Visible and near-infrared intense luminescence from water-soluble lanthanide [Tb(III), Eu(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), Er(III)] complexes

The synthesis of a new ligand (1) containing a single phenanthroline (phen) chromophore and a flexibly connected diethylenetriamine tetracarboxylic acid unit (DTTA) as a lanthanide (Ln) coordination site is reported [1 is 4-[(9-methyl-1,10-phenantrol-2-yl)methyl]-1,4,7-triazaheptane-1,1,7,7-tetraacetic acid]. From 1, an extended series of water-soluble Ln.1 complexes was obtained, where Ln is Eu(III), Tb(III), Gd(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III). The stoichiometry for the association was found 1:1, with an association constant K(A) > or = 10(7) s(-1) as determined by employing luminescence spectroscopy. The luminescence and photophysical properties of the series of lanthanide complexes were investigated in both H2O and D2O solutions. High efficiencies for the sensitized emission, phi(se), in air-equilibrated water were observed for the Ln.1 complexes of Eu(III) and Tb(III) in the visible region (phi(se) = 0.24 and 0.15, respectively) and of Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III) in the vis and/or near-infrared region [phi(se) = 2.5 x 10(-3), 5 x 10(-4), 3 x 10(-5), 2 x 10(-5), 2 x 10(-4), 4 x 10(-5), and (in D2O) 4 x 10(-5), respectively]. For Eu.1 and Tb.1, luminescence data for water and deuterated water allowed us to estimate that no solvent molecules (q) are bound to the ion centers (q = 0). Luminescence quenching by oxygen was investigated in selected cases.     

Syntheses, structures, near-infrared and visible luminescence, and magnetic properties of lanthanide-organic frameworks with an imidazole-containing flexible ligand

Reactions of tripodal ligand 1,3,5-tris(imidazole-1-ylmethyl)-2,4,6-trimethylbenzene (L) with lanthanide metal salts and triethyl orthoformate led to the formation of six bowl-like dinuclear compounds [Ln2(L)(HL)(NO3)6(HCOO)].3CH3OH (Ln = Gd 1, Tb 2, Dy 3, Er 4, Yb 5, and Eu 6). The single-crystal X-ray diffraction analysis revealed that six complexes are isomorphous and isostructural and that the dinuclear molecules are further connected by hydrogen bonds and pi-pi interactions, resulting in 3D channel-like structures. The luminescence properties have been studied, and the results showed that the Tb(III) (2) and Eu(III) (6) complexes exhibited sensitized luminescence in the visible region and their luminescence lifetimes in powder and DMSO-d6 solution are in the range of milliseconds. The Yb(III) complex (5) emits typical near-infrared luminescence in DMSO-d6 solution. Variable-temperature magnetic susceptibility measurements of 1-6 showed that complex 1 (Gd) is nearly a paramagnet and complexes 2 (Tb), 3 (Dy), and 4 (Er) show the ferromagnetic coupling between magnetic centers, whereas the depopulation of the Stark levels in complexes 5 (Yb) and 6 (Eu) leads to a continuous decrease in (chi M)T when the sample is cooled from 300 to 1.8 K.     

杂金属配位聚合物[Ln2Zn2(2,5-pydc)5(H2O)2]·4H2O的合成、结构及发光特性

采用水热法通过Ln2O3、Zn(CH3COO)2·2H2O与2,5-吡啶二羧酸为配体的反应合成出两个新型三维杂金属配位聚合物[Ln2Zn2(2,5-pydc)5(H2O)d·4H2O (Ln=Sm(1),Eu(2);2,5-pydc:2,5-吡啶二羧酸).通过元素分析、红外光谱、X射线粉未衍射方法以及X射线单晶衍射方法对配合物进行了表征.结构分析表明,配合物1和2的结构是相同的,其晶体均为单斜晶系,空间群为P21/C.配合物1和2中2,5-吡啶二羧酸配体共有两种配位方式.通过配位模式Ⅰ连接Ln和Zn形成二维层状结构;而层与层之间通过配位模式Ⅱ进一步连接起来形成三维复杂网状结构.此外,还对配合物的荧光性质和热分解过程进行了详细分析.荧光分析表明,金属Zn的引入有效增强了配合物中稀土金属的发光.     

