两种双核稀土配合物的光致变色和光磁效应

利用光诱导电子转移机理和配位驱动组装策略探索室温光磁效应材料的合成. 通过组装稀土硝酸盐与1,10-菲罗啉(phen)获得2种同构双核稀土配合物[Ln₂(NO₃)₆(phen)₂](1: Ln=Gd; 2: Ln=Dy). 由于具有电子给体-受体结构特征, 目标产物在光照后发生电子转移, 电子由硝酸根的氧原子转移到phen的氮原子, 进而产生光生自由基并发生肉眼可见的颜色变化. 除光致变色外, 配合物1和2在室温下具有光磁效应. 本研究为构筑室温光致变色和光磁效应杂化材料提供了一种通用方法: 配位组装顺磁金属盐与菲罗啉衍生物.     

锌-稀土矩形纳米簇的构筑及近红外发光性能

本文设计了一个新型含苯-甲基-苯骨架的席夫碱配体,构筑了两个具有矩形结构的锌-稀土纳米簇[Ln₂Zn₂L₂(OAc)₆] (Ln = Yb (1)和Er (2))。该席夫碱配体以“伸展型”配位模式与稀土离子进行配位,使这些锌-稀土纳米簇表现出较大的分子尺寸结构(0.7 nm × 1.1 nm × 2.2 nm)。荧光性质研究表明,由Zn/L组成的发色基团能有效敏化1和2中Yb³⁺和Er³⁺离子的近红外发光。通过对荧光量子产率及寿命进行分析发现,Zn/L对Yb³⁺离子的传能效率要高于Er³⁺离子。     

多齿席夫碱配体构筑的Ln2Ⅲ配合物的晶体结构及磁性

使用多齿席夫碱配体,通过溶剂热法,设计与合成了3例新的稀土配合物[Ln₂(L)₂(acac)₂(CH₃OH)₂]·2CH₃OH(Ln=Sm(1)、Gd(2)、Ho(3),H₂L=吡啶?2?羧酸?(1?甲基?3?氧代丁烯基)?酰肼),并对配合物1~3的结构与磁性质进行了系统的研究。单晶结构测试结果表明配合物1~3为同构,每个中心稀土Ln(Ⅲ)离子为八配位,其配位几何构型为扭曲的四方反棱柱;相邻的中心稀土Ln??离子通过2个μ₂?O连接形成了平行四边形的[Ln₂O₂]核心。磁性测试揭示配合物2具有磁制冷性质,其最大磁熵变(-ΔS_max)为31.9 J·K^-1·kg^-1(T=2.0 K,ΔH=70 kOe);配合物3表现出了慢磁驰豫行为。     

基于席夫碱配体构筑的LnⅢ2配合物的结构、荧光性质及生物活性

以多齿席夫碱配体H₂L(H₂L=(E)-N′-(3-乙氧基-2-羟基亚苄基)-3-羟基吡啶甲酰肼)为配体,与Ln(acac)₃·2H₂O(Ln=Tb、Ho、Er;acac^-=乙酰丙酮根)反应,通过溶剂热法,成功得到了3例新的双核稀土配合物[Ln₂(acac)₂(L)₂(C₂H₅OH)₂](Ln=Tb((1)、Ho((2)、Er(3))。单晶X射线衍射分析表明：配合物1～3的结构主要由2个Ln^Ⅲ离子、2个乙酰丙酮根(acac^-)、2个L^2-及2个C₂H₅OH组成,中心Ln^Ⅲ离子通过2个μ₂-O原子相互连接,形成一个平行四边形的Ln₂O₂核心。固体荧光实验测...     

镧系元素-锑-硫三元体系的研究(Ⅳ)——CeSbOS2的合成及晶胞参数的测定

作为无机新材料的开发,近年来,我们系统地研究了Ln-Sb-S三元体系,先后合成了Ln₈Sb₈S₂₁(Ln=La,Ce)、Ln₃Sb₃S₁₀(Ln=La,Ce)、Ln_3-xSb_xS₄(Ln=La,Ce,Sm)、Ln_1-xSb_xS₂(Ln=Nd)和Ln₃SbS₆(Ln=Pr,Nd)等十余种新化合物的单晶。同时也注意到法国M.Pardo等人在报导LnOBiS₂(Ln=La,Ce,Pr)型化合物时,曾提及LnOSbS₂型化合物的存在,并给出了NdOSbS₂的部分数据。     

钼和稀土的二乙基二硫代甲酸盐配合物的电化学研究

研究了N,N-二乙基二硫代甲酸根(dtc)作配体的双核配位化合物[Mo(dtc)₄][Ln(dtc)₄](Ln=La,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho和Er)的氧化还原性质及其在电极过程中的电化学特性.     

