Showing papers on "Coordination polymer published in 2017"
TL;DR: It is shown that amorphous CP can be used as general synthesis precursors of highly complex mixed metal oxide shells and can be applied to produce ternary and quaternary metal oxide onions with tunable size and composition.
Abstract: Metal-organic frameworks (MOFs) or coordination polymers (CPs) have been used as precursors for synthesis of materials. Unlike crystalline MOF, amorphous CP is nonspecific to metal cation species, therefore its composition can be tuned easily. Here, it is shown that amorphous CP can be used as general synthesis precursors of highly complex mixed metal oxide shells. As a proof of concept, NiCo coordination polymer spheres are first synthesized and subsequently transformed into seven-layered NiCo oxide onions by rapid thermal oxidation. This approach is very versatile and can be applied to produce ternary and quaternary metal oxide onions with tunable size and composition. The NiCo oxide onions exhibit exceptional charge storage capability in aqueous electrolyte with high specific capacitance (≈1900 F g-1 at 2 A g-1 ), good rate capability, and ultrahigh cycling stability (93.6% retention over 20 000 cycles). A hybrid supercapacitor against graphene/multishelled mesoporous carbon sphere shows a high energy density of 52.6 Wh kg-1 at a power density of 1604 W kg-1 (based on active materials weight), as well as remarkable cycling stability.
344 citations
TL;DR: In this paper, a cationic crystalline coordination polymer SBN was used to trap ReO4-incorporated phase (SBR) of anionic radioactive contaminant of great concern.
Abstract: We report one of the most efficient scavenger materials, a cationic crystalline coordination polymer SBN for trapping ReO4–, a surrogate for 99TcO4–, as an anionic radioactive contaminant of great concern. The uptake capacity for ReO4– reaches 786 mg/g, a value noticeably higher than the state of art anion-exchange resins and other inorganic or hybrid anion sorbents. Once being captured, ReO4– is greatly immobilized, as almost no ReO4– can be eluted using large excess of nitrate, carbonate, and phosphate anions. The processes are featured by a complete and irreversible single-crystal to single-crystal structural transformation from SBN to the ReO4–-incorporated phase (SBR). The coordination environments of NO3– and ReO4– probed by single-crystal structures clearly unravel the underlying mechanism, where each ReO4– in SBR binds to multiple Ag+ sites forming strong Ag–O–Re bonds, and to 4,4′-bipyridine through a dense hydrogen bond network. These structural insights lead to a significant difference in solub...
171 citations
TL;DR: In this article, a new luminescent nanoscale Zn(II) coordination polymer (TB-Zn-CP) was synthesized in quantitative yield using ZnOAc2·2H2O and tetraacid linker L (1':'0.5) in DMF at room temperature.
Abstract: A V-Shaped 4-amino-1,8-napthalimide derived tetracarboxylic acid linker (L; bis-[N-(1,3-benzenedicarboxylic acid)]-9,18-methano-1,8-naphthalimide-[b,f][1,5]diazocine) comprising the Troger's base (TB) structural motif was rationally designed and synthesised to access a nitrogen-rich fluorescent supramolecular coordination polymer. By adopting the straight forward precipitation method, a new luminescent nanoscale Zn(II) coordination polymer (TB-Zn-CP) was synthesized in quantitative yield using Zn(OAc)2·2H2O and tetraacid linker L (1 : 0.5) in DMF at room temperature. The phase-purity of as-synthesised TB-Zn-CP was confirmed by X-ray powder diffraction analysis, infra-red spectroscopy, and elemental analysis. Thermogravimetric analysis suggests that TB-Zn-CP is thermally stable up to 330 °C and the morphological features of TB-Zn-CP was analysed by SEM and AFM techniques. The N2 adsorption isotherm of thermally activated TB-Zn-CP at 77 K revealed a type-II reversible adsorption isotherm and the calculated Brunauer–Emmett–Teller (BET) surface area was found to be 72 m2 g−1. Furthermore, TB-Zn-CP displayed an excellent CO2 uptake capacity of 76 mg g−1 at 273 K and good adsorption selectivity for CO2 over N2 and H2. The aqueous suspension of as-synthesized TB-Zn-CP showed strong green fluorescence (λmax = 520 nm) characteristics due to the internal-charge transfer (ICT) transition and was used as a fluorescent sensor for the discriminative sensing of nitroaromatic explosives. The aqueous suspension of TB-Zn-CP showed the largest quenching responses with high selectivity for phenolic-nitroaromatics (4-NP, 2,4-DNP and PA) even in the concurrent presence of other potentially competing nitroaromatic analytes. The fluorescence titration studies also provide evidence that TB-Zn-CP detects picric acid as low as the parts per billion (26.3 ppb) range. Furthermore, the observed fluorescence quenching responses of TB-Zn-CP towards picric acid were highly reversible. The highly selective fluorescence quenching responses including the reversible detection efficiency make the nanoscale coordination polymer TB-Zn-CP a potential material for the discriminative fluorescent sensing of nitroaromatic explosives.
