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有点长，请高手帮忙一下，呵呵 Abstract Solid complexes of lanthanide picrates with a new amide type tripodal ligand, 2,2 ,2 -nitrilotris-(N-phenylmethyl)-acetamide (L) have been prepared. The X-ray single-crystal di?raction analysis indicates that the ML2 type complexes [PrL2(Pic)](Pic)2 and [NdL2(Pic)](Pic)2 are isomorphous. And the ML2 complex units are hydrogen bonded to give infinite one-dimensional zigzag supra- molecular chains which are further linked by the interchain hydrogen bonds and p–p interactions of the picrate groups to form two- dimensional layer. The luminescent property of the Eu (III) complex is described. 2005 Elsevier B.V. All rights reserved. Keywords: Lanthanide picrate complexes; Tripodal ligand; Crystal structure; Luminescent properties Podand-type ligands have drawn much attention in recent years, mainly due to their selective coordinating capacity, spheroidal cavities and hard binding sites, therefore stabilizing their complexes, acquiring novel coordination structure and shielding the encapsulated ion from interaction with the surroundings [1]. Among numerous podands which have demonstrated their po- tential use in functional supramolecular chemistry [2], amide type podands are important for preparing the rare earth complexes possessing strong luminescent properties. The design and synthesis of luminescent lan- thanide complexes have attracted considerable current attention due to their potential uses as supramolecular devices, as fluorescent sensors, or as luminescent probes [3]. In order to obtain strongly luminescent complexes, the chromophoric ligands which chelate to lanthanide metals should be able: (1) to encapsulate and protect the lanthanide ion from the solvent molecules and (2)to absorb energy and transfer it e?ciently to the central metal [4]. Our group is interested in the supramolecular coordination chemistry and the luminescent properties of lanthanide (III) ions with the amide type tripodal ligands which possess spheroidal cavities and hard bind- ing sites. As a part of our systematic studies, this paper reports the structures and luminescent properties of the lanthanide picrate complexes with a new tripodal ligand 2,2 ,2 -nitrilotris-(N-phenylmethyl)-acetamide (L). It is noteworthy that the crystal structures of [PrL2(Pic)] (Pic)2 and [NdL2(Pic)](Pic)2 demonstrate 1:2 (M:L) type coordination structures. To our best knowledge, it is the first example of 1:2 (M:L) coordination structure of lan- thanide picrate complexes with tripodal ligand. Thus, the lanthanide ion could be e?ectively encapsulated and protected by the coordinated ligands. Lanthanide picrates [5] and (bis-carboxymethyl- amino)-acetic acetate [6] were prepared according to the literature method. The synthetic route for the tripo- dal ligand L and the complexes 1–5 (Ln = Pr, Nd, Eu, Gd, Tb) is shown in Scheme 1 [7]. All complexes were carefully investigated by elemental analysis and spectral characterization. The analytical data for