Showing papers on "Coordination polymer published in 2016"
TL;DR: It is shown that HER-active a-MoSx, prepared either as nanoparticles or as films, is a molecular-based coordination polymer consisting of discrete [Mo3S13](2-) building blocks that provides a basis for revisiting the mechanism of a- MoSx catalytic activity, as well as explaining some of its special properties such as reductive activation and corrosion.
Abstract: Molybdenum sulfides are very attractive noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER) from water. The atomic structure and identity of the catalytically active sites have been well established for crystalline molybdenum disulfide (c-MoS2) but not for amorphous molybdenum sulfide (a-MoSx), which exhibits significantly higher HER activity compared to its crystalline counterpart. Here we show that HER-active a-MoSx, prepared either as nanoparticles or as films, is a molecular-based coordination polymer consisting of discrete [Mo3S13]2- building blocks. Of the three terminal disulfide (S22-) ligands within these clusters, two are shared to form the polymer chain. The third one remains free and generates molybdenum hydride moieties as the active site under H2 evolution conditions. Such a molecular structure therefore provides a basis for revisiting the mechanism of a-MoSx catalytic activity, as well as explaining some of its special properties such as reductive activation and corrosion. Our findings open up new avenues for the rational optimization of this HER electrocatalyst as an alternative to platinum.
444 citations
TL;DR: The structural change by photochemical transformation of this PCP via [2 + 2] photodimerization leads to the removal of inverse CO2/C2H2 selectivity, verifying the mechanism of the guest discriminatory gate effect.
Abstract: The adsorptive separation of C2H2 and CO2 via porous materials is nontrivial due to the close similarities of their boiling points and kinetic diameters. In this work, we describe a new flexible porous coordination polymer (PCP) [Mn(bdc)(dpe)] (H2bdc = 1,4-benzenedicarboxylic acid, dpe = 1,2-di(4-pyridyl)ethylene) having zero-dimensional pores, which shows an adsorbate discriminatory gate effect. The compound shows gate opening type abrupt adsorption for C2H2 but not for CO2, leading to an appreciable selective adsorption of CO2 over C2H2 at near ambient temperature (273 K). The origin of this unique selectivity, as unveiled by in situ adsorption-X-ray diffraction experiments and density functional theory calculations, is due to vastly different orientations between the phenylene ring of bdc and each gas in the nanopores. The structural change by photochemical transformation of this PCP via [2 + 2] photodimerization leads to the removal of inverse CO2/C2H2 selectivity, verifying the mechanism of the guest discriminatory gate effect.
316 citations
TL;DR: In this article, a survey on transition metal containing coordination polymers and metal-organic frameworks (MOFs) with poly(pyrazole)-and poly (pyrazolate)-based ligands is presented, where up to three N-donor heterocyclic rings are organized on rigid or flexible cores.
201 citations
TL;DR: The PCP-Ru(II) composite showed improved CO2 adsorption behavior at ambient temperature and catalytic activity was maintained even under a 5 % CO2 /Ar gas mixture, revealing a synergistic effect between the Adsorption and catalytically active sites within the PCP -Ru( II) composite.
Abstract: Direct use of low pressures of CO2 as a C1 source without concentration from gas mixtures is of great interest from an energy-saving viewpoint. Porous heterogeneous catalysts containing both adsorption and catalytically active sites are promising candidates for such applications. Here, we report a porous coordination polymer (PCP)-based catalyst, PCP-Ru(II) composite, bearing a Ru(II) -CO complex active for CO2 reduction. The PCP-Ru(II) composite showed improved CO2 adsorption behavior at ambient temperature. In the photochemical reduction of CO2 the PCP-Ru(II) composite produced CO, HCOOH, and H2 . Catalytic activity was comparable with the corresponding homogeneous Ru(II) catalyst and ranks among the highest of known PCP-based catalysts. Furthermore, catalytic activity was maintained even under a 5 % CO2 /Ar gas mixture, revealing a synergistic effect between the adsorption and catalytically active sites within the PCP-Ru(II) composite.