148 citations
TL;DR: In this paper, the synthesis, characterization, and crystal structure of a neutral two-dimensional adenine-based luminescent coordination polymer (LCP) with Zn(II) metal nodes were reported.
Abstract: The present work reports the synthesis, characterization, and crystal structure of a neutral two-dimensional adenine-based luminescent coordination polymer (LCP) with Zn(II) metal nodes. The photoluminescence property of the d10 LCP [Zn(μ2-1H-ade)(μ2-SO4)] (1) has been exploited to use 1 as a dual detection probe for the selective sensing of Hg2+ and 2,4,6-trinitrophenol (TNP) in the aqueous phase from among a variety of cations and a pool of aromatic nitro compounds, respectively. Competitive fluorometric experiments involving a series of cation combinations or mixture of nitro compounds established 1 as an efficient and selective sensor for Hg2+ and TNP in aqueous solutions. The limits of detection for sensing of Hg2+ and TNP in aqueous solutions using LCP 1 are 70 and 0.4 nM, respectively. For in-field sensing applications, 1-coated test paper strips have been developed. They show luminescence upon exposure to UV radiation, and the luminescence intensity is quenched upon addition to aqueous solutions o...
125 citations
TL;DR: In this article, the authors reported the preparation of porous coordination polymers with active silver sites and efficient silver-silver bond formation by carefully modifying the coordination geometries of the silver sites.
Abstract: The widely studied porous coordination polymers, possessing large pores to adsorb waste carbon dioxide gas and further transform it into valuable chemical products, have been attracting research interest, both industrially and academically. The active silver(I) ions endow the specific alkynophilicity to activate C≡C bonds of alkyne-containing molecules via π activation. Incorporating catalytic Ag metal sites into the porous frameworks represents a promising approach to construct heterogeneous catalysts that cyclize propargylic alcohols with CO2, which is highly desirable for the environmentally benign conversion of carbon dioxide to fine chemicals. We report the preparation of porous coordination polymers (PCPs) with active silver sites and efficient silver–silver bond formation by carefully modifying the coordination geometries of the silver sites. The decentralized silver(I) chains in the porous frameworks enable the efficient conversion of CO2 and derivatives of acetylene to α-alkylidene cyclic carbona...
118 citations
TL;DR: Density functional theory calculations suggest that the "Cu-edge site" on the (100) surface plays an important role in improving the HER catalytic performance of Cu-BHT nanoparticles.
Abstract: A graphene-like coordination polymer based on copper(II) benzenehexathiol (Cu-BHT, 1) with high electric conductivity (103 S·cm–1) was prepared recently. The high conductivity makes this material a good candidate for electrocatalysis, and here its catalytic activity toward hydrogen evolution reaction (HER) was evaluated. Cu-BHT shows good activity and stability for HER in acidic solutions under high current densities. By changing the preparation conditions, the morphology of Cu-BHT materials was controlled at the mesoscale, which allows the preparation of a thin film (TF-1), nanocrystal (NC-1), and amorphous nanoparticle (NP-1) of Cu-BHT. The overpotential of Cu-BHT toward HER shows an improved activity from 760 mV (NC-1) to 450 mV (NP-1) at a current density of 10 mA·cm–2. A Tafel slope of ∼95 mV·dec–1 and an exchange current density of 10–3 mA·cm–2 were achieved under optimized conditions. Density functional theory calculations suggest that the “Cu-edge site” on the (100) surface plays an important role...
111 citations
TL;DR: The structural analyses conclude that the ordering of the methanol induces the chirality while the available space controls the dynamic motion of the knitted 2D networks into the 3D interpenetrated framework.
Abstract: An unprecedented reversible dynamic transformation is reported in a metal-organic framework involving bond formation, which is accompanied by two important structural changes; achiral to chiral and two- to three-dimensions. Using two bent organic ligands (diimpym=4,6-di(1H-imidazol-1-yl)pyrimidine; H2 npta=5-nitroisophthalic acid) and CoII (NO3 )2 ⋅6 H2 O the coordination polymer Co(diimpym)(npta)⋅CH3 OH, (1⋅CH3 OH), was obtained solvothermally. Its structure consists of knitted pairs of square layers (44 -sql net) of five-coordinated Co and disordered methanol, and it crystallized in the achiral Pbca space group at room temperature. It undergoes a single crystal to single crystal (SC-SC) transformation to a 3D interpenetrated framework (α-polonium-type net, pcu) of six-coordinated Co and ordered methanol in the chiral P21 21 21 space group below 220 K. Most unusual is the dynamic temperature-dependent shortening of a Co⋅⋅⋅O connection from a non-bonded 2.640 A (298 K) to a bonded 2.347 A distance (100 K) transforming the square pyramidal cobalt polyhedron to a distorted octahedron. The desolvated crystals (1) obtained at 480 K retain the full crystallinity and crystallize in the achiral Pbca space group between 100 and 298 K but the dynamic shortening of the Co⋅⋅⋅O distance connecting the layers into the 3D pcu framework structure is observed. Following post-synthetic insertion of ethanol (1⋅CH3 CH2 OH) it does not exhibit the transformation and retains the knitted 2D achiral Pbca structure for all temperatures (100-298 K) and the ethanol is always disordered. The structural analyses thus conclude that the ordering of the methanol induces the chirality while the available space controls the dynamic motion of the knitted 2D networks into the 3D interpenetrated framework. Consequently, 1 selectively adsorbs CO2 to N2 and exhibits Type-III isotherms indicating dynamic motion of the 2D networks to accommodate the CO2 at 273 and 298 K in contrast to the rigidity of the 3D framework at 77 K preventing N2 from penetrating the solid. The magnetic properties are also reported.
