Neodymium Complexes Research Articles

Electronic Structure of a Neodymium(III) Tris(oxidiacetate) Complex from Luminescence Data and Ab Initio Calculations.

Neodymium(III) is a near-infrared emissive and magnetic ion, which has found use in various high-technology applications. Yet, accurate predictions of the luminescent and magnetic properties of neodymium(III) based on the coordination environment remain to be done. Guidelines exist, but to build structure-property relationships for this element, more data are needed. Herein, we present a high-symmetry starting point. The tris(oxidiacetate) complex of neodymium(III) was prepared and crystallized, and access to the experimentally determined structure allowed us to quantify the symmetry of the compound and to perform calculations directly on the same structure that is investigated experimentally. The luminescent properties were determined and the electronic structure was computed using state-of-the-art ab initio methods. All electronic transitions in the range from 490 to 1400 nm were mapped experimentally. Using a Boltzmann population analysis, the combination of the excitation and emission spectra revealed the crystal field splitting of the 18 lowest-energy Kramers levels that experimentally could be unambiguously resolved. This assignment was supported by ab initio calculations, and the crystal field splitting was well reproduced. The electronic structure reported for the tris(oxidiacetate) complex was used to deduce the coordination structure in aqueous solution. Finally, the results are compared to empirical trends in the literature for the electronic structure of neodymium(III).

Antitumor neodymium(III) complex with 1,10-phenanthroline and nitrate ligands: A comprehensive experimental-theoretical study, in silico pharmacokinetic and cytotoxic properties

Here we report the crystallization of the tris(nitrate-O,O')-bis(1,10-phenanthroline-N,N')-neodymium(III) complex by the slow solvent evaporation method. Structural, electronic, thermal, and vibrational properties have been explored and discussed. Additionally, all vibrational modes were carefully assigned, and geometric parameters and chemical reactivity indices were obtained from the results of density functional theory (DFT) calculations including solvation effects in dimethylformamide and water, as well as in vacuum. Moreover, a computational study using Hirshfeld surfaces identified and quantified the intermolecular interactions that stabilize the crystal lattice. X-ray powder diffraction results showed that the system has monoclinic symmetry with C2/c-space group and four monomers per unit cell (Z = 4). The thermoanalytical measurements revealed that the material has high thermal stability (≈ 300°C) and the experimental Raman and FT-IR spectroscopic data showed good correlation with the spectra calculated via DFT, where it was confirmed the influence of the solvents on the structure of the complex. Finally, cell viability assays showed that the neodymium(III) complex has cytotoxic activity and selectivity against MCF-7 (breast) and SiHa (cervical) cancer cells, with a potent biological effect. Complementary, a computational study of the pharmacokinetic profile was performed to support the experimental biological data via absorption, distribution, metabolism and elimination (ADME), and druglikeness.

Retraction: Studying the interaction between the new neodymium (Nd) complex with the ligand of 1,10-phenanthroline with FS-DNA and BSA.

[This retracts the article DOI: 10.3389/fchem.2023.1208503.].

Temperature Induced Reversible Switching of the Magnetic Anisotropy in a Neodymium Complex Adsorbed on Graphite.

Controlling the magnetic anisotropy of molecular layers assembled on a surface is one of the challenges that needs to be addressed to create the next-generation spintronic devices. Recently, metal complexes that show a reversible solid-state switch of their magnetic anisotropy in response to physical stimuli, such as temperature and magnetic field, have been discovered. The complex Nd(trensal) (H3trensal=2,2',2''-tris(salicylideneimino)triethylamine) is predicted to exhibit such property. An ultra-thin film of Nd(trensal) is deposited on highly ordered pyrolytic graphite as a proof-of-concept system to show that this property can be retained at the nanoscale on a layered material. By combining single crystal magnetometric measurements and synchrotron X-ray-based absorption techniques, supported by multiplet ligand field simulations based on the trigonal crystal field surrounding the lanthanide centre, it is demonstrated that changing the temperature reverses the magnetic anisotropy of an ordered film of Nd(trensal), thus opening significant perspectives for the realization of a novel family of temperature-controlled molecular spintronic devices.

