Sm Complexes Research Articles

Electronic structure and optical properties of Sm(III) and Eu(III) complexes with hexamethylphosphoramide

Nitrate complexes Ln(NO3)3 of Sm(III) and Eu(III) lanthanides with three neutral ligands HMPA (OP(NMe2)3) possessing triboluminescent properties were studied by X-ray photoelectron spectroscopy (XPS MgKα) and quantum chemistry (DFT/TDDFT). Interpretation of the bands of XPS spectra of the valence levels and core levels was carried out using the calculated energies and localization of the Kohn-Sham orbitals. Using the DFT/TDDFT methods the influence of HMPA molecules on the electronic structure of lanthanide ion nitrate complexes was studied and the electronic effects of adduct formation are described. The nature of the bond of nitrate complexes with neutral molecules was revealed. The binding energy of Ln(NO3)3 (Ln = Sm, Eu) with three HMPA molecules was determined theoretically (Sm(NO3)3(HMPA)3–5.17 eV, Eu(NO3)3(HMPA)3–4.11 eV). The relationship of the electronic structure with the absorption and excitation spectra, optical characteristics and its role in reducing the probability of the energy transfer from ligands to metal within the LMCT (ligand-to-metal charge-transfer) model is shown. The experimental and theoretical absorption spectra were obtained for the studied adducts possessing promising solubility properties in water. Prospects of further research of the intermolecular layers are shown for the crystals under study.

The selective colorimetric probe based on a macrocyclic Sm(III) complex for detecting lithium ion and its performance in the psychiatric drug

Herein a 23-membered macrocyclic mononuclear Sm(III) complex Sm-2f has been designed and synthesized via the Schiff-base cyclocondensation between extended dialdehyde H2Qf and 1,2-bis(2-aminoethoxy)ethane in the presence of Sm(NO3)3. The analyses of single-crystal structure reveal that central ten-coordinate Sm(III) ion is capsulated by the macrocyclic cavity microenvironment forming the “lasso-type” protection. The sensing ability of complex Sm-2f is also carefully evaluated for four alkali metal ions in mixture of methanol and water. Interestingly, this complex could serve as a colorimetric molecular probe and selectively recognize Li(I) ion in solution, easily distinguished by naked eye, whether or not other alkali metal ions are present, which is derived from the formation of a new species containing a probe molecule and one Li(I) ion. The limit of detection for Li(I) ion is calculated as 1.147 mM determined by UV–vis titration experiments, and the sensing process is rapid within 60 s. Moreover, this probe also shows satisfactory performances for determining Li(I) ion content in the psychosis drug. The special architecture in macrocyclic complex Sm-2f as well as the combination of size and electronic effects of Li(I) ion are believed to play important roles for this convenient method of sensing Li(I) ions in solution.

Activity of Fluorescent Samarium Complex Containing 1,10 Phenanthroline Ligand against Human T-Cell Acute Lymphoblastic Leukaemia Cell Line

This paper is the study of the structure effect of samarium-phenanthroline complex on DNA molecule binding for cancer treatment. So the water soluble complex has been synthesized and characterized by using chemical analysis. By positive cooperative interaction, Sm complex was connected with calf thymus DNA (ct-DNA) and this interaction was investigated by circular dichroism and fluorescence spectroscopy. The result indicates that samarium complex with phenanthroline ligands can be as a fluorescence probe and intercalate in DNA additionally groove binding. Also, the cytotoxicity of this complex was investigated against human T-cell acute lymphoblastic leukemia, MOLT-4 cell line. Finally, the interaction of complex was studied by molecular docking. The results showed during DNA-Sm complex formation, the complex is surrounded by DT8, DC9, DG10, DA18, DT19 and DT20 via hydrophobic forces.

Series of Highly Luminescent Macrocyclic Sm(III) Complexes: Functional Group Modifications Together with Luminescence Performances in Solid-State, Solution, and Doped Poly(methylmethacrylate) Film.

