配位聚合物

配位聚合物是通过过渡金属和有机配体的自组装而形成的 ,它结合了复合高分子和配位化合物两者的特点 ,表现出其独特的性质 ,在非线性光学材料、磁性材料、超导材料及催化等诸多方面都有极好的应用前景。本文根据有机配体种类的不同 ,将配位聚合物分为五大类 ,以便于对它们进行研究。1.含氮杂环类配体的配位聚合物 ;2.含CN有机配体的配位聚合物 ;3.含氧有机配体的配位聚合物 ;4.通过两种配体与一种金属组装成的配位聚合物 ;5.两种以上的金属与相应的配体组装而成的配位聚合物。     

Transition metal(II) ions with dinegative tetradentate schiff base

Some new coordination polymers of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), obtained from the interaction of metal acetate with dipotassium salt of N,N’-di(carboxyethylidene)terephthalaldehydediimine (K₂SB) are described. The products, which have been characterized by elemental analyses, magnetic measurements, thermogravimetric analyses, electronic and infrared spectral studies, have composition, [M(SB)(H₂O)₂]_n. These colored coordination polymers are non-hygroscopic and quite stable at room temperature. On the basis of analytical data and IR studies, a 1:1 metal to ligand stoichiometry has been suggested to these coordination polymers. The IR studies have also revealed that ligands are coordinated to metal ion through carboxy oxygen and azomethine nitrogen. All the studies suggested tetradentate nature of the ligand with octahedral symmetry of the coordination polymers. All the coordination polymers are insoluble in acetone, ethanol, chloroform, methanol, benzene, DMF and DMSO. The thermal decomposition of the coordination polymers is studied and indicates that not only the coordinated water is lost but also that the decomposition of the ligand from the coordination polymers is necessary to interpret the successive mass loss.     

2,6-萘二甲酸构筑配合物的研究进展

2,6-萘二甲酸是一个具有多个配位原子的线性刚性配体,迄今,已报道的2,6-萘二甲酸构筑的配合物有100多个,它们展现了丰富的拓扑结构和潜在的应用价值。本文总结了2,6-萘二甲酸配体的结构特点以及配位模式,并按照金属离子的种类对2,6-萘二甲酸配合物进行分类归纳总结。着重介绍了2,6-萘二甲酸配合物在气体吸附分离、光致发光、磁性及多相催化方面的应用性质,对该类配合物的发展前景进行了展望。     

几种三维镧系配位聚合物的合成、结构表征及其性质测定

在水热条件下合成了四个氨三乙酸配合物[Ln(NTA)(H2O)]n(Ln=Sm(III)、Gd(III)、Dy(III)和Er(III);NTA=氨三乙酸),分别标记为1、2、3和4;利用元素分析、红外光谱和X射线单晶衍射等对其进行了结构表征.结果表明,配合物1-4同晶同构,中心原子采取N1O7的配位模式形成扭曲的十二面体几何构型.配合物以菱形四面体Ln8C14O28为基本构筑块,通过O—C—O和氢键形成有序的三维结构.此外,四个配合物均存在镧系收缩效应;配合物1显示出反铁磁性,配合物2对Hg2+有良好的荧光选择性.     

吡啶-2,6-二甲酸配位聚合物的研究进展

概述了以吡啶-2,6-二甲酸为配体的配位聚合物的研究进展.按照同多核和异多核配位聚合物进行分类,并介绍了它们的合成技巧、结构特点以及突出性能等.     