184 citations
TL;DR: Important examples of newly developed CPGs, which show potential applications in different fields are covered, including drug-delivery, gas storage, optoelectronics, chemo-sensing, self-healing, etc.
157 citations
TL;DR: It is concluded that the defect sites provide space for mobile uncoordinated H3PO4, H2PO4(-), and H2O, which play a key role in expanding the proton-hopping path and promoting the mobility of protons in the coordination framework, leading to high proton conductivity and fuel cell power generation.
Abstract: We describe the encapsulation of mobile proton carriers into defect sites in nonporous coordination polymers (CPs). The proton carriers were encapsulated with high mobility and provided high proton conductivity at 150 °C under anhydrous conditions. The high proton conductivity and nonporous nature of the CP allowed its application as an electrolyte in a fuel cell. The defects and mobile proton carriers were investigated using solid-state NMR, XAFS, XRD, and ICP-AES/EA. On the basis of these analyses, we concluded that the defect sites provide space for mobile uncoordinated H3PO4, H2PO4–, and H2O. These mobile carriers play a key role in expanding the proton-hopping path and promoting the mobility of protons in the coordination framework, leading to high proton conductivity and fuel cell power generation.
136 citations
TL;DR: This work synthesized novel cerium coordination polymer nanoparticles ATP-Ce-Tris CPNs in a simple and quick way using ATP molecules as the biocompatible ligands to Ce(3+) ions in tris(hydroxymethyl)aminomethane hydrochloric (Tris-HCl) solution to selectively and sensitively detect H2O2.
Abstract: Lanthanide coordination polymer nanoparticles (Ln-CPNs) have been recently demonstrated as excellent platforms for biomolecule detection. In this work, we synthesized novel cerium coordination polymer nanoparticles ATP-Ce-Tris CPNs in a simple and quick way using ATP molecules as the biocompatible ligands to Ce3+ ions in tris(hydroxymethyl)aminomethane hydrochloric (Tris-HCl) solution. In view of the excellent free radical scavenging property of cerium compounds, which is ascribed to the mixed valence state (Ce3+, Ce4+) and the reversible switch from Ce3+ to Ce4+, the synthesized ATP-Ce-Tris CPNs was used as artificial peroxidase to selectively and sensitively detect H2O2. The sensing mechanism depends on the oxidation of the fluorescent ATP-Ce(III)-Tris CPNs to nonfluorescent ATP-Ce(IV)-Tris CPNs by H2O2. Compared with those inorganic cerium oxide sensors, this kind of fluoresence ATP-Ce-Tris CPNs sensor needs no additional organic redox dye, such as ABTS (2,20-azino-bis(3-ethylbenzthiazoline-6-sulfonic ...
134 citations
TL;DR: The present study demonstrates the potential of crystalline copper CPs for the practical utilization of light by demonstrating the charge separation and transfer process in the catalytic system.
Abstract: A crystalline coordination polymer (CP) photocatalyst (Cu-RSH) which combines redox-active copper centers with photoactive rhodamine-derived ligands remains stable in acid and basic solutions from pH 2 to 14, and efficiently catalyzes dihydrogen evolution at a maximum rate of 7.88 mmol g−1 h−1 in the absence of a mediator and a co-catalyst. Cyclic voltammetry, control experiments, and DFT calculations established that copper nodes with open coordination sites and favorable redox potentials, aided by spatially ordered stacking of rhodamine-based linkers, account for the high catalytic performance of Cu-RSH. Emission quenching, time-resolved fluorescence decay, and transient photocurrent experiments disclosed the charge separation and transfer process in the catalytic system. The present study demonstrates the potential of crystalline copper CPs for the practical utilization of light.
127 citations
TL;DR: Ruthenium(ii) polypyridyl-doped metal–organic framework sensitized films on TiO2 for photovoltaics reveal that the preparative method of dye doping/incorporation into the MOF is integral to the total solar cell efficiency.