Luminescence tuning of imidazole-based lanthanide(III) complexes [Ln = Sm, Eu, Gd, Tb, Dy

To tune the lanthanide luminescence in related molecular structures, we synthesized and characterized a series of lanthanide complexes with imidazole-based ligands: two tripodal ligands, tris{[2-{(1-methylimidazol-2-yl)methylidene}amino]ethyl}amine (Me(3)L), and tris{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(3)L), and the dipodal ligand bis{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(2)L). The general formulas are [Ln(Me(3)L)(H(2)O)(2)](NO(3))(3)·3H(2)O (Ln = 3+ lanthanide ion: Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)), [Ln(H(3)L)(NO(3))](NO(3))(2)·MeOH (Ln(3+) = Sm (6), Eu (7), Gd (8), Tb (9), and Dy (10)), and [Ln(H(2)L)(NO(3))(2)(MeOH)](NO(3))·MeOH (Ln(3+) = Sm (11), Eu (12), Gd (13), Tb (14), and Dy (15)). Each lanthanide ion is 9-coordinate in the complexes with the Me(3)L and H(3)L ligands and 10-coordinate in the complexes with the H(2)L ligand, in which counter anion and solvent molecules are also coordinated. The complexes show a screw arrangement of ligands around the lanthanide ions, and their enantiomorphs form racemate crystals. Luminescence studies have been carried out on the solid and solution-state samples. The triplet energy levels of Me(3)L, H(3)L, and H(2)L are 21?000, 22?700, and 23?000 cm(-1), respectively, which were determined from the phosphorescence spectra of their Gd(3+) complexes. The Me(3)L ligand is an effective sensitizer for Sm(3+) and Eu(3+) ions. Efficient luminescence of Sm(3+), Eu(3+), Tb(3+), and Dy(3+) ions was observed in complexes with the H(3)L and H(2)L ligands. Ligand modification by changing imidazole groups alters their triplet energy, and results in different sensitizing ability towards lanthanide ions.     

Cooperative processes governing formation of small pentanuclear lanthanide(III) nanoclusters and energy transport within and between them

Syntheses, lanthanide quantitative analyses, mass spectrometry and luminescence spectroscopy, and decay dynamics of crystals containing pentanuclear hetero-lanthanide(III) nanoclusters [(Ln'(5-x)Ln(x))(NO(3))(6)(mu(5)-OH)(mu(4)-L)(2)] (0 < or = x < or = 5), Ln' = Eu or Tb; Ln = La-Nd, Sm-Ho (hereafter Ln'(5-x) Ln(x)) were undertaken in search of information on factors governing self-assembly processes by which the clusters are formed and electronic interactions within and between them. The data obtained are consistent with the self-assembly of Ln'(5-x) Ln(x) nanoclusters being a concerted process featuring a profound expression of complementarity among mutually bridging [Ln(mu(4)-L](-) and [Ln(NO(3))(2)](+) components. The energy transport regime in crystals of Eu(5-x) Ln(x) is in the dynamic regime when x = 0 or Ln = La and, at 293 K, Ln = Dy, despite the presence of two crystallographically different Eu(3+) coordination environments which give rise to a doublet in the excitation and emission spectra of Eu(3+)((5)D(0)). The luminescence decay behavior of Eu(3+)((5)D(0)) in Eu(5-x) Ln(x) (Ln = Dy (for 77 K), Sm) is intermediate between the static and dynamic limits and reveals extensive electronic coupling among lanthanide ions, including many-body processes at relatively high Dy(3+) or Sm(3+) concentrations.     