手性配位聚合物的构筑及其应用

手性配位聚合物因其结构多样性、可调控性以及潜在的多功能性,已经成为当前化学和材料学的研究热点。在合成中,可以通过选择特定的非手性配体、手性配体、手性溶剂或手性模板剂等来构筑手性配位聚合物。此外,还可以选择特定的金属离子赋予目标手性配位聚合物光、电、磁、催化和非线性光学等性能。本文详细综述了近年来纯手性配位聚合物的合成方法,以及在手性分离、手性催化、非线性光学、铁电和多铁等领域的应用研究进展。最后,对手性配位聚合物的合成方法及应用前景进行了展望。     

配位聚合物的三阶非线性光学性质

本文概括了配位聚合物的三阶非线性光学性质，并总结了其结构与三阶非线性光学性质之间的关系。对于一维结构的配位聚合物，因配体不同或者中心金属离子的价层电子构型不同可呈现自聚焦或自散焦效应;二维结构配位聚合物的三阶非线性光学性质则与配体和中心金属离子无关，均呈现自聚焦效应;三维结构配位聚合物的自聚焦或自散焦效应主要受中心金属离子价层电子构型的影响。     

微孔镧系配位聚合物

微孔配位聚合物与通常的微孔无机材料相比, 具有非常明显的优势. 而镧系离子特殊的光学和磁学性质, 更使得微孔镧系配位聚合物的研究成为热点. 本文简要地报道了微孔镧系配位聚合物的研究现状, 对一些微孔镧系配位聚合物的结构特点进行了描述, 讨论了影响微孔配位聚合物形成的主要因素. 一般来说, 线型配体往往能很好地将金属离子连接起来, 得到理想的微孔镧系配位聚合物; 选择合适的第二配体, 有利于构筑结构新颖的微孔镧系配位聚合物; 镧系收缩对能否形成微孔配位聚合物的影响并不明显, 只是轻稀土离子往往倾向于多结合一些小分子配体来满足更高的配位数.     

Specific features of the structure of coordination polymers of silver with ditopic nitrogen-containing ligands

Chemistry of coordination polymers and metal-supramolecular ensembles attracts attention due to their structural diversity and potential physical and chemical properties. In this article, the works on the synthesis and structure of coordination polymers of silver published by the authors and coworkers are briefly reviewed and compared with literature data on the structure of coordination polymers of silver published in the recent five years.     

Isostructural metal-anion radical coordination polymers with tunable phosphorescent colors (deep blue, blue, yellow, and white) induced by terminal anions and metal cations

Five phosphorescent metal-anion radical coordination polymers based on a new anion radical ligand generated by in situ deprotonation of a stable zwitterionic radical are described. The N,O,N-tripodal anion radical ligand links metal cations, which leads to five isostructural coordination polymers, [M(3)(bipo(-.))(4)(L)(2)](n) (M=Cd or Mn, Hbipo(-.)=2,3'-biimidazo[1,2-a]pyridin-2'-one, L=Cl(-), HCOO(-) or SCN(-)). The isostructural coordination polymers exhibit novel one-dimensional spirocycle-like structures. Three isostructural Cd(II) coordination polymers display unusual phosphorescent color changes (blue, yellow, and white) induced by terminal anions. Significantly, the Cd(II) coordination polymer with terminal Cl(-) possesses moderate quantum yield, and shows a bright white-light phosphorescence emission, which is independent of excitation wavelength and can even be excited by visible light. Upon adjusting the metal cation to Mn(II), two isostructural Mn(II) coordination polymers reveal deep-blue-light phosphorescence emissions that are independent of terminal anions. As radical-based coordination polymers, some of them show antiferromagnetic interactions between radical species or radical and metal center.     

液晶金属配位聚合物的合成及性能

基于国内外最新研究文献 ,系统论述了近年来液晶金属配位聚合物的合成方法、液晶行为及应用前景。指出液晶金属配位聚合物的合成方法可归纳为直接配位法、单体配位法、交联配位法和聚合物反应法四种。液晶金属配位聚合物一般呈现热致液晶行为 ,显示稳定的向列液晶相或近晶液晶相。有些金属配位聚合物还呈现互变性近晶态或单变液晶性。液晶金属配位聚合物具有金属的特殊性质 ,是一种新型高性能磁导、电导和光导材料 ,可望应用于液晶显示材料、磁性信息储存薄膜材料、润滑剂和各向异性催化剂等。     