Here, we report our trials to regulate the luminescence performance of the macrocyclic samarium(III) complex and prepare four excellent luminescent Sm(III) complex-doped poly(methylmethacrylate) (PMMA) composites. Four 23-membered [1 + 1] Schiff-base macrocyclic mononuclear Sm(III) complexes, Sm-2a–Sm-2d, originating from dialdehydes with different pendant arms and 1,2-bis(2-aminoethoxy)ethane, have been constructed by the template method. Crystal structures reveal that every Sm(III) ion with the coordination geometry of a distorted bicapped square antiprism is capsulated by the macrocyclic cavity environment forming the “lasso-type” protection. Relative photophysical properties of macrocyclic Sm(III) complexes are carefully investigated in solid-state, methanol solution, and doped PMMA film, and all these show characteristic emissions of the Sm(III) ion associated with satisfactory lifetimes and quantum yields in all media, which could be comparable to reported outstanding examples. Especially, the luminescence performance for this type of Sm(III) complex could be regulated in the solid state by the use of different functional groups in the pendant arm while it is not achieved in solution and the doped PMMA composite. High emitting and air-stable plastic materials could be obtained when these Sm(III) complexes are doped in PMMA with 0.1 wt % mixing ratio, and the corresponding maximum lifetime and quantum yield are 61.2 μs and 0.63% in the case of complex Sm-2a, respectively. We believe that these highly luminescent “lasso-type” Sm(III) complexes and doped PMMA composites are valuable references in the design of luminescent lanthanide(III) hybrid materials.

Yb(III), Sm(III) and La(III) complexes of a tetradentate pyridoxal Schiff base ligand: Their DNA-binding activity and bio-imaging applications

Yb(III), Sm(III) and La(III) complexes of a tetradentate Schiff base ligand, bis(pyridoxylidene)ethyelenediamine, are reported. Single crystal X-ray structures of the complexes reveal that in all the three complexes the Ln(III) ions are in a distorted dodecahedral geometry with N4O4-coordination environment provided by two coordinated ligands. Fluorescence spectroscopy shows that in the Yb(III) and Sm(III) complexes energy transfer from ligand centered excited state leads to population of an emissive f-f excited state. The complexes bind to ct-DNA, with high binding constant (Kb) comparable to those compounds (like ethydium bromide) which bind by intercalative mode. Cytotoxicity study shows that the complexes have quite low cytotoxicity towards HeLa cells. Further, they exhibited fast response, bright fluorescence and stability at physiological pH, making them suitable for use in fluorescence bio-imaging.

Photoluminescence Properties of a New Sm(III) Complex/PMMA Electrospun Composite Fibers

In this paper, a Sm(III) cluster-based 2D coordination polymer {[Sm(2-stp)·3(H2O)]·(H2O)}n, (where 2-stp = 2-sulfoterephthalate), 1 has been synthesized hydrothermally and doped into poly(methyl methacrylate (PMMA) fibers through electrospinning technique to get a new 1D luminescent composite fibers, Sm/PMMA. The crystal structure of Sm(III) complex has been determined by single crystal X-ray diffraction measurements. Sm/PMMA composite fibers have been characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy (PL), and thermogravimetric analysis (TGA) in comparison to that of the pure Sm(III) complex. The luminescent spectra of the composite nanofibers (Sm/PMMA) has demonstrated strong characteristic emission of Sm(III) ions and has also pointed out much better thermal stability than the pure Sm(III) complex.

Impact of n,\u03b3-irradiation on organic complexes of rare earth metals

The complexes of La, Ce, Nd, Sm, Eu, Tb and Yb with benzoxazolyl-phenolate, benzothiazolyl-phenolate, benzoxazolyl-naphtholate, benzothiazolyl-naphtholate and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione ligands were treated with n,γ-irradiation upon a sustained (45 h, absorbed dose of 120 krad, flux of neutrons 5·1013 n/cm2) and a pulse mode (3 ms, absorbed dose of 130 krad, flux of neutrons 3.6·1013 n/cm2). It was found that main characteristics of the compounds (shape of substance, color, IR absorption and photoluminescent spectra) have not changed. With an example of cerium complex [Ce(OON)3]2 it was revealed that the molecular structure of compounds after strong pulse irradiation also does not changed. However, computer simulations of neutron exposure on the same complexes showed significant shift of metal atoms and ligands. Possible reasons for the detected discrepancy between experimental and calculated data are discussed.