the newly syn- thesized complexes indicate that the five complexes all conform to a 1:2 metal-to-ligand stoichiometry. And the molar conductance values of the complexes indicate the presence of a 1:2 type electrolyte [8]. Thus, the for- mula of the complexes 1–5 can be denoted as [LnL2(Pic)](Pic)2. The five complexes have similar IR spectra, of which the characteristic bands have similar shifts [9], suggesting that they have a similar coordina- tion structure. Slow diffusionof diethyl ether into the ethyl acetate solution of the Pr complex (1) and Nd complex (2) a?orded the block crystals [10]. The single-crystal X- ray analysis of the complexes [PrL2(Pic)](Pic)2 (1) and [NdL2(Pic)](Pic)2 (2) reveal that they are isomorphous with the central metal Pr or Nd atom coordinated with nine donor atoms, eight of which belong to the two tet- radentate ligands including one nitrogen atom and three oxygen atoms from carbonyl groups and the remaining one to oxygen atom of one monodentate picrate group. The other two picrate groups act as the counter anions. The coordination sphere of the complex 1 and 2 is shown in Fig. 1(a). The coordination polyhedron around Pr or Nd is a distorted monocapped antisquare prism (Fig. 1(b)). In both complexes, the ligand L exhibits a tripodal coordination mode [11] with three oxygen atoms and one amino nitrogen atom as donors. Thus, the tertiary nitrogen atom as well as its three acetyl benzyl amine arms form a cone-shaped cave with the metal atom lying out of the trigonal plane defined by the three oxy- gen atoms from carbonyl groups. The average Ln–O (c=o)distances (2.487 (1) and 2.472 A (2)) are signif- icantly shorter than Ln–N distances (2.765 (1) and 2.751 A (2)), respectively. A similar phenomenon was reported for TbL (Pic)3 (L = 2-(bis-dibutylcarbamoyl- methyl-amino)-N,N-dibutyl-acetamide) [12]. The con- figurations of the two ligands in one complex molecule are both pincer-like configurations because the O–Pr–O angles (70.30, 97.76, 124.46 and 71.40, 96.20, 125.76) and O–Nd–O angles (70.53, 97.86, 124.00 and 71.58, 96.66, 125.96) are both quite di?erent from each other [13]. The hydrogen bonds and p–p interactions between the coordinated ligands and picrate groups play important roles in the crystal packing of the com- plexes. In 1 (or 2), atoms O(17), O(18) of the one free picrate group and O(25) of the other free picrate an- ion act as hydrogen bond acceptors to form O...H– N(2) [O(17)...H, 2.61 (1) and 2.61 A (2), O(18)...H, 2.42 (1) and 2.41 A (2), O(17)...H–N(2), 155.7 (1)and 155.0 (2), O(18)...H–N(2), 147.7 (1) and 148.7 (2)] and O(25)...H–N(4) [O(25)...H, 2.09 (1) and 2.07 A (2), O(25)...H–N(4), 175.1 (1) and 175.1 (2)], respectively, with a neighboring molecule, where N(2) and N(4) of ligand are the hydrogen donors [14], thus generating a one-dimensional supramolecu- lar zigzag chain as shown in Fig. 2. In addition, the chains are linked by intermolecular hydrogen bond O(20)...H–N(3) [O(20)... H, 2.32 (1) and 2.33 A (2), O(20)... H–N(3), 