Synthesis and Structural Analysis of a Helical Coordination Polymer Formed by the Self-Assembly of a 2,2′-Bipyridine-Based exo-Ditopic Macrocyclic Ligand and Silver Cations

The overall topology of coordination polymers can be controlled by means of the coordination preferences of the metal center and the structure of the bridging ligand. This is demonstrated here by the synthesis of a single-stranded helical coordination polymer by the self-assembly of the exo-ditopic ligand 1 and silver ions.     

Interweaving 3D network with double helical tubes filled by 1D coordination polymer chains

The hydrothermal reaction of mellitic acid, 4,4'-bipydine, and Cu(CH(3)COO)(2).H(2)O gave rise to a novel 3D supramolecular architecture interpenetrated by three types of coordination polymer motifs. Two independent [[Cu(2)(mellitate)(4,4'-bpy)(H(2)O)(2)](2)(-)] 3D polymers incorporating helical substructures were interwoven into a 3D network with double-stranded helical tubes that host 1D linear polymers [Cu(4,4'-bpy)(H(2)O)(4)](2+)](n).     

1D and 2D homochiral metal-organic frameworks built from a new chiral elongated binaphthalene-derived bipyridine

Six homochiral coordination polymers 1-6 based on a new enantiopure elongated (S)-2,2'-diethoxy-1,1'-binaphthyl-6,6'-bis(4-vinylpyridine) ligand (L) and divalent metal (Zn, Cd, and Ni) connecting points were synthesized and characterized by single-crystal X-ray diffraction studies. These new homochiral coordination polymers adopt two distinct framework structures: a one-dimensional infinite chain structure with bridging L ligands occupying the axial positions of the metal centers and a two-dimensional rhombic grid structure formed by linking octahedrally coordinated metal centers with four pyridyl groups of bridging L ligands in the equatorial positions. The structures of these coordination polymers are sensitive to the nature of the anions as well as the solvents from which the coordination polymer crystals were grown. Powder X-ray diffraction studies showed that the two-dimensional chiral rhombic grids exhibited porosity, which could potentially find applications in enantioselective separations and catalysis.     

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes

A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, (1)H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand.     

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.     

Synthesis and characterization of self-assembled coordination polymers of N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide

The azo dye ligand N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide (HL) and Cu(II), Co(II), and Mn(II) coordination polymers were synthesized in addition to a non-polymeric Pd(II) complex. In all complexes, the ligand bonds to the metal ion through the formyl and α-hydroxy oxygen atoms. The sulfonamide oxygen also coordinates to the metal. The complexes are formulated as [ML₂] _n , where M?=?Cu(II), Co(II), and Mn(II), and [ML(Cl)(H₂O)], where M?=?Pd(II). On the basis of spectral studies and magnetic susceptibility measurements, an octahedral geometry was assigned to Co(II) and Mn(II) complexes, tetragonally elongated octahedral geometry for Cu(II) complex, while the Pd(II) complex was found to be square planar. Crystallization of Cu(II) complex from DMF afforded single crystals of general formula {[Cu(L)₂]?·?3DMF} _n (2). X-ray structural analysis of 2 revealed that each Cu(II) adopts elongated octahedral geometry affording 1-D chains. The chains are connected by hydrogen bonds, resulting in the formation of 2-D supramolecular assemblies. The crystal structure of HL has also been determined and discussed. Cyclic voltammetric behavior of the ligand and some complexes are also discussed.     

A nickel(II) coordination polymer derived from a tridentate Schiff base ligand with N,O-donor groups: synthesis,crystal structure,spectroscopy, electrochemical behavior and electrocatalytic activity for H<Subscript>2</Subscript>O<Subscript>2</Subscript> electroreduction in alkaline medium

A Ni(II) coordination polymer [C₄₂H₄₂K₂N₄Ni₄O₂₇] has been synthesized under open-air mild reaction conditions and characterized by physicochemical and spectroscopic methods. The X-ray crystal structure of the complex has been obtained. The crystallographic data revealed that each metal center is in a distorted octahedral geometry where the ligand coordinates to the metal centers by a nitrogen from the imine group, an oxygen from the carboxylic acid and a phenoxide group as an endogenous bridge to the metal centers. The coordination sphere is completed by an acetate, coordinated as an exogenous bridging ligand to both nickel centers, plus one terminal water ligand on each nickel. The polymeric structure is an infinite chain involving the binuclear nickel structure and K⁺ ions. Carbon paste electrodes modified with the Ni(II) coordination polymer were prepared, and the electrochemical behavior and electrocatalytic activity toward H₂O₂ reduction were investigated. The electrochemical results suggest that this Ni(II) coordination polymer has good catalytic activity with respect to H₂O₂ reduction.     