106 citations
TL;DR: In this article, a covalent triazine framework with an Ir(III)-N-heterocyclic carbene complex was synthesized and characterized to have a coordination environment similar to that of its structurally related molecular Ir complex.
Abstract: Functionalizing the recently developed porous materials such as porous organic frameworks and coordination polymer networks with active homogeneous catalytic sites would offer new opportunities in the field of heterogeneous catalysis. In this regard, a novel covalent triazine framework functionalized with an Ir(III)-N-heterocyclic carbene complex was synthesized and characterized to have a coordination environment similar to that of its structurally related molecular Ir complex. Because of the strong σ-donating and poor π-accepting characters of the N-heterocyclic carbene (NHC) ligand, the heterogenized Ir-NHC complex efficiently catalyzes the hydrogenation of CO2 to formate with a turnover frequency of up to 16 000 h–1 and a turnover number of up to 24 300; these are the highest values reported to date in heterogeneous catalysis for the hydrogenation of CO2 to formate.
101 citations
TL;DR: The remarkable character of these frameworks is that coordination polymer II demonstrates highly selective and sensitive bifunctional luminescent sensor toward nitrobenzene and Cu2+ ion.
Abstract: Two metal–organic frameworks (MOFs), namely, [Ni(DTP)(H2O)]n (I) and [Cd2(DTP)2(bibp)1.5]n (II) (H2DPT = 4′-(4-(3,5-dicarboxylphenoxy) phenyl)-4,2′:6′,4″-terpyridine; bibp = 1,3-di(1H-imidazol-1-yl)propane), that present structural diversity were solvothermally prepared. Single-crystal X-ray diffraction analysis indicates that they consist of {NiN2O4} building units (for I) and {CdO4N2} and {CdO3N3} building units (for II), which are further linked by multicarboxylate H2DPT to construct microporous three-dimensional frameworks. The remarkable character of these frameworks is that coordination polymer II demonstrates highly selective and sensitive bifunctional luminescent sensor toward nitrobenzene and Cu2+ ion. The fluorescence quenching mechanism of II caused by nitrobenzene is ascribed to electron transfer from electron-rich (II) to electron-deficient nitrobenzene. The result was also evidenced by the density functional theory. Furthermore, anti-ferromagnetic as well as electrochemical characters of Ni-...
90 citations
TL;DR: In this paper, the first piezochromic metal-viologen material and the modulation of the pressure-responsive behavior through coordination structures were presented by means of ultraviolet-visible spectroscopy, X-ray photoelectron spectrogrammy, electron paramagnetic resonance, in situ/ex situ Xray diffraction and DFT calculations.
Abstract: While stimuli-responsive chromic phenomena are well known for various viologen-containing organic and metal–organic materials, viologen-based piezochromism is a very recent discovery in organic compounds. Here we present the first piezochromic metal–viologen material and the modulation of the pressure-responsive behavior through coordination structures. By means of ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, in situ/ex situ X-ray diffraction and DFT calculations, we demonstrated that a zigzag-chain CdII coordination polymer (1) with a viologen-dicarboxylate zwitterionic ligand shows reversible piezochromism, with modulations in threshold pressure and visible-light absorption (color) compared with the free ligand. We also illustrated that piezochromism can be suppressed upon coordination of the same ligand in a rigid 3D framework with the same metal ion. Two basic requirements were proposed from viologen-based piezochromism: appropriate donor–acceptor contacts providing electron transfer pathways, and structural flexibility allowing pressure to further reduce the contacts. We expect great prospects in tuning piezochromism and designing new pressure-responsive materials through diverse metal–viologen combinations. The very fast photochromic response of compound 1 at ambient pressure was also studied, which was attributed to the rather short donor–acceptor contacts in the structure.
79 citations
TL;DR: Zn(DMA)(TBA) (1) (H2TBA = 4-(1H-tetrazol-5-yl)-benzoic acid) features a unique two-dimensional (2D) network structure, exhibiting excellent luminescence and good stability in both water and other organic solvents.