4-甲基-1,2,3-噻二唑-5-甲酸构筑的一维稀土配位聚合物的合成与晶体结构

由4-甲基-1,2,3-噻二唑-5-甲酸(HL,C_4H_4N_2O_2S)和相应的稀土硝酸盐Ln(NO_3)3·n H_2O(Ln=Tb,Dy,Ho,Yb)合成了4个一维稀土配位聚合物{[Ln(L)_3(H_2O)2]·H_2O}_n(Ln=Tb,1;Dy,2;Ho,3;Yb,4),均得到单晶,用元素分析、红外光谱、热重分析和X射线单晶衍射确定了产物的组成和结构。结构分析表明:4种晶体属于异质同晶型,同属于三斜晶系,空间群为Pī。每个中心金属离子Ln(III)与5个噻二唑甲酸根中的6个羧基氧原子和2个配位水分子上的两个O原子配位,配位数为8,形成一个三角十二面配位多面体。     

轴向卤离子配位调控金属冠醚铽(III)配合物的慢磁弛豫行为

以金属冠醚[15-MC_Ni（II）-5]和卤素离子分别作为Tb（III）在赤道平面和轴向上的配体,成功地组装了三例混合过渡金属-稀土配合物{TbNi₅X₂}（X=F,Cl,Br）,其中TbNi₅F₂为首例双氟端基配位的稀土配合物.X射线单晶衍射分析结果表明,配合物中Tb（III）离子采用具有高轴次对称性的五角双锥（D_5h）配位方式,表明利用金属冠醚策略可以定向构筑含五角双锥稀土基元的混合过渡金属-稀土配合物.交流磁化率的测试结果表明,Tb（III）轴向的电荷分布对配合物的慢磁弛豫行为有着重要的影响.依次削弱轴向配体X^-的电负性,在1 kOe外场下{TbNi₅F₂}和{TbNi₅Cl₂}分别表现出场诱导的单分子磁体和弱的慢磁弛豫行为,而{TbNi₅Br₂}则由于快速的磁量子隧穿而不表现出慢的磁弛豫行为.     

Molecular solid solution of lanthanide-titanium-oxo clusters with enhanced photocatalytic hydrogen evolution

Molecular solid solutions of metal clusters containing different metal centers with well-defined structures can accurately regulate the HOMO-LUMO gap,but are rarely available.Herein,a series of colorless lanthanide-titanium-oxo clusters Ln₂Ti₄(μ₂-O)₂(μ₃-O)₄(Piv)₁₀(THF)₂(Ln₂Ti₄,Ln = Eu,Gd,Tb,and Ce,HPiv = pivalic acid) were synthesized by the reaction of pivalic acid with Ln(Ac)₃     

基于锌(Ⅱ)Schiff碱构筑模块和6-羧基吡啶-2-甲醇的3d-4f异金属四核簇合物的荧光和磁弛豫性质

用溶剂热方法合成了2个新的3d-4f异金属四核簇合物：[Zn₂Ln₂（salen）₂（CO₂PyCH₂O）₂（MeOH）2]（ClO₄）₂·2MeOH（Ln=Dy（1）,Tb（2）;H₂salen=N,N'-双（3-甲氧基水杨基）-1,3-二氨基丙烷;HCO₂PyCH₂OH=6-羧基吡啶-2-甲醇）。它们是由锌（Ⅱ）Schiff碱构筑模块和6-羧基吡啶-2-甲醇辅助配体组装而成的Zn-Ln₂-Zn型簇合物。磁性测量表明稀土离子间存在铁磁性相互作用。Zn₂Dy₂配合物1在2 000 Oe直流磁场下显示出磁弛豫行为;而Zn₂Tb₂配合物2不但有磁场导致的磁弛豫行为,而且还具有荧光性质。     

Investigation on lanthanide binuclear complexes of 1,5-bis-(1′-phenyl-3′-methyl-5′-pyrazolone-4′)-1,5-pentanedione and 2,2′-bipyridine

The coordination of 1,5-bis-(1′-phenyl-3′-methyl-5′-pyrazolone-4′)-1,5-pentanedione (BPMPPD) and 2,2′-bipyridine (bipy) with lanthanide ions in water-alcohol solution has been studied. Binuclear complexes of the types : Ln₂(BPMPPD)₃(bipy)₂·nH₂O (n = 2 for Y, n = 4 for Eu, Gd, Dy, Ho, Er, Tm and Yb); Ln₂(BPMPPD)₃bipy·nH₂O (n = 10 for La, n = 3 for Pr, Nd, Sm and Tb) were formed. The compounds were characterized by elemental analysis, molar conductance, IR, UV, ¹H NMR spectroscopy, thermogravimetric analysis and fluorescence spectra.     