系列Cu(Ⅱ/Ⅰ)配聚物的合成、结构及光电性能

采用水热方法合成了3种Cu(Ⅱ/Ⅰ)配聚物及超分子, (1) [K₂Cu₂(ox)(btec)(MeOH)₂]_n, (2) {[Cu(pdc)(H₂O)₂]?H₂O}_n, (3) [Cu(cyan)(phen)]?H₂O (H₂ox: 草酸, H₄btec: 均苯四甲酸, MeOH: 甲醇, H₂pdc: 2, 5-吡啶二羧酸, phen: 邻菲啰啉, Hcyan: 氰尿酸). 通过X射线单晶衍射、表面光电压光谱(SPS)、固体紫外-可见(UV-Vis)、傅里叶变换红外(FTIR)光谱、元素分析等方法对配合物进行了表征. 结构解析结果表明, 配合物(1)是具有三维(3D)无限结构的配聚物; (2)是具有二维(2D)无限结构的配聚物, 但又通过氢键进一步连成了三维(3D)网络, (1)与(2)的中心金属均为Cu(II)离子; (3)为含Cu(I)的单核配合物, 但又通过氢键和π-π堆积作用, 使它成为2D超分子化合物. 配合物SPS结果显示, 配合物(1)-(3)在300-800 nm范围内都呈现光伏响应, 表明三者均具有一定的光电转换能力. 讨论了配合物的组成、结构、维数、配体种类、中心金属离子价态及配位微环境对SPS的影响,并将SPS与UV-Vis 光谱进行了关联.     

Syntheses, Structures and Fluorescent Properties of Copper（II） and Manganese（II） Helical Complexes Bridged by 4,4＇-Dipyridylsulfide

Two isostructural helical coordination polymers, {[Cu(dps)2(Hssa)-(H2O)2]·3H2O}n (1) and {[Mn(dps)2(Hssa)(H2O)2]·2H2O}n (2), have been synthesized by the solvothermal reaction of dps and H3ssa with CuCl2 or Mn(CH3COO)2 (dps = 4,4'-dipyridylsulfide, H3ssa = 5-sulfosalicylic acid). Both compounds crystallize in monoclinic, space group P21/n. In either complex, the central metal ion (CuII for compound 1 and MnII for compound 2) is surrounded by one Hssa2ˉ ligand, two coordinated aquas and three dps molecules with a N3O3 donor set in a distorted octahedral coordination geometry. Half of the dps is monodentate and another half acts as μ2-bridging ligands. It is through the bridging function of dps that the neighbouring metal centers are connected and a one-dimensional helical structure of compound 1 or 2 forms. Fluorescence studies indicate that compounds 1 and 2 have blue emission bands centered at 403 and 405 nm, respectively.     

Enantiospecific syntheses of copper cubanes, double-stranded copper/palladium helicates, and a (dilithium)-dinickel coronate from enantiomerically pure bis-1,3-diketones--solid-state self-organization towards wirelike copper/palladium strands

