首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 937 毫秒
1.
Compositions of mixed ligand acetate, propionate, and pivalate complexes of rare earth metals of the cerium and yttrium groups with monoethanolamine are predetermined by the synthesis conditions and the nature of the carboxylate ligand and rare earth metal ion. Solid mixed ligand complexes [Ln(Piv)5(MEAH)][MEAH] and [Ln(Piv)3(MEA)], homoligand complexes [Ln(Piv)3] (HPiv is 2,2-dimethylpropionic (pivalic) acid), and gel-like hydroxo complexes [Ln(Carb)3–xy (NO3) x -(OH) y (MEA) w (H2O) z ] (HCarb is acetic (HAc) or propionic (HProp) acid) are isolated using original synthesis procedures involving ion pairs [MEAH]+[Carb] (MEA is monoethanolamine). The compounds are studied by IR spectroscopy, 1H NMR spectroscopy, elemental and thermal analyses, and mass spectrometry. Specific features for the complex formation of rare earth metal pivalates with MEA are additionally studied using quantum-chemical simulation.  相似文献   

2.
Y(III) and lanthanide(III) mesaconates were prepared as crystalline solids with general formula Ln2(C5H4O4)3nH2O, where n=7 for La−Pr, n=4 for Y,Nd−Ho, n=8 for Er−Lu. IR spectra of the prepared mesaconates suggest that carboxylate groups are bidentate bridging anf chelating. During heating the hydrated complexes are dehydrated in one (Y, Nd−Lu) or two steps (La−Pr) and then decompose directly to oxides (Y, Ce, Pr, Sm, Gd−Lu) or with intermediate formation Ln2O2CO3 (La, Nd, Eu). This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

3.
A series of neutral mononuclear lanthanide complexes [Ln(HL)2(NO3)3] (Ln = La, Ce, Nd, Eu, Gd, Dy, Ho) with rigid bidentate ligand, HL (4′-(1H-imidazol-1-yl)biphenyl-4-carboxylic acid) were synthesized under solvothermal conditions. The coordination compounds have been characterized by infrared spectroscopy, thermogravimetry, powder X-ray diffraction and elemental analysis. According to X-ray diffraction, all the complexes are a series of isostructural compounds crystallized in the P2/n monoclinic space group. Additionally, solid-state luminescence measurements of all complexes show that [Eu(HL)2(NO3)3] complex displays the characteristic emission peaks of Eu(III) ion at 593, 597, 615, and 651 nm.  相似文献   

4.
The interaction of lanthanide(III) ions with two N3O3-macrocycles, L1 and L2, derived from 2,6-bis(2-formylphenoxymethyl)pyridine and 1,2-diaminoethane has been investigated. Schiff-base macrocyclic lanthanide(III) complexes LnL1(NO3)3 · xH2O (Ln = Nd, Sm, Eu or Lu) have been prepared by direct reaction of L1 and the appropriate hydrated lanthanide nitrate. The direct reaction between the diamine macrocycle L2 and the hydrated lanthanide(III) nitrates yields complexes LnL2(NO3)3· H2O only for Ln = Dy or Lu. The reduction of the Schiff-base macrocycle decreases the complexation capacity of the ligand towards the Ln(III) ions. The complexes have been characterised by elemental analysis, molar conductivity data, FAB mass spectrometry, IR and, in the case of the lutetium complexes, 1H NMR spectroscopy.  相似文献   

5.
Formation thermodynamics of binary and ternary lanthanide(III) (Ln = La, Ce, Nd, Eu, Gd, Dy, Tm, Lu) complexes with 1,10-phenanthroline (phen) and the chloride ion have been studied by titration calorimetry and spectrophotometry in N,N-dimethyl-formamide (DMF) containing 0.2 mol-dm–3 (C2H5)4NClO4 as a constant ionic medium at 25°C. In the binary system with 1,10-phenanthroline, the Ln(phen)3+ complex is formed for all the lanthanide(III) ions examined. The reaction enthalpy and entropy values for the formation of Ln(phen)3+ decrease in the order La > Ce > Nd, then increase in the order Nd < Eu < Gd < Dy, and again decrease in the order Dy > Tm > Lu. The variation is explained in terms of the coordination structure of Ln(phen)3+ that changes from eight to seven coordination with decreasing ionic radius of the metal ion. In the ternary Ln3+-Cl-phen system, the formation of LnCl(phen)2+, LnCl2(phen)+, and LnCl3(phen) was established for cerium(III), neodymium(III), and thulium(III), and their formation constants, enthalpies, and entropies were obtained. The enthalpy and entropy values are also discussed from the structural point of view.  相似文献   

