Synthesis,characterization and thermal behaviour of solid-state compounds of yttrium and lanthanide benzoates

Solid-state Ln(Bz)₃·H₂O compounds where Ln stands for trivalent yttrium or lanthanides and Bz is benzoate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), X-ray powder diffractometry, infrared spectroscopy and chemical analysis were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.     

Synthesis, characterization and thermal behaviour of solid-state tartrates of heavy trivalent lanthanides and yttrium(III)

Solid state Ln₂-L₃ compounds, where Ln stands for heavy trivalent lanthanides (terbium to lutetium) and yttrium, and L is tartrate [(C₄H₄O₆)^?2] have been synthesized. Simultaneous thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, ligand??s denticity, thermal stability and thermal behaviour of these compounds.     

Synthesis,characterization and thermal behaviour of solid-state 3-methoxybenzoates of heavy trivalent lanthanides and yttrium(III)

Solid-state Ln(L)₃ compounds, where Ln stands for trivalent Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and L is 3-methoxybenzoate, have been synthesized. X-ray powder diffractometry, infrared spectroscopy, complexometry and elemental analysis were used to characterize the compounds. In order to study the thermal behaviour of these compounds simultaneous thermogravimetry and differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC) were used. The results provided information on the composition, dehydration, polymorphic transformation, thermal stability and thermal decomposition of the synthesized compounds.     

Synthesis,characterization and thermal behaviour of solid 2-methoxybenzoates of trivalent metals

Solid-state Ln(L)₃ compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and L is 2-methoxybenzoate have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information on the composition, dehydration, coordination mode, structure, thermal behaviour and thermal decomposition.     

Synthesis,characterisation and solid state thermal behaviour of nickel(II) diamine complexes

Summary [NiL₂X₂] (L =N,N-dimethyl-1,2-ethanediamine; X = Cl^–, CF₃CO ₂ ^– , CC1₃CO ₂ ^– and CBr₃CO ₂ ^– ), [NiL₂C₂O₄] · H₂O and [NiL₂X₂] · 2 H₂O (X = Br^–, 0.5 SO ₄ ^2– and 0.5 SeO ₄ ^– ) have been synthesised and their thermal studies carried out. Thermally induced phase transition phenomena are noticed in [NiL₂X₂] (X = CF₃CO ₂ ^– and CCl₃CO ₂ ^– ) and their probable mechanisms are described. [NiL₂X₂] (X = Br^–, 0.5 SO ₄ ^2– and 0.5 SeO ₄ ^2– ) and [NiLX₂] (X = Cl^–, 0.5 C₂O ₄ ^2– and 0.5 SO ₄ ^2– ) have been prepared by solid state pyrolysis from the respective parent diamine complexes. [NiL₂X₂] have been made in solid state by temperature arrest technique from [NiL₂(CX₃CO₂)₂] (X = Cl^– and Br^–).     

Synthesis,characterization and thermal behaviour of adducts

The photoproduct of octacyanomolybdate(IV) and -tungstate(IV) with ethylenediamine and triethylenetetramine give complexes of the type K₃[Mo(O₂)(O)(OH)(C₉H₇ON)]·3C₉H₇ON I, K₂[W(O₂)(O) (C₉H₇ON)₃] II and K₃[Mo(CN)₃(OH)₄(C₉H₇ON)]·2C₉H₇ON·3H₂O III with 8-quinolinol (oxine). The IR spectra of the complex III shows the presence ofv(CN) peaks in the range 2047–2108 cm^?1 and oxine groupv(C-O) in the complex I, II and III in the range of 1100–1150 cm^?1. The lower region of IR spectra shows the M=O stretching while the higher thev(N-H) andv(OH). Thermal studies show the removal of uncoordinated water at 131?C from complex III. The decomposition of complexes I and II start from 150 and 212?C respectively. Oxine and cyano molecules were removed in stages at higher temperatures. The final product of the thermal decomposition was oxide which was of polymeric nature. The kinetic parameters viz. order of reaction ‘n’ and activation energy ‘E’ were determined by different methods.     

Synthesis,characterization and thermal behaviour of some metal indigodisulphonates

Some indigodisulphonates of Cr(III), Cu(II), Ag(I), An(II) and Cd(II) have been prepared in aqueous medium and characterized on the basis of elemental analyses, diffuse reflectance infrared spectra and magnetic measurements.The thermal behaviours of these salts were studied by TG, DTG and DSC techniques. Cr(III), Cu(II), Zn(II) amd Cd(II) indigodisulphonates contain 12, 2, 2 and 2 molecules of crystallization water, respectively. The end-products of thermal decomposition have been verified by infrared spectroscopy and X-ray diffraction. Values of dehydration enthalpies have been calculated from the DSC curves.

