Lanthanide Nitrate Research Articles

Low-temperature green synthesis of nanocrystalline La2O2S:Pr3+ powders and investigation of photoluminescence

Calcining an amorphous precursor in flowing hydrogen at 900 °C directly produced nanocrystalline La2O2S:Pr3+ powder (LOS:Pr3+; average size ∼35 nm) of a unimodal distribution of particle size (mean diameter ∼90 nm). The precursor, precipitated by titrating an aqueous solution of rare-earth nitrate and ammonium sulfate with ammonia water, was deduced to have an approximate composition of (La,Pr)2(OH)2.6(CO3)0.7SO4·2H2O. Aside from simplicity, the synthesis method reported herein has the obvious advantage of environmental friendliness, as it did not involve any harmful sulfidizing agent. The products were characterized in detail by XRD, FTIR, TG/DTA, and SEM/TEM to reveal the process of phase/morphology development and fine microstructure. Photoluminescence study found that the LOS:Pr3+ nanopowder exhibited strong luminescence at ∼508 nm (3P0,1 → 3H4 transition), with a fluorescence lifetime of ∼4.22 ± 0.03 μs, either through exciting the LOS host (∼263 nm, more efficient) or directly exciting the Pr3+ activator (∼304 nm), and retained ∼45% of its room-temperature intensity at 150 °C. Aside from phosphor application, the thus-synthesized powder would be useful for the fabrication of ceramic scintillators because of its nanosized crystallites and narrow distribution of particle size.

Syntheses directed by ionic liquids: structures and properties of six novel lanthanide 1,3,5-benzenetrisbenzoate frameworks

Abstract Reactions of lanthanide nitrate, 1,3,5-benzenetrisbnzoic acid (H3BTB) and [RMI]Br ionic liquids (RMI = 1-alkyl-3-methylimidazolium; R = ethyl, propyl or butyl), gave rise to six novel lanthanide–organic frameworks (LOFs) [Ln(BTB)H2O], where Ln = Nd 1, Sm 2, Gd 3, Dy 4, Ho 5 and Er 6. These compounds have been characterized by elemental analysis, IR spectra, thermogravimetric analysis, single-crystal and powder X-ray diffraction. Compounds 1–6 are isostructural and consist of infinite rod-shaped lanthanide-carboxylate building units, which are further bridged by trigonal-planar BTB ligands to give non-interpenetrated open 3D frameworks. The results of variable-temperature magnetic studies have shown that the magnetic interaction between the Ln(III) ions in 3, 5 and 6 is mainly due to antiferromagnetic coupling as well as the depopulation of the Stark levels.

Up-conversion luminescence and optical temperature sensing of Er3+, Yb3+ co-doped Gd2O3 phosphors with different F-/Ln3+

In this work, the Er3+, Yb3+co-doped Gd2O3 phosphors have been prepared through a facile hydrothermal method. The optimum doping concentration of the Er3+, Yb3+ co-doped Gd2O3 phosphors are studied in detail. By studying the samples calcined at different temperatures, the process of grain forming self-assembled structure was revealed. The up-conversion luminescence intensity of the phosphors can be regulated by the ratio of NH4F and lanthanoid nitrate (F-/Ln3+) in the synthesis process. The enhancement of red and green emission intensities can reach 8.0 times, 6.7 times respectively than the sample with F-/Ln3+ = 0.5. In addition, the florescence intensity ratio based on thermally coupled energy levels by the Stark sublevels is also investigated. The maximal absolute sensitivity of optical temperature sensing reaches 1.27% K−1 at 574 K, which is 1.51 times higher than that based on traditional thermally coupled energy levels by Stark levels. Therefore, the results show that this is a useful method to improve the absolute sensitivity of optical temperature sensing and the Er3+, Yb3+ co-doped Gd2O3 phosphors have application potential in high sensitivity optical temperature sensing.

