Metal-organic Composites Research Articles

A highly sensitive electrochemiluminescence sensor for the detection of l-cysteine based on the rhombus-shaped rubrene microsheets and platinum nanoparticles

We present a highly sensitive platinum nanoparticles (PtNPs), rhombus-shaped rubrene microsheets (RubRMs) and dissolved oxygen (O2) system for the monitoring of l-cysteine by the quenched electrochemiluminescence (ECL) signals. Firstly, RubRMs has been prepared through reprecipitation method, then the metal organic composites of PtNPs-RubRMs was synthesized by a simple in situ reduction of PtNPs on RubRMs surface. The composites combined the high ECL characteristic of RubRMs, the wonderful catalytic efficiency and good electron transfer ability of PtNPs. With the synergistic effect between RubRMs and PtNPs, the proposed ECL sensors exhibited excellent responses for l-cysteine. Under the optimum conditions, the linear range was from 1.0 × 10−9 mol L-1 to 5.0 × 10-4 mol L-1 with a detection limit of 3.3 × 10-10 mol L-1 (S/N = 3). And the results shows high sensitivity, excellent stability, and low background signal. It is simple to prepare and operate for the practical application.

In Situ‐Formed Hierarchical Metal–Organic Flexible Cathode for High‐Energy Sodium‐Ion Batteries

Metal-organic compounds are a family of electrode materials with structural diversity and excellent thermal stability for rechargeable batteries. Here, we fabricated a hierarchical nanocomposite with metal-organic cuprous tetracyanoquinodimethane (CuTCNQ) in a 3 D conductive carbon nanofibers (CNFs) network by in situ growth, and evaluated it as flexible cathode for sodium-ion batteries (SIBs). CuTCNQ in such flexible composite electrode is able to exhibit a high capacity of 252 mAh g-1 at 0.1 C and highly reversible stability for 1200 cycles within the voltage range of 2.5-4.1 V (vs. Na+ /Na). A high specific energy of 762 Wh kg-1 was obtained with high average potential of 3.2 V (vs. Na+ /Na). The in situ-formed electroactive metal-organic composites with tailored nanoarchitecture provide a promising alternative choice for high-performance cathode materials in SIBs with high energy.

Metallophilic interactions and structure-stability relationship with secondary interactions in [ZnX]− based hybrid derivatives

To scrutinize the role of the weak interactions in structure-stability of zinc based metal-organic compounds a series of seventy derivatives were analyzed through single crystal X-ray crystallographic data obtained from IUCr. The structural parameters obtained from the cif file were simulated for molecular dynamics to calculate the weak interactions in series of zinc chloride, zinc bromide, zinc iodide and zinc fluoride based metal-organic composites. The structural frameworks depict that the metal halides are holding the organic moieties within the inorganic patterns through XH … A, CH … π, π … π, halogen-halogen and Metallophilic secondary interactions. The different structural motifs from 1D chain, 2D ribbons and 3D dimmer patterns were observed in the selected series. The comprehensive structural statistics results that the average Zn-X bond distance = 2.375 (4)Å [ZnCl2 = 2.465 (4)Å, ZnBr2 = 2.396 (4)Å, ZnI2 = 2.557 (6)Å, ZnF2 = 2.019 (5)Å] and X-Zn-X bond angles lie in the range of 64.77–126.45° in these compounds. The XH … A hydrogen bond calculations result the average H … A bond length = 2.38 Å [ZnCl2 = 2.37 Å, ZnBr2 = 2.44 Å, ZnI2 = 2.65 Å, ZnF2 = 2.28 Å] and the average XH … A bond angle = 125.5° [ZnCl2 = 139°, ZnBr2 = 130.5°, ZnI2 = 119.5°, ZnF2 = 133.5°]. This indicates that these hydrogen interactions are in the category of strong to moderate type of hydrogen bonds. The minimum value of H … π = 2.800 (4) Å is observed in ZnBr17 at symmetry position -x, 1-y, 1-z shows that such interactions are stabilizing the organic moieties within the metal-organic derivatives. It is observed that the minimum value of halogen … halogen weak interaction is 2.382 (2)Å for ZnF1 at symmetry position -x, 0.5-y, 0.5-z and the minimum value of metallophilic interaction distance is observed as 2.508 (6)Å in ZnBr32 at symmetry position,1 + x, y, z, which are linking the inorganic components of metal-organic derivatives. The IR and Raman spectra tensors were calculated for the selected series of derivatives which indicates that IR, Raman and Hyper-Raman modes are dominant in ZnCl2 based derivatives as compared to ZnBr2, ZnI2 and ZnF2 based metal-organic compounds. The structural and spectroscopic parameters reveal that such weak interactions can be used to design the materials with spectroscopic applications.

Redox-Active Metal-Organic Composites for Highly Selective Oxygen Separation Applications.

A redox-active metal-organic composite material shows improved and selective O2 adsorption over N2 with respect to individual components (MIL-101 and ferrocene). The O2 sensitivity of the composite material arises due to the formation of maghemite nanoparticles with the pore of the metal-organic framework material.

Synthesis and Characterization of a Novel Metal–Organic Compound: 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-Oxide (DOPO)–Mg

Abstract For the first time, a metal was introduced into the structure of the flame retardant, 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO). A novel metal–organic composite, DOPO–Mg, was synthesized upon the reaction between melt DOPO and activated magnesium powder. The results show that DOPO–Mg has a high initial thermal decomposition temperature of up to 400 °C (5%). In addition, it was an amorphous-like material with minimal water absorption, which decomposed without a melting point. The product after the combustion of DOPO–Mg was magnesium pyrophosphate.