6.
Europium and terbium mixed-ligand complexes with cinnamic acid of composition Ln(Cin)3· nD · xH2O, where Ln = Eu3+or Tb3+, Cin is a cinnamate ion (C6H5CH=CHCOO), D = 1,10-phenantroline, 2,2"-dipyridyl, benzotriazole (n= 2, x= 0), triphenylphosphine oxide (n= 1, x= 2), or H2O (n= 0 or 1, x= 0), were synthesized. The compounds were characterized by elemental analysis, IR and luminescence spectroscopy. The Stark structure of the 5 D 07 F j(j= 0, 1, 2) electronic transitions in the low-temperature luminescence spectra of europium complexes was analyzed. IR study has revealed a bidentate coordination of the cinnamate ion in the compounds.  相似文献   

7.
The complexation between the lanthanide metal ions Ce(III), Gd(III), Nd(III), Tb(III), and Er(III) and gliclazide produced 1 : 1 molar ratio metal: gliclazide (Glz) complexes coordinated in a monodentate fashion via the OH group and having the general formulas [M(Glz)Cl3(H2O)]·xH2O (M = Ce, Gd, Nd and x = 1, 3, 4, respectively) and [M(Glz)(H2O)4]Cl3·yH2O (M = Tb, Er and y = 1, 2, respectively). The structure of the synthesized lanthanide gliclazide complexes was assigned by IR, 1HNMR, and UV-Vis spectroscopy. Thermal analysis and kinetic and thermodynamic parameters gave evidence for the thermal stability of the Glz complexes. The latter showed a significant antimicrobial effect against some bacteria and fungi.  相似文献   

8.
The Ln2(H2O)4(L)3·2H2O and Ln2(phen)2(L)3·2H2O complexes [Ln = Eu(III), Sm(III), or Dy(III); H2L = C6F4(COOH)2, phen = 1,10-phenanthroline] have been prepared. Structures of the prepared compounds have been confirmed by X-ray diffraction and IR spectroscopy studies. The complexes of Eu(III) have exhibited red photoluminescence stronger than that of the complexes of Sm(III) and Dy(III).  相似文献   

9.
Summary Solid complexes of 3-acetyl-1,5-diaryl and 3-cyano-1,5-diaryl formazans were prepared and characterized by elemental analysis, IR, NMR, TGA and DTA analyses. Based on these studies, the suggested general formula for the complexes is [M(HL) m (OH) n or (NO 3 or Cl) x ·(H2O) y or (C2H5OH orDMSO) z , where HL=formazanM=Ce3+, Th4+, and UO 2 2+ ,m=1–2,n=0–3,x=0–3,y=0–4 andz=0–3. The metal ions are expected to have coordination numbers 6–8.
Strukturuntersuchungen an 3-Acetyl-1,5-diaryl- und 3-Cyan-1,5-diaryl-formazan-Chelaten mit Cer(III), Thorium(IV) und Uran(VI)
Zusammenfassung Die hergestellten Chelate wurden mittels Elementaranalyse, IR, NMR, TGA und DTA charakterisiert. Darauf basierend wird die generelle Formel [M(HL) m (OH) n bzw. (NO 3 oder Cl) x ·(H2O) y oder (C2H5OH bzw.DMSO) z ] vorgeschlagen, wobei HL=Formazan,M=Ce3+, Th4+ oder UO 2 2+ ,m=1–2,n=0–3,x=0–3,y=0–4 undz=0–3. Die Metallionen haben Koordinationszahlen von 6–8.
  相似文献   

