7439-91-0Relevant academic research and scientific papers
Thermal decomposition behaviour of lanthanum(III) tris-tartrato lanthanate(III) decahydrate
Deb
, p. 227 - 237 (2004)
Lanthanum(III) tris-tartrato lanthanate(III) decahydrate, La[La(C 4H4O6)3]·10H2O has been synthesized and characterized by elemental analysis, IR, electronic spectral and X-ray powder diffraction studies. Thermal studies (TG, DTG and DTA) in air showed a complex decomposition pattern with the generation of an anhydrous species at ～170°C. The end product was found to be mainly a mixture of La2O3 and carbides at ～970°C through the formation of several intermediates at different temperature. The residual product in DSC study in nitrogen at 670°C is assumed to be a similar mixture generated at 500°C in TG in air. Kinetic parameters, such as, E*, ΔH, ΔS, etc. obtained from DSC are discussed. IR and X-ray powder diffraction studies identified some of the decomposition products. The tentative mechanism for the thermal decomposition in air of the compound is proposed.
Reprocessing of spent hydrogen absorbing alloys by using electrochemical techniques in molten salts
Matsuura,Numata,Fujita,Akatsuka
, p. 439 - 442 (2005)
Rare earths separation from hydrogen absorbing alloys by using molten salt media is proposed. The procedure consists of the following three electrochemical techniques.Rare earths are anodically electro-dissolved into ionic melt bath from spent hydrogen ab
Transport and kinetics properties of LaF3 in FLiNaK molten salt determined by electrochemical methods
Wang, Yafei,Yang, Qiufeng,Zhang, Jinsuo
, (2020)
It is found that lanthanum species can exist in the form of LaF63? in FLiNaK (46.5 LiF-11.5 NaF-42 KF, mol%) molten salt in previous studies. The understanding of transport and reaction kinetics parameters of LaF63? ions in FLiNaK molten salt is essential for the electrochemical separation of lanthanum from FLiNaK melt to achieve the coolant clean-up in fluoride salt cooled high-temperature reactor (FHR). Through conducting chronopotentiometry tests, the diffusion coefficients of LaF63? ions in FLiNaK molten salt at the temperature range of 923 K–1023 K were determined. By conducting potentiodynamic polarization measurements at different concentrations and temperatures, the exchange current density, reaction rate constant, and charge transfer coefficient were obtained. The experiment data of potentiodynamic polarization were analyzed using a non-simplified electrode kinetics equation which incorporates both mass transfer and reaction kinetics.
Preparation of lanthanum and cerium metals by hydrometallurgy
Hasegawa,Sano,Aoshima,Shiokawa
, p. 246 - 249 (2003)
Lanthanum and cerium metals were prepared by electrolytic synthesis of amalgams in aqueous solutions followed by the thermal decomposition. The amalgamation yields were almost quantitative. The preparation yield of lanthanide metals, however, deteriorated during thermal decomposition due to a density difference between lanthanide and mercury. The gaseous impurities in the prepared metals were found to be comparable with those in commercially available ones.
Synthesis, dft calculations, antiproliferative, bactericidal activity and molecular docking of novel mixed-ligand salen/8-hydroxyquinoline metal complexes
Abdalla, Ehab M.,Abdel Rahman, Laila H.,Al-Farhan, Badriah Saad,Basha, Maram T.,El-Ezz, Doaa Abou,El-Saghier, Ahmed M. M.,Marzouk, Adel A.,Shehata, Mohamed R.