Abstract: A novel coordination polymer Zn(DMA)(TBA) (1) (H2TBA = 4-(1H-tetrazol-5-yl)-benzoic acid) features a unique two-dimensional (2D) network structure, exhibiting excellent luminescence and good stability in both water and other organic solvents. 1 shows excellent selectivity, fast detection time and high sensitivity (detection limit, 1.97 × 10−6 M) for Al3+ in the aqueous phase via fluorescence enhancement, which represents a rare example in the reported sensors for Al3+ detection. It is worth noting that 1 not only exhibits a highly selective fluorescence enhancement (turn on) effect for Al3+ in aqueous solution, but can also resist the interference of other metal ions. Meanwhile, 1 can act as a promising functional fluorescent sensor for detecting and recognizing trace nitroaromatic explosives (NACs) through fluorescence quenching with high selectivity and sensitivity in aqueous solutions. Experimental and theoretical calculations indicate that the luminescence quenching is attributed to an electron and resonance energy transfer between CPs and analytes.
TL;DR: Utilization of CP crystal in liquid state enables to be a novel route to incorporate functional molecules and defects, and it provides a tool to control the bulk properties of the CP material.
Abstract: The melting behavior of a coordination polymer (CP) crystal was utilized to achieve enhanced and optically switchable proton conductivity in the solid state. The strong acid molecules (triflic acid) were doped in one-dimensional (1D) CP, [Zn(HPO4 )(H2 PO4 )2 ](ImH2 )2 (ImH2 =monoprotonated imidazole) in the melt state, and overall enhancement in the proton conductivity was obtained. The enhanced proton conductivity is assigned to increased number of mobile protons and defects created by acid doping. Optical control over proton conductivity in the CP is achieved by doping of the photo acid molecule pyranine into the melted CP. The pyranine reversibly generates the mobile acidic protons and local defects in the glassy state of CP resulting in the bulk switchable conductivity mediated by light irradiation. Utilization of CP crystal in liquid state enables to be a novel route to incorporate functional molecules and defects, and it provides a tool to control the bulk properties of the CP material.
TL;DR: A cationic Ag(i) coordination polymer with 1D nanoporous channels shows the selective and complete removal of carcinogenic dye Acid Red 26 from aqueous solution upon the size-exclusion and charge-matching effect.
TL;DR: In this paper, a luminescent terbium-III-based coordination polymer, [Tb(BTEC)0.5(HCOO)(H2O)2] (1) has been successfully synthesized by solvothermal reaction of Tb(NO3)3·6H 2O with 1,2,4,5-tetracarboxylic acid (H4BTEC), in N,N-dimethylformamide (DMF) and H2O at 160°C.
Abstract: A luminescent terbium(III)-based coordination polymer, [Tb(BTEC)0.5(HCOO)(H2O)2] (1) has been successfully synthesized by solvothermal reaction of Tb(NO3)3·6H2O with 1,2,4,5-tetracarboxylic acid (H4BTEC) in N,N-dimethylformamide (DMF) and H2O at 160 °C. Compound 1 possesses dimeric [Tb2(BTEC)4(HCOO)2(H2O)4] building blocks which are linked by BTEC linkers to generate a two-dimentional honeycomb layer. 1 shows intense characteristic green emission in both solid state and organic solvents including acetone, ethanol, acetonitrile, benzene, dichloromethane, methanol, tetrahydrofuran, dimethyl sulfoxide and water at ambient temperature. Strong emission of 1 could be highly and selectively quenched by 4-nitropenol (4-NP) even in the coexistence of other competing nitroaromatics such as 2,4,6-trinitrophenol, 2,6-dinitrotoluene, nitrobenzene, 4-nitrotolune, 4-bromophenol, phenol, bromobenzene, and 1,2-dimethylbenzene. In addition, 1 exhibited superior selectivity and sensitivity towards Fe3+ ion over other metal ions including Al3+, Ca2+, Cd2+, Co2+, Cr3+, Cu2+, Ni2+, K+, Mg2+, Mn2+, Pd2+ and Zn2+ ions. The possible detection mechanisms have been proposed. More interestingly, the trace amounts of 4-NP and Fe3+ ions were selectively detected using visual luminescent test papers based on 1, which could further contributes a credible potential sensing application of coodination polymers for the biological and environmental concerns.
TL;DR: The experimental results indicate that CP 1 is an efficient luminescent sensor for the detection of Fe3+ ions in an aqueous solution and exhibits a sensitive and rapid electrochemical response to nitrite ions in water solution.