ACUTE CHRONICAL TOXICITY AND INTOLERANCE OF SM - COMPLEX

The researchers elaborated pharmacological complex of SM at the Chair of Morphology, Physiology and Pharmacology atSouth-UralStateAgrarianUniversity. The complex contains butafosfan, vitamins, vitamin-like substances, selected on the basis of synergistic effect on the body. The parameters of acute toxicity of the SM-complex were explored in the experiment on clinically healthy adult white mice of both genders by a single injection of the solution in the maximum permissible dose according to GOST 31926-2013. Intolerance on the skin of animals was detected in line with GOST R ISO 10993.10-2009. GOST R ISO 10993.10-99 became a guideline for evaluating SM-complex intolerance on the eye conjunctiva. Chronic toxicity was investigated on non-linear rats; the rates were divided into 4 groups of 6. The first group became a control group, the second group received the SM-complex in a therapeutic dose (255mg/kg), the third group - in a 5 -fold therapeutic dose (1275mg/kg), the fourth group - in a 10-fold dose (2550mg/kg). Pharmacological substance was applied through the probe in the form of an aqueous solution for 30 days. The researchers found out that at single oral introduction of SM-complex in the maximum possible doses it does not affect mice organism and it is referred to the 4th class of danger according to GOST 12.1.007-76. Local application in the form of applications on the skin and mucous membranes of rabbits, the complex does not have a local irritant effect. Long-term application of pharmacological composition (30 days) in high doses causes functional and morphological changes of the liver in the form of gray foci and flabbiness, as well as it increases the volume of the organ. Due to the fact that the therapeutic doses are 5 and 10 times lower than the toxic ones and the period of application does not exceed 7-14 days, the authors make a conclusion that SM-complex is safe and secure and can be used in the recommended doses.

Light-induced rare earth organic complex/shape-memory polymer composites with high strength and luminescence based on hydrogen bonding

Shape-memory polymer composites (SMPCs) with multi-capabilities have attracted growing attention in both academia and industry. However, the known fillers suffer from the deficient functionalization, which would limit the compatible capabilities and applications. Herein, we report the manufacturing of SMPCs based on the hydrogen bonding between nitrate groups from Sm(TTA)Phen(NO3)3 (STPN) and carboxyl groups from crosslinked poly(methyl methacrylate-co-itaconic acid) (P(MMA-co-IA)). SMPCs were prepared by immersing P(MMA-co-IA) in STPN solution with the concentrations of 0.001–0.03 mol L−1. The dispersion of STPN in P(MMA-co-IA) was highly improved in comparison with the rare earth organic complex of Sm(TTA)3Phen without hydrogen bonding. By employing STPN, the flexural modulus and strength were increased by 2.5 and 3.9 times, respectively. The properties of good transparency, fluorescence and near-infrared light induced shape-recovery were also achieved. This work provides an approach to prepare novel SMPCs with different properties including high strength, fluorescence, and light-induced shape-recovery.

Spectral-luminescent properties of Sm(III) complexes with unsaturated b-diketones

Spectral-luminescent properties of Sm(III) complexes with unsaturated b-diketones

Syntheses, crystal structures, and solid-state photoluminescence properties of heterotrinuclear Zn2Ln (Ln: La, Sm, Eu, Tb) complexes derived from 1,4-diaminobutane-based N2O4 compartmental ligand