Synthesis, Crystal Structures and Magnetic Properties of Trinuclear {Ni2Ln} (LnIII = Dy, Ho) and {Ni2Y} Complexes with Schiff Base Ligands

The reaction of the Schiff base ligand o-OH-C6H4-CH=N-C(CH2OH)3, H4L, with Ni(O2CMe)2∙4H2O and lanthanide nitrate salts in a 4:2:1 ratio lead to the formation of the trinuclear complexes [Ni2Ln(H3L)4(O2CMe)2](NO3) (Ln = Dy (1), Ho (2), and Y (3)) which crystallize in the non-centrosymmetric space group Pna21. The complex cation consists of the three metal ions in an almost linear arrangement. The {Ni2Ln} moieties are bridged through two deprotonated Ophenolato groups from two different ligands. Each terminal NiII ion is bound to two ligands through their Ophenolato, the Nimino atoms and one of the protonated Oalkoxo groups in a distorted octahedral. The central lanthanide ion is coordinated to four Ophenolato oxygen from the four ligands, and four Ocarboxylato atoms from two acetates which are bound in the bidentate chelate mode, and the coordination polyhedron is biaugmented trigonal prism, which probably results in a non-centrosymmetric arrangement of the complexes in the lattice. The magnetic properties of 1–3 were studied and showed that 1 exhibits field induced slow magnetic relaxation.

Thermal decomposition and crystallization behavior of Yb/Y co-doped SrZrO3 precursor used in the suspension plasma spray process

A double rare-earth (Yb/Y) co-doped SrZrO 3 [Sr 1.0 (Zr 0.9 Yb 0.05 Y 0.05 )O 2.95 ] thermal barrier coating was prepared via suspension plasma spraying (SPS). The rare-earth nitrates [Zr(NO 3 ) 4 ·5H 2 O, Sr(NO 3 ) 2 , Yb(NO 3 ) 3 ·6H 2 O, Y(NO 3 ) 3 ·6H 2 O] and NH 4 (C 2 O 4 ) 2 ·H 2 O were used to prepare the precursor suspension by co-precipitation. The thermal decomposition and crystallization of the precursor suspension powders calcined at 1200 °C were characterized with X-ray diffraction and a synchronous thermal analyzer coupled with quadrupole mass spectrometry . Zr 2 (C 2 O 4 ) 2 (OH) 4 decomposed into Zr(C 2 O 4 ) 2 , ZrO 2, and H 2 O initially, followed by the decomposition of Zr(CO 3 ) 2 into ZrO 2 . The SrC 2 O 4 precursor decomposed into SrCO 3 and SrO consecutively. The ZrO 2 reacted with SrO (Yb 2 O 3 , Y 2 O 3 ) to generate the Yb/Y co-doped SrZrO 3 . And the Yb/Y co-doped SrZrO 3 coating with a columnar crystal structure was prepared by SPS, which was analyzed with scanning electron microscopy, an inductively coupled plasma atomic emission spectrometer, and a laser flash analyzer. The thermal conductivity of the as-prepared coating was 1.77 W·m −1 ·K −1 at 1000 °C, which was more than 19% lower than that of the SPS SrZrO 3 coating. • The precursor suspension was prepared by co-precipitation using Zr(NO 3 ) 4 ·5H 2 O, Sr(NO 3 ) 2 , Yb(NO 3 ) 3 ·6H 2 O, Y(NO 3 ) 3 ·6H 2 O and NH 4 (C 2 O 4 ) 2 ·H 2 O. • The phase evolution of the precursor suspension was investigated. • The Yb/Y co-doped SrZrO 3 coating was prepared by suspension plasma spray using the prepared precursor suspension. • The Yb/Y co-doped SrZrO 3 coating has a low thermal conductivity of 1.77 W·m -1 ·K -1 at 1000 °C compared to SrZrO 3 coating.

