Lanthanide Perchlorates Research Articles

Lanthanide tri- and tetrathionates and their complexes with triphenylphosphine oxide

Lanthanide tri- and tetrathionate containing species have been prepared in solution by the reaction of potassium tri- and tetrathionate with lanthanide perchlorates. Unstable solid materials from these reactions have been examined by infrared spectroscopy and electrospray mass spectrometry (ESI MS). There was evidence of the formation of S3O62− and S4O62− coordination to lanthanide ions, but it was not possible to produce material suitable for single crystal X-ray studies. The reaction of ethanol solutions from Ln(ClO4)3/K2SnO6 (n = 3,4) with triphenylphosphine oxide yielded crystalline materials which have been characterised by infrared spectroscopy, electrospray mass spectrometry, elemental analysis and single crystal X-ray diffraction. The trithionate complexes [Ln(S3O6)(Ph3PO)4]ClO4·3H2O (Ln = Nd, Tb) have been isolated. The tetrathionate/Ph3PO reaction gave rise to significant disproportionation giving a small quantity of [Nd(S4O6)(Ph3PO)4(H2O)]ClO4, a different isomer of [Nd(S3O6)(Ph3PO)4H2O]ClO4, neodymium sulfate and elemental sulfur. The crystal structures of the two isomers of [Nd(S3O6)(Ph3PO)4H2O]ClO4 and that of [Nd(S4O6)(Ph3PO)4H2O]ClO4 are reported. The structure of [Er(H2O)5(Ph3PO)2].5Ph3PO.3[ClO4], formed during the attempted preparation of erbium trithionate complexes, is also described.

Fe microenvironments in heat treated rare-earth exchanged montmorillonites

The rare-earth bentonites were prepared from Ca-bentonite by suspending Ca-bentonite in rare-earth (Ce, La, Y) perchlorate solution. 57Fe Mössbauer spectra of rare earth montmorillonites before heat treatments showed a doublet envelop at room temperature, reflecting dominantly Fe3+ assigned to (cis) octahedral site in the montmorillonite. At the same time, the 80 K spectra of these rare-earth exchanged montmorillonites revealed an additional magnetically split component, too, associated with iron atoms intercalated in the interlayer space. In the case of heat treated samples (250 °C, 360 °C and 500 °C for 4 h), a new doublet component associated with Fe3+ at trans octahedral site, appeared in both the 295 K and 80 K Mössbauer spectra. Powder X-ray diffractometry (XRD) measurements of the heat treated rare earth montmorillonites revealed that a gradual mineral phase transformation of montmorillonite to muscovite occurred upon the applied heat treatments, being consistent with the completing electron magnetic resonance (EMR) and Mössbauer spectroscopy (MS) results.

Synthesis and Characterization of Complexes of Lanthanide Perchlorate with DDO

The complexes of lanthanide perchlorates in conjunction with N,N′-diethyl-N,N′- diphenyl-3-oxapatanediamide (DDO) ligand have been prepared in non-aqueous media. These complexes with general formulation [Ln(DDO)2(H2O)2](ClO4)3 (Ln = La, Pr, Nd, Sm, Eu) have been characterized by elemental analysis, conductivity measurement, IR spectra, 1H NMR spectra and TG-DTA techniques. In all the complexes, the ligand (DDO) shows tridentate behavior.

Lanthanide coordination polymers with N-methyliminodipropionic acid: Synthesis, crystal structures and luminescence

The synthesis, crystal structures and luminescence of a novel family of lanthanide polymer complexes with general formula [Ln2(Hmidp)3(H2O)3](ClO4)3·6H2O (Ln=Nd, Sm, Eu, Gd, Dy, Ho, Tm; H2midp=N-methyliminodipropionic acid) are reported. The compounds were obtained by direct reaction of H2midp and lanthanide(III) perchlorate in aqueous solution. The choice of the conditions of synthesis were selected from speciation studies. The structure of the polymer complexes contains bimetallic cationic units [Ln2(Hmidp)3(H2O)3]3+ in which one of the Ln ions is eight-coordinated and the other nine-coordinated, linked by carboxylate bridges. This is expanded to a 2D network through carboxylate linkers. The solid state luminescence of the Eu complex was observed and an average lifetime value of 0.5ms was verified for the red emitting 5D0 excited state.