Enantiomerically pure, vicinal diols 1 afforded in a two-step synthesis (etherification and subsequent Claisen condensation) chiral bis-1,3-diketones H(2)L((S,S)) (3 a-c) with different substitution patterns. Reaction of these C(2)-symmetric ligands with various transition-metal acetates in the presence of alkali ions generated distinct polynuclear aggregates 4-8 by diastereoselective self-assembly. Starting from copper(II) acetate monohydrate and depending on the ratio of transition-metal ion to alkali ion to ligand, chiral tetranuclear copper(II) cubanes (C,C,C,C)-[Cu(4)(L((S,S)))(2)(OMe)(4)] (4 a-c) or dinuclear copper(II) helicates (P)-[Cu(2)(L((S,S)))(2)] (5) could be synthesized with square-pyramidal and square-planar coordination geometry at the metal center. In analogy to the last case, with palladium(II) acetate double-stranded helical systems (P)-[Pd(2)(L((S,S)))(2)] (6,7) were accessible exhibiting a linear self-organization of ligand-isolated palladium filaments in the solid state with short inter- and intramolecular metal distances. Finally, the introduction of hexacoordinate nickel(II) in combination with lithium hydroxide monohydrate and chiral ligand H(2)L((S,S)) (3 a) allowed the isolation of enantiomerically pure dinuclear nickel(II) coronate [(LiMeOH)(2) subset{(Delta,Lambda)-Ni(2)(L((S,S)))(2)(OMe)(2)}] (8) with two lithium ions in the voids, defined by the oxygen donors in the ligand backbone. The high diastereoselectivity, induced by the chiral ligands, during the self-assembly process in the systems 4-8 could be exemplarily proven by circular dichroism spectroscopy for the synthesized enantiomers of the chiral copper(II) cubane 4 a and palladium(II) helicate 6.     

Structural, MALDI-TOF-MS, magnetic and spectroscopic studies of new dinuclear copper(II), cobalt(II) and zinc(II) complexes containing a biomimicking μ-OH bridge

The Py(2)N(4)S(2) octadentate coordinating ligand afforded dinuclear cobalt, copper and zinc complexes and the corresponding mixed metal compounds. The overall geometry and bonding modes have been deduced on the basis of elemental analysis data, MALDI-TOF-MS, IR, UV-vis and EPR spectroscopies, single-crystal X-Ray diffraction, conductivity and magnetic susceptibility measurements. In the copper and zinc complexes, a μ-hydroxo bridge links the two metal ions. In both cases, the coordination geometry is distorted octahedral. Magnetic and EPR data reveal weakly antiferromagnetic high spin Co(II) ions, compatible with a dinuclear structure. The magnetic characterization of the dinuclear Cu(II) compound indicates a ferromagnetically coupled dimer with weak antiferromagnetic intermolecular interactions. The intra-dimer ferromagnetic behaviour was unexpected for a Cu(II) dimer with such μ-hydroxo bridging topology. We discuss the influence on the magnetic properties of non-covalent interactions between the bridging moiety and the lattice free water molecules.     

Solvothermal synthesis and structural characterization of a new one-dimensional metal-organic framework [Co(Atibdc)(Dpa)] n (H2Tibdc = 5-amino-2,4,6-triiodoisophthalic acid, Dpa = 2,2′-dipyridylamine)

The title cobalt(II) coordination polymer, [Co(Atibdc)(Dpa)] _n (I) (H₂Atibdc = 5-amino-2,4,6-triiodoisophthalic acid, Dpa = 2,2′-dipyridylanine), has been synthesized under solvothermal conditions and characterized by elemental analysis, IR, and X-ray crystallography structural analysis. Complex I exhibits a one-dimensional chain structure in which 5-amino-2,4,6-triiodoisophthalate as a bridging ligand interconnects adjacent two Co(II) centers to form a helical chain structure. The asymmetric unit includes one Co(II) center, one atibdc ligand, and one Dpa ligand. Each Co(II) center is five-coordinated and surrounded by two nitrogen atoms and three oxygen atoms from one Dpa ligand and two individual Atibdc ligands, leading to distorted trigonal bipyramid geometry. Adjacent chains are further linked through hydrogen bonds, C-H-π and π-π stacking interactions to form a three-dimensional supramolecular framework.     

氮杂环配体自组装螺旋链状结构配位聚合物的研究进展

螺旋结构配位聚合物在光学装置、生物模拟化学、非对称催化化学、手性识别、生物结构等多学科领域的应用,引起了人们极大的兴趣。本文综述了氮杂环配体自组装螺旋结构配位聚合物的最新进展,按照咪唑、三唑、吡啶、嘧啶及其衍生物配体分类总结了它们构建螺旋配位聚合物的结构,并简述了通过自发手性识别过程得到纯手性螺旋配位聚合物的影响因素,展望了具有螺旋链状配位聚合物的发展前景以及其开发应用潜能。     

Soluble 1D coordination polymers based on dendron-functionalized bispyridine ligand for linking between immobilized molecules on substrates