Abstract: Herein, a nickel coordination polymer (CP 1), {Ni(1,4-bib)1.5(TPA-Cl2)·H2O}n (1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene, H2TPA-Cl2 = 2,5-dichloro-terephthalic acid), has been synthesized under solvothermal conditions. The structure of CP 1 is a 3D 3-fold interpenetrating framework with the sqc12 topology. The thermal stability and luminescence properties of CP 1 were investigated. Scanning electron microscopy (SEM) images of this material display that it possesses an irregular block 3D structure. Interestingly, CP 1 can serve as a multifunctional material via its luminescence sensing, electrochemical sensing, and photocatalytic properties. The experimental results indicate that CP 1 is an efficient luminescent sensor for the detection of Fe3+ ions in an aqueous solution. In addition, CP 1 exhibits a sensitive and rapid electrochemical response to nitrite ions in water solution. The photocatalytic activities of CP 1 were evaluated in the degradation of different dye contaminants (MB, RhB, and MO), and the results demonstrate that its photocatalytic efficiency for the degradation of MB is highest (92.1% for MB, 85.7% for RhB, and 86.2% for MO). The effects of different dyes, different powers of UV light, and different amounts of catalyst CP 1 on the photocatalytic efficiency were also explored. Finally, the mechanism of the luminescence quenching effect toward Fe3+ ions, electroreduction of nitrite ions, and photocatalytic degradation of different dyes have been investigated in detail.
TL;DR: Compound 1 represents the first PL Mg-CP as a fluorescent probe for detecting metal ions, and because of the in situ encapsulation of photochromic [CH3-dpb]+ guests, 1 exhibited reversible photo chromic behavior.
Abstract: Here we report a fluorescent magnesium coordination polymer (Mg-CP), namely, [CH3-dpb]2[Mg3(1,4-NDC)4(μ-H2O)2(CH3OH)(H2O)]·1.5H2O (1, 1,4-H2NDC = 1,4-naphthalene dicarboxylic acid, dpb = 1,4-bis(pyrid-4-yl)benzene). Compound 1 possesses a three-dimensional (3D) host–guest structure constructed by the 1,4-NDC linkers bridging the linear trinuclear secondary building units of [Mg3(COO)8(μ-H2O)2]. The dpb molecules were in situ reacted with CH3OH resulting in photochromic cations of [CH3-dpb]+ that acted as guests located in the channels parallel to the b-axis. Photoluminescence (PL) studies indicated that 1 showed a strong green emission demonstrating sensitive fluorescence sensing of Fe3+/Cr3+ metal ions and nitro-explosive compounds. Compound 1 represents the first PL Mg-CP as a fluorescent probe for detecting metal ions. Moreover, because of the in situ encapsulation of photochromic [CH3-dpb]+ guests, 1 exhibited reversible photochromic behavior.
TL;DR: A novel hybrid system with a highly efficient, bioresponsive, and controlled release of antibacterial activity via the metal ion coordination polymer on titania nanotubes (TNTs) formulates a controllable delivery system for the long-lasting treatment of biomaterial-related bacterial infections.
Abstract: The current work reports a novel hybrid system with a highly efficient, bioresponsive, and controlled release of antibacterial activity via the metal ion coordination polymer on titania nanotubes (TNTs). These hybrid systems exhibited a self-defense behavior that is triggered by the change of the ambient environment acidity due to bacterial infection with Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Escherichia coli (E. coli). The antibacterial agents, including antibiotics and nanosilver particles, can be loaded into TNTs and then sealed with coordination polymers (CPs) through the attachment of metallic ions such as Zn2+ or Ag+. The zinc and silver ions work as intermediate coordination bonds, and they are sensitive to the change in H+. Because of the strong bonding of CPs, the amount of released antimicrobial agents is maintained at a nonsignificant level when pH is maintained at 7.4. However, the coordination bond of the capped CPs was triggered to open and relea...
TL;DR: In this article, the molar ratio of Zn(NO3)2·6H2O, 1,4-bpyvna, and 1,3,5-H3BTC was changed to 1:1:2.
Abstract: Solvothermal reactions of Zn(NO3)2·6H2O with 1,4-bis(2-(pyridin-4-yl)vinyl)naphthalene (1,4-bpyvna) and 1,3,5-benzenetricarboxylic acid (1,3,5-H3BTC) (molar ratio = 1:1:1) at 120 °C in CH3CN/H2O (v/v = 1:2) afforded one three-dimensional (3D) coordination polymer [Zn2(1,4-bpyvna)(1,3,5-HBTC)2(H2O)]n (1) Similar reactions with the same three components at 140 °C in dimethylformamide (DMF)/CH3CN/H2O produced another 3D coordination polymer {[Zn2(1,4-bpyvna)(1,3,5-BTC)(OH)]·H2O}n (2) in 72% yield When the molar ratio of Zn(NO3)2·6H2O, 1,4-bpyvna, and 1,3,5-H3BTC was changed to 1:1:2, the analogous treatment at 140 °C yielded one one-dimensional coordination polymer {[Zn(1,3,5-HBTC)2(H2O)][1,4-bpyvna-H2]·CH3CN}n (3, 1,4-bpyvna-H2 = 4,4′-((1,1′)-naphthalene-1,4-diylbis(ethene-2,1-diyl))bis(pyridin-1-ium)) Solvothermal reactions of Zn(NO3)2·6H2O with equimolar 1,4-bpyvna and 1 or 2 equiv of 4,4′-oxidibenzoic acid (4,4′-H2OBA) at 120 °C in DMF/CH3CN/hexane resulted in the formation of {[Zn2(1,4-bpyvna)(4,4′-O
TL;DR: This work demonstrated for the first time the crucial role of metal salts in the supramolecular polymerization and corresponding properties, in which symmetry breaking played an important role for the dynamic assembly difference.