150.2 (1) and 149.7 (2)] and p–p interaction between the free picrate groups which are almost parallel (the vertical distance between them are 3.59 and 3.44 A) [15] to form a two-dimensional (2-D) layer supermolecule (Fig. 2). The crystal structures of both complexes indicate that the coordination environment of the metal ion is pro- tected by two tetradentate ligands and one monodentatepicrate ligand. Since coordinated solvent molecules, especially water, can e?ciently quench lanthanide lumi- nescence, the ability to satisfy the coordination require- ments of the lanthanide (III) centre with nine donors without additionally bond solvent molecules becomes an important criterion in the design of supramolecular photonic devices [5]. It is noteworthy that the ligand shield Ln3+ using all three arms, thus the solid Eu com- plex does possess comparatively strong luminescence at room temperature. The luminescence emission spectra of the ligand L and Eu complex (3) in solid state (the excitation and emission slit widths were 2.5 nm, Fig. 3(a)) and in ethyl acetate, acetone, acetonitrile, ethanol and methanol31 solutions (concentration: 1.0· 10 mol L , the excita- tion and emission slit widths were 10.0 nm, Fig. 3(b)) were recorded at room temperature. It can be seen from Fig. 3(a) that the Eu complex shows strong emission when excited with 420 nm in the solid state. This indicates that the tripodal ligand L is a good organic chelator to absorb energy and transfer them to Eu ion. The most intensity ratio 5 7 5 7 value g( D0 ! F2/ D0 ! F1) is 9.6, showing that the Eu (III) ion does not lie in a centro-symmetric coordination site [16], in agreement with the crystal structure analysis. A triplet excited state T1 which is localized on one li- gand only and is independent of the lanthanide nature [17]. In order to acquire the triplet excited state T1 of the ligand L, the phosphorescence spectrum of the Gd (III) complex (4) was measured at 77 K in a metha- nol–ethanol mixture (V:V = 1:1). The triplet state en- ergy level T1 of the ligand L, which was calculated from the shortest-wavelength phosphorescence band1 [18],is21,645 cm .Thisenergylevelisabovethelowest 51 excited resonance level D0 of Eu (III) (17,286 cm ) 51 and D4 (20,545 cm ) of Tb (III). Thus the absorbedenergy could be transferred from ligand to the Eu or Tb ions. And we may deduce that the triplet state energy level T1 of this ligand L matches better to the lowest1 resonance level of Eu (III) (Dm = 4359 cm ) than to1 Tb (III) (Dm= 1100 cm ) ion, because such small Dm 5 (T1 D4) could result in the non-radiative deactivation of the terbium emitting state via a back-energy transfer 5 process (T1 Tb( D4)) and quench the luminescence of the Tb complex (5) [17,19]. Actually, we do not observe the luminescence of the Tb complex (5) at room temper- ature in solid state or in solutions. It could be seen from Fig. 3(b) that in ethyl acetate solution the Eu complex has the strongest luminescence, and then in acetone, acetonitrile, ethanol and