As a monomeric ligand for a soluble 1D coordination polymer, a benzyl-ether based dendrimer having a rigid 4,4'-bispyridine ligand at the focal point has been synthesized and the coordination chemistry with Pd(II) investigated by nuclear magnetic resonance, ultraviolet-visible and fluorescence spectroscopies, gel permeation chromatography measurement, and X-ray photoelectron spectroscopy. As a result, it was found that the synthesized dendrimer forms a stable, soluble Pd(II) coordination polymer with rough estimation of degree of polymerization of 10 in organic solvents. Furthermore, through the coordination polymer we attempted to link fourth-generation poly(amidoamine) dendrimers (PAMAM) individually immobilized on mica and confirmed the interconnection of the PAMAM through coordination polymers by atomic force microscopy.     

A new soft-matter material with old chemistry: Passerini multicomponent polymerization-induced assembly of AIE-active double-helical polymers with rapid visible-light degradability

Mimicking the superstructures and functions of natural chiral materials is beneficial to understand specific biological activities in living organisms and broaden applications in the fields of chemistry and materials sciences. However, it is still a great challenge to construct water-soluble, double-helical polymers with multiple responsiveness. Herein, we report for the first time a straightforward, general strategy to address this issue by taking advantage of Passerini multicomponent polymerization-induced assembly (PMPIA). The polymerization-induced generation of supramolecular interactions in chiral α-acyloxy amides drives the assembly of polymers and improves their stability in various solvents. This double-helical polymer is sensitive to metal ions, temperature, pH, and solvents, making both the superstructure and the AIE effect reversibly adjustable. Meanwhile, the hydrogen-bonding-assisted cyclization of photolabile α-acyloxy amides accelerates the degradation of helical polymers under visible-light irradiation. It is anticipated that this novel PMPIA strategy opens new horizons to inspire the design of advanced chiral/helical polymers with multiple functions.

Passerini multicomponent polymerization-induced assembly is reported to design a water-soluble, AIE-active, double-helical polymer with reversible multi-responsiveness to external stimuli and rapid visible-light degradability.     

Synthesis of Some Polymer‐Metal Complexes and Elucidation of their Structures

In this study, the nine coordination polymers of Fe(III), Co(II) and Ni(II) salts have been synthesized using polyacrylamide (PAA), polt(ethylene glycol) (PEG) and poly(vinyl alcohol) (PVA) and their structures were characterized by magnetic and conductivity measurements, ultraviolet‐visible (UV‐VIS), FTIR spectroscopy and thermogravimetric analysis (TGA). The structures of Fe(III) complexes in the all coordination polymers were found as tetrahedral. The structures of PAA‐Co(II) coordination polymer was determined as octahedral geometry whereas PEG‐Co(II) and PVA‐Co(II) complexes showed as tetrahedral structure. PAA‐Ni(II) and PEG‐Ni(II) complexes have octahedral geometry, whereas PVA‐Ni(II) has a square planar structure. Besides, the stress‐strain experiments of PVA‐metal coordination polymers obtained rubber‐like structure were carried out and the value of breaking‐strain of PVA‐Ni(II) complex was found to be about 17% of vulcanized natural rubber. The conductivities of the resulting polymer‐metal complexes were measured by four‐probe technique and were found in the range 10^?5?10^?6 Scm^?1. Thus, it was suggested that they can be used in the field potential application of conducting polymers. TGA results revealed that among the complexes PEG‐Fe(III) and PVA‐Fe(III) complexes have the highest thermally stable.     

Coordination polymers of glutaraldehyde with glycine metal complexes: synthesis,spectral characterization,and their biological evaluation

Glycine metal complexes were prepared by the reaction of glycine with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) in 1?:?2 molar ratio. Thereafter their condensation polymerization was done with glutaraldehyde to obtain polymer metal complexes. All the synthesized polymer metal complexes were characterized by elemental analysis, FT-IR, ¹H-NMR, and UV-Vis spectrometry, magnetic susceptibility, and thermogravimetric studies. The analytical data of all the polymers agreed with 1?:?1 molar ratio of metal complex to glutaraldehyde and magnetic moment data suggest that PGG–Mn(II), PGG–Co(II), PGG–Ni(II), and PGG–Cu(II) have an octahedral geometry around the metal atom, whereas the tetrahedral geometry was proposed for PGG–Zn(II) polymer. The PGG–Mn(II) and PGG–Cu(II) showed octahedral geometry. Thermal behavior of the polymer metal complexes was obtained at a heating rate of 10°C?min^?1 under nitrogen atmosphere from 0°C to 800°C. The antimicrobial activities of synthesized polymers were investigated against Streptococcus aureus, Escherichia coli, Bacillus sphaericus, Salmonella sp. (Bacteria), Fusarium oryzae, Candida albicans, and Aspergillus niger (Yeast).     