Near‐Infrared and Visible Dual‐Emitting Peptide by Modular Assembly of Nitrobenzoxadiazole and Neodymium Complexes

AbstractThe synthetic difficulty of target‐specific lanthanide complexes, despite their unique characteristics, limits their use in in vitro/ in vivo studies and biomedical applications. With commercially available and affordable reagents, a facile synthetic approach is developed to modularly deploy nitrobenzoxadiazole and neodymium complexes onto bioactive peptides. The yielded probes show observable neodymium emission with specific localization to corresponding biotargets in vitro, which became the first example of a stable, water‐soluble, and target‐specific neodymium(III) complex applicable for in vitro imaging with detectable brightness.

Photophysical and optoelectronic studies of 1.06 and 13.3 μm emissive neodymium complexes

This paper presents the synthesis, thorough characterizations, and near-infrared (NIR) photophysical and optoelectronic properties of four original ternary neodymium complexes, [Nd(hth)3(L)x] (x = 1 or 2).

A new neodymium complex on renewable magnetic biochar nanoparticles as an environmentally friendly, recyclable and efficient nanocatalyst in the homoselective synthesis of tetrazoles.

Inexpensive, stable, selective, and recyclable nanocatalysts, waste regeneration, and utilization of safe and available solvents are of interest and important factors in laboratory science and industrial applications of green chemistry. Therefore, herein, biochar nanoparticles (BNPs) were synthesized through chicken manure pyrolysis as a novel method for waste recycling. Then, in order to improve their recyclability, the obtained BNPs were magnetized using magnetic nickel nanoparticles. Then, the surface of the biochar magnetic nanoparticles (BMNPs) was modified by (3-chloropropyl)trimethoxysilane (3-CPTMS) and further a novel neodymium Schiff-base complex was immobilized on the surface of the modified BMNPs, denoted as Nd-Schiff-base@BMNPs. The obtained supported neodymium complex was used as a practical, selective, biocompatible, commercial, and reusable heterogeneous nanocatalyst. The biochar support of this nanocatalyst was formed from pyrolysis of chicken manure; therefore, it is cheap, economically viable, green and also compatible with the principles of green chemistry. Nd-Schiff-base@BMNPs acts selectively in organic reactions and also it can easily be recovered using an external magnet and reused, which is compatible with the principles of green chemistry. This nanocatalyst was characterized by wavelength-dispersive X-ray spectroscopy (WDX), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma (ICP), and N2 adsorption-desorption (BET method) techniques. In the next step, the catalytic utilization of Nd-Schiff-base@BMNPs was investigated in the homoselective synthesis of 5-substituted 1H-tetrazole compounds from [3 + 2] cycloaddition of sodium azide (NaN3) and organo-nitriles in PEG-400 as a green solvent. Utilizing PEG-400 as a solvent offers various advantages, e.g. cheap, readily available, and environmentally friendly solvent as well as rapid separation and high purity of products. Therefore, this work is fully compatible with the principles of green chemistry.

Synthesis and Characterization of Borohydride Rare-Earth Complexes Supported by 2-PyridinemethanAmido Ligands and their Application towards Ring-Opening Polymerization of Cyclic Esters

The synthesis of 2-pyridinemethanamido borohydride complexes of yttrium and neodymium was achieved through the in situ deprotonation of the protio-ligand 2-pyridinemethanamine C5H3R1N-C(CH3)R2-NH(2,6-iPr2C6H3), noted as PyAH (with PyAH1: R1 = R2...

Synthesis of stereoregular polymyrcenes using neodymium-, iron- and copper-based catalysts

β-Myrcene was polymerized with catalysts based on pyridyl-imino complexes of neodymium, iron and copper to highly stereoregular polymers.

Neodymium Complex with a Scorpionate Phosphoryl Pyridyl Ligand: Structure in Crystal and in Solution

Neodymium Complex with a Scorpionate Phosphoryl Pyridyl Ligand: Structure in Crystal and in Solution

Synthesis, crystal structure and Hirshfeld surface analysis of the tetra-kis complex NaNdPyr4(i-PrOH)2·i-PrOH with a carbacyl-amido-phosphate of the amide type.