Synthesis, Structures, and Magnetic Properties of Binuclear [CrLn] (Ln = Gd or Dy) and Trinuclear [Cr2Ln] (Ln = Gd, Dy, or Tb) Heterometallic Clusters with 2,2′‐Bipyridine as Ligand

AbstractThe syntheses, structures, and magnetic properties of two series of Cr–Ln heterometallic clusters based on the 2,2′‐bipyridine (bipy) ligand are reported; binuclear [LnCr(bipy)2(μ2‐OH)2(H2O)6](ClO4)4·2H2O {Ln = Gd (1Gd) or Dy (1Dy)} and trinuclear [LnCr2(bipy)4(μ2‐OH)4(H2O)4](ClO4)5·H2O {Ln = Gd (2Gd), Dy (2Dy), or Tb (2Tb)}. Their syntheses could be controlled by the amount of lanthanide perchlorate used. The binuclear [CrLn] clusters could be formed with 24 equivalents of Ln(ClO4)3, whereas 12 equivalents of Ln(ClO4)3 gave the trinuclear [Cr2Ln] species with a CrLnCr core. The Cr3+ and Ln3+ ions are bridged by μ2‐OH groups in the two systems, and the [Cr2Ln] cluster is further assembled into a 1D supramolecular architecture by weak intermolecular π–π interactions. Magnetic analyses reveal that the Cr···Gd interactions in 1Gd and 2Gd are both antiferromagnetic.

Synthesis and Characterization of 18- and 20-Membered Dioxa Tetraaza Macrocylic Dysprosium(III) and Holmium(III) Complex Nanoparticles Encapsulated Within Nanopores of Zeolite Y

Dy(III) and Ho(III) complexes of the 18- and 20-membered dioxa tetraaza macrocyclic ligands were synthesized by the Schiff base condensation of 2,6-diformyl-4-methylphenol with aliphatic and aromatic diamine in presence of hydrated lanthanide(III) perchlorate in dry ethanol at ambient temperature. Discrete mononuclear lanthanide(III) complexes of the type [LnL1–4(ClO4)](ClO4)2. 2H2O (Ln = Dy(III), Ho(III)). These complexes were entrapped in the nanopores of Y-zeolite by in-situ one pot template synthesis 2,6-diformyl-4-methylphenol with diamine in the presence of Ln(III)-NaY.

Syntheses and luminescence properties of two novel lanthanide (III) perchlorate complexes with phenacyl p-tolyl sulfoxide

Two novel solid binary complexes of rare earth perchlorate with phenacyl p-tolyl sulfoxide were synthesized and characterized by elemental analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, 1HNMR and UV spectra. The results indicated that the composition of these complexes was REL7 (ClO4)3·6H2O (RE=Eu (III), Tb (III), L=C6H5COCH2SOC6H4CH3). The study on IR spectra and 1HNMR spectra revealed that phenacyl p-tolyl sulfoxide bonded with RE3+ ions by the oxygen atom in sulfinyl group. The emission spectra illustrated that both the Eu (III) and Tb (III) complexes displayed excellent luminescence in solid state, and The most intensive characteristic emission of the Eu(III) and Tb(III) complexes were 245,400a.u. and 298,000a.u. respectively. The slit with was 1nm. By analysis luminescence and phosphorescence spectrum, it was found that the ligand had the advantage to absorb energy and transfer it to the Eu (III) and Tb (III) ions. The fluorescence lifetimes of the complexes were measured as well as the quantum yield of the Eu (III) complex.