Abstract: Herein, ditopic ligand DTA comprised of terpyridine and acetylene segments with only one aromatic π-conjugated building block was designed and synthesized. Driven by metal–ligand coordination interactions, we presented that the use of metal salts can direct the self-assembly of DTA in the generation of fluorescent and electrochemical polymers that entrapped water to form ambidextrous hydrogels. These were characterized by several approaches including fluorescent titrations, UV–vis, circular dichroism, and X-ray diffraction spectra as well as scanning electron microscopy and transmission electron microscopy experiments. DTA can selectively recognize Zn2+ ions and gelate water in the presence of ZnC6H10O6 (zinc lactate), giving Zn2+-specific fluorescent metallogels. Otherwise, DTA/Cu(OAc)2 forms nonfluorescent, electrochemical, and chiral hydrogel that responds to multiple stimuli such as heat, light, shearing, electrolysis, and reducer. The ion-controlled gelation approach, morphology, rheology, as well as...
TL;DR: In this article, a ternary resistive random access memory (RRAM) is fabricated from 1D d-π conjugated coordination polymer chains, which are synthesized via the coordination between Ni(II) salts and benzenetetramine or 3,3′,4,4′-biphenyltetramerine in a solution process.
Abstract: Ternary resistive random access memory (RRAM) devices are fabricated from 1D d-π conjugated coordination polymer chains, which are synthesized via the coordination between Ni(II) salts and benzenetetramine or 3,3′,4,4′-biphenyltetramine in a solution process. The as-fabricated devices can retain their memory states for as long as three months at room temperature or work for at least 10 000 s at 150 °C, which is the highest working temperature reported for a ternary RRAM at the time of writing this paper. Thermogravimetric analysis indicates good thermal stability of these two materials because of their good crystallinity and strong intermolecular interaction. The long-term and high-temperature stability makes 1D conjugated coordination polymer chains a promising candidate for use as next-generation material for high-density data storage via RRAM techniques.
TL;DR: Electrochemical and spectro-electrochemical investigations indicate that the fluoranilate ligand is redox-active in both complexes; a reduced form of (NBu4)2[Fe2(fan)3] was generated by chemical reduction, which is attributed to the mixed valency of the fluoranolate ligands.
Abstract: A pair of coordination polymers of composition (NBu4)2[M2(fan)3] (fan = fluoranilate; M = Fe and Zn) were synthesized and structurally characterized. In each case the compound consists of a pair of interpenetrating three-dimensional, (10,3)-a networks in which metal centers are linked by chelating/bridging fluoranilate ligands. Tetrabutylammonium cations are located in the spaces between the two networks. Despite the structural similarity, significant differences exist between (NBu4)2[Fe2(fan)3] and (NBu4)2[Zn2(fan)3] with respect to the oxidation states of the metal centers and ligands. For (NBu4)2[Fe2(fan)3] the structure determination as well as Mossbauer spectroscopy indicate the oxidation state for the Fe is close to +3, which contrasts with the +2 state for the Zn analogue. The differences between the two compounds extends to the ligands, with the Zn network involving only fluoranilate dianions, whereas the average oxidation state for the fluoranilate in the Fe network lies somewhere between −2 and ...
TL;DR: 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.
Abstract: 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...
TL;DR: A soft porous crystal possessing hemilabile cross-links in its framework that exhibits exclusive gate opening for ethylene, enabling the discriminatory adsorption of ethylene over ethane is reported, demonstrating the potential of the "gate-locking/unlocking" mechanism that exploits the hemilabsili cross-linking in soft porous crystals.
Abstract: Here we report a soft porous crystal possessing hemilabile cross-links in its framework that exhibits exclusive gate opening for ethylene, enabling the discriminatory adsorption of ethylene over ethane. A Co-based porous coordination polymer (PCP) bearing vinylogous tetrathiafulvalene (VTTF) ligands, [Co(VTTF)], forms Co–S bonds as intermolecular cross-links in its framework in the evacuated closed state. The PCP recognizes ethylene via d−π complexation on the accessible metal site that displaces and cleaves the Co–S bond to “unlock” the closed structure. This ethylene-triggered unlocking event facilitates remarkable nonporous-to-porous transformations that open up accessible void space. This structural transformation follows a two-step gate-opening process. Each phase, including the intermediate structure, was successfully characterized by single-crystal X-ray diffraction analysis, which revealed an intriguing “half-open” structure suggestive of a disproportionate gate-opening phenomenon. The gate-openin...
TL;DR: In this article, a tricarboxylic acid block with phthalate and picolinate functionalities was applied for the aqueous medium assembly of seven new coordination compounds.