10.
Binuclear complexes of Sm(III), Eu(III), Gd(III), Tb(III), and Dy(III) nitrates with 4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione (C11H20N4O2, SC)—[Sm(NO3)3(SC)(H2O)]2(I), [Eu(NO3)3(SC)(H2O)]2 (II), [Gd(NO3)2(SC)(H2O)3)]2(NO3)2 (III), [Tb(NO3)3(SC)(H2O)]2 (IV), [Dy(NO3)3(SC)(H2O)]2 (V), are synthesized, and their X-ray diffraction analyses are carried out. The crystals of complexes I–V are monoclinic: space group P21/n for III and P21/c for I, II, IV, and V. In centrosymmetric coordination complexes II, III, IV, and V, the Ln atoms are coordinated by two O(1) and O(2) atoms of two molecules of the SC ligands bound by a symmetry procedure (1 ? x, ?y, 1 ? z), three bidentate nitrate anions, and a water molecule. The coordination numbers of the metal atoms are equal to 9, and the coordination polyhedra are considerably distorted three-capped trigonal prisms, whose bases include the O(1), O(2), O(12) and O(3), O(7), O(9) atoms. The dihedral angle between the bases of the prism is 18°, and that between the mean planes of the side faces is 55°–71° for I, 17° and 55°–71° for II, 16° and 55°–70° for IV, and 16° and 55°–70° for V. The Sm...Sm distance in complex I is 9.44 Å, Eu...Eu in II is 9.42 Å, Tb...Tb in IV is 9.36Å, and Dy...Dy in V is 9.36Å. The gadolinium atom in complex III is coordinated by two oxygen atoms of two ligand molecules bound by a symmetry procedure (?x, ?y + 1, ?z + 1), two bidentate nitrate anions, and three water molecules. One of the nitro groups in compound III is localized in the external coordination sphere of the metal. The coordination number of gadolinium is 9, and the coordination polyhedron is a significantly distorted three-capped trigonal prism, whose base includes the O(1), O(2), O(7) and O(4), O(5), O(9) atoms. The dihedral angle between the bases of the prism is 22.8°, and that between the mean planes of the side faces is 53°–72°. The Gd...Gd distance in complex III is 9.17 Å.  相似文献   

11.
A series of five l ‐di‐p‐toluoyl‐tartaric acid (l ‐DTTA) lanthanide coordination polymers, namely {[Ln4K4 L6(H2O)x]?yH2O}n, [Ln=Dy ( 1 ), x=24, y=12; Ln=Ho ( 2 ), x=23, y=12; Ln=Er ( 3 ), x=24, y=12; Ln=Yb ( 4 ), x=24, y=11; Ln=Lu ( 5 ), x=24, y=12] have been isolated by simple reactions of H2L (H2L= L ‐DTTA) with LnCl3?6 H2O at ambient temperature. X‐ray crystallographic analysis reveals that complexes 1 – 5 feature two‐dimensional (2D) network structures in which the Ln3+ ions are bridged by carboxylate groups of ligands in two unique coordinated modes. Luminescent spectra demonstrate that complex 1 realizes single‐component white‐light emission, while complexes 2 – 4 exhibit a characteristic near‐infrared (NIR) luminescence in the solid state at room temperature.  相似文献   

12.
《化学:亚洲杂志》2018,13(16):2126-2134
The chemistry of metal–organic frameworks has been progressing fast with its exciting potential in multifunctional applications. A series of three‐dimensional lanthanide‐based metal–organic frameworks, {[Ln(HTPO)(NO3)(H2O)]⋅x(CH3CN)⋅y(H2O)}n (Ln=Eu ( 1 ), Tb ( 2 ), Gd ( 3 ), Sm ( 4 ), Dy ( 5 ), Nd ( 6 )), {[Eu(TPO)(HCOO)0.5]⋅(H3O)0.5}n ( 7 ), {[Eu(TPO)(DMF)]⋅(solv)x}n ( 8 ; DMF= N,N‐dimethylformamide), and {[Eu(TPO)(DMA)]⋅(solv)x}n ( 9 ; DMA=dimethylacetamide) were synthesized with semirigid C3‐symmetric ligand tris(4‐carboxylphenyl)phosphine oxide (H3TPO). In these frameworks, the H3TPO ligand exists in a totally different configuration. Framework 1 exhibits good breathing properties for absorbing more guest molecules through a solvent‐induced single‐crystal‐to‐single‐crystal (SC–SC) transformation involving a configuration transformation of the organic linker in the framework. The ytterbium ion was doped into 1 to improve the luminescent performance (lifetime and quantum yield) of the red europium emission. Among a series of Eu1−xYbxTPO samples, Eu0.88Yb0.12TPO showed enhanced luminescence intensity (≈5.1 times that of the pure europium system), and the lifetime increased from 1073.08 to 1236.57 μs. Moreover, the porosity of these frameworks allows them to efficiently adsorb dye molecules with high selectivity and efficiency.  相似文献   