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Zusammenfassung Einige Indigodisulphonate von Cr(III), Zn(II), Ag(I), Zn(II) und Cd(II) wurden in wäßrigem Medium dargestellt und durch Elementaranalyse, diffuse Reflektions-IR-Spektren und magnetische Messungen charakterisiert. Das thermische Verhalten dieser Salze wurde mittels TG, DTG und DSC untersucht. Die Indigodisulphonate von Cu(II), Zn(II) und Cd(II) kristallisieren mit 2 Molekülen Kristallwasser, die von Cr(III) mit 12 Molekülen. Die Endprodukte der thermischen Zersetzung wurden infrarotspektroskopisch und röntgendiffraktometrisch identifiziert. Die Werte der Dehydratisierungsenthalpien wurden aus den DSC-Kurven berechnet.

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Synthesis, characterization and thermal studies on solid compounds of 2-chlorobenzylidenepyruvate of heavier trivalent lanthanides and yttrium(III)

Solid-state compounds of general formula LnL_3⋅nH₂O, where Ln represents heavier lanthanides and yttrium and L is 2-chlorobenzylidenepyruvate, have been synthesized. Chemical analysis, simultaneous thermogravimetry-differential analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, elemental analysis and infrared spectroscopy have been employed to characterize and to study the thermal behaviour of these compounds in dynamic air atmosphere. On heating these compounds decompose in four (Gd, Tb, Ho to Lu, Y) or five (Eu, Dy) steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds up to 1200°C occurs with the formation of the respective oxide, Tb₄O₇ and Ln₂O₃ (Ln=Eu, Gd, Dy to Lu and Y) as final residue. The dehydration enthalpies found for these compounds (Eu, to Lu and Y) were: 65.77, 55.63, 86.89, 121.65, 99.80, 109.59, 131.02, 119.78, 205.46 and 83.11 kJ mol^-1, respectively.     

Synthesis, characterisation and thermal behaviour of solid state compounds of 4-methylbenzylidenepyruvate with some bivalent metal ions

Solid state M-4-Me-BP compounds, where M stands for bivalent Mn, Fe, Co, Ni, Cu, Zn, Pb and 4-Me-BP is 4-methylbenzylidenepyruvate, have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterise and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes.     

Synthesis,characterization and thermal behaviour of four homoleptic titanium silanolates

Four titanium silanolates Ti(OSiR₂R′)₄ (1, R = Ph, R′ = ^tBu; 2, R = R′ = Ph; 3, R = R′ = ⁱPr; 4, R = Me, R′ = ^tBu) were synthesised starting from Ti(OⁱPr)₄ and the corresponding silanol, and their thermally induced decomposition was studied. Colourless single crystals of Ti(OSiPh Bu) CHCl C₇H₈ ( CHCl C₇H₈) were obtained from a mixture of chloroform and toluene (1:1) at ?20 °C. The compound crystallizes in the space group R3 c with Z = 18. The metal atom shows an almost ideal tetrahedral coordination, as is demonstrated by the O? Ti? O angles of 108.4(1)–111.1(1)°. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and structural characterization of lanthanide(III) nitrate complexes of a tetraiminodiphenol macrocycle in the solid state and in solution

The lanthanide(III) complexes [Ln(LH2)(NO3)3] 1-11(La-Er), 15(Y) and [Ln(LH2)(NO3)2(H2O)](NO3) 12-14 (Tm-Lu) of the tetraiminodiphenolate macrocycle L2- have been prepared by the transmetallation reaction between [Pb(LH2)(NO3)2] and Ln(NO3)3.nH2O. In these compounds, the uncoordinated imino nitrogens are protonated and are hydrogen bonded to the phenolate oxygens. The X-ray crystal structures of the La (1), Ho (10) and Lu (14) compounds have been determined. Compounds 1 and 10, in which all the three nitrates are bound in bidentate fashion, are isostructural with distorted bicapped square antiprism geometry for the metal centre. In [Lu(LH2)(NO3)2(H2O)](NO3) 14, of the two metal bound nitrates one is bidentate and the other is unidentate, while the metal centre obtains a distorted square antiprism coordination environment. Proton NMR spectra of the paramagnetic lanthanide complexes have been studied in detail. Contributions of contact and pseudo-contact shifts to the lanthanide induced isotropic shifts (LIS) of the macrocycle protons have been separated and good agreement has been obtained between the calculated LIS values and the experimentally observed values. Analysis of the NMR data has led us to conclude that all the complexes in dimethyl sulfoxide solution attain similar configurations. The absorption and emission spectral characteristic of several compounds have been investigated. The complexes of samarium (5) and europium (6) on photoexcitation at 400 nm exhibit well-resolved luminescence spectra at 77 K both in the solid state and a methanol-ethanol (1 : 4) glassy matrix. For the terbium (8) and dysprosium (9) complexes, however, the observed luminescence peaks are less resolved and weak in intensity.     