methanol. This is due to the coordinating e?ects of solvents, namely solvate e?ect [20]. Together with the raising coordination abilities of ethyl acetate, acetone, acetoni- trile, ethanol and methanol for the lanthanide ions, the oscillatory motions of the entering molecules consume more energy which the ligand triplet level transfer to the emitting level of the lanthanide ion. Thus, the energy transfer could not be carried out perfectly. Supplementary data Crystallographic data for the structures reported in this paperhave deposited with theCambridge Crystallo- graphic Data Centre and allocated the deposition num- bers CCDC 277139 and CCDC 261821. Copies of the data can be obtained free of charge on application to CCDC 12 Union Road, Cambridge CB2 1EW, UK (email: deposit@ccdc.cam.ac.uk). Acknowledgements This work was supported by the National Natural Science Foundation of China (Project 20401008) and the Research Foundation for the Young Teachers Pos- sessing Doctors Degree of Lanzhou University. |
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bhz_2001
铁杆木虫 (著名写手)
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2楼2010-02-11 15:07:00
bhz_2001
铁杆木虫 (著名写手)
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bhz_2001
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4楼2010-02-11 15:23:43
bhz_2001
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zap65535(金币-5):机器翻译 2010-02-11 16:00
zap65535(金币-5):机器翻译 2010-02-11 16:00
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摘要 固体稀土苦味酸盐配合物的一个新的酰胺型三足配体，2,2，2 nitrilotris -（正苄基）乙酰胺（长） 已经编制完成。 X -射线单晶迪？raction分析表明，项目ML2型配合[PrL2（图）]（图）2 [NdL2（图）]（图）2的同晶。和复杂的项目ML2单位氢键给予无限的一维锯齿超 这是进一步的链间氢键和P -的苦味组P互动联系，形成两个分子链， 维层。欧盟（三）荧光性质复杂的描述。 2005年Elsevier B.诉保留所有权利。 关键词：稀土苦味酸盐配合物;三脚架配体;晶体结构，发光性能 醚型配体，一向备受关注 近年来，主要是由于其选择的协调 能力，椭腔和硬结合位点， 因此，稳定他们的配合，获得小说 协调结构和屏蔽封装的 从与环境[1互动离子]。在 这表明了他们的坡众多podands， 电位使用功能超分子化学[2]， 酰胺型podands是重要的准备 稀土配合物具有强烈的荧光 属性。的设计和发光局域网合成 thanide物吸引了大量的电流 由于作为分子的注意其潜在的用途 作为荧光传感器，或荧光探针设备， [3]。为了获得强烈的发光体， 哪些螯合配体的镧系发色 金属应能：（1）封装和保护 从溶剂分子稀土离子和（2）吸收能量并将其传输的位置？ciently中央 金属[4]。我们集团有兴趣的超分子 配位化学和发光性质 稀土（Ⅲ）离子与酰胺型三足 配体具有椭腔的硬约束， 荷兰国际集团网站。由于我们的系统研究的一部分，本文 报告的结构和发光特性 一个新的三足配体稀土配合物的苦味 2,2，2 nitrilotris -（正苄基）乙酰胺（长）。它是 值得指出的晶体结构[PrL2（图）] （图）2和[NdL2（图）]（图）2演示1:2（男：L）型 协调结构。据我们所知，这是 第一个例子1:2（男：长）协调网络结构 与三足配体thanide苦味物。因而， 在稀土离子可通过电子邮件？ectively封装 和保护的协调配体。 稀土苦味酸盐[5]和（之二-羧甲基- 氨基）-醋酸酯[6]准备按照 文献的方法。为tripo合成路线 德尔配体L和配合物1-5（稀土=镨，钕，铕， 钆，铽）显示在计划1 [7]。所有配合物进行了认真的调查，通过元素分析和光谱 定性。为新综合征的分析数据 thesized表明，复合物的所有五个 符合1:2金属对配体化学计量。和 配合物的摩尔电导值表明 一个1:2型电解质[8存在]。因此，换 配合物1-5穆拉可以表示为 [LnL2（图）]（图）2。五个物有类似的红外 谱，其中有类似的特征谱带 变化[9]，这表明它们有类似的coordina， 重刑结构。 慢到乙酸乙酯diffusionof乙醚 解决复杂的镨（1）和Nd复杂（2） 1？orded块晶体[10]。在单晶X - 射线分析物[PrL2（图）]（图）2（1）和 [NdL2（图）]（图）2（2）表明，它们是同晶 按照中央的金属镨钕原子或协调 9捐助原子，其中8个属于两个四环素 其中氮原子和三个radentate配 从羰基，其余的氧原子 一个一个齿苦味组氧原子。 其他两个苦味集团作为反阴离子。 在复杂的协调1和2球 如图。 1（1）。配位多面体 钕镨或周围是扭曲的单帽antisquare 棱镜（图1（b））。 在这两种配合物，配体蜇呈现出三脚架 协调模式[11]有三个氧原子和 捐助者之一氨基氮原子。因此，高等教育 氮原子以及其三乙酰苄胺 军火形成锥与金属原子形成洞穴 躺在由三个氧定义的三角平面 从羰基根原子。平均稀土氧 （C = O的）距离（2.487（1）和2.472甲（2））是signif - icantly少于稀土氮距离（2.765（1） 2.751甲（2）），分别为。