Abstract: A series of Ru(II)L2L′ (L = 2,2′-bipyridyl, L′ = 2,2′-bipyridine-5,5′-dicarboxylic acid), RuDCBPY, -containing zirconium(IV) coordination polymer thin films have been prepared as sensitizing materials for solar cell applications. These metal–organic framework (MOF) sensitized solar cells, MOFSCs, each are shown to generate photocurrent in response to simulated 1 sun illumination. Emission lifetime measurements indicate the excited state quenching of RuDCBPY at the MOF–TiO2 interface is extremely efficient (>90%), presumably due to electron injection into TiO2. A mechanism is proposed in which RuDCBPY-centers photo-excited within the MOF-bulk undergo isotropic energy migration up to 25 nm from the point of origin. This work represents the first example in which a MOFSC is directly compared to the constituent dye adsorbed on TiO2 (DSC). Importantly, the MOFSCs outperformed their RuDCBPY–TiO2 DSC counterpart under the conditions used here and, thus, are solidified as promising solar cell platforms.
126 citations
TL;DR: Jiang et al. as discussed by the authors developed a porous coordination polymers containing copper ions and fluorinated organic ligands to clean up toxic spills and organic solvent leakage into water by using a commercial sponge in graphene oxide to enhance copper binding, which yielded a corrugated surface with high hydrophobicity.
Abstract: For the remediation of oil spills and organic solvent leakage into water, it is desirable to develop not only advanced sorbents with a high adsorption capability but also labor- and time-saving apparatuses that can work continuously without human intervention. In this work, we synthesized a novel and highly stable porous coordination polymer (PCP, also called metal-organic framework), University of Science and Technology of China-6 (USTC-6), with a corrugated -CF3 surface that features high hydrophobicity. The uniform growth of USTC-6 throughout a graphene oxide (GO)-modified sponge was achieved and yielded a macroscopic USTC-6@GO@sponge sorbent, which repels water and exhibits a superior adsorption capacity for diverse oils and organic solvents. Remarkably, the sorbent can be further assembled with tubes and a self-priming pump to build a model apparatus that affords consecutive and efficient oil recovery from water. The easy and fast recovery of oils/organic solvents from water based on such an apparatus indicates that it has great potential for future water purification and treatment. A non-stick coordination polymer coating helps sponges absorb and recover up to 40 times their own weight in oil under extreme temperatures. Using passive sorbents to clean up toxic spills normally requires specially engineered materials, such as biomimetic surfaces with nanoscale rough features, to repel water molecules and attract oil particles. Now, Hai-Long Jiang from the University of Science and Technology of China and co-workers have developed a way to achieve these properties using porous coordination polymers containing copper ions and fluorinated organic ligands. After dipping a commercial sponge in graphene oxide to enhance copper binding, the team grew their coordination polymer coating in situ and found it yielded a corrugated surface with high hydrophobicity. Intriguingly, a prototype assembled from the coated sponge and a self-priming pump enabled labor-free cleanup of oil spills from water. A hydrophobic porous coordination polymer (PCP) has been synthesized and its growth throughout the graphene oxide (GO)-modified sponge yields a macroscopic PCP@GO@sponge sorbent, which repels water and exhibits superior adsorption for diverse oils. Remarkably, the sorbent is further assembled with tubes and a self-priming pump to build a model apparatus that can afford consecutive and efficient oil recovery from water.
106 citations
TL;DR: The study demonstrates a strategy for the design of new multifunctional materials with photoresponsive properties by developing a coordination polymer of formula [Mn4(L)(N3)6(H2O)2]n, which shows photochromic and photomagnetic properties.
Abstract: The solvothermal reaction of Mn(ClO4)2, NaN3, and a rigid viologen-tethered tetracarboxylic acid (1,1′-bis(3,5-dicarboxyphenyl)-4,4′-bipyridinium chloride, [H4L]Cl2) led to a coordination polymer of formula [Mn4(L)(N3)6(H2O)2]n. X-ray analysis revealed a 3D coordination structure. The Mn(II) ions are connected by mixed azide and carboxylate bridges to give 2D layers, which are pillared by the viologen tether of the zwitterionic ligand. Magnetic analyses suggested that the compound features antiferromagnetism and field-induced metamagnetism. The compound also shows photochromic and photomagnetic properties. The long-range magnetic ordering is owed to the spin-canting structure of the Mn(II)-azide-carboxylate layer; the photochromism involves the formation of viologen radicals via photoinduced electron transfer, and the photomagnetism is related to the interactions between the metal ion and the photogenerated radicals. The study demonstrates a strategy for the design of new multifunctional materials with ph...