Abstract: 5-(3,4-Dicarboxylphenyl)picolinic acid (H3dppa) was applied as a novel tricarboxylic acid block with phthalate and picolinate functionalities for the aqueous-medium assembly of seven new coordination compounds, namely, [Mn2(μ-Hdppa)2(phen)2(H2O)2] (1), {[Mn(μ-Hdppa)(2,2′-H2biim)(H2O)]·H2O}n (2), [Ni(Hdppa)(phen)2]·4H2O (3), {[Ni(μ-Hdppa)(μ-4,4′-bipy)(H2O)]·H2O}n (4), {[Cu3(μ3-dppa)(μ-Hdppa)(phen)4]2[Cu(μ-Hdppa)2]·10H2O}n (5), {[Ni3(μ-dppa)2(μ-1,4-bpb)2(H2O)6]·4H2O}n (6), and {[Zn3(μ4-dppa)2(phen)2(H2O)2]·4H2O}n (7). These products 1–7 represent the first structurally characterized examples of the coordination compounds derived from H3dppa. Compounds 1–7 were assembled in the presence of various N-donor supporting ligands acting as crystallization mediators, which were selected from 1,10-phenanthroline (phen), 2,2′-biimidazole (H2biim), 4,4′-bipyridine (4,4′-bipy), or 1,4-bis(pyrid-4-yl)benzene (1,4-bpb). Full characterization of 1–7 by IR spectroscopy, thermogravimetric (TGA), elemental, and topological analyses, as well as powder (PXRD) and single-crystal X-ray diffraction, was performed. The structural types range from the discrete 0D complexes (1 and 3) and 1D coordination polymers with a 2C1 topology (2, 5, and 6) to the 2D metal–organic layers with an sql topology (4 and 7). The structural diversity of 1–7 is driven by various factors, including the metal(II) node nature, deprotonation degree of H3dppa, or type of crystallization mediator. The magnetic properties of 1, 2, 4, and 6 were studied and modeled, revealing antiferromagnetic (in 1, 2, and 6) or ferromagnetic (in 4) interactions between adjacent metal(II) centers. The luminescence of 7 was also investigated. Moreover, the photocatalytic activity of 1–7 was studied for the degradation of methylene blue as a model dye pollutant, disclosing that the nickel(II) coordination polymer 4 is the most active catalyst. The observed catalytic activity of 1–7 correlates well with their band gap energies determined by the UV-diffuse reflectance method.
TL;DR: The self-assembly of a photoactive 1,1′-bis(4-carboxybenzyl)-4,4′-bipyridinium ligand with cadmium chloride in the presence of a strong electron-donating oxalate anion has successfully afforded a photochromic coordination polymer, which shows high sensitivity not only to ultraviolet-visible radiation but also to X-rays.
Abstract: The self-assembly of a photoactive 1,1′-bis(4-carboxybenzyl)-4,4′-bipyridinium ligand with cadmium chloride in the presence of a strong electron-donating oxalate anion has successfully afforded a photochromic coordination polymer, which shows high sensitivity not only to ultraviolet-visible radiation but also to X-rays.
TL;DR: This work synthesized two new coordination polymers with a bipyridinium-functionalized m-benzenedicarboxyl ligand that allow the two title compounds to exhibit eye-detectable color development with different photoresponsive rates, and distinct luminescence behaviors.
Abstract: The past ten years have evidenced the rapid development of bipyridinium-based coordination polymers, however, the design and synthesis of photo-switchable luminescent materials with a non-destructive readout capability based on bipyridinium ligands are still at the primary stage. In this work, two new coordination polymers with a bipyridinium-functionalized m-benzenedicarboxyl ligand were synthesized for this purpose. By using anions with different geometries, the molecular linkage and packing structure have been adjusted, and thus allow the two title compounds to exhibit eye-detectable color development with different photoresponsive rates, and distinct luminescence behaviors. Furthermore, compound 2 is the first reported Zn-based luminescent coordination polymer with a non-destructive readout capability. These results can not only help to further understand the structure-photosensitivity relationships of bipyridinium-based systems but also guide the design and synthesis of more luminescent materials with a non-destructive readout capability.
TL;DR: This spray technique simplifies the nanosheet production process by industrialized means and enhances its controllability by the fast liquid-liquid interfacial fabrication, thus allowing access to the industrialized fabrication of MOF and ICP nanosheets.
Abstract: We have developed a rapid and convenient method for fabricating metal-organic framework (MOF) and infinite coordination polymer (ICP) nanosheets by spraying the atomized solution of metal ions onto the organic ligand solution. Nanosheet formation could be attributed to the anisotropic diffusion of metal ions in the ligand solution, which may give rise to a lateral interface of metal ions and organic ligands, where the crystals tend to grow laterally in the form of nanosheets. Three kinds of Zn- and Cu-based MOF nanosheets and two kinds of Co-based ICP nanosheets have been successfully obtained by spraying under mild conditions. The two-dimensional structures of nanosheets with a nanometer thickness and a homogeneous size can be evidenced by scanning electron microscopy, atomic force microscopy, X-ray diffraction, Brunauer-Emmett-Teller, and Fourier transform infrared spectroscopy measurements. Furthermore, the fabricated ICP nanosheets have exhibited efficient catalytic performance for the conversion of CO2 to high-value-added chemicals. This spray technique simplifies the nanosheet production process by industrialized means and enhances its controllability by the fast liquid-liquid interfacial fabrication, thus allowing access to the industrialized fabrication of MOF and ICP nanosheets.