镧系元素硝酸盐与1,8-萘啶氮单氧化物固态配合物的合成及性质研究

合成了组成为Ln(C8H6N2O)2(NO3)3.(Ln=La-Lu)的镧系硝酸盐化合物与1,8-二氮萘-N-单氧化物的固体络合物,用元素分析,UV,IR,摩尔电导,差热分析,热重分析及X光粉末衍射等测定了新化合物的组成及有关性质.     

Preparation and characterization of heavy lanthanide thiodiglycolates

Thiodiglycolates of heavy lanthanides, prepared in the reactions of the hydroxides of the rare earths with thiodiglycolic acid, have the general formula Ln₂(C₄ H ₄O₄S)₃·nH₂O, wheren=5 for Ln=Tb and Dy,n=6 for Ln=Ho, Er and Tm, andn=7 for Ln=Yb and Lu. On heating, the hydrated complexes lose the crystallization water in two steps, and the resulting anhydrous complexes decompose to the oxides Ln₂O₃ and Tb₄O₇ via the intermediate formation of Ln₂O_3–x(SO₄)_x.The temperatures of oxide formation decrease with increasing atomic number of the lanthanides. The solubilities of the heavy lanthanide thiodiglycolates are of the order of 10^–2 mol · dm^–3.

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Zusammenfassung In der Reaktion von Seltenerdenhydroxiden und Thiodiglykolsäure wurden die Thiodiglykolate von Lanthaniden mit der allgemeinen Formel Ln₂(C₄H₄O₄S)₃ ·nH₂O hergestellt (mitn=5 für Ln=Tb und Dy, mitn=6 für Ln=Ho, Er und Tm und mitn=7 für Ln=Yb und Lu). Die Hydratkomplexe verlieren ihr Kristallwasser beim Erhitzen in zwei Stufen, die entstehenden wasserfreien Komplexe zerfallen über die intermediäre Form Ln₂O_3–x (SO₄)_x in die Oxide Ln₂O₃ und Tb₄O₇. Die Temperatur der Oxidbildung nimmt mit steigender Ordnungszahl der Lanthaniden ab. Die Löslichkeit der untersuchten Lanthanidenthiodiglykolate liegt in der Größenordnung 10^–2 mol/dm^–3.

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Ln₂(C₄H₄O₄S)₃-n₂, =5 Ln=Tb Dy,=6 Ln=, m, =7 Ln=Yb Lu. , Ln₂O₃ b₄₇ Ln₂O_3–x(SO₄) _x . . 10^–2 · ^–3.

     

Synthesis and solid state characterization of two insoluble tetrathiometalates

The aqueous reaction of ammonium tetrathiometalates (NH₄)₂[MS₄] (M = Mo or W) with (dbtmen)Br₂ · 2H₂O (dbtmen = N,N′-dibenzyl-N,N,N ′, N′-tetramethylethylenediammonium dication) results in the formation of the highly insoluble compounds (dbtmen)[MoS₄] (1) and (dbtmen)[WS₄] (2) in near quantitative yields. Compounds (1) and (2) have been characterized by elemental analysis, spectroscopic methods, X-ray powder diffraction and TG–DTA. Both compounds exhibit nearly identical IR spectra and X-ray powder patterns. The compounds exhibit a single strong signal for the asymmetric M–S stretching vibration at 475 cm⁻¹ in (1) and at 457 cm⁻¹ in (2). Complex (2) is thermally more stable than the corresponding Mo analogue (1). Thermal decomposition products of (1) and (2) are carbon contaminated amorphous metal disulfides and are formulated as MoS_1.99C_2.06N_0.07 and WS_1.75C_3.02 based on elemental analysis of the residue.     

