) trinuclear complexes with N,N′-bis(2-aminopropyl)-oxamido ligand

Six novel μ-oxamido trinuclear complexes, namely Cu₂(oxap)₂Ln(ClO₄)₃ (Ln: La, Pr, Nd, Gd, Yb, Ho), where oxap is N,N′-bis(2-aminopropyl)oxamido, have been synthesized. The complex Cu₂(oxap)₂Gd(ClO₄)₃ was characterized with variable temperature magnetic susceptibility (4—300 K). The exchange integrals J (Cu—Gd) and J′ (Cu–Cu) were found to be 0.83 cm^?1 and ?1.62 cm^?1, indicating that very weakly ferromagnetic spin-exchange interaction operates between Cu(II) and Gd (III) ions.