, (2021/08/13)
Despite the common use of salens and hydroxyquinolines as therapeutic and bioactive agents, their metal complexes are still under development. Here, we report the synthesis of novel mixed-ligand metal complexes (MSQ) comprising salen (S), derived from (2,2′-{1,2-ethanediylbis [nitrilo(E) methylylidene]}diphenol, and 8-hydroxyquinoline (Q) with Co(II), Ni(II), Cd(II), Al(III), and La(III). The structures and properties of these MSQ metal complexes were investigated using molar conductivity, melting point, FTIR,1H NMR,13C NMR, UV–VIS, mass spectra, and thermal analysis. Quantum calculation, analytical, and experimental measurements seem to suggest the proposed structure of the compounds and its uncommon monobasic tridentate binding mode of salen via phenolic oxygen, azomethine group, and the NH group. The general molecular formula of MSQ metal complexes is [M(S)(Q)(H2O)] for M (II) = Co, Ni, and Cd or [M(S)(Q)(Cl)] and [M(S)(Q)(H2O)]Cl for M(III) = La and Al, respectively. Importantly, all prepared metal complexes were evaluated for their antimicrobial and anticancer activities. The metal complexes exhibited high cytotoxic potency against human breast cancer (MDA-MB231) and liver cancer (Hep-G2) cell lines. Among all MSQ metal complexes, CoSQ and LaSQ produced IC50 values (1.49 and 1.95 μM, respectively) that were comparable to that of cisplatin (1.55 μM) against Hep-G2 cells, whereas CdSQ and LaSQ had best potency against MDA-MB231 with IC50 values of 1.95 and 1.43 μM, respectively. Furthermore, the metal complexes exhibited significant antimicrobial activities against a wide spectrum of both Gram-positive and-negative bacterial and fungal strains. The antibacterial and antifungal efficacies for the MSQ metal complexes, the free S and Q ligands, and the standard drugs gentamycin and ketoconazole decreased in the order AlSQ > LaSQ > CdSQ > gentamycin > NiSQ > CoSQ > Q > S for antibacterial activity, and for antifungal activity followed the trend of LaSQ > AlSQ > CdSQ > ketoconazole > NiSQ > CoSQ > Q > S. Molecular docking studies were performed to investigate the binding of the synthesized compounds with breast cancer oxidoreductase (PDB ID: 3HB5). According to the data obtained, the most probable coordination geometry is octahedral for all the metal complexes. The molecular and electronic structures of the metal complexes were optimized theoretically, and their quantum chemical parameters were calculated. PXRD results for the Cd(II) and La(III) metal complexes indicated that they were crystalline in nature.
Synthesis, Characterization, Theoretical Studies, and Antimicrobial/Antitumor Potencies of Salen and Salen/Imidazole Complexes of Co (II), Ni (II), Cu (II), Cd (II), Al (III) and La (III)
Abdalla, Ehab M.,Abdel Rahman, Laila H.,Abdelhamid, Antar A.,Shehata, Mohamed R.,Alothman, Asma A.,Nafady, Ayman
, (2020/07/13)
Although salens and imidazoles are well-studied motifs among bioactive and therapeutic agents, their properties when combined in transition metal complexes are not well developed. To explore the structure/reactivity of this class of compounds, a salen-based ligand, namely (2,2′-{1,2-ethanediylbis[nitrilo(E)methylylidene]}diphenol, S), and its binary (MS) and ternary (MSI) complexes (I = imidazole; M = Co (II), Ni (II), Cu (II), Cd (II), Al (III), and La (III)) have been synthesized and fully characterized by standard physicochemical and theoretical methods. Evidence from structural analysis tools along with DFT modeling revealed an unusual monobasic tridentate salen binding mode, involving the phenolic oxygen, the nitrogen of the azomethine group, and NH group formed via phenol-to-cyclohexadienone tautomerization, giving rise to a general molecular formula of MSI complexes as [M(S)(I)2(Cl)] for M (II) = Co, Ni, Cu and Cd or [M(S)(I)(Cl)2] for M (III) = Al and La, respectively. The antimicrobial activities of S, MS, and MSI were screened against several bacterial and fungal strains. Of all tested complexes, CdS and CuSI were the most effective antimicrobials, giving larger inhibition zones than the reference antibiotics. The antimicrobial efficacy for the MS complexes follows the order: CdS > gentamicin > CuS > NiS > CoS > LaS > AlS > S, whereas MSI complex, potencies are ordered as CuSI > gentamicin > CdSI >NiSI > CoSI > LaSI > AlSI > S. In vitro cytotoxicity screening of MSI complexes disclosed that both CuSI and CdSI exhibited higher activity against human liver (Hep-G2) and breast (MDA-MB231) carcinoma cell lines than the reference (cisplatin) drug. The satisfactory bioactivities observed for several of these compounds supports the underlying design idea for combining important bioactive motifs for possible therapeutic benefit.
