Neodymium Complexes Research Articles

A simple way to obtain stable mono-decker porphyrin complexes with heavy metal atoms

The article presents data on the development of simple and efficient ways to obtain stable mono-decker complexes of porphyrins with rare-earth elements. Non-metallic porphyrins with halogen atoms as substituents on the periphery of various structures were cleaned and characterized. Further, by reacting the deprotonated forms of the obtained porphyrin-ligands with the acetates of rare-earth elements, mono-decker complexes of neodymium and samarium were synthesized with 5,10,15,20-tetra(trifluoromethyl)porphyrin and 5,10,15,20-tetra (trifluoromethyl)-2,3,7,8,12,13,17,18-octabromoporphyrin, respectively. The significance of converting porphyrin-ligands into anionic form is noted as a key factor in obtaining metal: ligand = 1: 1 structures. The structures of all the compounds obtained were confirmed by IR, NMR spectroscopy, electron absorption spectroscopy, elemental analysis, and mass spectrometry. The spectral and luminescent properties of the compounds were studied. The resulting complexes, potentially, can be used to produce thin films used in electrical engineering.

Organometallic complexes of neodymium: an overview of synthetic methodologies based on coordinating elements

Abstract Organometallic complexes of neodymium have unique coordinating ability to form both micro and macromolecules as well as metal-based polymers. These complexes have been reported in different fields and play a tremendous role in luminescence, catalytic, biological and magnetic applications. So, the current study will comprise all possible routes for the synthesis of organometallic complexes of neodymium. Neodymium complexes have been synthesized of single, double, triple and tetra linkages with H, C, N, O as well as S, B, and X. The detailed synthetic routes have been classified into four categories but in brief, neodymium forms complexes by reacting metal chloride, nitrate or oxide (hydrated or dehydrated) as precursor along with appropriate ligand. Most applied solvents for neodymium complexes were Toluene and THF. These complexes required a range of temperature based on the nature of complexes as well as linkages. The authors have surveyed the research work published through 2011–2020 and provide a comprehensive overview to understand the synthetic routes of organometallic complexes of neodymium.

Studies on the structural and optical properties of pure and structurally modified electrospun poly(methyl methacrylate) nanofibers incorporated with lanthanide complex

ABSTRACT Pure, surface-roughened and coaxial hollow poly(methyl methacrylate) (PMMA) nanofibers are produced through electrospinning. These nanofibers are incorporated with synthesized neodymium β-diketonate complex. Structurally modified PMMA nanofibers show the best host matrix nature to neodymium complex. Neodymium complexes have significant contribution on the optical properties of these fibers with enhanced photoluminescence intensity and blue shift in peaks. The advancements made in the optical and structural properties of pure and structurally modified electrospun PMMA nanofibers are further improved by neodymium complexes. This intensity enhanced pure and structurally modified PMMA nanofibers incorporated with neodymium complex can be used in lasers and optical devices.

SYNTHESIS AND STRUCTURE OF A NEW NEODYMIUM COMPLEX WITH AN UNUSUAL TYPE OF COORDINATION OF THE BENZYL LIGAND

A reaction of $$[{\text{Cp}'''}_{\text{2}}\,\text{NdI}]$$ (1) (Cp′′′ = 1,3,4-tris(tert-butyl)cyclopentadienide) with BzK (Bz = C6H5CH2) in toluene is studied. The result of this reaction was expected to be Bz–substitution for I–, however, it is found that the main reaction product is a new binuclear neodymium complex [(Cp′′′BzNd)2O] (2), containing a bridging oxygen atom. Structures of (1) and (2) are determined by single crystal X-ray diffraction analysis.