类似的现象 报告的三重底线（图）3（1 = 2 - （双dibutylcarbamoyl - 甲基氨基）- N的，N -二丁基乙酰胺）[12]。结果表明，Con - 两个配体figurations在一个复杂的分子 钳形都像配置，因为O型镨氧 角（70.30，97.76，124.46和71.40，96.20， 125.76）和O -钕氧角度（70.53，97.86，124.00 和71.58，96.66，125.96）都相当迪？erent 相互[13]。 氢键和p磷之间的相互作用 协调配体和苦味团体发挥 在包装的COM晶体重要作用 丛。在1（或2），原子为O（17），0（18）在一个自由 苦味组和O（25）其他免费苦味的， 离子作为氢键受体的行为，形成澳..魔， N（下2）[0（17）...小时，2.61（1）和2.61（2），0（18）...小时， 2.42（1）和2.41（2），0（17）...氢氮（2），155.7（1）和155.0（2），0（18）...氢氮（2），147.7 （1）和148.7 （2）]和O（25）...氢氮（4）[0（25）...小时，2.09（1）和 2.07甲（2），0（25）...氢氮（4），175.1（1）和175.1 （2）]，分别与周边分子，在那里 N（下2）和N（4配体）是供氢 [14]，从而产生一维supramolecu - 拉尔锯齿链，如图所示。 2。此外， 链连接起来，分子间氢键 0（20）...氢氮（3）[0（20）...每小时2.32（1）和2.33（2）， 0（20）...氢氮（3），150.2（1）和149.7（2）]和p磷 自由之间的互动是苦味群体 它们之间几乎平行（垂直距离 是3.59和3.44甲）[15]，形成一个二维 （2 - D型）超分子层（图2）。 两者配合物的晶体结构表明， 对金属离子的协调环境亲 tected两个四齿配体和一个monodentatepicrate配体。由于协调溶剂分子， 尤其是水，可以用电子邮件？ciently淬火稀土荧荧 nescence，能够满足需要的协调， 镧系（三）有9个发言：捐助中心 另外债券成为无溶剂分子 一个重要的设计标准超分子 光子器件[5]。值得注意的是，配体 屏蔽稀土离子使用过的武器，因此，固体铕的COM - 丛具备了较强的发光 室温。 配体的荧光发射光谱蜇 和Eu配合物（3固态）（激励和 发射狭缝宽度分别为2.5纳米，图。 3（1））和乙基 乙酸，丙酮，乙腈，乙醇和methanol31 解决方案（浓度：1.0•10摩尔L时，excita， 重刑和排放缝隙宽度分别为10.0纳米，图。 3（b）项） 录在室温下。 它可以从图。 3（1），欧盟复杂 调查显示，大量排放的420纳米时，在兴奋 固态。这表明，三脚架配体 L是一个很好的有机螯合剂吸收能量 他们转移到铕离子。最强度比值 5 7 5 7 价值克（第0！F2代/ D0！F1）的为9.6，表明 欧盟（III）离子，不在于一中心对称 协调网站[16]，同意与晶体 结构分析。 阿三重激发态T1是在一个李本地化， 甘德只，是独立的镧系元素的性质 [17]。为了获得三重激发国有T1 配体L时，磷光光谱的GD （三）配合物（4）77测定在梅塔的K - 北环线乙醇混合物（五：V = 1:1）。在三重态恩 配体升，能量水平T1的计算 从最短波长磷光band1 [18]，is21，645厘米。Thisenergylevelisabovethelowest 51 兴奋共振欧盟一级D0（三）（一七二八六厘米） 51 和D4（二〇五四五厘米）对铽（III）。因此，absorbedenergy可以转让的配体对欧盟或Tb 离子。我们可以推断，三线态能量 本级配蜇T1比赛踢得更好的lowest1 共振水平铕（III）（弥散=4359厘米）比训练主任1 铽（III）（管理部= 1100厘米）离子，因为这样的小弥散 5 （T1 D4）的行为可能会导致非辐射失 铽发光的国家通过备用能量转移 5 进程（T1铽（D4）的）和淬火的发光 铽配合物（5）[17,19]。其实，我们不遵守 在室内锻炼的稀土发光配合物（5） ature在固态或解决方案。 可以看出，从图。 3款（b）在醋酸乙酯 解决方案的铕配合有很强的发光， 然后在丙酮，乙腈，乙醇和甲醇。 这是由于协调é？常态的溶剂， 即溶剂化é？抽搐[20]。连同提高 乙酸乙酯，丙酮，乙腈协调能力， 腈，乙醇和甲醇的，稀土离子的 进入分子的振荡运动消耗 更多的能源，配体三元水平转移到 对稀土离子发光的水平。因此，能源 转让无法进行完美。 补充数据 晶体的结构数据报告 与theCambridge交存Crystallo这paperhave， 图形数据中心和分配的沉积数量， 别尔斯城市当代舞蹈团城市当代舞蹈团277139和261821。副本 数据可以免费索取有关申请 城市当代舞蹈团12联盟道，剑桥CB2 1EW，英国 （电子邮件： deposit@ccdc.cam.ac.uk）。 鸣谢 这项工作得到国家自然科学 中国科学基金（项目20401008）和 为青年教师名次研究基金会 sessing医生兰州大学学位。 |
6楼2010-02-11 15:37:28
bhz_2001
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7楼2010-02-11 15:42:43
bhz_2001
铁杆木虫 (著名写手)
- 应助: 62 (初中生)
- 金币: 7515.9
- 散金: 60
- 红花: 5
- 帖子: 1861
- 在线: 178.8小时
- 虫号: 165507
- 注册: 2006-01-13
- 性别: GG
- 专业: 金属有机化学
8楼2010-02-11 15:58:30
9楼2010-02-12 15:28:52
bhz_2001
铁杆木虫 (著名写手)
- 应助: 62 (初中生)
- 金币: 7515.9
- 散金: 60
- 红花: 5
- 帖子: 1861
- 在线: 178.8小时
- 虫号: 165507
- 注册: 2006-01-13
- 性别: GG
- 专业: 金属有机化学
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按照文献方法镧系苦味酸盐[5]和（双-羧甲氨基）-乙酸酯[6]被合成出来了.在路线图1中指出了三齿配体L和相应络合物1–5 (Ln = Pr, Nd, Eu,Gd, Tb)的合成路线 [7].所有络合物都进行了元素分析和光谱鉴定.新合成的络合物的分析数据指出这五个络合物都符合金属:配体为1:2的计量关系. 络合物的摩尔电导值也表明其为1:2型的电解质[8].因此, 络合物1–5的分子式可以表示为 [LnL2(Pic)](Pic)2. 这五个络合物有类似的红外光谱，其中有类似的特征谱带位移[9]，这表明它们有类似的配位结构。 [ Last edited by bhz_2001 on 2010-2-12 at 21:46 ] |
10楼2010-02-12 17:25:47