Study of the chemical structure and their nematicidal activity of N2O2 tetradentate Schiff base metal complexes
Abd El-Hamid,Sadeek,Abd El-Lattif
, (2019/06/21)
Coordination compounds of Cu (II), Y (III), Zr (IV) and La (III) with the tetradentate Schiff base (H2L) obtained through the condensation of p-phenylenediamine with salicylaldehyde under reflux conditions. The complexes were characterized by elemental analysis, magnetic susceptibility, molar conductance and also, with various spectroscopic techniques such as 1H NMR, UV–Vis., IR and XRD techniques. Electrolytic nature of complexes was ascertained by molar conductance values. In these four complexes, the ligand chelates act in a tetradentate manner via azomethine nitrogen and oxygen atoms of phenolic groups. Electronic spectroscopic data are in agreement with an octahedral geometrical structure. Thermal degradation analyses in nitrogen gas were used to investigate the number and location of water molecules. The chemical formulae of metal complexes were confirmed by microanalytical data. The activation thermodynamic parameters, such as, E*, ΔH*, ΔS* and ΔG* were calculated from the DTG curves using Coats Redfern (CR) and Horowitz–Metzeger (HM) methods at n?=?1 or n?≠?1. Nematicidal activities indicate that the ligand exhibit greater activity when compared to its complexes. In addition metal complexes displayed good moderate nematicidal activities.
New synthesis route to and physical properties of lanthanum monoiodide
Ryazanov, Mikhail,Kienle, Lorenz,Simon, Arndt,Mattausch, Hansjuergen
, p. 2068 - 2074 (2008/10/09)
A fast procedure to produce Lal by reduction of Lal2 or Lal 3 in a Na melt under argon at 550°C is given. The structural studies performed by means of powder X-ray diffraction as well as transmission electron microscopy are consistent with previous single-crystal results. Measurements of the electrical resistance on polycrystalline samples reveal metallic behavior for Lal in the range 10-300 K. Upon cooling, a small maximum in the resistivity has been observed at 67 K. This anomaly disappears upon heating a sample, however, yielding a hysteresis in ρ(T) above 70 K. From the Pauli susceptibility, an electron density of states at the Fermi level of about 0.3 eV-1·formula unit-1 has been estimated, as compared with a value of 1.0 eV-1·formula unit-1 derived from ab initio LMTO band structure calculations.
Interaction between lanthanum trifluoride and zirconium metal in NaF-ZrF4 melts
Savchuk,Kompanichenko,Omel'Chuk
, p. 1946 - 1952 (2008/10/09)
The interaction between lanthanum trifluoride and zirconium metal in sodium fluoride-zirconium tetrafluoride melts is studied by differential thermal analysis, X-ray powder diffraction, and IR spectroscopy. Between 440 and 560°C, zirconium metal in a molten mixture reacts with ZrF4 and LaF3 to yield lanthanum metal and compounds of zirconium in lower oxidation states. An attempt is made to describe the processes occurring in the system. Copyright
Reduction of rare-earth fluorides with zirconium
Savchuk,Nagornyi,Kompanichenko,Omel'chuk
, p. 1454 - 1458 (2008/10/08)
The reactions of rare-earth (La, Pr, Nd, Gd, Dy, and Yb) fluorides with zirconium in molten mixtures of alkali-metal halides have been studied by differential thermal X-ray diffraction, and chemical analyses and IR spectroscopy. It has been shown that zirconium reduces rare-earth fluorides in the 465-625°C range. The onset temperature of the reaction increases with an increase of the melting point of the rare-earth fluoride. The degree of reduction of rare-earth fluorides with zirconium for the MF3:Zr (mol/mol) feed ratio varying from 1.5 to 6 does not exceed 35%.