Interaction of Trivalent Lanthanide (III) Cations with Bidentate Schiff Base (1E,2E) Diphenylethane-1,2- Hydrazone Oxime

The novel lanthanide (III) complexes [Ln(BMOH)3] (NO3) (Ln=Pr, Nd and La), where (BMOH)-= (1E,2E)-1,2- diphenylethane – 1,2 – diene hydrazone oxime, have been obtained by direct condensation reaction of the Schiff base HBMOH ligand and corresponding hydrated lanthanide (III) nitrates in ethanol. All prepared complexes were characterized by traditional physico-chemical and spectral techniques. In the molecular structure of synthesized complexes, central inner transition metal ions are surrounded by all donor atoms of the HBMOH ligand (two nitrogen donor atoms) and nitrogen atom belonging to monodentatae chelating nitrito ligand.

SEARCH FOR WAYS OF CONTROLLED MODIFICATION OF CHARACTERISTICS OF FUNCTIONAL UNITS OF ADAPTIVE AIR PURIFICATION SYSTEMS

Information on alkaline coordination nitrates of rare-earth elements of the cerium subgroup - precursors of promising modern multifunctional materials - on the conditions of their formation and existence, the nature of the chemical bond, the composition, structure, shape of the Ln coordination polyhedra, the type of ligand coordination, and the existence of isotypic series in stoichiometry are generalized. composition, structure, characteristic properties. The data obtained (as primary information) is the basis for the detection, identification, and control of the phase state of processing objects in the preparatory stages, the choice of criteria for the compatibility of the components in the formation of single-layer and layered nanostructured oxide composite systems of lanthanides and transition elements for general purposes, with catalytic and photocatalytic activity, coatings self-cleaning with hydrophilic properties; development of various combined methods for their activation and identification of technological functional dependencies; controlled modification of the properties of the obtained target products. To increase the photocatalytic activity of coating samples based on highly dispersed anatase TiO2, a methodology for chemical modification of oxidation centers in their surface layer with heat treatment in contact with thermolysis products of alkaline coordination lanthanide nitrate melts is proposed. An effective test photocatalytic destruction of organic substrates vapors has been discovered using ethanol as an example.Effective activation of the functioning of functional units in the composition of self-adjusting air purification complexes using new photocatalytically active three-layer perovskite-like oxide materials M2Ln2Ti3O10 (M - Li, Na, K; Ln - La, Nd) has been proven. The variability of such methods for creating and modifying the characteristics of polyfunctional coatings is determined by the number and individual properties of representatives of the natural series of lanthanides, alkali metals of the periodic system, the peculiarities of their cooperative behavior in the preparatory technological stages, conditions and methods of activation of formation processes, the nature of the substrate, and other factors.

A series of urea complexes with rare-earth nitrates: Synthesis, structure and thermal decomposition

Complexes of rare-earth nitrates with urea (Ur), [Nd(Ur)4(NO3)3], [Ln(H2O)(Ur)4(NO3)2]NO3 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Y), and [Lu(Ur)4(NO3)2]NO3, were synthesized and characterized by elemental analysis, IR spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. Molecular and crystal structures of [Sm(H2O)(Ur)4(NO3)2]NO3 and [Er(H2O)(Ur)4(NO3)2]NO3 were determined. All complexes were studied as precursors for preparing rare-earth oxides by solution combustion synthesis. Processes at 300–500 °C associated with conditions of combustion resulted in formation of rare-earth basic carbonates, which lost carbon dioxide at further heating. Powder X-ray diffraction showed formation of cubic rare-earth oxides at 900 °C.

Field-Induced SMM and Vis/NIR Luminescence on Mononuclear Lanthanide Complexes with 9-Anthracenecarboxylate and 2,2′:6,2″-Terpyridine

Five new mononuclear lanthanide complexes are synthesized by adding the several lanthanide nitrate hexahydrate salts, which for lanthanide (Ln) are Eu, Tb, Dy, Er, and Yb, with 9-anthracenecarboxylic acid (9-Hanthc) and 2,2′:6,2″-terpyridine (TPY) in mixed solution of methanol and dimethylformamide (DMF). The general formula is [Eu(9-anthc)3(TPY)(DMF)]·H2O (1Eu) where Eu(III) is ennea-coordinated or [Ln(9-anthc)3(TPY)(H2O)]·H2O·DMF (Ln = Tb (2Tb), Dy (3Dy), Er (4Er), and Yb (5Yb)) where Ln(III) is octa-coordinated. For compounds 3Dy, 4Er, and 5Yb, the dynamic ac magnetic study indicated field-induced single molecule magnet (SMM) behavior. The photoluminescence studies in the solid state of these complexes show the sensitization of 4f-4f transitions for 4Er and 5Yb in the NIR region.