The tetra-kis complex of neodymium(III), tetra-kis-{μ-N-[bis-(pyrrolidin-1-yl)phos-phor-yl]acet-am-id-ato}bis(pro-pan-2-ol)neodymiumsodium pro-pan-2-ol monosol-vate, [NaNd(C10H16Cl3N3O2)4(C3H8O)2]·C3H8O or NaNdPyr4(i-PrOH)2·i-PrOH, with the amide type CAPh ligand bis(N,N-tetra-methylene)(tri-chloro-acetyl)phos-phoric acid tri-amide (HPyr), has been synthesized, crystallized and characterized by X-ray diffraction. The complex does not have the tetra-kis-(CAPh)lanthanide anion, which is typical for ester-type CAPh-based coordin-ation compounds. Instead, the NdO8 polyhedron is formed by one oxygen atom of a 2-propanol mol-ecule and seven oxygen atoms of CAPh ligands in the title compound. Three CAPh ligands are coordinated in a bidentate chelating manner to the NdIII ion and simultaneously binding the sodium cation by μ2-bridging PO and CO groups while the fourth CAPh ligand is coordinated to the sodium cation in a bidentate chelating manner and, due to the μ2-bridging function of the PO group, also binds the neodymium ion.

СOMPLEXES OF Nd(III) AND 3d-METALS BASED ON ETHYLENEDIAMINEDISUCCINIC ACID AS POTENTIAL ANTIFUNGAL AGENTS

Neodymium heterometallic complexes [(NdМIIEDDS)(H2O)6]∙n2H2O (МII=Zn, Co; n = 3; 2) were synthesized by the «block» synthesis method using protonated ethylenediaminedisuccinate of the 3-d metal and NdIII nitrate. The complexes were characterized by spectroscopic methods (UV-VIS electronic absorption spectroscopy and FT-IR) and elemental ana­lysis. It is shown that the f-d-complexes belong to the «folded» type complexes, in which the ligand-EDDS realizes the maximum dentateness to NdIII, and the coordination sphere of the 3-d cation is formed by chain carboxyl groups of EDDS and intraspherical water molecules. At the same time, the cations of 3d metals are in a distorted octahedral environment, and the coordination polyhedron of the neodymium ion corresponds to a square antiprism (C4v) with the coordination number NdIII = 8. In solutions and in the solid state, the complexes have the same type of structure. The sensitivity of various morphological forms of Candida albicans in Spider and Saburo media to neodymium complexes NdIII with ethylene diamine disuccinate: NdEDDS (I), NdEDDSZn (II) NdEDDSСo (III) in the range of concentrations of the studied compounds 1; 10 and 100 μM was studied. It is shown that the antifungal properties of the complexes vary in the range NdEDDSСo> NdEDDSZn ≥ NdEDDS. The inhibition index of C. albicans in the composition of the biofilm in the Saburo medium under the action of the complexes was 20–25% of the control value, and in the Spider medium the complexes led to 95% of cell death.

STRUCTURE OF MOLTEN MX–NdX<sub>3</sub> (M – Na, K, Rb, Cs; X – F, Cl) SALTS: AN <i>ab initio</i> STUDY

The paper presents an ab initio study of neodymium containing clusters modeling the structure of corresponding molten salts. The relevance of such study is dictated by development of new methodologies and technologies for processing electronic and magnetic wastes, which are a valuable source of rare earth metals. In turn, quantum chemical calculations provide a powerful tool for investigation of structural features of model systems mimicking high temperature molten salts. In the present study, the simulations are performed within the Hartree–Fock and density functional theory approaches using the Firefly 8.20 software package. We propose a methodology for calculation of interaction energies in ternary systems including the neodymium complex, the outer-sphere cation shell, and the rest of the cluster. The interaction energies between the neodymium complex and other parts of a system are calculated. The dependence of interaction energies on the number of outer-sphere cations is investigated and the most stable “neodymium complex + outer-sphere shell” structures are determined. The calculated data are compared to direct spectroscopic investigations available in literature. The obtained interatomic Nd–X (X – F, Cl) distances coincide with experimentally deduced values. The computed Raman spectra for the 18MCl + M3NdCl6 (M – Na, K, Rb, Cs) model systems demonstrate a good agreement between calculated and experimentally observed positions of the most intense peak. Therefore, the chosen systems provide a reliable minimalistic model for quantum chemical investigations of molten salts structure.

Studying the interaction between the new neodymium (Nd) complex with the ligand of 1,10-phenanthroline with FS-DNA and BSA.