Crystal structure of the Np(IV) compound [Np(DMSO)7(NO3)](ClO4)3 (DMSO = dimethyl sulfoxide)

The Np(IV) complex [Np(DMSO)7(NO3)](ClO4)3 was synthesized and studied by single crystal X-ray structural analysis. The crystal structure contains three crystallographically independent formula units. The complex cations [Np(DMSO)7(NO3)]3+ contain bidentate chelate nitrate ions and DMSO molecules coordinated to the Np atom via O atom. The coordination polyhedra (CPs) of the two crystallographically independent Np atoms can be described as base-monocapped tetragonal antiprisms, whereas the CP of the third crystallographically independent Np atom should be described as a trigonal prism tricapped at lateral faces. In contrast to many other structures of dimethyl sulfoxide complexes of actinide and lanthanide perchlorates, the DMSO molecules and perchlorate ions in the structure under consideration show no disordering.

Syntheses and Fluorescence Properties of Two Novel Lanthanide (III) Perchlorate Complexes with Bis(benzylsulfinyl)methane

A novel ligand with double sulfinyl groups, bis(benzylsulfinyl)methane, was synthesized by a new method and its two lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, (1)HNMR and UV spectra. The results indicated that the composition of these complexes was REL(2.5)(ClO(4))(3)·3H(2)O (RE = Tb (III), Dy (III), L = C(6)H(5)CH(2)SOCH(2)SOCH(2)C(6)H(5)). The FT-IR results revealed that the perchlorate group was bonded with the lanthanide ion by the oxygen atoms, and the coordination was bidentate. The fluorescent spectra illustrated that both the Tb (III) and Dy (III) complexes displayed characteristic fluorescence in solid state, especially for the Tb (III) complex, the peak of (5)D(4) → (7)F(5) of the Tb (III) ion in 544 nm was stronger than that of others. It indicated that the Tb (III) complex could emit purer green fluorescence. By analysis fluorescence and phosphorescence spectra, it was found that the ligand had the advantage to absorb energy and transfer it to the Tb (III) and Dy (III) ions. The phosphorescence spectra and fluorescence lifetimes of the complexes were also measured.

Heterometallic Cubanes: Syntheses, Structures, and Magnetic Properties of Lanthanide(III)−Nickel(II) Architectures

Reactions of lanthanide(III) perchlorate (Ln = Dy, Tb, and Gd), nickel(II) acetate, and ditopic ligand 2-(benzothiazol-2-ylhydrazonomethyl)-6-methoxyphenol (H(2)L) in a mixture of methanol and acetone in the presence of NaOH resulted in the successful assembly of novel Ln(2)Ni(2) heterometallic clusters representing a new heterometallic 3d-4f motif. Single-crystal X-ray diffraction reveals that all compounds are isostructural, with the central core composed of distorted [Ln(2)Ni(2)O(4)] cubanes of the general formula [Ln(2)Ni(2)(μ(3)-OH)(2)(OH)(OAc)(4)(HL)(2)(MeOH)(3)](ClO(4))·3MeOH [Ln = Dy (1), Tb (2), and Gd (3)]. The magnetic properties of all compounds have been investigated. Magnetic analysis on compound 3 indicates ferromagnetic Gd···Ni exchange interactions competing with antiferromagnetic Ni···Ni interactions. Compound 1 displays slow relaxation of magnetization, which is largely attributed to the presence of the anisotropic Dy(III) ions, and thus represents a new discrete [Dy(2)Ni(2)] heterometallic cubane exhibiting probable single-molecule magnetic behavior.

Observation of slow magnetic relaxation in triple-stranded lanthanide helicates

Two dinuclear triple-stranded helicates [Ln(2)L(3)](3+) (Ln = Dy and Tb) obtained via self-assembly from the ligand HL (2,6-diformyl-4-methylphenol di(benzoylhydrazone)) and lanthanide perchlorate have been synthesized and characterized. The crystal structural analysis demonstrates that three ligand strands wrap around a pseudo-threefold axis defined by the two metal ions, leading to a 'meso'-relation between the right- (Δ) and left-hand (Λ) configurations of [Ln(2)L(3)](3+) in the crystal. Each Ln(III) ion is coordinated by nine donor atoms in a distorted tricapped trigonal-prismatic arrangement. Alternating current (ac) susceptibility measurements of [Dy(2)L(3)](3+) reveal a frequency-dependent out-of-phase signal under a 700 Oe dc field, indicating the onset of the slow relaxation of magnetization with a roughly estimated activation energy of ∼5 K and τ(0) of 10(-7) s.