Separation of yttrium from heavy lanthanide by CA-100 using the complexing agent

The selective extraction of yttrium from heavy lanthanide by liquid-liquid extraction using CA-100 in the presence of the complexing agent, such as EDTA, DTPA, and HEDTA was investigated. The extraction of heavy lanthanide in the present of the complexing agent was suppressed when compared to that of Y because of the masking effect, but the selective extraction of Y was enhanced. All complexing agents formed 1:1 complex with rare earth elements (RE), and only free rare earth ions could take part in the extraction. The condition for separation was obtained by exploring the effects of the complexing agent concentration, the extractant concentration, pH and the equilibration time on the extraction of the heavy rare earth elements.     

Synthesis, characterization and thermal behaviour of new copper and rare-earth metal tungstates

Three series of new copper and rare-earth metal tungstates with the formulas: CuRE ₂W₂O₁₀ (RE = Nd, Sm, Eu) and Cu₃ RE ₂W₄O₁₈ (RE = Sm, Eu or RE = Dy, Ho, Er) were synthesized by the solid-state reaction method. The CuRE ₂W₂O₁₀ and Cu₃ RE ₂W₄O₁₈ (RE = Dy, Ho, Er) compounds crystallize in the monoclinic system. The Cu₃ RE ₂W₄O₁₈ phases with the large rare-earth ions crystallize in the triclinic system. All obtained compounds melt incongruently below 1273 K. The anion lattice of the Cu₃ RE ₂W₄O₁₈ phases is built from isolated groups of octahedra (W₄O₁₆)^8?, while CuRE ₂W₂O₁₀ from WO₆ octahedra forming structural elements [(W₂O₉)^6?]^∞. The EPR spectra of analyzed compounds consisted of an intense line originating generally from the rare-earth ions and a weak, narrow line from Cu²⁺ separate centers appearing only on the surface of the grains. The absence of bulk copper in the EPR spectrum is probably due to a very short relaxation time of the Cu²⁺ subsystem.     

Thermal behaviour and microstructural characterization of lanthanide sulphides

Thermal decomposition processes of rare earth sesquisulfides Ln₂S₃ (Ln= Lu, Y and Er) in O₂ flow up to 1590 K, have been studied. Decomposition takes place through incomplete oxidations and overlapping decomposition reactions. Two intermediate phases such as Ln₂O₂S and Ln₂O₂SO₄ are formed before the final more stable phase Ln₂O₃ (C-type) is obtained. Microstructural studies show the poor crystallinity of the intermediate products.We wish to thank the Centro de Microscopia Electrónica, U.C.M.) for facilities. This research was supported by the CYCIT project MAT 89-0768.     

Synthesis,characterization and fluorescence of lanthanide Schiff-base complexes

Six new lanthanide Schiff-base complexes were synthesized by reactions of hydrated lanthanide nitrates with H₂L (H₂L?=?N,N′-bis(salicylidene)-1,2-cyclohexanediamine) and characterized by elemental analysis, DTA–TG, IR, UV and luminescence spectra. The microanalyses and spectroscopic analyses indicate a 1D polymeric structure with the formula of [Ln(H₂L)(NO₃)₃(MeOH)₂] _n [Ln?=?La (1), Ce (2), Pr (3), Sm (4), Gd (5) & Dy (6)]. The fluorescence spectrum of complex 4 exhibited Sm³⁺ centered, Schiff-base sensitized orange fluorescence, indicating that energy levels of the triplet state of H₂L match closely to the lowest excited state (⁴G_5/2) of Sm³⁺ ion.     

Synthesis,characterization and thermal behavior on solid tartrates of light trivalent lanthanides

Solid state Ln–L compounds, where Ln stands for light trivalent lanthanides (L–Gd) and L is tartrate, have been synthesized. Thermogravimetry and differential thermal analysis (TG/DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration and thermal decomposition of the isolated compounds.     

Carbohydrazone polychelates: Synthesis,physicochemical characterization,solid state conductance and biological studies

The polychelates of Ti(III), VO(IV), Cr(III), Mn(III), Fe(III), Zr(IV), MoO₂(VI) and UO₂(VI) with the chelating hydrazone derived from 2,4-dihydroxy-5-acetylacetophenone and carbohydrazide have been synthesized. The polychelates have been characterized on the basis of elemental analyses, IR, magnetic moment, electronic spectral data and thermal analysis. Various kinetic parameters have been determined from the thermal data and decomposition follows first order kinetics. The solid—state electrical conductivity has been measured over 40–130°C-temperature range and all the compounds showed semiconducting behavior as their conductivity increases with increase in temperature. The ligand and its polychelates have also been screened for their antimicrobial activities using various microorganisms and all of them were found to be active against the organisms.