To learn more about the chemotherapeutic and pharmacokinetic properties of a neodymium complex containing 1,10-phenanthroline (dafone), In vitro binding was investigated with bovine serum albumin and fish-salmon DNA, using a variety of molecular modeling research and biophysical approaches. A variety of spectroscopic techniques including fluorescence and absorption were used to investigate the interplay between DNA/BSA and the neodymium complex. The findings revealed that the Nd complex had a high affinity for BSA and DNA interplays through van der Waals powers. In addition, the binding of the Nd complex to FS-DNA mainly in the groove binding mode clearly reflects with iodide quenching studies, ethidium bromide (EtBr) exclusion assay, ionic strength effect, and viscosity studies. It was observed that the Nd complex binds to FS-DNA through a minor groove with 3.81 × 105(M-1). Also, Kb for BSA at 298K was 5.19×105(M-1), indicating a relatively high affinity of the Nd complex for DNA and BSA. In addition, a competitive study of a docking investigation revealed that the neodymium complex interacts at BSA site III. The results obtained from the binding calculations are well consistent with the experimental findings. Also, cytotoxicity studies of Nd complex were performed in MCF-7 and A-549 cell lines and the results show that this new complex has a selective inhibitory effect on the growth of various cancer cells.

Dual function of new Nd(III) and Gd(III) complexes for cytotoxic and optoelectronic fields: Synthesis, characterization, DFT calculations, and PVA composite films

New two lanthanide complexes of Neodymium (III) and Gadolinium (III) ions were prepared based on 2‐Cyano‐N′‐([4‐oxo‐4H‐chromen‐3‐yl]methylene) acetohydrazide as a chelating agent. The prepared Nd(III) and Gd(III) complexes were characterized via elemental analysis, molecular conductance, IR, and TGA. The obtained results showed the chelating agent behaves as tridentate via oxygen of γ pyrone and carbonyl groups and nitrogen of the azomethine group. The antitumor activity of isolated complexes was investigated against the Ehrlich Ascites Carcinoma cell line (E.A.C). The results of antitumor activity cleared that Gd(III) complex has higher activity than Nd(III) complex and moderate activity relative to cisplatin and 5‐Furacil. Besides, DFT calculations were estimated for prepared Nd(III) and Gd(III) complexes by the Gaussian program. Theoretical parameters were calculated. The energy gap values confirmed the higher activity of the Gd(III) complex over the other Nd(III) complex. In addition, the composite films of Nd(III) and Gd(III) complexes were prepared using the cast technique. The electrical and optical absorption properties of these polymer composites were analyzed.

A New Neodymium Complex on Boehmite Nanoparticles with 1,3‐Bis(pyridine‐3‐ylmethyl)thiourea as a Practical and Reusable Nanocatalyst for the Chemoselective Synthesis of Tetrazoles

AbstractIn first part, boehmite nanoparticles were synthesized using aqueous solutions of NaOH and Al(NO3)3 ⋅ 9H2O. Then, it surface was modified by 3‐choloropropyltrimtoxysilane, and further 1,3‐bis(pyridin‐3‐ylmethyl)thiourea was anchored on the modified boehmite nanoparticles. In the final step, a neodymium complex was stabilized on its surface (Nd‐bis(PYT)@boehmite NPs). The obtained nanoparticles were characterized by TGA, BET, ICP, EDS, WDX, SEM, and XRD techniques. In the second part, Nd‐bis(PYT)@boehmite NPs were employed as an efficient, recoverable, and organic‐inorganic hybrid nanocatalyst in the homo‐selective synthesis of tetrazole compounds. The chemoselectivity of Nd‐bis(PYT)@boehmite NPs was studied in the [3+2] cycloaddition of phthalonitrile and sodium azide (NaN3). This catalyst is stable and has heterogeneous nature therefore it can be recovered and used again for several consecutively run without any re‐activation

Electronic Structure of Neodymium(III) and Europium(III) Resolved in Solution Using High-Resolution Optical Spectroscopy and Population Analysis.

Solution chemistry of the lanthanide(III) ions is unexplored and relevant: extraction and recycling processes exclusively operate in solution, MRI is a solution-phase method, and bioassays are done in solution. However, the molecular structure of the lanthanide(III) ions in solution is poorly described, especially for the near-IR (NIR)-emitting lanthanides, as these are difficult to investigate using optical tools, which has limited the availability of experimental data. Here we report a custom-built spectrometer dedicated to investigation of lanthanide(III) luminescence in the NIR region. Absorption, luminescence excitation, and luminescence spectra of five complexes of europium(III) and neodymium(III) were acquired. The obtained spectra display high spectral resolution and high signal-to-noise ratios. Using the high-quality data, a method for determining the electronic structure for the thermal ground states and emitting states is proposed. It combines Boltzmann distributions with population analysis and uses the experimentally determined relative transition probabilities from both excitation and emission data. The method was tested on the five europium(III) complexes and was used to resolve the electronic structures of the ground state and the emitting state of neodymium(III) in five different solution complexes. This is the first step toward correlating optical spectra with chemical structure in solution for NIR-emitting lanthanide complexes.