Fluorescence enhancement of lanthanide(III) perchlorate by 1,10-phenanthroline in bis(benzoylmethyl) sulfoxide complexes and luminescence mechanism

Two novel ternary rare earth complexes LnL5L′(ClO4)32H2O (Ln=Eu(III), Tb(III); L=bis(benzoylmethyl) sulfoxide, L′=phen) were synthesized and characterized by elemental analysis, coordination titration analysis, molar conductivity, IR, TG–DSC,1H NMR and UV spectra. The fluorescence spectra illustrated that both the Eu(III) and Tb(III) ternary complexes displayed strong characteristic metal-centered fluorescence in solid state. After the introduction of the second ligand phen group, the relative emission intensities and fluorescence lifetimes of the ternary complex EuL5L′(ClO4)32H2O (L=C6H5COCH2SOCH2COC6H5, L′=phen) enhanced more obviously than that of the binary complex EuL5(ClO4)33H2O. This indicated that the presence of both organic ligands bis(benzoylmethyl) sulfoxide and the second ligand phen could sensitize fluorescence intensities of Eu(III) ions, and the introduction of phen group was resulted in the enhancement of the fluorescence properties of the Eu(III) ternary rare earth complexes. The phosphorescence spectra are also discussed.

Enhanced fluorescence of Tb(III), Dy(III) perchlorate by salicylic acid in bis(benzoylmethyl) sulfoxide complexes and luminescence mechanism

Two novel ternary rare earth perchlorate complexes had been synthesized by using bis(benzoylmethyl) sulfoxide as first ligand (L=C 6H 5COCH 2SOCH 2COC 6H 5), salicylic acid as second ligand (L ′=C 6H 4OHCOO −). The compounds were characterized by elemental analysis, TG-DSC and molar conductivities in DMF solution. The composition was suggested as [REL 5L′](ClO 4) 2· nH 2O (RE=Tb, Dy; n=6, 8 ). Based on IR, 1HNMR and UV spectra, it showed that the first ligand, bis(benzoylmethyl) sulfoxide (L), bonded with Tb(III), Dy(III) ions by the oxygen atom of sulfinyl group. The second ligand, salicylic acid group (L′), not only bonded with RE(III) ions by one oxygen atom of carboxyl group but also bonded with RE(III) ions by oxygen atom of phenolic hydroxyl group. In bis(benzoylmethyl) sulfoxide system, fluorescent spectra of the complexes showed that the luminescence of Tb(III), Dy(III) ions was enhanced by the second ligand salicylic acid. The ternary complexes had stronger fluorescence than the binary ones where only bis(benzoylmethyl) sulfoxide acted as ligand. Phosphorescent spectra of the two ligands indicated that the coordination of salicylic acid resulted in the matching extent increasing between the triplet state of ligand and excited state of the rare earths. The relationship between fluorescence lifetime and fluorescence intensity was also discussed.

Synthesis and Luminescence Properties of Two Novel Lanthanide (III) Perchlorate Complexes with Bis(benzoylmethyl) Sulfoxide and Benzoic Acid

Two novel ternary rare earth complexes of Tb(III) and Dy(III) perchlorates with bis(benzoylmethyl) sulfoxide (L) and benzoic acid (L') had been synthesized and characterized by elemental analysis, coordination titration analysis, molar conductivity, IR, TG-DSC, (1)HNMR and UV spectra. The results indicated that the composition of these complexes was REL(5)L'(ClO(4))(2) x nH(2)O (RE = Tb(III), Dy(III); L = C(6)H(5)COCH(2)SOCH(2)COC(6)H(5), L' = C(6)H(5)COO; n = 6,8). The fluorescence spectra illustrated that the ternary rare earth complexes presented stronger fluorescence intensities, longer lifetimes and higher fluorescence quantum efficiencies than the binary rare earth complexes REL(5) x (ClO(4))(3) x 2 H(2)O. After the introduction of the second ligand benzoic acid group, the relative fluorescence emission intensities and fluorescence lifetimes of the ternary complexes REL(5)L'(ClO(4))(2) x nH(2)O (RE = Tb(III), Dy(III)) enhanced more obviously than the binary complexes. This indicated that the presence of both organic ligands bis(benzoylmethyl) sulfoxide and the second ligand benzoic acid could sensitize fluorescence intensities of rare earth ions, and the introduction of benzoic acid group was resulted in the enhancement of the fluorescence properties of the ternary rare earth complexes. The phosphorescence spectra were also discussed.