Crystal structures and magnetic and luminescent properties of a series of homodinuclear lanthanide complexes with 4-cyanobenzoic ligand

A series of homodinuclear lanthanide(III) complexes with the 4-cba ligand, [La2(4-cba)6(phen)2(H2O)6] (1) and [Ln2(4-cba)6(phen)2(H2O)2] (Ln = Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), and Dy (7); 4-Hcba = 4-cyanobenzoic acid; phen = 1,10-phenanthroline), have been synthesized and structurally characterized by single-crystal X-ray diffraction. In 1, two water molecules bridge two nine-coordinated La ions, and six 4-cba ligands coordinate to the two La ions in terminal mode. In the isostructural complexes 2-7, two eight-coordinated Ln ions are connected by four bidentate 4-cba ligands, and another two 4-cba ligands terminate the two Ln ions. The variable-temperature magnetic properties of 2-7 have been investigated. Complex 7 shows a significant ferromagnetic interaction between Dy(III), while no magnetic interaction exists between Gd(III) ions in 6. In 2-5, the value of chi(M)T decreases with decreasing temperature, but the magnetic interactions between the Ln(III) ions cannot definitely be concluded. Notably, the spin-orbit coupling parameters, lambda, for Sm(III) (216(2) cm(-1)) and Eu(III) (404(2) cm(-1)) have been obtained in 4 and 5, respectively. The strong fluorescent emissions of 4, 5, and 7 demonstrate that ligand-to-Ln(III) energy transfer is efficient and that the coordinated water molecules do not quench their luminescence by the nonradiative dissipation of energy.     

Cobalt-lanthanide coordination polymers constructed with metalloligands: a ferromagnetic coupled quasi-1D Dy3+ chain showing slow relaxation

Four types of cobalt-lanthanide heterometallic compounds based on metalloligand Co(2,5-pydc)(3) (3-) (2,5-H(2)pydc=pyridine-2,5-dicarboxylate acid), [Ln(2)Co(2)(2,5-pydc)(6)(H(2)O)(4)](n) 2n H(2)O (1) (Ln=Tb, Dy for 1 a, 1 b respectively), [Tb(2)Co(2)(2,5-pydc)(6)(H(2)O)(4)](n)3n H(2)O (2), [Tb(2)Co(2)(2,5-pydc)(6)(H(2)O)(9)](n)4n H(2)O (3), and [LaCo(2,5-pydc)(3)(H(2)O)(2)](n)2n H(2)O (4) have been synthesized. Compound 1 has a layer structure with well-isolated carboxylate-bridged Ln(3+) chains, compound 2 is a three-dimensional (3D) porous network with Tb(3+) chains that are also well isolated and carboxylate bridged, 3 is a layer structure based on dinuclear units, and 4 is a 3D network with boron nitride (BN) topology. DC magnetic studies reveal ferromagnetic coupling in all the carboxylate-bridged Ln(3+) chains in 1 a, 1 b, and 2. Compared to the silence of the out-of-phase ac susceptibility of 2, above 1.9 K the magnetic relaxation behavior of both 1 a and 1 b is slow like that of a single-chain magnet.     

Synthesis and single-crystal x-ray diffraction examination of a structurally homologous series of tetracoordinate heteroleptic anionic lanthanide complexes: Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(L)3 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb; (L)3 =(THF)3, (Et2O)3, (THF)2(Et2O)

Anhydrous lanthanide(III) chlorides (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) react with 3 equiv of lithium 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentanide, Li[N[Si(CH3)2CH2Ch2Si(CH3)2]], in THF or Et(2)O to afford the monomeric four-coordinate heteroleptic ate complexes Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(THF/Et2O)3 (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Tm (8), Yb (9)), whose solid-state structures were determined by the single-crystal X-ray diffraction technique. All complexes additionally were characterized by melting point determination, elemental analyses, and mass spectrometry.     

