Series Of Coordination Polymers Research Articles

Synthesis of isophthalic acid-carbazole coordination polymers with stacking-dependent ultralong room temperature phosphorescence and white-light emission

Exploiting the relationship between the stacking modes of molecules and room-temperature phosphorescence (RTP) performance is of great important to design afterglow materials. A series of coordination polymers [Cd(CzIP)] (1) (H2CzIP = 5-(carbazol-9-yl) isophthalate), [Cd(CzIP)(DMI)] (2) (DMI = 1,3-Dimethyl-2-imidazolidinone) and [Cd2(CzIP)2(H2O)2] (3) base on carbazole–isophthalic acid are synthesized via a solvothermal method. These compounds exhibit stacking-dependent RTP. Compounds 1 and 2 exhibit obvious time-dependent RTP with the afterglow color from orange to green, and show white-light emission owing to fluorescence and phosphorescence dual emission. Compound 3, which features the strong π‒π stacking, showed the weakest phosphorescence with the shortest lifetime. It reveals that the phosphorescence efficiency is not proportional to the overlap of π-π stacking, the triplet excited states of discrete dimer mode rather than H-aggregation can dominate the generation of room-temperature phosphorescence. These results indicate that coordination induction is an efficient approach to regulate the aggregation of chromophores, further modulating the room-temperature phosphorescence.

Highly selective and recyclable lanthanoids coordination polymers fluorescent sensors for 1-Hydroxypyrene

Based on trivalent lanthanides, fumaric acid (H2F) and 4-(pyridyl-N-oxide) methylphosphonic acid (H2L), a new series of coordination polymers (the CP), namely, [Ln(HL)(F)(H2O)]n (Ln = La(1), Ce(2), Pr(3), Nd(4), Sm(5), Eu(6), Gd(7)) were obtained under hydrothermal condition. Data for the prepared CPs was collected using single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and luminescence spectra. The results show that, on the hand, complexes 1–7 are isomorphic, having 2D layered structures. On the other hand, the Eu3+ ion content greatly affects the luminescence characteristic of complex 6, which is a novel fluorescence sensor for detecting trace amounts of 1-Hydroxypyrene (1-HP), with excellent sensitivity and high selectivity. For the fluorescent determination of 1-HP, complex 6 shows a linear response range of 0–100 µM, with an ultralow detection limit (LOD) of 2.76 μM. The fluorescence quenching mechanism of complex 6 by 1-HP may be result from spectral overlap and energy absorption competition.

Nitrile-Containing Terpyridyl Zn(II)-Coordination Polymer-Based Metallogelators Displaying Helical Structures: Synthesis, Structures, and "Druglike" Action against B16-F10 Melanoma Cells.

An attempt has been made to develop a self-drug-delivery system against melanoma from a series of metallogelators derived from coordination polymers. Thus, a series of coordination polymers (CP1-CP6) derived from a nitrile-containing terpyridyl ligand (L) and transition metal salts (Cu(I)/Zn(II)) have been synthesized and thoroughly characterized by a number of physicochemical techniques including single crystal X-ray diffraction. Reactions of the ingredients of the coordination polymers guided by their single crystal structures produced four metallogels (CPG2-CPG5) which were characterized by dynamic rheology and TEM. The metallogelator CPG3 turned out to be the best suited for further studies as revealed from MTT assay against melanoma (B16-F10) and macrophage (RAW 264.7) cells. Various experiments (scratch, cell cycle, nuclear condensation, annexin V-FITC/PI, mitochondrial membrane potential, Ho-efflux assays) not only supported the "druglike" action against melanoma B16-F10 cells but also suggested that the mechanism of cancer cell death was via mitochondrial membrane potential depolarization-driven apoptosis. Because melanoma B16-F10 is a model cell line for human skin cancer, the metallogel CPG3 may, therefore, be further developed for such treatment.

A Series of Coordination Polymers Constructed by 2-Phenylsuccinic Acid and Flexible Bis(Imidazole) Ligands: Syntheses, Structures, and Photoluminescent Properties

A Series of Coordination Polymers Constructed by 2-Phenylsuccinic Acid and Flexible Bis(Imidazole) Ligands: Syntheses, Structures, and Photoluminescent Properties

Anchoring Drugs to a Zinc(II) Coordination Polymer Network: Exploiting Structural Rationale toward the Design of Metallogels for Drug-Delivery Applications.