TL;DR: The glassy state of a two-dimensional (2D) Cd(2+) coordination polymer crystal was prepared by a solvent-free mechanical milling process and displays superior properties compared to the crystalline state; specifically, it shows anhydrous proton conductivity and a dielectric constant two orders of magnitude greater than the crystallines material.
Abstract: The glassy state of a two-dimensional (2D) Cd(2+) coordination polymer crystal was prepared by a solvent-free mechanical milling process. The glassy state retains the 2D structure of the crystalline material, albeit with significant distortion, as characterized by synchrotron X-ray analyses and solid-state multinuclear NMR spectroscopy. It transforms to its original crystal structure upon heating. Thus, reversible crystal-to-glass transformation is possible using our new processes. The glass state displays superior properties compared to the crystalline state; specifically, it shows anhydrous proton conductivity and a dielectric constant two orders of magnitude greater than the crystalline material. It also shows material flexibility and transparency.
TL;DR: In this article, a Mn-1,4-benzenedicarboxylate (Mn-1-4-BDC) MOF was synthesized by reaction of 1, 4-benzedic-carboxylic acid with manganese(II) chloride (mnCl2) using a solvothermal method and applied as an anode for lithium-ion batteries.
Abstract: Metal organic frameworks (MOFs) with considerable structural versatility are considered to be potential materials for energy storage. In this work, a Mn-1,4-benzenedicarboxylate (Mn-1,4-BDC) MOF was synthesized by reaction of 1,4-benzenedicarboxylic acid (1,4-BDC) with manganese(II) chloride (MnCl2) using a solvothermal method. When applied as an anode for lithium-ion batteries, the activated Mn-1,4-BDC@200 electrode delivered a high reversible lithium storage capacity of 974 mA h g−1 after 100 cycles at a current density of 100 mA g−1, exhibiting one of the best lithium storage properties among the reported metal organic frameworks (MOFs), also known as coordination polymer (CP) anodes. The excellent electrochemical performance of the Mn-1,4-BDC electrode is also comparable with those reported for Mn2O3 and Mn3O4 nanostructures calcined from Mn-based MOF templates.
TL;DR: Deposition of Ni-based cyanide bridged coordination polymer (NiCNNi) flakes onto the surfaces of graphene oxide (GO) sheets, which allows precise control of the resulting lamellar nanoarchitecture by in situ crystallization, is reported.
Abstract: Deposition of Ni-based cyanide bridged coordination polymer (NiCNNi) flakes onto the surfaces of graphene oxide (GO) sheets, which allows precise control of the resulting lamellar nanoarchitecture by in situ crystallization, is reported. GO sheets are utilized as nucleation sites that promote the optimized crystal growth of NiCNNi flakes. The NiCNNi-coated GO sheets then self-assemble and are stabilized as ordered lamellar nanomaterials. Regulated thermal treatment under nitrogen results in a Ni3C–GO composite with a similar morphology to the starting material, and the Ni3C–GO composite exhibits outstanding electrocatalytic activity and excellent durability for the oxygen reduction reaction.
TL;DR: This paper introduced acidic functional groups into a porous coordination polymer (PCP) or metal-organic framework (MOF) and constructed a proton-conductive electrolyte for fuel cells.
Abstract: Proton-conductive electrolytes are key materials in fuel cells. We introduced acidic functional groups into a porous coordination polymer (PCP), or metal–organic framework (MOF), and constructed pr...
TL;DR: It is found that the chosen substrate not only plays an important role as catalyst for the Ullmann reaction, but also influences the formation of different types of intermolecular bonds and thus, determines the final polymer network morphology.