Influence of the nature of the substitute on the luminescent properties of β-diketonate complexes of neodyme (III)

There neodymium complexes with new β-diketones (2,7-dimethyl-octene-1-dione-3,5) (dmokd), 2,6-dimethyl-heptene-1-dione-3,5 (dmhpd) Nd (β-dik)3·2H2O were synthesized. Heteroligand complexes with phenanthroline Nd (β-dik)3·Phen were obtained. On the basis of all monomer complexes were obtained homo polymers of the composition [Nd(β-dik)3]n by the method of radical polymerization. It is shown that the emission intensity depends on the nature and geometry of the substituent in the chelate fragment. It is defined that the maximum luminescence intensity is typical for compounds with aryl substitutes for monoligand complexes. For heteroligand complexes, the maximum emission is typical for Nd(dmhpd)3·Phen, which is due to its geometric structure.

Lanthanide Complexes of Bis(tetrazolato)amine: A Route to Lanthanide Nitride Foams.

Metal nitrides are strong refractory ceramic materials known for applications in the coatings, catalysis, and semiconductor industries. Lanthanide nitrides are difficult to prepare in high purity and often require high temperatures and sophisticated equipment. In this work, we present an approach to the synthesis of high-purity f-element nitrides through the use of simple lanthanide salts and the nitrogen-rich ligand 5,5'-bis(1H-tetrazolyl)amine (H2BTA) to form lanthanide complexes of 5,5'-bis(tetrazolato)amine (BTA2-). We have demonstrated that, when dehydrated, these types of complexes undergo a self-sustained combustion reaction under an inert atmosphere to yield nanostructured f-element nitride foams for lanthanum and cerium. The synthesis, characterization, and single-crystal X-ray crystallography of the BTA2- complexes of lanthanum, cerium, praseodymium, neodymium, and europium are also discussed.

Optical properties of organic neodymium complex doped optical waveguides based on the intramolecular energy transfer effect

We report a method of using neodymium complexes as active waveguide core materials to achieve optical gain at the 1060 nm wavelength when using an LED instead of an 808 nm semiconductor laser as the pump source. Through the intramolecular energy transfer mechanism between ligands and Nd3+ ions, the photoluminescence spectrum could be obtained on a 100µm thick film of neodymium complex doped PMMA polymer under excitation of a 380 nm-450 nm LED. We also present calculations showing that the pump power required to generate optical gain (turn-on power) for a LED and 808 nm laser is 3.3 mW and 40 mW, respectively. An optical gain of about 6 dB can be obtained on a 20-mm-long waveguide when pumped by a 25 mW LED compared with that of about 1.4 dB excited by a 60 mW 808 nm semiconductor laser.

Molecular structure and spectroscopic properties of new neodymium complex with 3-bromo-2-chloro-6-picolinic N-oxide showing the ligand-to-metal energy transfer

A new neodymium [Nd(BCPN)3(NO3)3(H2O)2] complex with 3-bromo-2-chloro-6-picolinic N-oxide was synthesized and characterized by means of spectroscopic studies and DFT quantum chemical calculations. The IR, Raman, electron UV-VIS and emission spectra measurements were performed. The femtosecond excitation was used to establish an excited energy level depopulation mechanism. The influence of the halo-groups position on the structural and optical properties of the studied compound was discussed. Ligand-to-metal energy transfer in the studied neodymium complex was analysed.

Highly Cis-1,4 Selective Polymerization of Conjugated Dienes Catalyzed by N-heterocyclic Carbene-ligated Neodymium Complexes