A new series of coordination polymers (CPs) were synthesized and crystallographically characterized by single-crystal X-ray diffraction with the aim of developing drug-delivery systems via metallogel formation. Structural rationale was employed to design such coordination-polymer-based metallogels. As many as nine CPs were obtained by reacting two bis(pyridyl)urea ligands, namely, 1,3-dipyridin-3-ylurea (3U) and 1,3-dipyridin-4-ylurea (4U), and the sodium salt of various nonsteroidal antiinflammatory drugs, namely, ibuprofen (IBU), naproxen (NAP), fenoprofen (FEN), diclofenac (DIC), meclofenamic acid (MEC), mefenamic acid (MEF), and Zn(NO3)2. All of the CPs displayed 1D polymeric chains that were self-assembled through various hydrogen-bonding interactions involving the urea N-H and carboxylate O atoms and, in a few cases, lattice-occluded water molecules. The reacting components of the CPs produced five metallogels in dimethyl sulfoxide/water. The gels were characterized by rheology and transmission electron microscopy. Three selected metallogelators, namely, 3UMEFg, 3UNAPg, and 3UMECg, showed in vitro anticancer, cell imaging, and multidrug delivery for antibacterial applications, respectively. The shear-thinning properties of 3UMECg (rheoreversibility and injectability) make it a potential candidate for plausible topical application.

Use of highly stable phosphonate coordination polymers as adsorbents for wastewater

A series of coordination polymers (CPs) based on phosphonates, M‐VP, and M‐Phen‐VP (M = Ce, La, Phen = 1,10‐phenanthroline, Im‐imidazole, VP = vinylphosphonate) were obtained by hydrothermal reactions in different conditions: room temperature, 75°C, 180°C, at pH 1.5–7 aqueous solutions. The materials were characterized by Fourier‐transform infrared (FTIR), X‐ray powder diffraction, and thermogravimetric analysis. The samples are characterized by a high degree of crystallinity, judging from the intensity of the peak in the 2θ region 8–9°. Thermogravimetric analysis performed on cerium and lanthanum CPs crystals indicate that the compounds are stable up to 360°C, after which it undergoes degradation corresponding to loss of the organic unit. The obtained materials were further used as adsorbent in the removal process of cesium (Cs(I)) and thalium ions (Tl(I)) from aqueous solutions. In order to establish the maximum adsorption capacity of the studied CPs and for the interpretation of the results obtained in the equilibrium study, several empirical isotherms were used: Freundlich, Temkin, Langmuir, and Dubinin–Radushkevich. The particular parameters for each isotherm and correlation coefficient (R2) have been determined.

Zn(II)-Coordination Polymers with a Right- and Left-Handed Twist: Multifunctional Metal–Organic Hybrid for Dye Adsorption and Drug Delivery

A relatively less explored bis-pyridyl-bis-amide ligand (L1) having a diphenylmethane backbone was exploited to generate a new series of coordination polymers as potential multifunctional materials...

Transition Metal Ions Regulated Structural and Catalytic Behaviors of Coordination Polymers

Three new coordination polymers (CPs), I [Cu­(L)­(H2O)]·2H2O, II [Zn­(L)], and III [Ag­(HL)­(CH3CN)], were synthesized by employing a novel pyrazole-based dicarboxylate ligand (H2L) through a solvothermal strategy. Single-crystal structural analysis established that compounds I and II exhibit two-dimensional (2D) sheet structures, while compound III possesses a one-dimensional (1D) ladder structure due to the connectivity of terminal solvent moiety. The geometries of metal ions vary from square planar (Cu2+ ion) to distorted tetrahedral (Zn2+ and Ag+ ion). Topological study showed that compound I has made a (4·62)2(42·62·82) net, while compounds II and III have exposed common (44·62) sql net and (42·6) net, respectively. The Lewis acidic nature of compounds I, II, and III has been confirmed with various heterogeneous catalytic reactions. For the first time, one-pot multicomponent synthesis of α-amino amidine has been performed by the three CPs and the reaction kinetics has been altered by the variation of Lewis acidic metal centers. The roles of metal ions for structural variations and the catalytic performances are investigated in a series of CPs.

Extrinsicvs.intrinsic luminescence and their interplay with spin crossover in 3D Hofmann-type coordination polymers

Two series of coordination polymers have been synthesized to exhibit extrinsic or intrinsic luminescence modulated by spin crossover behavior. This study provides further insight into the features governing the synergy between both properties.

Construction of functional coordination polymers derived from designed flexible bis(4-carboxybenzyl)amine

A series of coordination polymers (CPs) have been constructed from bis(4-carboxybenzyl)amine and a series of bis(imidazole) linkers. Luminescence sensing measurements indicate that two zinc-based CPs both show highly selective and sensitive sensing for acetone and Cr2O72−/CrO42−.

Contribution to the coordination chemistry of transition metal nitroprussides: a cryo-XPS study

The XPS Fe 2p3/2 core-level spectra of sodium hexacyanoferrate(ii) and sodium nitroprusside.