TL;DR: In this paper, a bifunctional luminescent coordination polymer, formulated as {[Zn(μ-HCIP)(μ-pbix]·2H2O}n (1) (H3CIP = 5-(4-carboxybenzylamino)isophthalic acid, pbix: 1,4-bis(imidazol-1ylmethyl)benzene), was synthesized under solvothermal conditions by using reduced Schiff base and neutral Pbix ligands and characterized by IR spectrosc
Abstract: New bifunctional luminescent coordination polymer, formulated as {[Zn(μ-HCIP)(μ-pbix)]·2H2O}n (1) (H3CIP = 5-(4-carboxybenzylamino)isophthalic acid, pbix: 1,4-bis(imidazol-1ylmethyl)benzene), was synthesized under solvothermal conditions by using reduced Schiff base and neutral pbix ligands and characterized by IR spectroscopy, elemental analysis, single-crystal and powder X-ray diffraction, and thermal analysis. X-ray results indicated that the HCIP ligand acted as a bidentate bridging ligand and was partly deprotonated in 1. Complex 1 exhibited a 2D + 2D → 2D interpenetrated structure with sql topology. Complex 1 displayed high emission at the solid state. Luminescence titration experiments showed that complex 1 dispersed in dimethylformamide (DMF) detected the picric acid in the presence of other interfering nitroaromatic compounds with a detection limit of 56.46 ppb. In addition, complex 1 displayed highly sensitive and selective detection toward Fe3+ ion in the presence of other interfering metal ion...
TL;DR: While 1 was employed as the electrode in a supercapacitor, the cycling stability and specific capacitance of the 1-based electrode are better than those of the parent α-K6P2W18O62-based electrodes, demonstrating more outstanding electrochemical performances of 1.
Abstract: A new coordination polymer, (H2bpe)(Hbpe)2{[Cu(pzta)(H2O)][P2W18O62]}·5H2O (1) (pztaH = 5-(2-pyrazinyl) tetrazolate, bpe = bis(4-pyridyl)ethylene), was synthesized by the hydrothermal method. The structure was determined by single crystal X-ray diffraction analyses and further characterized by the SEM, EDS, BVS, FTIR, and PXRD techniques. In 1, the [P2W18O62]6- (P2W18) clusters as bidentate connectors link [Cu(pzta)(H2O)]24+ dinuclear copper(ii) complexes to form inorganic-organic chains. These chains and the [H2bpe]2+ counter-cations are fused together via hydrogen bonding to form a 3D supramolecular architecture. While 1 was employed as the electrode in a supercapacitor, the cycling stability (90.7% capacitance retention after 1000 circles) and specific capacitance (168 F g-1 at a current density of 5 A g-1) of the 1-based electrode are better than those of the parent α-K6P2W18O62-based electrode, demonstrating more outstanding electrochemical performances of 1. Besides, the 1-based electrode showed excellent electrocatalytic activities towards the reduction of H2O2 and KIO3.
TL;DR: In this article, a new coordination polymer, formulated as {[Co2(μ8-abtc)(betib)]·DMF}n (1) (abtc, 3,3′,5,5′-azobenzenetetracarboxylate; betib, 1,4-bis(2-ethylimidazol-1-yl)butane), was synthesized with 3, 3′, 5,5-6-8-acid and flexible betib ligand.
Abstract: A new coordination polymer, formulated as {[Co2(μ8-abtc)(betib)]·DMF}n (1) (abtc, 3,3′,5,5′-azobenzenetetracarboxylate; betib, 1,4-bis(2-ethylimidazol-1-yl)butane), was synthesized with 3,3′,5,5′-azobenzenetetracarboxylic acid and flexible betib ligand. Complex 1 was immersed in methanol to obtain {[Co2(μ8-abtc)(betib)]·H2O}n (2). The complexes were characterized by IR spectra, elemental analyses, single-crystal and powder X-ray diffractions, and thermal analyses. X-ray results demonstrated that complexes 1 and 2 had a porous 3D framework with sqc5381 net. Complex 2 was activated at 105 °C (2a), and CO2 and iodine adsorption properties of 2a were studied. The CO2 uptake capacity of 2a was 52.94 cm3/g (10.40%). Moreover, complex 2a encapsulated 30.34 and 21.98% iodine in the vapor phase and solution, respectively, which corresponded to 1.975 and 1.42 molecules of iodine per formula unit, respectively.