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101.
Mikhail E. Minyaev Alexandr A. Vinogradov Dmitrii M. Roitershtein Konstantin A. Lyssenko Ivan V. Ananyev Ilya E. Nifant'ev 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(7):578-584
The significant variety in the crystal structures of rare‐earth carboxylate complexes is due to both the large coordination numbers of the rare‐earth cations and the ability of the carboxylate anions to form several types of bridges between rare‐earth metal atoms. Therefore, these complexes are represented by mono‐, di‐ and polynuclear complexes, and by coordination polymers. The interaction of LnCl3(thf)x (Ln = Eu or Y; thf is tetrahydrofuran) with sodium or diethylammonium diphenylacetate in methanol followed by recrystallization from a DME/THF/hexane solvent mixture (DME is 1,2‐dimethoxyethane) leads to crystals of the non‐isomorphic dinuclear complexes tetrakis(μ‐2,2‐diphenylacetato)‐κ4O:O′;κ3O,O′:O′;κ3O:O,O′‐bis[(1,2‐dimethoxyethane‐κ2O,O′)(2,2‐diphenylacetato‐κ2O,O′)europium(III)], [Eu(C14H11O2)6(C4H10O2)2], (I), and tetrakis(μ‐2,2‐diphenylacetato)‐κ4O:O′;κ3O,O′:O′;κ3O:O,O′‐bis[(1,2‐dimethoxyethane‐κ2O,O′)(2,2‐diphenylacetato‐κ2O,O′)yttrium(III)], [Y(C14H11O2)6(C4H10O2)2], (II), possessing monoclinic (P21/c) symmetry. The [Ln(Ph2CHCOO)3(dme)]2 molecule (Ln = Eu or Y) lies on an inversion centre and exhibits three different coordination modes of the diphenylacetate ligands, namely bidentate κ2O,O′‐terminal, bidentate μ2‐κ1O:κ1O′‐bridging and tridentate μ2‐κ1O:κ2O,O′‐semibridging. The terminal and bridging ligands in (I) are disordered over two positions, with an occupancy ratio of 0.806 (2):0.194 (2). The interaction of EuCl3(thf)2 with Na[Ph3CCOO] in methanol followed by crystallization from hot methanol produces crystals of tetrakis(methanol‐κO)tris(2,2,2‐triphenylacetato)‐κ4O:O′;κO‐europium(III) methanol disolvate, [Eu(C19H15O2)3(CH3OH)4]·2CH3OH, (III)·2MeOH, with triclinic (P) symmetry. The molecule of (III) contains two O,O′‐bidentate and one O‐monodentate terminal triphenylacetate ligand. (III)·2MeOH possesses one intramolecular and four intermolecular hydrogen bonds, forming a [(III)·2MeOH]2 dimer with two bridging methanol molecules. 相似文献
102.
New crystal structure of Eu(DMF)4(H2O)3Co(CN)6·H2O (DMF = N,N′-dimethylformamide) (Eu-Co) has been determined to be monoclinic, P2(1)/n, a = 19.796(12) Å, b = 8.862(11) Å, c = 17.525(10) Å, β = 96.26(5)°, V = 3056(5) Å3, Z = 4. The Eu(III) ion adopts an antiprismatic eight-coordination and forms a cyano bridge with r(Eu-N) = 2.496(7) Å and Θ(Eu-N-C) = 165.7(7)° to the Co(III) ion. The complex exhibits some common features with the Eu-Fe complex. Diffuse reflectance electronic spectra and magnetic susceptibility of Eu-Cr, Eu-Mn, Eu-Fe, and Eu-Co complexes were compared. By substituting the metal ions, both electronic and structural features affected the charge transfer bands and superexchange interactions concerning cyanide ligands. In addition, only Eu-Co exhibited 5 D 0 → 7 F 2 and 5 D 0 → 7 F 1 luminescence bands at 16300 cm?1 and 16900 cm?1, respectively at 298 K (λex = 360 nm (27000 cm?1)), because quenching by cyano-bridged ions did not prevent Eu(III) ion from exhibiting emission. Thus, only Eu-Co may be suitable for verification of an assumption of mechanism concerning drastic photoinduced magnetic changes for Nd-Fe. Merely small decrease of magnetization was observed for Eu-Co after UV light irradiation at 2.0 K. This result was attributed to slight structural changes around cyano bridges without transitions of spin states. 相似文献
103.