Radical-Doped Crystalline Lanthanide-Based Photochromic Complexes: Self-Assembly Driven by Multiple Interactions and Photoswitchable Luminescence.

Stimuli-responsive functional materials, especially the light stimulation color change and tunable fluorescent materials, have received considerable attention because of their broad applications in smart materials. Herein, a series of lanthanide-based [Ln = Nd(III) (1), Sm(III) (2), Eu(III) (3), Gd(III) (4), Tb(III) (5), Yb(III) (6), and Lu(III) (7)] crystalline complexes were attained by simply adding the aqueous lanthanide nitrate solution to the water-soluble naphthalenediimide derivative. The obtained lanthanide-based crystalline materials not only show significant photochromism but also possess reactive organic radicals under ambient conditions. Intriguingly, photoswitchable near-infrared (NIR) fluorescence was realized in the crystalline complex 1. The structures of these crystalline materials were systematically studied to clarify the weak interaction-assisted charge-transfer process. The underlying multiple-interaction-assisted supramolecular self-assembly, the radical-doped nature, and the corresponding photochromic mechanism were thoroughly unearthed by single-crystal X-ray diffraction, in situ solid-state UV-vis diffuse reflectance, and electron paramagnetic resonance spectrometric analysis.

Lanthanide dicyanoaurate coordination polymers containing 1,10-phenanthroline: Synthesis, structure, and luminescence

The synthesis of two novel lanthanide dicyanoaurates containing the bidentate ligand 1,10-phenanthroline (phen) have been carried out by reaction of select lanthanide nitrate salts with phen and potassium dicyanoaurate. The resultant compounds, [Ln(C12H8N2)(H2O)2{Au(CN)2}3] (Ln = Gd, Tb), are isostructural as established by single-crystal X-ray diffraction studies. Prominent structural features in these one-dimensional polymeric compounds are the existence of hexameric aurophilic interactions containing kinked Au6 units, π-stacking from partial phen ring alignment, and strong H-bonding interactions. Photoluminescence measurements illustrate that [Tb(C12H8N2)(H2O)2{Au(CN)2}3] displays enhanced Tb-based emission due to intramolecular energy transfer from the coordinated ligands while [Gd(C12H8N2)(H2O)2{Au(CN)2}3], which lacks low-lying electronic states, exhibits broad-band ligand-based emission.

A new family of Ln-BTC-AC-FM framework intelligent materials: Precise synthesis, structure and characterization for fluorescence detecting of UO22+ and adsorbing dyes

The unique fluorescence properties of rare earth ions and subtle interactions with organic ligands make the target lanthanide metal-organic frameworks show potential development prospects in many fields. Based on this situation, a series of new lanthanide metal-organic frameworks Ln-BTC-AC-FM: (CH3)2NH2[Ln2(BTC)(AC)3(FM)], (Ln=Pr (1), Ce (2), Nd (3), Eu (4), Sm (5), Gd (6), Tb (7), Ho (8), Er (9) and Yb (10), H3BTC=1,3,5-benzenetricarboxylic acid) were synthesized through the reaction of triangular polycarboxylic acid ligand (H3BTC) and rare earth nitrate Ln(NO3)3·6H2O with mixed formic acid (FM) and glacial acetic acid (AC) system. Due to this new type of Ln-BTC-AC-FM MOFs have unique and excellent fluorescence properties, we selected (CH3)2NH2[Eu2(BTC)(AC)3(FM)] (4) to explore its detection performance for UO22+ in aqueous solution. The study found that 4 is a high-efficiency fluorescent probe, which has a good quenching effect on uranium solution, and the quenching rate can reach 98.01%. At the same time, 4 has a good fluorescent response to UO22+, with a higher KSV value of 8.56 × 103 M−1 and a lower detection limit of 4.12 μM. In addition, we also studied the adsorption properties of this series of Ln-BTC-AC-FM MOFs for dyes because of their novel three-dimensional microporous structures. The results showed that 4 has a good adsorption effect on Coomassie Brilliant Blue (CBB) and Eosin. Moreover, it was found that the dye adsorption process was proved to be a suitable pseudo-second-order kinetic model.