The one-pot reaction of N,N′-bis(3-methoxysalicylidene)-1,4-diaminobutane (MeOsalbnH2), zinc(II) perchlorate, and lanthanide(III) acetate by a molar ratio of 2:2:1 affords a heterotrinuclear Zn2Ln (Ln: La, Sm, Eu, Tb) complex formulated as [Ln(CH3COO)2{Zn(MeOsalbn)}2]ClO4. In this complex, the central Ln(III) atom is bridged by two {Zn(MeOsalbn)} units and two acetate ligands to form ten-coordination environment. Each Zn(II) atom is coordinated by MeOsalbn2− through the N2O2 site and one oxygen atom from the bridging acetate to afford a five-coordination geometry. In the crystalline state at room temperature, the La(III) complex exhibits a bright blue fluorescence, while the Sm(III) complex shows a reddish-orange colored f–f photoluminescence via an energy transfer from the T1 state localized on the {Zn(MeOsalbn)} units to the acceptor level of the central Sm(III) ion. The results of TD-DFT calculations show that the lowest excited singlet state or triplet state involved in photoluminescence of the La(III) or Sm(III) complex has some intramolecular charge-transfer (CT) character from the phenoxo or methoxy groups to the imino groups in the coordinated MeOsalbn2− moieties.

Synthesis and thermal, emission and dielectric properties of liquid crystalline Eu(III), Sm(III) and Tb(III) complexes based on mesogenic 4-pyridone ligands functionalized with cyanobiphenyl groups

New thermotropic lanthanidomesogens based on Eu(III), Sm(III) and Tb(III) with N-alkylated 4-pyridones mesogenic ligands, having two cyanobiphenyl groups attached via long alkoxy spacers, with 6, 9 and 10 carbons atoms in 3,5 - positions of a benzyl unit, have been designed and investigated. The liquid crystal behavior was assessed by differential scanning calorimetry, the mesophases being assigned by polarized light microscopy based on their characteristic textures and confirmed by variable temperature X-ray powder diffraction analysis. The three N-alkylated 4-pyridones nematic ligands reacted with lanthanide nitrates to yield new lanthanidomesogens with a stable and reproducible smectic A phase up to 125°C. The emission spectra of the complexes have shown the characteristic emission of the lanthanide trivalent ions, over the entire temperature range of SmA phase up to isotropic state. The dielectric spectroscopy measurements performed in the temperature range of existence of the liquid crystal phase, both in the low frequency (LF) domain 0.01–10MHz and in the high frequency (HF) range, 1MHz–3GHz, revealed three dipolar relaxation processes. The characteristic times have been obtained by fitting the spectra of the dielectric loss with a two component Havriliak-Negami function. The activation constant/energy was determined from the Vogel-Fülcher-Tammann law.

Computer Simulation of the Destruction of the Organic Lanthanide Complexes under Ionizing Radiation

The calculation of defects in the structures of the Sc, La, Nd, Sm, Tb, and Yb complexes with substituted phenolate and naphtholate ligands formed under the action of neutrons with a mean energy of 2 MeV shows that the shifts of the target atoms depend on their masses and can achieve 1 μm for O, N, and S. A similar result is obtained for the calculation of the destruction of the Eu(TTA)3(DME)2 complex (HTTA is thenoyltrifluoroacetone). However, the treatment of the samples with the n,γ radiation does not result in destruction. Possible reasons for the found divergence between the calculated and experimental data are discussed.

Highly‐Luminescent DTTA‐Appended Water‐Soluble Lanthanide Complexes of 4‐(Het)aryl‐2,2′‐bipyridines: Synthesis and Photophysical Properties

AbstractNew series of highly luminescent DTTA (DTTA=diethylenetriaminetetraacetic acid) ‐ appended water‐soluble lanthanide complexes of 4‐(het)aryl‐2,2′‐bipyridines were prepared. By using the Kröhnke method and the alkylation reaction sequence, the corresponding 4‐(het)aryl‐2,2′‐bipyridines were synthesized in good yields, and their Eu(III), Tb(III), Dy(III) and Sm(III) complexes were prepared. Photophysical properties were studied for all the obtained complexes and the influence of the nature of the (het)aromatic substituent of 2,2′‐bipyridine moiety on the photoluminescence of the resulted lanthanide complexes was investigated. An efficient sensitization of lanthanide luminescence by halogen‐ and methoxyphenyl‐substituted 2,2′‐bipyridine ligands were observed to result in up to 56% and up to 25% quantum yields for Tb(III) and Eu(III) luminescence accordingly.