Two- and three-dimensional lanthanide complexes: synthesis, crystal structures, and properties

3,5-pyrazoledicarboxylic acid (H3L) reacts with nitrate salts of lanthanide(III) (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er) under hydrothermal conditions to form a series of lanthanide polymers 1-9. These nine polymers have the same crystal system of monoclinic, but they exhibit three different kinds of metal-organic framework structures. The complexes {[Ln2(HL)3(H2O)4].2H2O}n (Ln=Pr (1), Nd (2), and Sm (3)) were isostructural and exhibited porous 3D frameworks with a Cc space group. The complexes {[Ln2(HL)3(H2O)3].3H2O}n (Ln=Eu (4), Gd (5), and Tb (6)) were isostructural and built 2D double-decker (2DD) frameworks with a P21/c space group. The complexes {[Ln(HL)(H2L)(H2O)2]}n ((Ln=Dy (7), Ho (8), and Er (9)) were also isostructural and formed 2D monolayer (2DM) frameworks with a P21/n space group. The structure variation from the 3D porous framework to the 2D double-decker to the 2D monolayer is attributed to the lanthanide contraction effect. Notably, six new coordination modes of 3,5-pyrazoledicarboxylic acid were observed, which proved that 3,5-pyrazoledicarboxylic acid may be used as an effective bridging ligand to assemble lanthanide-based coordination polymers. The photophysical and magnetic properties have also been investigated.     

Structures and magnetic properties of several novel lanthanide coordination polymers based on thiophene-2,5-dicarboxylic acid

Eight novel lanthanide complexes: {Ln(TDA)1.5(H2O)2}n (Ln = Pr(1a), Nd(2a)) and {Ln(TDA)(Ac)(H2O)}n (Ln = Pr(1), Nd(2), Eu(3), Gd(4), Tb(5), Dy(6); TDA = Thiophene-2,5-dicarboxylic acid anion) have been constructed by hydrothermal reaction. Structural analyses reveal that complexes 1a and 2a belong to the space group C2/c, exhibiting three-dimensional (3D) frameworks. Complexes 1-6 with P21/c space group were prepared in the presence of excessive ammonium acetate, giving rise to interesting 3D frameworks different from those of 1a and 2a. Magnetic property studies of 4-6 reveal the weak antiferromagnetic interaction exists between adjacent Gd3+ in 4. The complex 6 displays rather rare slow magnetization relaxation behavior in 3D frameworks.     

Hydrothermal synthesis, crystal structure and properties of Ni(II)-4f complexes based on 1H-benzimidazole-5,6-dicarboxylic acid

Nine novel heterometallic coordination polymers [Ln(2)Ni(Hbidc)(2)(SO(4))(2)(H(2)O)(8)](n) (Ln = Pr (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Ho (7), Er (8), Yb (9), H(3)bidc = 1H-benzimidazole-5,6-dicarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, FT-IR, TG analysis and single crystal X-ray diffraction. X-ray analysis revealed that all complexes present almost identical three-dimensional (3D) structures with PtS-type topology. Complexes 1-7 are all isomorphous, and the structure variation of polymers 8 and 9 is induced by the lanthanide contraction effect. In additional, the luminescence properties of complexes 2, 3 and 5-7, and the magnetic properties of complexes 4 and 6-8 were investigated.     

Diversity of lanthanide(iii)-2,5-dihydroxy-1,4-benzenedicarboxylate extended frameworks: syntheses, structures, and magnetic properties