Neodymium complexes containing N-heterocyclic carbene (NHC) ligands, NdCl3[1,3-R2(NCH=)2C:]·THFx(Nd1: R = 2,6-iPr2C6H3, x = 0; Nd2: R = 2,6-Et2C6H3, x = 1; Nd3: R = 2,4,6-Me3C6H2, x = 1) were synthesized and employed as precatalysts for the coordination polymerization of conjugated dienes (butadiene and isoprene). In combination with triisobutylaluminium (TIBA), Nd1 promoted butadiene polymerization to produce extremely high cis-1,4 (up to 99.0%) polybutadienes with high molecular weight (Mw = 250–780 kg·mol−1). The Nd1/TIBA catalytic system also exhibited both high catalytic activity and cis-1,4 selectivity (up to 97.8%) for isoprene polymerization. The catalytic activity, molecular weight and molecular weight distribution of resulting polydienes were directly influenced by Al/Nd molar ratio, aging method, and polymerization temperature. Very interestingly, the high cis-1,4 selectivity of the catalyst towards butadiene and isoprene kept almost unchanged under different reaction conditions. The cis-1,4 polyisoprenes with high molecular weight (Mw = 210–530 kg·mol−1) and narrow molecular weight distribution (Mw/Mn = 1.9–2.7) as well as high cis-1,4 selectivity (~97%) could be synthesized by using the aged Nd1/TIBA catalytic system in the presence of isoprene (100 equivalent to Nd) at low Al/Nd molar ratios of 6–10. Polyisoprenes with low molecular weights (Mw = 12–76 kg·mol−1) and narrow molecular weight distributions (Mw/Mn = 1.7–2.6) were obtained by using Nd2 and Nd3 as precatalysts, indicating that the molecular weight of resulting polyisoprenes can be adjusted by changing the substitutes of ligand in Nd complex.

Peroxide-Templated Assembly of a Trimetal Neodymium Complex Single-Molecule Magnet

In this work, we present a trimetal neodymium complex with two notable qualities. First, the assembly of the complex is templated by peroxide derived from atmospheric oxygen. Second, the bulk material behaves as a superparamagnet, implying that the individual complexes are molecular magnets. Peroxide-templated assembly is possible because of the confluence of the high oxophilicity of neodymium along with the use of an azeotropic distillation synthesis method, which excludes water but admits oxygen. SQUID magnetometry measurements show an extremely high magnetic susceptibility as well as a lack of remanence.

Luminescent Properties of Mixed-Ligand Neodymium β-Diketonates Obtained in Supercritical Carbon Dioxide in Polymer Matrices of Various Nature

Diverse-ligand phosphor complexes of neodymium acetylacetonate with phenanthroline have been synthesized in polymer matrices (oligourethanmethacrylate, fluoroplast, and polycarbonate) in the medium of supercritical carbon dioxide, while the role of one of the ligands in such complexes is performed by the polymer matrix fragments. The luminescence spectra of the obtained triple systems have been described and it has been shown that the position of the luminescence maxima is bathochromically shifted relative to the Nd(Acac)3/polymer double systems obtained in a similar way and the shift magnitude depends on the polymer matrix nature. It has been shown that when these components are introduced into polymers from a solution, such phosphor diverse-ligand neodymium complexes are not formed. The formation of new Nd(Acac)3/1,10-phenanthroline/polymer structures at the impregnation of oligourethane methacrylate by neodymium β-diketonate and phenanthroline in the supercritical CO2, which are not formed by the introduction of these components from solution, has been confirmed by differential thermal analysis.

Synthesis and Properties of Heteroligand Sandwich Complexes of Lantanides Containing 5-(Quinolin-2-yl)tetrabenzoporphyrin and Phthalocyanine Chromophores

The reaction of phthalimide with zinc acetate gave a previously unknown three-unit condensation product 3-[(E,Z)-{(E,Z)-3-[(1-hydroxy-1-methyl-1H-isoindol-3-yl)methylene]isoindolin-1-ylidene}methyl]-1H-isoindol-1-one. Heating the latter with 2-methylquinoline and zinc oxide followed by treatment with sulfuric acid resulted in the synthesis of 5-(quinoline-2-yl)tetrabenzoporphyrin, which was used to synthesize heteroligand sandwich complexes of lanthanum, neodymium, gadolinium, erbium, and lutetium, containing a phthalocyanine fragment. The spectral properties and thermal stability of the sandwich complexes linearly depend on the ionic radii of the metals. The synthesized complexes are more sensitive to oxidation than lanthanide diphthalocyaninates.