Heterometallic cubanes: syntheses, structures, and magnetic properties of lanthanide(III)-nickel(II) architectures

Reactions of lanthanide(III) perchlorate (Ln = Dy, Tb, and Gd), nickel(II) acetate, and ditopic ligand 2-(benzothiazol-2-ylhydrazonomethyl)-6-methoxyphenol (H(2)L) in a mixture of methanol and acetone in the presence of NaOH resulted in the successful assembly of novel Ln(2)Ni(2) heterometallic clusters representing a new heterometallic 3d-4f motif. Single-crystal X-ray diffraction reveals that all compounds are isostructural, with the central core composed of distorted [Ln(2)Ni(2)O(4)] cubanes of the general formula [Ln(2)Ni(2)(μ(3)-OH)(2)(OH)(OAc)(4)(HL)(2)(MeOH)(3)](ClO(4))·3MeOH [Ln = Dy (1), Tb (2), and Gd (3)]. The magnetic properties of all compounds have been investigated. Magnetic analysis on compound 3 indicates ferromagnetic Gd···Ni exchange interactions competing with antiferromagnetic Ni···Ni interactions. Compound 1 displays slow relaxation of magnetization, which is largely attributed to the presence of the anisotropic Dy(III) ions, and thus represents a new discrete [Dy(2)Ni(2)] heterometallic cubane exhibiting probable single-molecule magnetic behavior.     

Planar tetranuclear Dy(III) single-molecule magnet and its Sm(III), Gd(III), and Tb(III) analogues encapsulated by salen-type and β-diketonate ligands

The syntheses, structures, and magnetic properties are reported for four new lanthanide clusters [Sm(4)(μ(3)-OH)(2)L(2)(acac)(6)]·4H(2)O (1), [Gd(4)(μ(3)-OH)(2)L(2)(acac)(6)]·4CH(3)CN (2), and [Ln(4)(μ(3)-OH)(2)L(2)(acac)(6)]·2H(2)L·2CH(3)CN (3, Ln = Tb; 4, Ln = Dy) supported by salen-type (H(2)L = N,N'-bis(salicylidene)-1,2-cyclohexanediamine) and β-diketonate (acac = acetylacetonate) ligands. The four clusters were confirmed to be essentially isomorphous by infrared spectroscopy and single-crystal X-ray diffraction. Their crystal structures reveal that the salen-type ligand provides a suitable tetradentate coordination pocket (N(2)O(2)) to encapsulate lanthanide(III) ions. Moreover, the planar Ln(4) core is bridged by two μ(3)-hydroxide, four phenoxide, and two ketonate oxygen atoms. Magnetic properties of all four compounds have been investigated using dc and ac susceptibility measurements. For 4, the static and dynamic data indicate that the Dy(4) complex exhibits slow relaxation of the magnetization below 5 K associated with single-molecule magnet behavior.     

Surface modification of high-nuclearity lanthanide clusters: two tetramers constructed by cage-shaped [Dy26] clusters and isonicotinate linkers

By incorporation of NO3- ligands with trigonal planar geometry as surface modifiers into the lanthanide cluster core backbone to remarkably improve the dimension of cluster cores, two novel lanthanide cluster compounds, Dy30I(micro3-OH)24(micro3-O)6(NO3)9(IN)41(OH)3(H2O)38 (1) and Dy104I4(micro3-OH)80(micro3-O)24(NO3)36(IN)125(OH)19(H2O)167 (2) (HIN = isonicotinic acid), have been obtained under hydrothermal conditions. Single-crystal X-ray diffraction shows that in both cluster compounds, the block blocks of [Dy26(micro3-OH)20(micro3-O)6(NO3)9I]36+, [Dy26], are the largest cage-shaped lanthanide cluster cores known. Compound 1 is the first tetramer based on the linkage of two different types of high-nuclearity lanthanide clusters and IN ligands, while compound 2 represents the first tetramer constructed by [Dy26] clusters and IN linkers.     

Using the flexible ligand bis(2-hydroxyethyl)amino-tris (hydroxymethyl)methane ("bis-tris") to access a family of 3d-4f Mn(III)4Ln4 complexes

A series of isostructural 3d-4f coordination clusters (CCs) [Mn(4)Ln(4)(OH)(6)(H(2)L)(2)(H(3)L)(2)(PhCO(2))(2)(N(3))(2)(MeOH)(4)]Cl(1.6)(N(3))(0.4)(NO(3))(2)·2.4H(2)O·1.6MeOH where Ln = Gd, Tb, Dy, Ho and Er and H(5)L = bis(2-hydroxyethyl)amino-tris(hydroxymethyl)methane (bis-tris) has been synthesised and structurally characterised. The paramagnetic metal ions within the clusters are weakly antiferromagnetically coupled, with the Tb and Dy compounds displaying slow relaxation of their magnetisation. This is the first report of this versatile ligand being used to target 3d-4f CCs.     