CHARACTERIZATION OF BIS-SALICYLALDEHYDE O-PHENYLENEDIAMINE SCHIFF BASE AND ITS DY(III), GD(III), ND(III) AND SM(III) LANTHANOIDS COMPLEXES

Schiff bases have versatile chemical properties and numerous utilities in various industries consequent of their excellent coordination ability with numerous metal ions especially transition metals. To further exploit the chemical versatility of this promising compound, we thoroughly characterize the aged long synthesized Schiff base; Bis-salicylaldehyde o-phenylenediamine (Salphen) and its Lanthanoid (III) complexes of Neodymium, Samarium, Gadolinium and Dysprosium using solubility test, melting and decomposition analysis, FTIR, Uv-visible spectroscopy, conductivity measurement, elemental analysis, magnetic susceptibility and NMR. The Salphen ligand was soluble in chloroform and carbon tetra chloride among others while its complexes were not soluble in most common organic solvents tested. The melting point of Salphen was 1650C while its Lanthanoid (III) complexes decompose in the range of 210-2410C. The FTIR spectral patterns analysis of the ligand and its complexes conforms to fundamental vibration modes within the structure. Salphen and its Lanthanoid (III) complexes had low conductivity and were paramagnetic, non-hygroscopic and formed binuclear bridged structure with Metal: Ligand ratios of 2: 3. Series of characterization undertaken confirmed the formation of the bridged structured complex between Salphen and Lanthanoid (III) ions with high thermal stabilities, insolubility in most common organic solvents and poor electric conductance.

Novel neodymium complex on MCM‐41 magnetic nanocomposite as a practical, selective, and returnable nanocatalyst in the synthesis of tetrazoles with antifungal properties in agricultural

This project reports a simple procedure for the synthesis and characterization of neodymium on MCM‐41 magnetic nanoparticles (MNPs) as a reusable nanocatalyst. First, magnetite (Fe3O4) MNPs were prepared by chemical co‐precipitation procedure from FeCl3 hexahydrate and FeCl2 tetrahydrate in basic NH3 solution. At the second step, MCM‐41 magnetic nanocomposite (MCM‐41 MNC) was prepared by Fe3O4 doping into mesoporous MCM‐41 channels. At the third step, a novel neodymium Schiff base complex was immobilized on MCM‐41 MNC. At the fourth step, this catalyst (Nd‐LArg‐5BrSalen@MNC) was used as practicable and magnetically recoverable nanocatalyst in the homoselective synthesis of tetrazoles. This nanocatalyst was characterized via several analysis, for example, TGA, TEM, UV, SEM, FT‐IR, SEM‐EDS, VSM, ICP, XRD, WDX, and BET. All tetrazole products were synthesized with high yield in a short time. Despite high catalytic activity of neodymium, it has rarely used as a catalyst in the synthesis of organic compounds. All synthesized organic compounds were identified by 1H NMR, FT‐IR, and physical properties. Nd‐LArg‐5BrSalen@MNC nanocatalyst displays high activity, good selectivity, stability, and more important facile magnetic separation. Nd‐LArg‐5BrSalen@MNC nanocatalyst can be isolated and used again for several times consecutively without considerable loss of its catalytic activity. The recycled catalyst was characterized by SEM, EDS, WDX, XRD, and FT‐IR techniques and showed a good match with the fresh catalyst. Also, the antifungal activity of the some tetrazole derivatives was studied against Fusarium oxysporum (rot disease of chickpea root) and Botrytis cinerea (gray mold of strawberry) using the paper disk method on PDA culture medium.

Random copolymerization of trimethylene carbonate with L-lactide initiated by amine-bridged bis(phenolate) neodymium alkoxides.

Random copolymerization of trimethylene carbonate (TMC) with L-lactide (LA) under mild conditions is a challenging task in polymer synthesis. Two amino-bridged bis(phenolate) neodymium complexes were synthesized and employed as efficient initiators for the copolymerization of TMC and L-LA under mild conditions to give random copolymers. NMR monitoring experiments of the chain microstructure versus polymerization time confirmed that a TMC/LA random copolymer was generated by a random copolymerization.