Hydrothermal synthesis,structural investigation,and magnetic properties of 2-D layered lanthanide (Ln = Pr,Eu, Gd,Tb, and Er) coordination polymers possessing infinite 1-D nanosized cavities

Five 2-D Ln(III) coordination polymers, [Ln(PDA)(PDAH)]_n (PDA = 2,6-pyridinedicarboxylate), have been obtained under mild hydrothermal condition. In each coordination polymer, PDA is tetradentate and pentadentate, while lanthanides have coordination number eight to generate trigonal prismatic, triangular face bicapped LnO₆N₂ geometry having 9 triangular and 2 square faces. Two different types of bridging oxygens are responsible to grow the 2-D coordination polymers providing open channels possessing infinite 1-D nanosized cavities. Adjacent 2-D chains are further extended to a 3-D hydrogen-bonded layered network through intermolecular π–π interactions and C–H?O hydrogen bonds. Four lanthanides are arranged roughly at the vertices of a square and bridged by eight carboxylates leading to the overall tetrahedral shape of the secondary building units. The abnormal behavior of lanthanide contraction for the atomic radii of europium can be attributed to overlapping of electron clouds. The overall magnetic behavior is typical for the presence of antiferromagnetic exchange coupling interactions. Thermal decomposition analysis reveals that the coordination polymers have significant thermal stability. The coordination polymers are further characterized using elemental analysis and FT-IR spectroscopy.     

Homochiral porous solids based on 1D coordination polymers built from 46-membered macrocycles

Six homochiral coordination polymers 1-6 based on an enantiopure elongated and bent bipyridine ligand were synthesized and characterized by single-crystal X-ray diffraction studies. The framework structures of all six compounds were built up from similar 1D polymeric chains composed of 46-membered metallomacrocycles. Four distinct packing patterns were observed for this family of coordination polymers. With the exception of 1, the anions do not coordinate to the metal centers and reside in the open channels. Single-crystal X-ray diffraction studies show that the structures of these coordination polymers are sensitive to the anions even though they do not coordinate to the metal centers. The framework structures are somewhat tolerant of the change of metal centers and their local coordination environments. Gas sorption measurements on 1 suggest that chiral porous solids can be obtained with the present 1D coordination polymeric building blocks.     

Influence of CF3 Substituents on the Spin Crossover Behavior of Iron(II) Coordination Polymers with Schiff Base-like Ligands

A Schiff base-like ligand bearing CF₃ substituents was synthesized and converted to iron(II) coordination polymers [{FeL(L_ax)}_n] using five different bridging ligands L_ax. The structure of the coordination polymers was investigated using powder X-ray diffraction and single-crystal X-ray diffraction in the case of [{FeL(bipy)}_n]. The later revealed an untypical ABAB pattern of alternating equatorial ligands rotated by 180° with regard to each other along the chain. The temperature-dependent magnetic behavior was investigated with a SQUID magnetometer and the spin states at room temperature were confirmed by ⁵⁷Fe-Mössbauer spectroscopy. Three out of five coordination polymers show spin crossover behavior in the temperature range between 50 and 400 K with different kind of curve progressions (abrupt, gradual, step-wise). The other two coordination polymers are either fully highspin or fully low spin.     

Recent advances of discrete coordination complexes and coordination polymers in drug delivery

Coordination complexes (including discrete coordination complexes and coordination polymers) have demonstrated excellent performance in drug delivery. This review outlines recent advances of discrete coordination complexes, bulk coordination polymers, and nanoscale/microscale coordination polymers in drug delivery. Specifically, rationale and mechanism of coordination complexes in drug delivery are summarized in this contribution. In this review, we discuss applications of these coordination species in drug delivery from perspectives in chemistry and pharmaceutical sciences, and an outlook of these coordination species of interest in drug delivery will also be proposed.     