Abstract: The on-surface polymerization of 1,3,6,8-tetrabromopyrene (Br4 Py) on Cu(111) and Au(111) surfaces under ultrahigh vacuum conditions was investigated by a combination of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. Deposition of Br4 Py on Cu(111) held at 300 K resulted in a spontaneous debromination reaction, generating the formation of a branched coordination polymer network stabilized by C-Cu-C bonds. After annealing at 473 K, the C-Cu-C bonds were converted to covalent C-C bonds, leading to the formation of a covalently linked molecular network of short oligomers. In contrast, highly ordered self-assembled two-dimensional (2D) patterns stabilized by both Br-Br halogen and Br-H hydrogen bonds were observed upon deposition of Br4 Py on Au(111) held at 300 K. Subsequent annealing of the sample at 473 K led to a dissociation of the C-Br bonds and the formation of disordered metal-coordinated molecular networks. Further annealing at 573 K resulted in the formation of covalently linked disordered networks. Importantly, we found that the chosen substrate not only plays an important role as catalyst for the Ullmann reaction, but also influences the formation of different types of intermolecular bonds and thus, determines the final polymer network morphology. DFT calculations further support our experimental findings obtained by STM and XPS and add complementary information on the reaction pathway of Br4 Py on the different substrates.
TL;DR: In this paper, the authors briefly introduce recent progresses related to material construction with coordination as a structure-directing driving force based on two concepts: nanoarchitectonics and interfacial processes as well as their conversion into functional nanoporous materials.
TL;DR: Alternating-current magnetic susceptibility results indicate that 1 exhibits frequency-dependent out-of-phase signals with two relaxation processes, which suggests that it shows single-molecule magnet (SMM) behavior and represents the first example by using an SMM cluster as the building block to create a 3D Ni-Ln HCP.
Abstract: The solvothermal reaction of DyCl3·6H2O, Ni(NO3)2·6H2O, and H4abtc ligands (H4abtc = 3,3′,5,5′-azobenzene-tetracarboxylic acid) in the mixed DMF/H2O solvents (DMF = N,N-dimethylformamide) produced a three-dimensional (3D) NiII–DyIII heterometallic coordination polymer (HCP) formulated as {[NH2(CH3)2]2[NiDy2(HCOO)2(abtc)2]}n (1). In 1, DyIII and NiII ions interconnect through carboxylic O donors of abtc4– ligands to generate a linear trimer “Hourglass”-type {NiDy2} cluster, and the adjacent trinuclear {NiDy2} units are bridged by HCOO– groups to give a 1D “ladder” chain, which is further bridged by abtc4– ligands to form a new topology and named as “zsw3”. Alternating-current magnetic susceptibility results indicate that 1 exhibits frequency-dependent out-of-phase signals with two relaxation processes, which suggests that it shows single-molecule magnet (SMM) behavior and represents the first example by using an SMM cluster as the building block to create a 3D Ni–Ln HCP, to the best of our knowledge. The e...
TL;DR: An air-stable copper-phenylacetylide nanobelt is synthesized and applied in organic pollutants elimination under visible light, and its versatile activity and reusability indicate it is a promising photocatalyst.
Abstract: An air-stable copper-phenylacetylide nanobelt is synthesized and applied in organic pollutants elimination under visible light. Its versatile activity and reusability indicate it is a promising photocatalyst, arising from a band gap of 2.3 eV and the energetically favored electron transfer processes. The tunable structures and properties endow copper-based coordination polymers a prosperous prospect.
TL;DR: This focus review aims to provide an insight into the development of designing metallogelators derived from discrete coordination complexes, organometallic gelators, and coordination polymers.
Abstract: A supramolecular gel results from the immobilization of solvent molecules on a 3D network of gelator molecules stabilized by various supramolecular interactions that include hydrogen bonding, π-π stacking, van der Waals interactions, and halogen bonding. In a metallogel, a metal is a part of the gel network as a coordinated metal ion (in a discrete coordination complex), as a cross-linking metal node with a multitopic ligand (in coordination polymer), and as metal nanoparticles adhered to the gel network. Although the field is relatively new, research into metallogels has experienced a considerable upsurge owing to its fundamental importance in supramolecular chemistry and various potential applications. This focus review aims to provide an insight into the development of designing metallogelators. Because of the limited scope, discussions are confined to examples pertaining to metallogelators derived from discrete coordination complexes, organometallic gelators, and coordination polymers. This review is expected to enlighten readers on the current development of designing metallogelators of the abovementioned class of molecules.