PECULIARITIES OF STRUCTURE AND SPECTRAL-LUMINESCENT PROPERTIES OF CARBOXYMETHOXY-SUBSTITUTED CALIX[4]ARENES AND THEIR COMPLEXES WITH LANTHANIDES

Spectral-luminescent properties of a variety of carboxymethoxy-substituted p-tert-butyl-calix[4]arenes and their complexes with lanthanides (Nd, Er, Yb) that exhibit the 4f-luminescence in the IR-spectrum region have been investigated. The effect of substitution of hydrogen phenolic atoms by carboxymethoxy groups on the stability and spectral-luminescent characteristics of both the ligands and lanthanide complexes was analyzed. Thus, based on the combination of the results obtained by means of elemental analysis, mass spectrometry, IR and 1H NMR spectroscopy, and taking into account the data of pH-metric titration, spectrophotometric and luminescence measurements, it can be concluded that lanthanide ions form neutral complexes of 1:1 ratio with L1H4 - L4H4. This is explained by the presence of mobile hydrogen atoms of phenol and/or carboxyl groups in the molecules of these ligands. An increase in the number of donor substituents leads to changes in the number of solvent molecules in the series L3H4 < L1H4 < L2H4 < L4H4 from 0.8 to 2.4 for neodymium complexes, from 1.2 to 2.2 - for ytterbium complexes. Both the quantum yield and lifetime of the 4f-luminescence of the neodymium and ytterbium complexes and also the luminescence intensity of the erbium-containing compounds change in the same order.

Lanthanum(III) and neodymium(III) complexes with anti-inflammatory drug sulindac: Synthesis, characterization, thermal investigation using coupled techniques TG-FTIR, and in vitro biological studies

New lanthanum(III) and neodymium(III) complexes with the anti-inflammatory drug sulindac (Sul) were synthesized and characterized, and their biological activity was evaluated in vitro. The general formula [Ln(Sul)3]∙nH2O for these complexes was proposed based on thermogravimetry, differential scanning calorimetry, elemental analysis, and complexometric titration using EDTA results. 1H and 13C NMR combined with FTIR data results suggested that the carboxylate groups of all three sulindac molecules are coordinated to the metal ions in a bidentate chelate fashion, with no water molecules (OH2) nor sulfinyl groups (SO) coordinated to the metal center. During thermal decomposition of these complexes, the formation of lanthanide oxyfluorides LaOF and NdO1-xF1+2x, was observed and confirmed by powder X-ray diffraction. TG-FTIR coupled techniques were employed to evaluate volatiles released during thermal decomposition of these complexes and compared with the decomposition pattern of the free sulindac, interestingly providing valuable information about the thermosynthesis of the oxyfluorides as well as the coordination modes of sulindac in the complex. Additionally, cell viability and anti-inflammatory assays were performed with human cells to evaluate the in vitro effect of [Ln(Sul)3]∙nH2O.

Люминесцентные свойства разнолигандных beta-дикетонатов неодима, полученных в среде сверхкритического диоксида углерода в полимерных матрицах различной природы

Multi-ligand phosphor complexes of neodymium acetylacetonate with phenanthroline are synthesized in polymer matrices (oligourethane methacrylate, fluoroplast, polycarbonate) in supercritical carbon dioxide medium. At the same time the role of one of the ligands in such complexes is played by fragments of the polymer matrix. The luminescence spectra of the obtained ternary systems are described. It was shown that the position of the luminescence maxima is bathochromically shifted relative to the binary systems Nd(Acac)3/polymer obtained in a similar way and the magnitude of the shift depends on the nature of the polymer matrix. It was shown that upon the introduction of these components into polymers from a solution, similar phosphor mixed-ligand neodymium complexes do not form. The formation of new structures Nd(Acac)3/Phen/polymer upon impregnation of oligourethane methacrylate with neodymium β-diketonate and phenanthroline in a supercritical CO2 medium was confirmed by the method of differential thermal analysis. The same method confirmed that with the introduction of these components from the solution of the above systems do not form.