A mixed anionic lead(II) N-Oxide coordination polymer containing nitrato and benzoate ligands

The structures of two forms of a mixed anionic one-dimensional coordination polymers of lead(II) nitrate derived from benzoate and 2,2’-bipyridyl N-oxide are reported. The X-ray crystal structures show subtle differences in the two binding modes of nitrate in the coordination polymers obtained from two independent solvents. The solid state UV–Vis spectra show differences in the absorption pattern of the crystalline solids obtained from different solvents. The solid state UV–Vis spectra as well as the solution spectra are compared.     

Reversible Phase Transition of Porous Coordination Polymers

Porous coordination polymers or metal–organic frameworks with reversible phase-transition behavior possess some attractive properties, and can respond to external stimuli, including physical and chemical stimuli, in a dynamic fashion. Their phase transitions can be triggered by adsorption/desorption of guest molecules, temperature changes, high pressure, light irradiation, and electric fields; these mainly include two types of transitions: crystal–amorphous and crystal–crystal transitions. These types of porous coordination polymers have received much attention because of their interesting properties and potential applications. Herein, reversible phase transition porous coordination polymers are summarized and classified based on different stimuli sources. Corresponding typical examples are then introduced. Finally, examples of their applications in gas separation, chemical sensors, guest molecule encapsulation, and energy storage are also presented.     

Epoxide polymers: Synthesis,stereochemistry, structure,and mechanism

Epoxide polymerization studies have yielded technically important catalysts and polymers. The polymers were studied by cleaving them with Group IA organometallics to monomer, dimer, and trimer glycol fragments. The identification of these glycol fragments has established that the crystalline polymers from the cis- and trans-2,3-epoxybutanes are respectively racemic and meso-diisotactic and that the amorphous polymer from the cis-oxide is disyndiotactic. These studies also showed that the amorphous fraction from propylene oxide polymerization with coordination catalysts contains substantial head-to-head and tail-to-tail segments. This work has led to a much better understanding of the mechanism of epoxide polymerization. These facts were established: (1) epoxides polymerize with inversion of configuration of the ring-opening carbon atom; (2) monosubstituted epoxides polymerize largely by attack on the primary carbon with a coordination catalyst; and (3) two or more metal atoms must be involved in the coordination polymerization of epoxides.     

The magic of integration:Exploring the construction of dithienylethene-based infinite coordination polymers and their synergistic effect for gaseous ammonia probe applications

Infinite coordination polymers are recognized as excellent platform for functionalization.Dithienylethene motifs,which are one of the most attractive functional moieties,were incorporated into an infinite coordination polymer,to deliver a‘‘smart’’porous material that can response to external stimuli.The obtained dithienylethene-based infinite coordination polymers(named Cu-DTEDBA)share the advantages of both infinite coordination polymers(porosity and stability)and dithienylethene motifs(photochromism).The physical and chemical properties of Cu-DTEDBA were characterized by FTIR,TEM,SEM,XRD,TGA,UV–vis,EDX and BET.Moreover,the combination of dithienylethene and infinite coordination polymers gives rise to a synergistic effect,which induces functional behaviors of ammonia sensor applications.Both open and closed forms of Cu-DTEDBA exhibit distinct colorimetric change upon exposure to gaseous ammonia,which is not observed in dithienylethene free molecules.     

Koordinationspolymere aus Metallotripyrrinen

Coordination Polymers from Metal Tripyrrins This Research Report summarizes recent advances in the coordination chemistry of tripyrrins and related ligands with a special emphasis on the structural chemistry of coordination polymers with such ligands. The tripyrrin ligand is unique in supporting the formation of 1D‐ and 3D supramolecular structures from pentacoordinate transition metal ions due to an effective blockage of their sixths coordination site. Linear coordination polymers have been observed with a multitude of bidentate and tridentate bridging ligands like trifluoroacetate, azide, thio‐ and selenocyanate, and higher order pseudohalides. Homo‐ and heterodimetallic species have been obtained by the use of cyanometallates and could be characterized structurally in two cases. Besides the covalent coordination bonds several secondary interactions like hydrogen bonding and π‐stacking were found to support these coordination polymers and are demonstrated to allow the preparation of species with functionalized inner surfaces.