Exploration of N-oxo pyridine 2-carboxamide ligands towards coordination chemistry, solvent extraction, and DFT investigation for the development of novel solvent for lanthanide and actinide separation

In this study the coordination chemistry of three ligands, C5H4NOCONRR′ (where, R, R′ = iC3H7 (L1); R, R′ = iC4H9 (L2); and R = H, R′ = tC4H9 (L3) composed of N-oxide and carboxamide groups have been explored with uranyl nitrate and some selected lanthanide (La, Sm, and Eu) nitrates. All the synthesized ligands as well as their complexes (1–12) of type UO2(NO3)2L (where, L = L1, L2, and L3 for 1, 2, and 3 respectively) and Ln(NO3)3(H2O)L2 (where, Ln = La, L = L1 for 4, L = L2 for 5, and L = L3 for 6; Ln = Sm, L = L1 for 7, L = L2 for 8, and L = L3 for 9; Ln = Eu, L = L1 for 10, L = L2 for 11, and L = L3 for 12) have been characterized by elemental analysis, spectroscopic analyses such as FTIR, 1H NMR, and electrospray ionization mass spectrometry (ESI-MS). Solid-state structural analysis of L1, 3, and 10 is carried out by X-ray crystallographic technique. The CO and NO groups of L1 are placed almost mutually perpendicular to each other in the crystal structure of L1. The X-ray data show that in [UO2(NO3)2{C5H4NOCONH(tC4H9)}] (3), the ligand acts as a bidentate chelating ligand and is bonded through both the N-oxo and amide oxygen atoms, whereas, in [Eu(NO3)3(H2O){C5H4NOCON(iC3H7)2}2] (10), the ligands show monodentate behavior and are bonded only through N-oxo oxygen atoms. Quantum mechanical calculation at DFT level corroborates the possibility of various bonding modes of these ligands towards uranium and europium nitrate with the preference of bonding as observed in the synthesized complexes. Solvent extraction studies using N,N-dioctyl N-oxo pyridine 2-carboxamide ligand (L4) in n-dodecane with UO22+, Pu4+, Am3+ and Eu3+ indicate the trend Pu4+ ˃ UO22+ > Am3+ > Eu3+ at acidity range from 0.01 M to 6 M HNO3. The ligands show good radiation stability at gamma dose up to 500 kGy and chemical stability at 3 M HNO3 for up to 200 h without much affecting the metal ion extraction. Theoretical calculations show the possibility of presence of different metal species in the organic phase, other than the products obtained from dichloromethane during the solvent extraction of UO22+ and Eu3+ in water/dodecane biphasic media. Energy decomposition analysis supports the higher extraction coefficient of UO22+ than Eu3+ with an evidence of higher orbital interaction of the ligands with UO22+.

Synthesis, structure, melting and optical properties of three complex orthorhombic sulfides BaDyCuS3, BaHoCuS3 and BaYbCuS3

Complex sulfides BaDyCuS3, BaHoCuS3 and BaYbCuS3 were synthesized in a flow of sulfiding gases (CS2, H2S) at 900оC from standard solutions of lanthanide and copper nitrates, as well as from the same standard Ba(OH)2 solution. The crystal structures of BaDyCuS3, BaHoCuS3 and BaYbCuS3 were obtained by the Rietveld refinement method. All three compounds crystallize in the Cmcm space group (KZrCuS3 structural type) as predicted by the tolerance factor analysis. Their micromorphological, thermal and spectroscopic properties are evaluated. BaDyCuS3 and BaHoCuS3 melt congruently at 1376.5 °C and 1363.8 °C. BaYbCuS3 melts incongruently at 1353.3 °C. The optical band gap is 2.45 eV for BaDyCuS3, 2.37 eV for BaHoCuS3 and 1.82 eV for BaYbCuS3. The low bandgap of BaYbCuS3 is explained by the charge transfer band of Yb at the bottom of conduction band. The vibrational parameters of BaDyCuS3, BaHoCuS3 and BaYbCuS3 crystals were determined with the use of Raman and Infrared spectroscopies.