Six lanthanide(iii)-2,5-dihydroxy-1,4-benzenedicarboxylate frameworks, namely, [Ln(H(2)-DHBDC)(1.5)(H(2)O)(2)](n) (Ln = La (1) and Pr (2); H(4)-DHBDC = 2,5-dihydroxy-1,4-benzenedicarboxylic acid), {[Nd(H(2)-DHBDC)(1.5)(H(2)O)(3)](H(2)O)}(n) (3), {[Eu(H(2)-DHBDC)(NO(3))(H(2)O)(4)](H(2)O)(2)}(n) (4), and {[Ln(2)(H(2)-DHBDC)(2)(DHBDC)(0.5)(H(2)O)(3)](H(2)O)(4)}(n) (Ln = Gd (5) and Dy (6)), with four different structural types ranging from 1D chain, 2D layer to 3D networks have been synthesized and structurally characterized. Compounds La (1) and Pr (2) are isomorphous and exhibit 3D frameworks with the unique 1D tubular channels. Compounds Nd (3) and Eu (4) are 2D layer and 1D zigzag chain, respectively, which are further extended to 3D supramolecular frameworks through extensive hydrogen bonds. Isomorphous compounds of Gd (5) and Dy (6) are 3D frameworks constructed from secondary infinite rod-shaped metal-carboxylate/hydroxyl building blocks. While the hydroxyl groups as secondary functional groups in the 1D chain of Eu (4) and 2D layer of Nd (3) are not bonded to the lanthanide centers, the hydroxyl groups in the 3D frameworks of La (1), Pr (2), Gd (5), and Dy (6) participate in coordinating to lanthanide centers and thus modify the structural types of theses compounds. The magnetic data of compounds Pr (2), Nd (3), Gd (5), and Dy (6) have been investigated in detail. In addition, elemental analysis, IR spectra, powder X-ray diffraction (PXRD) patterns and thermogravimetric analysis of these compounds are described.     

Syntheses, crystal structures and luminescent properties of new lanthanide(III) organoarsonates

The first examples of lanthanide(III) organoarsonates, Ln(L(1))(H(2)O)(3) (Ln = La (1), H(3)L(1) = 4-hydroxy-3-nitrophenylarsonic acid), Ln(L(1))(H(2)O)(2) (Ln = Nd (2), Gd (3)), and mixed-ligand lanthanide(III) organoarsonates, Ln(2)(HL(1))(2)(C(2)O(4))(H(2)O)(2) (Ln = Nd (4), Sm (5), Eu (6)), were hydrothermally synthesized and structurally characterized. Compounds 1-3 feature a corrugated lanthanide arsonate layer, in which 1D lanthanide arsonate inorganic chains are further interconnected via bridging L(1)(3-) ligands. Compounds 4-6 exhibit a complicated 3D network. The interconnection of the lanthanide(III) ions by the bridging arsonate ligand leads to the formation of a novel 3D framework with long narrow 1D tunnels along the a-axis, with the oxalate anions are located at the above tunnels and bridging with lanthanide(III) ions. Compounds 2 and 4 exhibit the characteristic emission bands of the Nd(III) ion, whereas compound 6 displays the characteristic emission bands of the Eu(III) ion. The magnetic properties of compounds 3-6 were also investigated.     

Sensitized luminescence in dinuclear lanthanide(III) complexes of bridging 8-hydroxyquinoline derivatives with different electronic properties

Three new dinuclear lanthanide(III) complexes {Eu(hfac)(3)(H(2)O)}(2)(μ-HPhMq)(2) (2) and {Ln(hfac)(3)(H(2)O)}(2)(μ-HMe(2)NC(6)H(4)Mq)(2) (Ln = Eu, 3; Nd, 4) with 8-hydroxylquinoline derivatives in μ-phenol mode were synthesized and characterized, where hfac(-) = hexafluoroacetylacetonate, HPhMq = 2-methyl-5-phenylquinolin-8-ol, and HMe(2)C(6)H(4)Mq = 5-(4-(dimethylamino)phenyl)-2-methylquinolin-8-ol. Compared with that (400 nm) for {Eu(hfac)(3)}(2)(μ-HMq)(2) (1, HMq = 2-methy-8-hydroxylquinoline), the excitation wavelength for sensitized lanthanide luminescence is extended to ca. 420 nm for 2, and 500 nm for 4 by introducing a phenyl or 4-(dimethylamino)phenyl to 8-hydroxylquinoline. These dinuclear lanthanide(III) complexes exhibit distinctly fluoride-induced lanthanide(III) emission enhancement in both intensity and lifetime due to replacing coordination water molecules or formation of strong O-H···F hydrogen bonds with coordinated H(2)O and μ-phenol, thus suppressing significantly the non-radiative O-H oscillators.     