Interaction of 6,6′′-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2′:6′,2′′-terpyridine (CyMe4-BTTP) with some trivalent ions such as lanthanide(iii) ions and americium(iii)

The new ligand 6,6''-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2':6',2''-terpyridine (CyMe4-BTTP) has been synthesized in 4 steps from 2,2':6',2''-terpyridine. Detailed NMR and mass spectrometry studies indicate that the ligand forms 1:2 complexes with lanthanide(III) perchlorates where the aliphatic rings are conformationally constrained whereas 1:1 complexes are formed with lanthanide(III) nitrates where the rings are conformationally mobile. An optimized structure of the 1:2 solution complex with Yb(III) was obtained from the relative magnitude of the induced paramagnetic shifts. X-Ray crystallographic structures of the ligand and of its 1:1 complex with Y(III) were also obtained. The NMR and mass spectra of [Pd(CyMe4-BTTP)]n(2n+) are consistent with a dinuclear double helical structure (n = 2). In the absence of a phase-modifier, CyMe4-BTTP in n-octanol showed a maximum distribution coefficient of Am(III) of 0.039 (±20%) and a maximum separation factor of Am(III) over Eu(III) of 12.0 from nitric acid. The metal(III) cations are extracted as the 1:1 complex from nitric acid. The generally low distribution coefficients observed compared with the BTBPs arise because the 1:1 complex of CyMe4-BTTP is considerably less hydrophobic than the 1:2 complexes formed by the BTBPs. In M(BTTP)(3+) complexes, there is a competition between the nitrate ions and the ligand for the complexation of the metal.

Yttrium and lanthanide perchlorate complexes of 2,3-dimethyl-4-formyl- [2' -(aminomethyl)pyridine]-1-phenyl-3-pyrazoline-5-one and 2,3-dimethyl-4-formyl(benzhydrazide)-1-phenyl-3-pyrazolin-5-one

Two series of complexes of two Schiff bases, 2,3-dimethyl-4-formyl-[2'-(aminomethyl)pyridine]-1-phenyl-3-pyrazolin-5-one (L 1 ) and 2,3-dimethyl-4-formyl(benzhydrazide)-1-phenyl-3-pyrazolin-5-one (L 2 ), with the general compositions [Ln(L 1 ) 2 (ClO 4 ) 2 ](ClO 4 ) and [Ln(L 2 ) 2 (ClO 4 )](ClO 4 ) 2 (where Ln = Y, La, Pr, Nd. Sm, Eu, Gd, Dy, Ho or Er) have been synthesized and characterized. Both L 1 and L 2 are neutral ligands coordinating through the carbonyl oxygen(s) and the azomethine nitrogen in these complexes. Two perchlorate ions are bidentately coordinated in the complexes of L 1 and one perchiorate ion is bidentately coordinated in the complexes of L 2 . A coordination number of eight is assigned to the metal in both series of complexes.