Zirconium gallocyanin MS complex as a highly selective reagent for the spectophotometric determination of fluoride

A new photometric procedure for the determination of fluoride ion based on its destruction of zirconium-gallocyanin MS complex is described.The method exhibits great selectivity towards fluoride compared to alkaline-earth, non-ferrous and rare-earth metals, iron, sulfate, nitrate, and phosphate ions and allows to carry out the determination of fluoride in complex objects complex without a preliminary separation of matrix components. The linear range of the quantitative determination of F− was determined to be 0.03 to 2 mg/L with a detection limit of 0.02 mg/L and a correlation coefficient of 0.9989. This method has been successfully applied to the determination of fluorides in natural waters, metallurgic wastewaters, cryolite and condensates of volcanic gases and has good convergence with the results of potentiometric analysis.

Synthesis of fluorescent terbium-based metal-organic framework for quantitative detection of nitrite and ferric ions in water samples

Through a solvothermal reaction between the corresponding lanthanide(III) nitrate, 1,10 o-phenanthroline and pyridine 3,5-dicarboxylic acid ligands, a novel two-dimensional terbium-based metal-organic framework (Tb-MOF), named {Tb2O0.5(C12H8N2)2(C7H3NO4)3(H2O)2.75}n (1) with strong fluorescence was synthesized by hydrothermal method. The single crystal structure and phase purity of the as-synthesized Tb-MOF were verified by single crystal X-ray diffraction. Subsequently, some studies on the morphology, structure, and optical properties of the compound were carried out. The results show that the synthesized Tb-MOF (1) can be used for the fluorescence sensing of nitrite and ferric ions. Simultaneously, the as-synthesized crystal structure offers good chemical stability in different environments, such as common organic solvents, solutions with a wide pH range, and aqueous solutions of metal ions. Besides, it has good chemical stability in a certain temperature range. In addition, a detection method for nitrite and iron ions was established based on the principle of fluorescence quenching of Tb-MOF by the analytical target, showing good recovery and precision. The proposed method provides a reliable new method for detecting nitrite and ferric ions concentrations in actual water samples.

Preparation of rare earth complexes with curcumin and their stabilization for PVC

La, Nd, Pr, Ce, Eu and Sm complexes with curcumin have been prepared by the reaction of rare earth nitrate with curcumin in alcohol solution. Six complexes have been characterized by FT-IR, 1H NMR, ICP-MS and TG. The results reveal that the structure of complexes is binary complexes, and then the complexes are marked as RE⋅L2. The initial decomposition temperature of RE⋅L2 is above 260°C, much higher than the processing temperature of PVC. These RE⋅L2 are characterized as PVC heat stabilizers for the first time. The effect of RE⋅L2 on the static and dynamic thermal stability of PVC is investigated by Congo red test and torque rheometer. The results show that the static thermal stability time of PVC is higher than 25.1 min, especially that of PVC with Ce⋅L2 is up to 36.3 min. The dynamic thermal stability time of PVC is higher than 15.3 min, especially that of PVC with Nd⋅L2 is up to 22.0 min. The probably thermal stability mechanism of RE⋅L2 for PVC was proposed based on the measurement of FT-IR, Congo red test and torque rheometer. RE⋅L2 could coordinate with Cl and insular or conjugated double bonds on PVC chains. Also, the cross-linked chains through RE⋅L2 might be formed. Consequently, the dehydrochlorination of PVC and oxidative degradation of the insular or conjugated double bonds were relieved.