Syntheses, structures and properties of seven isomorphous 1D Ln3+complexes Ln(BTA)(HCOO)(H2O)3 (H2BTA = bis(tetrazoly)amine, Ln = Pr, Gd, Eu, Tb, Dy, Er, Yb) and two 3D Ln3+ complexes Ln(HCOO)3 (Ln = Pr, Nd)

Seven isomorphous 1D chain Ln3+ complexes Ln(BTA)(HCOO)(H2O)3 (Ln = Pr (1), Gd (2), Eu (3), Tb (4) Dy (5), Er (6) and Yb (7)), and two formate coordinating and bridging 3D Ln3+ complexes Ln(HCOO)3 (Ln = Pr (8) and Nd (9)) have been synthesized and characterized by single crystal X-ray diffraction analysis. Although the Ln3+ ions in 1-7 have different radius, the trivalent lanthanide ions in 1-7 show the same coordinated environment. The well-defined single crystal structures of 8 and 9 are first samples for formate-bridged Ln3+ metallic complexes. The luminescent properties of solid samples of 2-5 at room temperature and the magnetic property of 2 have been also reported and discussed in this paper.     

Heptanuclear heterometallic [Cu6Ln] clusters: trapping lanthanides into copper cages with artificial amino acids

Employment of the artificial amino acid 2-amino-isobutyric acid, aibH, in Cu(II) and Cu(II)/Ln(III) chemistry led to the isolation and characterization of 12 new heterometallic heptanuclear [Cu(6)Ln(aib)(6)(OH)(3)(OAc)(3)(NO(3))(3)] complexes consisting of trivalent lanthanide centers within a hexanuclear copper trigonal prism (aibH = 2-amino-butyric acid; Ln = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), and Yb (12)). Direct curent magnetic susceptibility studies have been carried out in the 5-300 K range for all complexes, revealing the different nature of the magnetic interactions between the 3d-4f metallic pairs: dominant antiferromagnetic interactions for the majority of the pairs and dominant ferromagnetic interactions for when the lanthanide center is Gd(III) and Dy(III). Furthermore, alternating current magnetic susceptibility studies reveal the possibility of single-molecule magnetism behavior for complexes 7 and 8. Finally, complexes 2, 5-8, 10, and 12 were analyzed using positive ion electrospray mass spectrometry (ES-MS), establishing the structural integrity of the heterometallic heptanuclear cage structure in acetonitrile.     

Low pH hydrothermal synthesis and properties of lanthanide-organic frameworks with (4(10),6(5))(4(9),6(6)) topology constructed from Ln-Hbptc building blocks

Two novel lanthanide-organic frameworks (LnOFs) with (4(10),6(5))(4(9),6(6)) topology, [Ln(Hbptc)(H(2)O)](n) (Ln = Eu(1), Gd(2); H(4)bptc = 3,3',4,4'-biphenyltetracarboxylic acid) were synthesized via the hydrothermal in situ reaction between lanthanide salts and 3,3',4,4'-biphenyltetracarboxylic dianhydride (bpta) under low pH conditions. In complexes 1 and 2, homohelix bundles with opposite chirality are assembled alternately and result in pillar-like 3D extended networks incorporated with coordinated water molecules, which show high thermal stability. The luminescence properties are illustrated by the Eu(III) complex (1) and its Gd-doped compound, which are intensive red emitters. The magnetic properties of complexes 1 and 2 are also investigated.     