Degradation of organic pollutants by heterogeneous electro-Fenton process using Mn-alginate composite

BACKGROUND The exploration of new technology based on electro-Fenton-like process has advantageous and unique environmental implications, however, scaling up to permit operation in continuous mode is a decisive stage to be researched. RESULTS A new metal–organic composite, manganese–alginate (Mn-AB) was synthesized. It was characterized by scanning electron microscopy and the results showed that manganese was uniformly distributed on the surface of alginate beads. A comparative study of the decolorization of Reactive Black 5 demonstrated that the best performance was obtained by heterogeneous electro-Fenton using Mn-AB as catalyst. In addition, operation over four successive batches and continuous mode, showed high activity and stability of the catalyst Mn-AB without operational problems, and maintained particle shape throughout the oxidation process. The ability of Mn-AB catalyst for the degradation of other pollutants (imidacloprid, di-2-ethylhexyl phthalate, 4-nitrophenol) was confirmed by identification of several reaction intermediates using liquid chromatography–mass spectrometry (LC-MS) and gas chromatography–mass spectrometry (GC-MS). CONCLUSION The efficiency of the new Fenton-like catalyst developed in this study was successfully demonstrated. Results validate an adequate heterogeneous electro-Fenton-like process to continuously remediate organic pollutants in aqueous medium. © 2014 Society of Chemical Industry

Understanding Oxygen Reduction in Complex Metal Organic and Inorganic Composites for Fuel Cell, Electrolyzer and Energy Storage Applications

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Multitemplates for the Hierarchical Synthesis of Diverse Inorganic Materials

Described here is a new and highly general strategy for multiple-template (multitemplate) patterning. This process is significant because it allows us to create various unusual shapes such as solid spheres, yolk-shell spheres, flowerlike particles, and structured nanocomponents. Alcoholysis of the metal-organic precursors with mixtures of glycerol and various amounts of ethanol followed by calcination yields oxides. The glycerol plays the dual role of hierarchically assembling the metal-organic composites and stabilizing the structures during the subsequent conversions. Furthermore, we demonstrate for the first time that these metal-organic composites can be converted into oxides, nitrides, and highly graphitized carbon nanostructures. We show that these yolk-shell structures display superior photocatalytic activity and electrochemical properties.

Entrapment of organic molecules within binary metal alloys

Within metallic materials, alloys form the largest and richest family. We describe here a method for extending the properties of alloys even further, namely by incorporating organic compounds within bimetallic alloys, thus forming three-component organic–metallic composite-alloys of a novel type. Specifically, thionin and neutral red were entrapped in the following bimetallic systems: Ag–Au, Cu–Pt and Cu–Pd. This was achieved by zinc co-reduction of the two metal salts in the presence of the dye molecule to be entrapped. It was found that the two metals in each composite formed a bimetallic alloy, and that the entrapment yields were 95% and above in most composites. Using alloys as entrapping metallic matrices allows for the preparation of a wide variety of metal–organic composites of potential use in fields such as catalysis and sensing.

Entrapment of dye molecules within submicron silver particles

We describe a method for the preparation of metal–organic composites submicron particles. Specifically, the preparation of silver particle-clusters 150–200 nm in size, doped with an organic dye Congo-red, is reported. The use of sodium citrate coupled with sodium hypophosphite facilitated the formation of these particle-clusters, which were fully characterized by TEM analysis, Zeta potential and size measurements, scanning electron microscopy, UV–Vis measurements, and thermogravimetric analysis. The latter reveals a catalytic action of the metal on the thermal oxidative decomposition of the entrapped dye. The use of these particles to obtain dense thin metallic films was demonstrated by the coating of ITO glass.

Mesoporous silica–metal organic composite: synthesis, characterization, and ammonia adsorption

A novel composite adsorbent composed of an inorganic silica phase impregnated with a metal organic phase is synthesized and characterized. Specifically, MCM-41 is impregnated with copper active sites, which are then functionalized with benzene-1,3,5-tricarboxylic acid, which is the linker in the metal organic framework CuBTC. X-ray diffraction, nitrogen adsorption isotherms, thermogravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, and equilibrium ammonia capacities are used to characterize the composite and control materials. Properties of the composite and control samples after conditioning at 85 °C in saturated water vapor for 5 h are also evaluated. Results show that the silica phase of the composite material provides an engineered phase that enhances the hydrothermal stability of the metal organic phase and the metal organic phase provides active sites for chemisorption. The composite material has a high ammonia capacity of 5.2 mol kg−1 and remains stable after conditioning. In comparison, the CuBTC structure degrades and shows low ammonia capacity after conditioning.

Understanding Oxygen Reduction in Complex Metal Organic and Inorganic Composites for Fuel Cell, Electrolyzer and Energy Storage Applications

not Available.

Molecular Designer Self‐Assembling Peptides

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Molecular designer self-assembling peptides

Chemistry has generally been associated with inorganic and organic syntheses, metal-organic composites, coordinate metal chemistry, catalyses, block copolymer, coating, thin film, industrial surfactants and small-molecule drug development. That is about to change. Chemistry will also expand to the discovery and fabrication of biological and molecular materials with diverse structures, functionalities and utilities. The advent of biotechnology, nanotechnology and nanobiotechnology has accelerated this trend. Nature has selected and evolved numerous molecular architectural motifs at nanometer scale over billions of years for particular functions. These molecular nanomotifs can now be designed for new materials and nanodevices from the bottom up. Chemistry will again harness Nature's enormous power to benefit other disciplines and society. This tutorial review focuses on two self-assembling peptide systems.