Synthesis and Fluorescence Properties of Lanthanide (III) Perchlorate Complexes with Naphthyl-Naphthalinesulphonylpropyl Sulfoxide

A ligand with double sulfinyl groups, naphthyl-naphthalinesulphonylpropyl sulfoxide(dinaphthyl disulfoxide, L), was synthesized by a new method and its several lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DTA, (1)HNMR and UV spectra. The composition of these complexes, were RE(2)(ClO(4))(6).(L)(5).nH(2)O (RE = La, Nd, Eu, Tb, Yb, n = 2 approximately 6, L = C(10)H(7)SOC(3)H(6)SOC(10)H(7)). The fluorescent spectra illustrated that the Eu (III) complex had an excellent luminescence. It was supposed that the ligand was benefited for transferring the energy from ligand to the excitation state energy level ((5)D(0)) of Eu (III). The Tb (III) complex displayed weak luminescence, which attributed to low energy transferring efficiency between the average triplet state energy level of ligand and the excited state ((5)D(4)) of Tb (III). So the Eu (III) complex displayed a good antenna effect for luminescence. The phosphorescence spectra and the relationship between fluorescence lifetime and fluorescence intensity were also discussed.

Heat capacity and thermodynamical properties of the crystal of [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE = Nd, Eu, Dy)

Thermodynamical data of rare earth complexes with amino acid are important for engineering chemistry and fundamental chemistry. However, they have rarely been reported. In this work, a series of crystalline complexes of rare earth perchlorate coordinated with glutamic acid have been synthesized in water medium, and their thermodynamical data, including the heat capacity in low temperature range and the standard enthalpy of formation, were determined. These complexes were identified to be [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE = Nd, Eu, Dy) by using thermogravimetric analysis (TG), differential thermal analysis (DTA), and chemical and elementary analyses. Their purity has been determined. No melting points were observed for all the three complexes. The heat capacity of the complexes was measured by an adiabatic calorimeter from 79 to 370 K. Abnormal heat capacity values were detected for two of the complexes and the decomposition range of one complex was found. The temperature, enthalpy change and entropy change of the decomposition processes of the three complexes were calculated. The polynomial equations of heat capacity in the experimental temperature range have been obtained by least squares fitting. The standard enthalpy of formation was determined by an isoperibol reaction calorimeter at 298.15 K.

Synthesis and Fluorescence Properties of Lanthanide (III) Perchlorate Complexes with Bis(benzoylmethyl) Sulfoxide

A ligand with two carbonyl groups and one sulfinyl group has been synthesized by a new method and its several lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, 1H NMR and UV spectra. The results indicated that the composition of these complexes is REL5(ClO4)(3).3H2O (RE=La(III), Pr(III), Eu(III), Tb(III), Yb(III), L=C6H5COCH2SOCH2COC6H5). The fluorescent spectra illustrate that both the Tb (III) and Eu (III) complexes display characteristic metal-centered fluorescence in solid state, indicating the ligand favors energy transfer to the excitation state energy level of them. However, the Tb (III) complex displays more effective luminescence than the Eu (III) complex, which is attributed to especial effectively in transferring energy from the average triplet energy level of the ligands (T) onto the excited state (5D4) of Tb (III) than that (5D0) of Eu (III), showing a good antenna effect for Tb(III) luminescence. The phosphorescence spectra and the relationship between fluorescence lifetimes and fluorescence intensities were also discussed.

Low-temperature heat capacity and standard enthalpy of formation of neodymium glycine perchlorate complex [Nd2(Gly)6(H2O)4](ClO4)6·5H2O

Rare-earth perchlorate complex coordinated with glycine [Nd2(Gly)6(H2O)4](ClO4)6·5H2O was synthesized and its structure was characterized by using thermogravimetric analysis (TG), differential thermal analysis (DTA), chemical analysis and elementary analysis. Its purity was 99.90%. Heat capacity measurement was carried out with a high-precision fully-automatic adiabatic calorimeter over the temperature range from 78 to 369 K. A solid-solid phase transformation peak was observed at 256.97 K, with the enthalpy and entropy of the phase transformation process are 4.438 kJ mol−1 and 17.270 J K−1 mol−1, respectively. There is a big dehydrated peak appears at 330 K, its decomposition temperature, decomposition enthalpy and entropy are 320.606 K, 41.364 kJ mol−1 and 129.018 J K−1 mol−1, respectively. The polynomial equations of heat capacity of this compound in different temperature ranges have been fitted. The standard enthalpy of formation was determined to be −8023.002 kJ mol−1 with isoperibol reaction calorimeter at 298.15 K.