Syntheses, crystal structures and photophysical properties of a series of Zn-Ln coordination polymers

A series of coordination polymers, {[LnZn(2,3-pydc)(1,3-bdc)(OH)(H2O)m]·H2O}n, (Ln = Sm 1, Eu 2, Gd 3, Tb 4, Dy 5, Er 6, Yb 7, Pr 8, Nd 9), (1–7, m = 1; 8, 9, m = 2), (2,3-H2pydc = pyridine-2,3-dicarboxylic acid, 1,3-H2bdc = isophthalic acid), are synthesized by the hydrothermal method and their crystal structures are determined by single-crystal X-ray diffraction. Structural analysis shows that coordination polymers 1–9 present two-dimensional layered structures and all of them are crystalized in triclinic system with space group Pī. Hereinto polymers 1–7 are isomorphous, while polymers 8 and 9 are also isomorphous and each of them includes one more coordinated water molecule than others. All coordination polymers are characterized by IR, UV–Vis–NIR and fluorescent spectra, and the luminescent properties are the research emphasis. In addition, except for polymer 3, the other eight Zn-Ln polymers exhibit the characteristic luminescence of corresponding Ln(III) ions, which should be owing to the sensitization of the Zn-Ligand moiety. With the influence of the crystal field and the introduction of Zn(II) ion, the internal energy levels of the system are tuned, which is reflected by shift and split of the partial characteristic bands of Ln(III) ions in their UV–Vis–NIR absorption spectra and NIR emission spectra, and both can corroborate each other.

Bringing 5-(3,4-dicarboxylphenyl)picolinic acid to crystal engineering research: hydrothermal assembly, structural features, and photocatalytic activity of Mn, Ni, Cu, and Zn coordination polymers

A novel tricarboxylic acid block with phthalate and picolinate functionalities was applied for the assembly of a new series of coordination polymers with interesting structural features and functional properties.

Hydrothermal recrystallization of transition metal nitroprussides. Formation of the most stable phases

Hydrothermal recrystallization appears to be an appropriate treatment to explore the structural diversity of porous coordination polymers. In this contribution, such a post-synthesis treatment is applied to divalent transition metal nitroprussides, T[Fe(CN)5NO]∙xH2O with T =Mn, Fe, Co, Ni, Cu, Zn, Cd. This family of compounds forms an interesting series of nanoporous coordination polymers with a wide structural diversity, related to the synthesis route used and the solid hydration degree (x). The effect of a hydrothermal recrystallization of previously prepared fine powders using the precipitation method, on their crystal structure and related properties is herein discussed. In this series of coordination polymers, for Fe, Co, Ni the precipitated powders are obtained as cubic phase, with a high porosity related to presence of systematic vacancies for building unit [Fe(CN)5NO]. For Fe and Co a structural transition, from cubic to orthorhombic, was observed, which is associated to formation of a most compact structure. The crystal structure for the new orthorhombic phases was refined from the collected powder HR-XRD patterns. For Ni, the cubic phase remains stable even for large heating time, which is ascribed to the high polarizing power of this metal. The high porosity for the cubic phase allows an easy accommodation for the local deformations around the Ni atom coordination sphere. The structural information from XRD was complemented with CO2 and H2 adsorption and TG data, IR and UV–vis spectra, and magnetic measurements. The magnetic data, through the presence of spin-orbit coupling for Fe and Co in the two phases, provide fine details on the coordination environment for the metal linked at the N ends of the CN group.

Host-Guest Engineering of Coordination Polymers for Highly Tunable Luminophores Based on Charge Transfer Emissions.

Aiming at the targeted construction of coordination polymer luminophores, the engineering of host-guest architectures with charge transfer based emissions is performed by utilizing the interactions between the electron-deficient 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (tpt) and electron-rich polycyclic aromatic hydrocarbons (PAHs) motifs as acceptors and donors, respectively. Through guest modulation of a prototype coordination polymer [Cd(tpt)(1,4-pda)(H2O)2]·(tpt)·(H2O)2 (1) (1,4-H2pda = 1,4-phenylenediacetic acid), a series of coordination polymers with different PAHs as guests, [Cd2(tpt)2(1,4-pda)2]·guest (2-5) (guest = triphenylene for 2, pyrene for 3, coronene for 4, and perylene for 5), are successfully fabricated. Distinct from 1, coordination polymers 2-5 reveal unique bilayer structures with PAHs interlayer and good stability, owing to the enhanced stacking interactions between tpt motifs and PAH guests. Moreover, their emissions cover a wide range of wavelength due to the effective guest to host charge transfer interactions between donor and acceptor motifs. Their readily tunable host-guest charge transfer based emissions make them good candidates as potential luminophores.

A series of anionic host coordination polymers based on azoxybenzene carboxylate: structures, luminescence and magnetic properties.