Quantitative formation of [2]catenanes using copper(I) and palladium(II) as templating and assembling centers: the entwining route and the threading approach

Transition metal-mediated templating and self-assembly have shown powerful potentials for the synthesis of interlocked molecules. These two strategies were combined in designing and preparing a new type of coordination catenanes incorporating Cu(I) and Pd(II) metal centers. The ligand designed here contains a phenanthroline core and pyridine sidearms (compound 1). Using this phenanthroline-pyridine conjugated ligand, two approaches were examined, which were shown to be surprisingly efficient for the catenane synthesis: the entwining route (entwining of two ligands around Cu(I) followed by Pd(II) clipping) and the threading approach (Cu(I)-templated threading of a cyclic ligand on an acyclic ligand followed by the Pd(II) clipping of the second ring). In the former method, stepwise treatment of 1 with Cu(CH(3)CN)(4)PF(6) (templating center) and enPd(NO(3))(2) (assembling center) gives rise to the quantitative formation of CuPd(2) catenane 18. In the latter method, Cu(I) templates the threading of phenanthroline-containing macrocycle 2 on ligand 1, which is followed by Pd(II) clipping to give hetero catenane 20. In both approaches, the formation of catenanes is convincing thanks to the strong templating effect of Cu(I), while the ring closure steps are efficiently furnished by Pd(II)-directed self-assembly.     

Metallomacrocycles as ligands: synthesis and characterisation of aluminium-bridged bisglyoximato complexes of palladium and iron

Dialuminiummacrocycles based on bisglyoximato moieties were prepared and their coordination chemistry with Fe(II) and Pd(II) was investigated. The bridging aluminium centers were supported by several types of tetradentate diphenoxide diamine ligands. The nature of the ancillary ligands bound to aluminium was found to affect the overall geometry and symmetry of the metallomacrocycles. Enantiopure, chiral diphenoxide ligands based on the (R,R)-trans-1,2-diaminocyclohexane backbone afforded cleanly one metallomacrocycle isomer. The size and electronic properties of remote substituents on aluminium-bound ligands affected the binding mode and electronic properties of the central iron. A structurally characterized iron complex shows trigonal prismatic coordination mode, with phenoxide bridges between iron and aluminium. Increasing the size of the phenoxide substituents led to square bipyramidal coordination at iron. Employing p-NO(2)- instead of p-tBu-substituted phenoxide as supporting ligands for aluminium caused a 0.27 V positive shift of the Fe(III)/Fe(II) reduction potential. These results indicate that the present synthetic approach can be applied to a variety of metallomacrocycles based on bisglyoximato motifs to affect the chemistry at the central metal.     

Double-stranded helices and molecular zippers assembled from single-stranded coordination polymers directed by supramolecular interactions

Using three nonlinear dicarboxylates, isophthalate (ipa), 4,4'-oxybis(benzoate) (oba), and ethylenedi(4-oxybenzoate) (eoba), we have prepared five neutral infinite copper(II) dicarboxylate coordination polymers containing lateral aromatic chelate ligands, namely [Cu(ipa)(2,2'-bpy)]n.2nH2O (1), [Cu2(ipa)2(phen)2H2O]n (2), [Cu(oba)(phen)]n (3), [Cu(oba)(2,2'-bpy)]n (4), and [Cu(eoba)(phen)]n (5; 2,2'-bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) by hydrothermal synthesis. X-ray single-crystal structural analyses of these complexes reveal that the nonlinear flexible or V-shaped dicarboxylates can induce the helicity or flexuousity of the polymeric chains and aromatic chelate ligands are important in providing potential supramolecular recognition sites for pi-pi aromatic stacking interactions. An appropriate combination of the bridging dicarboxylate and aromatic chelate can induce a pair of single-stranded helical or flexuous chains to generate a double-stranded helix or molecular zipper through supramolecular interactions, respectively.