Strong enhancement of ionic luminescence Dy(III), Tb(III), Eu(III) and Sm(III) by pyridyltriazoles

With the aim of finding new nitrogen-containing ligands capable of sensitizing the luminescence of lanthanide ion, we synthesized and characterized a series of Tb(III), Eu(III), Gd(III), Sm(III) and Dy(III) complexes with triazole-based ligands. The pyridyltriazole ligands sensitizes very efficiently both the visible emission of the lanthanides, with unusually high luminescence quantum yields in solid state (up to 97% for Tb, 82% for Eu, and 23% for Dy). The results show that the pyridyltriazole ligand provides a very attractive alternative to the classic diketonates and heterocyclic ligands.

Human Craniofacial Spliceosomopathies

Germline mutation of core components of the spliceosomes have been associated with a range of clinical disorders from isolated retinitis pigmentosa (RP) to developmental syndromes, while somatic mutations of spliceosome components are linked to cell cycle dysregulation and cancer. Recently a group of craniofacial and skeletal disorders caused by dominant mutations in spliceosomal genes has emerged. The first of these to be identified is mandibulofacial dysostosis type Guion‐Almeida (MFDGA), caused by haploinsufficiency of the U5 snRNP component EFTUD2. We recently identified haploinsufficiency of SF3B4 as the cause of Nager syndrome, an acrofacial dysostosis (AFD), although only in 60% of cases suggesting genetic heterogeneity. Mutation of SF3B4 was subsequently reported in AFD Rodriquez type. SF3B4 is part of the U2 snRNP of the major spliceosome. We also identified heterozygous mutations in a highly conserved regulatory exon of SNRPBas the cause of cerebro‐costo‐mandibular syndrome (CCMS). Our experimental data show that these mutations disturb highly conserved exonic splicing silencer sequences crucial to the regulation of the gene's expression. SNRPB encodes a component of the Sm complex of the spliceosome. Additional craniofacial spliceosomopathies result from mutations in splicing factors TXNL4A, RBM8A and CWC27. The frequent involvement of craniofacial structures invite questions on the sensitivity of craniofacial and in particular pharyngeal arch development to spliceosomal defects, and on the role of the spliceosome in the regulation of development. The report of a young patient with Nager syndrome with bilateral synchronous breast cancer raises the possibility of a link between germline mutation of splicing factors and cancer predisposition. We also have a patient with a pathogenic SNRPB mutation who is non‐penetrant for CCMS syndrome but was diagnosed with early onset breast cancer, further linking heritable splicing mutations with cancer predisposition.Many of the craniofacial spliceosomopathies share overlapping features with Treacher‐Collins syndrome (TCS), a ribosomopathy. We are currently validating mutations in a ribosomal gene in two patients with typical Nager syndrome. This finding may provide unique insight into the overlapping roles of transcription and translation in craniofacial development. A combination of human genetics and model systems research will be required to further unravel the role of the spliceosome and the ribosome in craniofacial and skeletal development.Support or Funding InformationGenome Canada, Alberta Children's Hospital Research Institute, Genome AlbertaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A New Samarium(III) Complex of Liriodenine: Synthesis, Crystal Structure, Antitumor Activity, and DNA Binding Study