Synthesis, structures, and magnetic properties of three fluoride-bridged lanthanide compounds: effect of bridging fluoride ions on magnetic behaviors

A family of fluoride-bridged lanthanide compounds, [Dy(III)F(oda)(H(2)O)(3)] (1, oda = oxidiacetate) and [Ln(III)(2)F(2)(oda)(2)(H(2)O)(2)] (Ln = Tb(2) and Dy(3)), was synthesized and characterized. To investigate the effects of bridging ligands on magnetic behaviors, two hydroxyl-bridged complexes of formulas [Ln(III)(2)(OH)(2)(oda)(2)(H(2)O)(4)] (Ln = Tb(4) and Dy(5)) were also synthesized. Magnetic measurements show that the magnetic behaviors of the compounds are obviously distinct. Compounds 1, 2, and 3 show ferromagnetic interactions, while only antiferromagnetic interactions are observed in compounds 4 and 5. Among these compounds, 1 and 3 show frequency-dependent ac-susceptibility indicative of slow magnetic relaxation. Because the structures of Dy(2) cores are very similar in compounds 3 and 5, it may be inferred that the differences of bridging ligands are mainly responsible for the distinct magnetic exchange interactions and relaxation dynamics.     

Nitrophenolate as a building block for lanthanide chains, layers, and clusters

Potassium o-nitrophenolate (1) was reacted with various lanthanide trichlorides under different reaction conditions. By using the smaller lanthanides and working under rigorous exclusion of air, infinite chains of composition [(THF)4[K(o-O2N-C6H4-O)4Ln]4]n (Ln = Y (2a), Er (2b), Lu (2c)) were obtained. Using the same conditions but performing the crystallization under air, tetradecanuclear clusters of composition H18[Ln14(micro-eta2-o-O2N-C6H4-O)8(eta2-o-O2N-C6H4-O)16(micro4-O)2(micro3-O)16] (Ln = Dy (3a), Er (3b), Tm (3c), Yb (3d)) were isolated. Using larger center metals such as samarium, europium, and terbium and working under rigorous exclusion of air, infinite layers of composition [[K2(o-O2N-C6H4-O)5Tb]n] (4) and [[K2(o-O2N-C6H4-O)5Ln)]n] (Ln = Sm (5a), Eu (5b)) were obtained. In 4 the layers have a closer packing than those in compound 5. The closer packing is a result of the increased coordination number of the lanthanide metal and the potassium atoms. In contrast, the more open structures of 5 results in channels which are rectangular through the layers. All compounds reported including 1 have been investigated by single-crystal X-ray diffraction.     

1,5-双(1'-苯基-3'-甲基-5'-吡唑啉酮-4')-戊二酮-[1,5]和十六烷基吡啶盐的稀土配合物的合成及表征

合成了13种1,5-双(1′-苯基-3′-甲基-5′-吡唑啉酮-4′)-戊二酮-[1,5](BPMPPD)和溴化十六烷基吡啶盐(CPB)的稀土配合物.研究了配合物的红外光谱、紫外可见光谱、差热-热重谱、荧光光谱、核磁共振谱及摩尔电导等性质,发现配合物属离子型缔合物CP⁺[Ln(BPMPPD)₂]^-.Pr、Nd、Ho、Er、Tm配合物发生超灵敏跃迁.配合物的热分解温度具有"四分组"效应,Sm、Eu、Tb、Oy为线性荧光。     

系列Ln(Ⅲ)配聚物的合成、结构及近红外发光性能

通过水热反应合成5种结构新颖的配聚物:{[Ln_2(1,3-bdc)_3(H_2O)_4](DMF(H_2O}_n[Ln=Pr(1),Nd(2),Gd(3)]和{[Ln_4(1,3-bdc)_6(H_2O)_4(DMF)](DMF(2H_2O}_n[Ln=Er(4),Ho(5)](1,3-bdc:间苯二甲酸,DMF:N,N-二甲基酰胺)。通过单晶X射线衍射、红外光谱、紫外-可见-近红外(UV-Vis-NIR)光谱、荧光光谱等技术手段对产物的结构和性能进行了表征。结果表明,配聚物1~3是同构的,属单斜晶系,P2(1)/n空间群;配聚物4、5是同构的,属三斜晶系,P-1空间群。在晶体中,间苯二甲酸根采用多样的配位模式,使配聚物呈现多维的结构。除配聚物4,其余均呈现Ln(Ⅲ)的特征NIR发光,并与其UV-Vis-NIR吸收光谱相关联。     

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.