13.
Synthesis of lanthanide-containing (Ln = Eu, Tb, Nd, Gd) monomers based on unsaturated acids is described, namely, of LnL1 3 · nH2O (L1 are anions of acrylic and methacrylic acids) and Ln2L2 3 · nH2O (L2 are anions of maleic and fumaric acids); n = 0–3, 6. The compounds were characterized by elemental analysis, thermogravimetry, and IR and luminescence spectroscopy. Europium methacrylate Eu(Macr)3 was studied using X-ray diffraction analysis: rhombic system, a = 14.831(3) Å, b = 12.964(2) Å, c = 7.761(1) Å, space group Cmc21, V = 1483.5(4) Å3, (calcd) = 1.823 g/cm3. Infinite chains of Eu(Macr)3 molecules are directed along crystallographic axis c and are bound by van der Waals interactions. Radical polymerization of Eu(III) and Tb(III) acrylates and Eu(III) methacrylate yields lanthanide-containing polymers with a high content of Ln (40–50 mass %). Their spectral and luminescent properties are studied.  相似文献   

14.
Complexes of lanthanide(III) (La–Lu) and Y(III) with 1-hydroxy-2-naphthoic acid were obtained as crystalline compounds with a general formula Ln[C10H6(OH)COO]3nH2O:n=6 for La–Tm and Y, n=2 for Yb and n=0 for Lu. IR spectra of the prepared complexes were recorded, and their thermal decomposition in air were investigated. Spectroscopic data suggest that in the coordination of metal-organic ligand only oxygen atoms from the carboxylate group take part. When heated, the complexes decompose to the oxides Ln2O3, CeO2, Pr6O11 and Tb4O7 with intermediate formation of Ln(C11H7O3)(C11H6O3). This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

15.
4-Chloro-2-methoxybenzoates of light lanthanides(III) were obtained as mono-, di-or trihydrates with metal to ligand ratio of 1:3 and general formula Ln(C8H6ClO3)3·nH2O, where n=1 for Ln=Ce, Pr, n=2 for Ln=Nd, Sm, Eu, Gd and n=3 for Ln=La. The complexes were characterized by elemental analysis, IR spectra, thermogravimetric studies, X-ray diffraction and magnetic measurements. The carboxylate group appears to be a symmetrical bidentate, chelating ligand. All complexes seem polycrystalline compounds. Their thermal stabilities were determined in air. When heated they dehydrate to form anhydrous salts which next are decomposed to the oxides of the respective metals. The solubilities of light lanthanide(III) 4-chloro-2-methoxybenzoates in water at 293 K are of the order of 10−5 mol dm−3. The magnetic moments were determined over the range of 77–300 K. They obey the Curie-Weiss law. The values of μeff calculated for all compounds are close to those obtained for Ln3+ by Hund and Van Vleck. The results indicate that there is no influence of the ligand field of 4f electrons on lanthanide ions and the metal ligand bonding is mainly electrostatic in nature.  相似文献   

16.
Twelve coordinate lanthanide (III) complexes with the general composition [Ln L3Xn(H2O)n] where Ln = Pr(III), Sm(III), Eu (III), Gd (III), Tb (III), Dy (III), X = Cl?1, NO3 ?2, n = 2–7, and L is 1-(4-chlorophenyl)-3-(4-fluoro/hydroxyphenyl)prop-2-en-1- thiosemicarbazone have been prepared. The lanthanide complexes (5) were derived from the reaction between 1-(4-chlorophenyl)-3-(4-fluoro/hydroxyphenyl)prop-2-en-1-thiosemicarbazone (4) with an aqueous solution of lanthanide salt. Chalcone thiosemicarbazone ligand (4) was prepared by the reaction of [1-(4-chlorophenyl)-3-(4-fluoro/hydroxyphenyl)]prop-2-enone (chalcone) (3) with thiosemicarbazide in the presence of hot ethanol. All the lanthanide-ligand 1:3 complexes have been isolated in the solid state, are stable in air, and characterized on the basis of their elemental and spectral data.