A novel SmIII complex [SmIII(LA)2(pic)3] (Hpic = picric acid), in which LA is a natural‐derived alkaloid, liriodenine, was synthesized and characterized by IR, elemental analysis, and single‐crystal X‐ray diffraction analysis. This complex showed enhanced solubility compared with liriodenine and its metal complexes that have been previously reported. The interaction of the SmIII complex with ct‐DNA was further investigated by various spectroscopic techniques, such as UV/Vis spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy (CD), and viscosity measurement. The results showed that the intrinsic binding constant Kb of the SmIII complex with ct‐DNA was calculated to be 5.03 × 103 L·mol–1 by UV/Vis absorption spectral analysis. The thermodynamic fluorescent spectral analysis suggested that the fluorescence intensity of the SmIII complex was weakened by ct‐DNA mainly through a dynamic quenching mechanism. The presence of Sm complex could increase the viscosity of DNA solution, so it was concluded that the complex bound with ct‐DNA via a moderate intercalative mode. Furthermore, this SmIII complex exhibited significant growth inhibition on the three typical tumor cell lines, HepG2, T‐24, and SK‐OV‐3, with the corresponding IC50 values, 10.76 ± 0.19, 8.85 ± 1.12, and 10.01 ± 0.55 μM, respectively. The in vitro antitumor activity was comparable with LA and cisplatin, which suggested that it might be a new broad spectrum antitumor agent with more satisfying solubility.

Self-assembly of one visible and NIR luminescent Sm(III) coordination polymer with flexible Schiff base ligand

Two mononuclear lanthanide complexes [EuL1(NO3)(H2O)DMF] (1) and [SmL1(OAc)(H2O)EtOH] (2), and one lanthanide coordination polymer {Sm(L2)(OAc)}n (3) were synthesized by the use of two Schiff base ligands with a long (CH2)2NH(CH2)2 backbone. The crystal structures of 1–3 were determined by X-ray crystallography. The chromogenic Schiff base ligands in 1–3 can transfer energy to lanthanide ions and these complexes exhibit the typical luminescence of lanthanide ions. In 1 and 2, there is a H2O molecule coordinated with the Ln3+ ion, while there are no solvent molecules coordinated with the lanthanide ion in 3. Interestingly, for the Sm(III) complexes, the lanthanide coordination polymer 3 has longer emission lifetime and higher quantum yield (Φem) than the mononuclear lanthanide complex 2.

Circularly polarized luminescence of Sm (III) and Eu (III) complexes with chiral ligand (R/S)-BINAPO.

Luminescent lanthanide (III) ions have been exploited for circularly polarized luminescence (CPL) for decades. However, very few of these studies have involved chiral samarium (III) complexes. Complexes are prepared by mixing axial chiral ligands (R/S))-2,2'-bis(diphenylphosphoryl)-1,1'-binaphthyl (BINAPO) with europium and samarium Tris (trifluoromethane sulfonate) (Eu (OTf)3 and Sm (OTf)3 ). Luminescence-based titration shows that the complex formed is Ln((R/S)-BINAPO)2 (OTf)3 , where Ln=Eu or Sm. The CPL spectra are reported for Eu((R/S)-BINAPO)2 (OTf)3 and Sm((R/S)-BINAPO)2 (OTf)3 . The sign of the dissymmetry factors, gem , was dependent upon the chirality of the BINAPO ligand, and the magnitudes were relatively large. Of all of the complexes in this study, Sm((S)-BINAPO)2 (OTf)3 has the largest gem =0.272, which is one of the largest recorded for a chiral Sm3+ complex. A theoretical three-dimensional structural model of the complex that is consistent with the experimental observations is developed and refined. This report also shows that (R/S)-BINAPO are the only reported ligands where gem (Sm3+ )>gem (Eu3+ ).

New Sm (III) and Nd (III) complexes: Synthesis, structural characterization and fluorescent sensing of nitro‐aromatic compounds

In this work, four new Nd (III) and Sm (III) complexes of two pentadendate ligands (L1 and L2) were prepared and their molecular structures were determined by single crystal X‐ray diffraction studies. X‐ray analysis showed that the Nd (III) and Sm (III) complexes of L1 sits on a twofold crystallographic axis while the complexes of L2 does not show crystallographically imposed symmetry. Absorption and photoluminescence properties of the complexes were studied both in the solid state and DMF solutions. The fluorescence sensing of nitro‐aromatic compounds [nitrobenzene (NB), 4‐nitrophenol (NP), 2,4‐dinitrophenol (DNP) and 2,4,6‐trinitrophenol (TNP)] were studied by photoluminescence spectroscopy. All four complexes showed better sensitivity towards nitrophenol (NP) with low LOD values.