Charbonnière LJ Weibel N Retailleau P Ziessel R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(1):346-358
A series of six new ligands (L(1)-L(6)) suitable for the formation of luminescent lanthanide complexes in water is described. Ligands L(1)-L(4) are constructed from two 6'-carboxy-6-methylene-2,2'-bipyridine chromophoric arms bonded to the amino function of a 2-aminomethylene-6-carboxy-pyridine (L(1)), an N,N-diacetate-ethylene diamine (L(2)), a serine (L(3)), or an aminomalonic acid (L(4)). For ligands L(5) and L(6), the linking amino function is provided by a glutamic acid, and the anionic functions at the 6'-position of the bipyridyl arms are made of the sodium salts of monoethylphosphonic ester (L(5)) and phosphonic acid (L(6)). The synthesis and characterisation of the ligands are described, together with the study of the formation of lanthanide complexes with europium and terbium. In the case of L(3), the europium complex obtained in acidic conditions was crystallised and the X-ray crystal structure is depicted. Photophysical properties of the complexes were studied by means of UV-visible absorption, and steady-state and time-resolved luminescence spectroscopy. Excited-state luminescence lifetimes of the complexes were determined in water and deuterated water to gain insight into the number of water molecules directly coordinated in the first coordination sphere of the complexes. The coordination behaviour of the series of ligands is questioned in the light of the spectroscopic data and discussed in terms of protection of the cation towards water molecules and their impact on the luminescence efficiency. 相似文献
104.
铕(Ⅲ)激活的磷酸镧发光性质研究 总被引:4,自引:0,他引:4
LaPO4:Eu3+的发射光谱包含较强的Eu3+5Do→7F1跃迁发射和较弱的6D1→7F1跃迁发射。主发射峰583nm,对应于Eu3+5Do→7F1跃迁.通过对Eu3+的两种跃迁发射强度及荧光寿命和Eu3+浓度关系的测定和理论分析,探讨了发光中心Eu3+离子同的交叉弛豫和能量迁移机理。 相似文献
105.
应用光谱技术研究铽及铕与水杨基羟肟酸所形成的配合物的发光性能,并探讨配合物的形成,以及溶剂、pH值及稀土含量对发光强度和能量传递的影响。 相似文献
106.
本文报导了Tb,Eu,La与邻氨基苯甲酸(o-AA)或N-苯基邻氨基苯甲酸(N-PAA)及邻菲啡啰啉(Phen)形成的固态三元配合物。通过元素分析,热谱分析和摩尔电导测定确定该类配合物的组成为Ln(Phen)(L)3(Ln=Tb、Eu、La,L=o-AA或N-PAA),考察了这类配合物的红外光谱、UV吸收光谱、核磁共振谱和x光电子能谱,确定其配位形式,并讨论了它们的发光性质。 相似文献
107.
ENHANCEMENT OF ENERGY TRANSFER FROM THE TERMINAL CHROMOPHORE OF POLYETHER TO EUROPIUM CATION(Ⅲ)VIA COMPLEXATION 下载免费PDF全文
The fluorescence spectra of naphthalene end-labelled polyethylene glycol)(N-PnN) in methanol solution in the presence of europium cation(Ⅲ) was investigated. Selective excitation of the naphthalene group of N-Pn-N re-sults in the emission of europium cation. suggesting that the polyether chain complexes with europium cation, thus efficient energy transfer from naphthalene chromophore to europium cation occurs. Photoirradiation of N-P-N in solution leads to intramolecular dimerization of the two terminal naphthalene groups to give a crown ether. The complexation of this photochemically synthesized crown ether and europium cation was also studied. 相似文献
108.
Europium hydroxide particles with an average diameter of 10 run and a BET surface area of 127 m2 /g have been prepared by controlled precipitation in the polyoxyethylene octylphenol (Triton X-100) (hex-anol)/cyclohexane/water microemulsion system. After calcination in air at 750℃, the obtained europium hydroxide particles were readily converted to the nanosize Eu2O3 particles with an average size of 30 nm and a high BET surface area of 36.5 m2/g. 相似文献
109.
V. V. Syt’ko N. A. Aleshkevich E. L. Tikhova D. S. Umreiko I. A. Khartonik 《Journal of Applied Spectroscopy》1999,66(1):94-99
Absorption and luminescence spectra of Me7Eu2UO2(PO4)5 crystals (Me represents Na, Rb, or Cs) are investigated. It is established that the luminescence of Eu3+ ions in these crystals is sensitized by uranyl. The effect of the outer-sphere cation Me+ on the spectroscopic properties and structural features of the compounds under study is considered.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 89–94, January–February, 1999. 相似文献
110.
The article considers the luminescence-kinetics properties of crystals of ternary uranyl orthephosphates Me7Eu2UO2(PO4)5 (Me — Na, Rb, Cs) obtained by the methods of solid-phase synthesis. The main parameters of conversion of the electron excitation
energy in the donor-acceptor UO
2
2+
—Ln3+ system are determined. The competition between the processes of nonradiative dissipation and energy transfer from UO
2
2+
to Eu3+ has been revealed. It is shown that the rate of the processes of nonradiative transitions in the uranyl complex is determined
by the degree of distortion of its local field, while the luminescence lifetime of the acceptors depends on the energy of
electrostatic interaction between Eu3+ and oxygen atoms of its first coordination sphere.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 333–335, May–June, 2000. 相似文献