Thiosemicarbazone ligands behave as bidentate ligands by coordinating through the sulfur of the isocyanide group and nitrogen of the cyanide residue. The probable structure for all the lanthanide complexes is also proposed. The chalcone thiosemicarbazone ligands and their lanthanide complexes have been screened for their antifungal and antibacterial studies. Some of the synthesized lanthanide complexes have shown enhanced activity compared with that of the free ligand.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.  相似文献   

17.
Summary The synergistic mixture comprising picrolonic acid (HPA) and benzo-15-crown-5 (B15C5) in chloroform has been used for the extraction of Ce(III), Eu(III) and Tm(III) as representatives of lanthanide(III) ions from pH 1-2 solutions having ionic strength of 0.1 mol. dm-3(K+/H+, Cl-). The composition of the extracted species has been determined as M(PA)3. nB15C5 where M is Ce, Eu and Tm and n=1 or 2. The influence of various anions and cations on the extraction of these ions has also been studied and only oxalate, cyanide and tartrate have some deleterious effect. The extraction equilibrium constants have been evaluated and discussed.  相似文献   

18.
Three new solid lanthanide(III) complexes, [Ln(1-AMUH)3] · (NO3)3 (1-AMUH = 1-amidino-O-methylurea; Ln = Eu(III), Gd(III), or Tb(III)) were synthesised and characterised by elemental analysis, infrared spectra, magnetic moment measurement, and electron paramagnetic resonance (EPR) spectra for Gd(III) complex. The formation of lanthanide(III) complexes is confirmed by the spectroscopic studies. The photophysical properties of Gd(III), Eu(III), and Tb(III) complexes in solid state were investigated. The Tb(III) complex exhibits the strongest green emission at 543 nm and the Eu(III) complex shows a red emission at 615 nm while the Gd(III) complex shows a weak emission band at 303 nm. Under excitation with UV light, these complexes exhibited an emission characteristic of central metal ions. The powder EPR spectrum of the Gd(III) complex at 300 K exhibits a single broad band with g = 2.025. The bi-exponential nature of the decay lifetime curve is observed in the Eu(III) and Tb(III) complexes. The results reveal them to have potential as luminescent materials.  相似文献   

19.
The [Ce(Piv)3(HPiv)3]2 complex was synthesized by reacting cerium(III) nitrate with NH4(Piv) (1 : 4) (HPiv is pivalic acid) in an aqueous solution and by further recrystallization of the obtained precipitate from a 5% HPiv solution in n-hexane. The complex structure and unit cell parameters were determined by X-ray diffraction analysis: a = 16.586(8) Å, b = 12.313(5) Å, c = 20.765(10) Å, = 109.27(2)°, V = 4003(2) Å3, Z = 4, R = 0.0546, R w = 0.0836, space group P21/n. The crystal structure of [Ce(Piv)3(HPiv)3]2 consists of centrosymmetric dimeric molecules with the Ce(III) atoms bound by four bridging pivalate ligands. Heating in an atmosphere of nitrogen is accompanied by the elimination of six HPiv molecules in the range of 90–190°C; the thermolysis of the obtained Ce(Piv)3 occurs at 290–450°C. In addition to the thermal decomposition, the sublimation of Ce(Piv)3 was also observed under reduced pressure (0.01 mmHg) in the temperature interval of 290–350°C.  相似文献   

20.
A new series of iron(III) complexes with different fourth generation of quinolone drugs of the type [Fe(L)n(Cl)x]?yH2O (( 1 ) L: nalidixic acid, n = 3, x = 3, y = 3; ( 2 ) L: oxolonic acid, n = 3, x = 3, y = 0; ( 3 ) L: pipemidic acid, n = 3, x = 3, y = 2; ( 4 ) L: lomefloxacin, n = 3, x = 3, y = 0; ( 5 ) L: pefloxacin mesylate, n = 3, x = 3, y = 2; ( 6 ) L: levofloxacin, n = 3, x = 3, y = 6) were synthesized and identified using microanalysis, Fourier transform infrared spectroscopy, conductance data, effective magnetic moments and electronic UV–visible spectra. In these six complexes, the quinolone drug chelates act in a unidentate manner via nitrogen atom of pyridone/piperazyl moiety. 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 thermal decomposition process is completed in 3?5 steps, the first step being responsible for loss of uncoordinated water molecules and the steady state of all complexes occurs at around 500 °C with oxide forms as residual products. The stabilities of iron(III) complexes 1 – 6 were studied in terms of activation energy E*, entropy ΔS*, enthalpy ΔH* and Gibbs free energy ΔG* that were estimated using Coats–Redfern and Horowitz–Metzger non‐isothermal methods. Molecular docking was used to predict the binding between some of the quinolone drugs and the receptor of prostate cancer 2q7k hormone.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号