Bright neodymium complexes for efficient near infra-red organic light emitting diodes

This paper reports the synthesis, structures, and photophysical and electroluminescence properties of low symmetry NIR emitting octa- and nona-coordinate Nd tris β-diketonate complexes.

Rare‐Earth Amido and Borohydrido Complexes Supported by Tetradentate Amidinate Ligands: Synthesis, Structure, and Catalytic Activity in Polymerization of Cyclic Esters

Amido [ButC(NC6H4‐2‐OMe)2]2LnN(SiMe3)2 (Ln = Y (3), Nd (4)) and borohydrido complexes [ButC(NC6H4‐2‐OMe)2]2LnBH4 (Ln = Y (5), Nd (6)) coordinated by new amidinate ligand bearing two pendant anisolyl groups are synthesized. According to X‐ray analysis in complexes 3 and 4 one amidinate ligand is coordinated to the Ln3+ cation in a bidentate fashion (κ2‐NN), while the second one is tetradentate (κ4‐NNOO). At the same time in borohydrido neodymium complex 6 the amidinate ligands demonstrate κ4‐NNOO and κ3‐NNO coordination modes. Complexes 3–6 proved to be efficient initiators for ring‐opening polymerization of rac‐lactide and allow for achieving quantitative conversion of 500 equivalents of monomer into polymer in 0.3–4.5 h at 25 °C. The polymerization of ε‐caprolactone initiated by 3–6 proceeds much faster under similar conditions.

Neodymium immobilized on Fe3O4: A new and recoverable catalyst for oxidation reactions and synthesis of 5‐substituted 1H-tetrazoles in green condition

Magnetic nanoparticle functionalized with neodymium complex as catalyst and characterized by SEM, XRD, FT-IR, TGA, EDX and ICP techniques. Then, catalytic activity of prepared catalyst was examined in the synthesis of tetrezoles and oxidation reactions in which observed short reaction time and high yield in these reactions.

Enhanced near-infrared electroluminescence from a neodymium complex in organic light-emitting diodes with a solution-processed exciplex host

We report enhanced near-infrared (NIR) electroluminescence from a Nd3+-complex with thenoyltrifluoroacetone and 1,10-phenanthroline ligands. The NIR-emitting complex was blended into an exciplex-forming co-host system comprising 2,7-bis(diphenylphosphoryl)-9,9′-spirobifluorene as the electron transport material and 4,4′,4″-tris(carbazol-9-yl)triphenylamine as the hole transport material in solution-processed small molecule organic light-emitting diodes (OLEDs). This binary ambipolar host system favors direct charge trapping and exciton formation on the Nd3+-complex molecules. Efficient energy transfer from the singlet and triplet exciplexes formed between the host molecules to the Nd3+ ions contributes to the enhanced luminescence efficiency. The photoluminescence quantum yield of this blend is 1.2%, and the optimized OLED shows a maximum electroluminescence external quantum efficiency of 0.034%. The device also exhibits a low efficiency roll-off of only 12% over a current density range of 100 mA/cm2, due to the reduced triplet-polaron annihilation.

Crystal Structure and Thermoanalytical Study of Neodymium(III) Complex with 2,4′-Bipyridyne

A novel neodymium(III) chloride complex with 2,4′-bipyridine (bpy), (bpyH)[Nd(H2O)9]Cl4·bpy·H2O is synthesized, crystallized, and characterized by single crystal X-ray diffraction and thermal analysis. The crystal is nine-coordinate homoleptic mononuclear aqua complex and crystallizes in the triclinic P-1 space group with two formula units in the unit cell related by a pseudo-translation of b/2. In the crystal structure, each [Nd(H2O)9]3+ ion is hydrogen bonded in the same way to one 2,4′-bipyridine molecule, one 2,4-bipyridinium cation, and chloride anions. Lattice water molecules form hydrogen bonds which further stabilize the framework. The thermal properties of the compound in the solid state are studied using TG-DTG techniques under the dynamic flowing air atmosphere.