Peculiarities of transformations in systems of coordination of nitrate precursors of REE and alkali metals during formation of polyfunctional photocatalytically active layered oxide materials

The information on alkaline coordination nitrates of rare-earth elements of the cerium subgroup – precursors of promising modern multifunctional materials – on the conditions of their formation and existence, nature of chemical bonding, composition, structure, shape of Ln coordination polyhedra, type of ligand coordination, existence of isotype series is generalized. on stoichiometry of structure, structure, the found out characteristic properties. The obtained data (as primary information) are the basis for detection, identification, control of the phase state of processing objects in the preparatory stages, selection of compatibility criteria of components in the formation of single-layer and layered nanostructured oxide composite systems of lanthanides and transition elements with catalytic activity and photocatalyst., a coating capable of self-cleaning with hydrophilic properties; development of various combined methods of their activation and establishment of technological and functional dependencies; controlled modification of the properties of the obtained target products. To increase the photocatalytic activity of coating samples based on highly dispersed TiO2 anatase modification, a methodology for chemical modification of oxidation centers in their surface layer with heat treatment in contact with thermolysis products of alkaline coordination nitrates of lanthanides is proposed. The effective test photocatalytic destruction of vapors of organic substrates on the example of ethanol is revealed.

Selective Coordination of Self-Assembled Hexanuclear [Ni4Ln2] and [Ni2Mn2Ln2] (Ln = DyIII, TbIII, and HoIII) Complexes: Stepwise Synthesis, Structures, and Magnetic Properties.

The versatility for a unique aggregation of heterometallic 3d-4f and 3d-3d'-4f ions by the new Schiff base ligand 2-{[(2-hydroxy-3-methoxybenzyl)imino]methyl}phenol (H2L) providing O3N donors has been examined. A series of complexes having the general formula [Ln2Ni4(L)4(μ1,3-CH3CO2)2(μ3-OH)4(MeOH)2]·xCH3OH·yH2O [where Ln = DyIII, x = 4, y = 0 (1), Ln = TbIII, x = 0, y = 4 (2), and Ln = HoIII, x = 4, y = 0 (3)] were obtained from the sequential use of lanthanide(III) nitrate salts and Ni(CH3CO2)2·4H2O. The incorporation of two different 3d ions and one 4f ion in the same coordination aggregate was achieved through the isomorphic replacement of two NiII centers by MnIII ions as second group of cationic complexes, [Ln2Ni2Mn2(L)4(μ1,3-CH3CO2)2(μ3-OH)4(MeOH)2](NO3)2·2CH3OH [where Ln = DyIII (4), TbIII (5), and HoIII (6)]. Direct-current (dc) magnetic susceptibility studies hint to the possibility of ferromagnetic interactions occurring in the aggregates, whereas alternating-current susceptibility measurements find both the DyIII analogues, 1 and 4, to show out-of-phase components at zero applied dc field, characteristic of single-molecule-magnet (SMM) behavior. Micro-SQUID studies reveal open hysteresis loops for 1, corroborating its SMM character. Further detailed complete-active-space self-consistent-field and density functional theory calculations were also performed, supporting the experimental findings in complexes 1 and 4.

The effect of lanthanides on the accumulation of rubber (1,4-Cis-polyizoprene) in Dandelion Crimean-Sagyz (Taraxacum hybernum) Under adverse climate, and its environmental consequences

The stimulating effect of lanthanides on the accumulation of rubber in the roots of dandelion Taraxacum hybernum (Krym-saghyz) was demonstrated along with its environmental consequences. The treatment of Krym-saghyz plants with nitrates of lanthanides led to the increase of poly (cis-1.4-isoprene) concentration by 80% compared to the untreated plants and by 45% compared to those treated with magnesium nitrate. The observed increase of rubber concentration in Krym-saghyz plants has been assumed to be related to the activation of photosynthesis (up to 40%) and the inclusion in the reactions of rubber synthesis of isopentenyl pyrophosphate (IPP) formed from methylerythritol phosphate (MEP) in green plastids.