TL;DR: A one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route and could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling.
Abstract: In this work, a one-dimensional Co3O4@TiO2 core–shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g−1, good cycling stability (around 803 mA h g−1 at a current density of 200 mA g−1 after 100 cycles), and stable rate performance (around 520 mA h g−1 at a current density of 1000 mA g−1). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling.
TL;DR: In this paper, four metal-organic coordination compounds Zn2(bcbp)Cl4 (1), Zn(bcBP)(PO3F) (2), [CdCl(Hbcbp)(bcbp)]·(ClO4)2 (3), and [Cc2(BCbp)4]·(clO4·F3 (4) (H2bcbp·2PF6 = 1,1′-bis(4-carboxyphenyl)-(4,4′-bipyridinium
Abstract: Four metal–organic coordination compounds Zn2(bcbp)Cl4 (1), Zn(bcbp)(PO3F) (2), [CdCl(Hbcbp)(bcbp)]·(ClO4)2 (3), and [Cd2(bcbp)4]·(ClO4)·F3 (4) (H2bcbp·2PF6 = 1,1′-bis(4-carboxyphenyl)-(4,4′-bipyridinium) hexafluorophosphate) have been synthesized via a solvothermal method and structurally characterized. Compound 1 is a 1D coordination polymer, while compound 2 shows a 2D + 2D → 3D inclined polycatenation structure. In the case of compound 3, due to the capped chlorine atoms and uncoordinated carboxyl of bcbp ligand, it exhibits a 1D T-shaped coordination configuration. Compound 4 is an unprecedented 13-fold interpenetrating structure with huge diamondoid frameworks. Because of the presence of electron-deficient bipyridinium moieties, the photochromic behaviors of these compounds have also been studied. Interestingly, only compounds 1–3 exhibit color changes under light irradiation. The impact of these anions on the photochromic process is discussed.
TL;DR: In this article, a dicarboxyl-functionalized arylhydrazone of barbituric acid ligand was used as a catalysts for the Knoevenagel condensation reaction of different aldehydes with malonitrile.
Abstract: Four novel Zn(II) and Cd(II) compounds based on a dicarboxyl-functionalized arylhydrazone of barbituric acid ligand, 5-[2-{2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene}hydrazinyl]isophthalic acid (H5L), namely [Zn(1κO:2κO′:3κO′′-H3L)(H2O)2]n (1), [Cd(1κO,O’:2κO′:3κO′′,O′′′-H3L)(H2O)2]n (2), [Zn(κN-H3L)(H2O)3]·3H2O (3) and [Cd(1κO,O′:2κN-H3L)(H2O)3]n·4nH2O (4), have been synthesized at different pHs under hydrothermal conditions and characterized by elemental and thermogravimetric, FT-IR, and X-ray single-crystal diffraction analyses. Compounds 1 and 2 prepared in acidic medium are coordination polymers exhibiting double chain type one-dimensional (1D) structures, whereas 3 and 4 are obtained in basic medium. Compound 3 is a mononuclear Zn(II) complex containing three lattice water molecules, but in 4, Cd(II) cations are bridged by H3L2− ligands to form an interesting zig-zag type 1D coordination polymer. The crystal structures of these compounds are stabilized by strong hydrogen bonding interactions, forming two and three-dimensional networks. The pH value of the reaction system plays a crucial role in the ligand deprotonation and in the assembly of the metal–organic polymers. These compounds act as effective heterogeneous catalysts, under mild conditions, for the Knoevenagel condensation reaction of different aldehydes with malononitrile and can be recycled at least five times without losing activity. Further, compounds 1–4 exhibit luminescence properties in the solid state at room temperature.
TL;DR: Bimetallic coordination polymers with Zn and Co were synthesized and applied as anode materials and a capacity of 622 mA h g(-1) after 500 cycles could still be maintained.