4-[(1,3-二氧代丁基)氨基]苯甲酸稀土配合物的合成、表征及发光性质

在乙醇体系中,由主配体4-[(1,3-二氧代丁基)氨基]苯甲酸(H2L,C11H11NO4)、稀土硝酸盐及辅助配体邻菲啰啉(phen)反应合成了两个系列8个配合物[Ln2(L)3(H2O)4]n(Ln=Sm(1),Eu(2),Tb(3),Dy(4));[Ln2(NO3)2(L)2(phen)2]n(Ln=Sm(5),Eu(6),Tb(7),Dy(8))。用元素分析、红外光谱、摩尔电导、热重分析进行表征,确定了产物的化学组成,推断了相应的结构。测定了室温时固体产物的激发和发射光谱,结果表明:由主辅配体共同配位的三元配合物的发光强度好于无辅助配体参与的二元配合物。测定了三元配合物的荧光寿命,其中铕和铽配合物显示较长的荧光寿命。     

Synthesis, structure and magnetic properties of a novel family of heterometallic nonanuclear Na(I)2Mn(III)6Ln(III) (Ln = Eu, Gd, Tb, Dy) complexes

The structures and magnetic properties of four isomorphous nonanuclear heterometallic complexes [Na(2){Mn(3)(III)(μ(3)-O(2-))}(2)Ln(III)(hmmp)(6)(O(2)CPh)(4)(N(3))(2)]OH·0.5 CH(3)CN·1.5H(2)O are reported, where Ln(III) = Eu (1), Gd (2), Tb (3) and Dy (4), H(2)hmmp = 2-[(2-hydroxyethylimino)methyl]-6-methoxyphenol. Complexes 1-4 were prepared by the reactions of hmmpH(2) with a manganese salt and the respective lanthanide salt together with NaO(2)CPh and NaN(3). Single-crystal X-ray diffraction analyses reveal that the six Mn(III) and one Ln(III) metal topology in the aggregate can be described as a bitetrahedron. The two peripheral [Mn(III)(3)(μ(3)-O(2-))](7+) triangles are each bonded to a central Ln(III) ion with rare distorted octahedral geometry. The magnetic properties of all the complexes were investigated using variable temperature magnetic susceptibility and both antiferromagnetic and ferromagnetic interactions exist in the [Mn(III)(3)(μ(3)-O(2-))](7+) triangle. Weak ferromagnetic exchange between the Ln(III) and Mn(III) ions has been established for the corresponding Gd derivative. The Gd, Tb and Dy complexes show no evidence of slow relaxation behaviour above 2.0 K.     

Synthesis,Structures, and Luminescent Properties of Chloride and Nitrate LnIII Complexes Coordinated by tris(Pyrazolyl)methane

We report the synthesis of Ln³⁺ nitrate [Ln(Tpm)(NO₃)₃] ⋅ MeCN (Ln=Yb ( 1Yb ), Eu ( 1Eu )) and chloride [Yb(Tpm)Cl₃] ⋅ 2MeCN ( 2Yb ), [Eu(Tpm)Cl₂(μ-Cl)]₂ ( 2Eu ) complexes coordinated by neutral tripodal tris(3,5-dimethylpyrazolyl)methane (Tpm). The crystal structures of 1Ln and 2Ln were established by single crystal X-ray diffraction, while for 1Yb high resolution experiment was performed. Nitrate complexes 1Ln are isomorphous and both adopt mononuclear structure. Chloride 2Yb is monomeric, while Eu³⁺ analogue 2Eu adopts a binuclear structure due to two μ²-bridging chloride ligands. The typical lanthanide luminescence was observed for europium complexes ( 1Eu and 2Eu ) as well as for terbium and dysprosium analogues ([Ln(Tpm)(NO₃)₃] ⋅ MeCN, Ln=Tb ( 1Tb ), Dy ( 1Dy ); [Ln(Tpm)Cl₃] ⋅ 2MeCN, Ln=Tb ( 2Tb ), Dy ( 2Dy )).