A series of coordination polymers {[Ln(aobtc)(H2O)4]·Hbipy·H2O}n (H4aobtc = azoxybenzene-2,2',3,3'-tetracarboxylic acid, bipy = 4,4'-bipyridine, and Ln = Sm(1), Eu(2), Gd(3), Tb(4), Dy(5), Er(6)) have been synthesized and characterized systematically. The cationic Hbipy+ guest incorporated polymers are isostructural sets, featuring a one-dimensional (1D) zigzag double chain edifice composed of binuclear clusters [Ln2(H4aobtc)2], with the Hbipy+ guest being located on two sides. These 1D chains are further interlinked into a 2D layer structure, and further extended into a 3D framework through hydrogen bonding interactions. The luminescence emission spectra of polymers 2 and 3 are based on the H4aobtc acid ligands, while 1 and 4 display the characteristic f-f transitions of Ln(iii) ions. Magnetic measurements revealed the presence of ferromagnetic behavior in polymer 3. The magnetic behaviors of 4 and 6 are ascribed to the depopulation of the Stark levels and/or weak antiferromagnetic interactions within MOFs at lower temperature. Slow relaxation is observed through the alternating-current susceptibility measurements for 5 at lower temperature, and the coexistence of weak ferromagnetism corresponding to the spin-canting-like behavior.

Cu(ii) frameworks from a “mixed-ligand” approach

Combination of di-2-pyridyl ketone with polycarboxylates in the CuII chemistry has afforded a series of coordination polymers and hydrogen-bonded frameworks.

Synthesis, structure and properties of four new coordination polymers based on 2-(4-Chloro-phenoxy)-N-pyridin-3-ylacetamide

A series of coordination polymers, namely, [Zn(L)(HIP)(H2O)] (1), [Cd(L)(HIP)]·1/2H2O (2), [Co1.5(L)(BTC)(CH3OH)(H2O)3]·2H2O (3), [Ni1.5(L)(BTC)(H2O)4]·3H2O (4), where L=2-(4-Chloro-phenoxy)-N-pyridin-3-ylacetamide, H2HIP=5-hydroxyisophthalic acid, H3BTC=1,3,5-benzenetricarboxylic acid, have been synthesized under hydrothermal conditions. Single crystal X-ray diffraction analysis reveals that the complexes 1, 3 and 4 display 1D chain structure. In complex 2, each Cd2 unit is linked into BTC form two dimensional layer structures, which are further connected by μ 2-L ligand to construct 3D architecture with {424;64}-bcu topology. Moreover, their powder X-ray diffraction analysis, thermostability and luminescence properties are explored.

A series of coordination polymers with 2D → 3D interdigitated structures self-assembled from 1,4-bis(4-(imidazole-1-yl)benzyl)piperazine

Six new coordination polymers, namely [Co2(1,2-bdc)2(bibp)2]·H2O (1), [Zn2(1,2-bdc)2(bibp)2]·H2O (2), [Ni2(1,2-bdc)2(bibp)3]·7H2O (3), [Cd(1,2-bdc)(bibp)0.5] (4), [Co(Hbtc)(bibp)] (5), [Cd(Hbtc)(bibp)] (6) (bibp=1,4-bis(4-(imidazole-1-yl)benzyl)piperazine, 1,2-bdc=1,2-benzenedicarboxylate, btc=1,3,5-benzenetricarboxylate), have been synthesized under hydrothermal conditions. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra and TG analyses. Compounds 1–6 display different 2D→3D interdigitated structures due to their different 2D layers. In 1 and 2, the 2D layers contain single-stranded meso-helical chains. In 3, there are large rhombic cavities in the 2D sheet. In 4, the 2D layer is built from rod-shaped SBUs. In 5 and 6, the 2D layers exhibit highly undulating 44-sql networks. In addition, the magnetic properties for compounds 1, 3 and 5, and the photoluminescence properties for compounds 2, 4 and 6 have also been investigated.

Systematic Study of Mutually Inclusive Influences of Temperature and Substitution on the Coordination Geometry of Co(II) in a Series of Coordination Polymers and Their Properties

In this contribution we have extended our current research goal of designing functional metal–organic frameworks (MOFs) using bispyrazole type ligands. Accordingly, ten new cobalt-based MOFs have been synthesized using a simple bispyrazole ligand, 4,4′-methylene-bispyrazole (H2MBP), and isophthalic acid (H2IPA) and its four 5-substituted derivatives R-H2IPA (R = COOH, OH, tBu, NH2). The major aim of this study was to validate the mutual influence of temperature and substitutions on the final structural self-assembly. Five different isophthalic acid derivatives were used to study the influence of substituents while each reaction was carried out at two different temperatures to assess the temperature effect. A clear correlation was observed between the reaction temperature and the coordination number of the cobalt atoms which consequently changes the self-assembly pattern. We have also shown that the periodical change in coordination number did bring about some systematic changes in the structural network v...