TL;DR: The seeded growth of a nucleotide coordinated polymer shell is reported, which can be considered as a special form of adsorption by forming a complete shell that provides better guest protein stability compared to that of simple physisorption while retaining guest activity as confirmed by the entrapped glucose oxidase assay.
Abstract: The introduction of functional molecules to the surface of magnetic iron oxide nanoparticles (NPs) is of critical importance. Most previously reported methods were focused on surface ligand attachment either by physisorption or covalent conjugation, resulting in limited ligand loading capacity. In this work, we report the seeded growth of a nucleotide coordinated polymer shell, which can be considered as a special form of adsorption by forming a complete shell. Among all of the tested metal ions, Fe3+ is the most efficient for this seeded growth. A diverse range of guest molecules, including small organic dyes, proteins, DNA, and gold NPs, can be encapsulated in the shell. All of these molecules were loaded at a much higher capacity compared to that on the naked iron oxide NP core, confirming the advantage of the coordination polymer (CP) shell. In addition, the CP shell provides better guest protein stability compared to that of simple physisorption while retaining guest activity as confirmed by the entr...
TL;DR: Six unprecedented structures of Cu(I) alkynyl complexes and a procedure to measure the cone angles of alkyny ligands based on the crystal structures of these complexes are reported.
Abstract: Copper(I) alkynyl complexes have attracted tremendous attention in structural studies, as luminescent materials, and in catalysis, and homoleptic complexes have been reported to form polymers or large clusters. Herein, six unprecedented structures of Cu(I) alkynyl complexes and a procedure to measure the cone angles of alkynyl ligands based on the crystal structures of these complexes are reported. An increase of the alkynyl cone angle in the complexes leads to a modulation of the structures from polymeric [((PhC≡CC≡C)Cu)2 (NH3 )]∞ , to a large cluster [(TripC≡CC≡C)Cu]20 (MeCN)4 , to a relatively small cluster [(TripC≡C)Cu]8 (Trip=2,4,6-iPr3 -C6 H2 ). The complexes exhibit yellow-to-red phosphorescence at ambient temperature in the solid state and the luminescence behavior of the Cu20 cluster is sensitive to acetonitrile.
TL;DR: This methodology is extended to the formation of 1D nickel, iron, and zinc dithiolene coordination polymers based on benzene-1,2,4,5-tetrathiolate (BTT) frameworks and investigates their catalytic H2-evolving activities under fully aqueous conditions.
Abstract: Immobilization of metal complexes to electrode surfaces has emerged as an attractive strategy to combine homogeneous and heterogeneous catalysis. We recently reported the immobilization of cobalt dithiolene catalytic units via incorporation into extended one and two dimensional (1D and 2D) frameworks. We extend here this methodology to the formation of 1D nickel, iron, and zinc dithiolene coordination polymers based on benzene-1,2,4,5-tetrathiolate (BTT) frameworks and investigate their catalytic H2-evolving activities under fully aqueous conditions. The nickel dithiolene coordination polymer is an active electrocatalyst for the hydrogen evolution reaction (HER). An overpotential of 470 mV was required to reach a current density of 10 mA cm−2 at pH 1.3, making this system one of the best performing heterogenized molecular catalysts for HER. This overpotential is 90 mV lower than that of the cobalt analogue, suggesting that the nickel coordination polymer is a more efficient H2-evolving catalyst. Additionally, no decrease in activity is observed for the nickel polymer during the first hour of electrolysis, indicating that it is stable under prolonged electrolysis.
TL;DR: In this paper, a two-dimensional coordination polymers with di-pyridin-2-yl]-phenyl]-amine (ppvppa) and 1,4naphthalenedicarboxylic acid (1,4-H2NDC) were used to detect Hg2+ or MeHgI in water under a UV lamp.
Abstract: Solvothermal reaction of Zn(NO3)2·6H2O with di-pyridin-2-yl-[4-(2-pyridin-4-yl-vinyl)-phenyl]-amine (ppvppa) and 1,4-naphthalenedicarboxylic acid (1,4-H2NDC) in H2O and MeCN at 150 °C yielded a two-dimensional (2D) coordination Zn(II) polymer [Zn(ppvppa)(1,4-NDC)]n (1). Compound 1 was characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction and thermogravimetric analysis. Compound 1 consists of dimeric [Zn2(ppvppa)2] units linked by 1,4-NDC bridges to generate a 2D honeycomb network. Either compound 1 or ppvppa alone can detect Hg2+ or MeHgI selectively and with good sensitivity. Upon addition of Hg2+ ions to a MeCN solution of ppvppa, marked changes in the UV-vis and fluorescence spectra are observed, associated with colour changes, which are easily identified by the naked eye. The pyridinyl rings of ppvppa are coordinated to the Hg2+ ion. This motif in the presence of NO3− ions forms a binuclear complex [Hg2(ppvppa)2(NO3)4] (2), which has been characterized as the solvate [Hg2(ppvppa)2(NO3)4]·H2O·4MeCN (2·H2O·4MeCN) by single-crystal X-ray diffraction studies. In aqueous solution, compound 1 emits pale orange light at ambient temperature and the addition of Hg2+ or MeHgI induces an change of fluorescence color from pale orange to blue. Compound 1 is a promising candidate as a sensitive naked-eye indicator for Hg2+ or MeHgI in water under a UV lamp.
Introduction to the international collaboration
Prof. Lang and Prof. Brammer met with each other in Nanjing, China when Prof. Brammer taught lectures at Nanjing Tech University last November. Prof. Lang's research involves metal sulfide cluster chemistry, design and development of new coordination complex-based catalysts, bioinorganic chemistry related to mimicking metal sites of enzymes and proteins, and so on. Prof. Brammer's research interest covers supramolecular chemistry and crystal engineering, in particular host–guest chemistry and catalysis in metal–organic frameworks, reactions in molecular solids and fundamentals of intermolecular interactions. Both professors recognised their many mutual research interests and decided to initiate an international collaborative project in the area of coordination polymers. Both will visit the partner's lab in China and UK in the near future and expand this project to a higher level.
TL;DR: A mixed-valence Fe(II) /Fe(III) cyanide-bridged coordination polymer, {[Fe(Tp)(CN)3 ]2 Fe(bpe)⋅5 H2 O}n, which demonstrates a thermally induced charge-transfer phase transition, is described.
Abstract: Heterometallic Prussian blue analogues are known to exhibit thermally induced charge transfer, resulting in switching of optical and magnetic properties. However, charge-transfer phase transitions have not been reported for the simplest FeFe cyanide-bridged systems. A mixed-valence Fe(II) /Fe(III) cyanide-bridged coordination polymer, {[Fe(Tp)(CN)3 ]2 Fe(bpe)⋅5 H2 O}n , which demonstrates a thermally induced charge-transfer phase transition, is described. As a result of the charge transfer during this phase transition, the high-spin state of the whole system does not change to a low-spin state. This result is in contrast to FeCo cyanide-bridged systems that exhibit charge-transfer-induced spin transitions.
TL;DR: By examining its electrical resistance and stability upon exposure to ammonia and seven common organic amines in water under ambient conditions, compound 1 is found to exhibit good stability and reproducibly high sensitivity toward these analytes at low concentrations.
Abstract: Reaction of AgBr with TabHPF6 (TabH = 4-(trimethylammonio)benzenethiol) readily produces a unique one-dimensional coordination polymer [(TabH)(AgBr2)]n (1), consisting of anionic chains [AgBr2]nn– with hydrogen bonds to TabH+ cations. By examining its electrical resistance and stability upon exposure to ammonia and seven common organic amines in water under ambient conditions, compound 1 is found to exhibit good stability and reproducibly high sensitivity toward these analytes at low concentrations. Especially, it can selectively detect NH3 in water with the detection limit as low as 0.05 ppm. This chemiresistive sensing system has the potential for highly efficient monitoring of ammonia and amines responsible for water pollution, eutrophication, food contamination, and industrial hazards.