Polymer-supported Metal Research Articles

Carbohydrate polymer-supported metal and metal oxide nanoparticles for constructing electrochemical sensors

Metal- and metal oxide-carbohydrate polymers are considered a promising tool for electrochemical detection of biological analytes and water pollutants.

Phosphine-Based Hyper-Cross-Linked Polymer-Supported Neutral Gold(I) Complex as a Recyclable Catalyst for the Regioselective Hydration of Alkynes to Ketones

Functionalized hyper-cross-linked polymer-supported metal complexes have been developed as heterogeneous catalysts for organic synthesis and have attracted much attention. In this regard, a phosphine-based hyper-cross-linked polymer-supported neutral gold(I) complex, Au@HCPs-PPh3, which is synthesized by incorporation of [(Me2S)AuCl] into a phosphine-based hyper-cross-linked polymer, is proven to be an efficient and general heterogeneous catalyst for the regioselective hydration of a series of alkynes to ketones. Furthermore, the synthesized catalyst is recycled six times without an obvious decrease in the catalytic activity.

Engineering the Interface: Effects of Interfacial Adhesion and Substrate Thickness on the Ductility of Polymer-supported Metal Films

Engineering the Interface: Effects of Interfacial Adhesion and Substrate Thickness on the Ductility of Polymer-supported Metal Films

Chemically Controllable Porous Polymer–Nanocrystal Composites with Hierarchical Arrangement Show Substrate Transport Selectivity

Functional organic–inorganic hybrid materials with tunable properties are useful across many application areas, ranging from gas storage to electronics, flame retardants, separations, and catalysis. Combining polymers, with a suite of functional groups and conformational flexibility, and inorganic nanoparticles, with tunable surface chemistry and composition, yields hybrids with novel functional properties. Specifically, in catalysis, control of the electronic environment at a metal interface is paramount in determining the catalytic properties. In this contribution, we describe a modular process to prepare porous polymer–nanocrystal (NC) composites in a hierarchical, multilayered synthesis, in which multiple parameters can be accurately tuned: polymer functional groups and the corresponding pore structure, the polymer layer thickness, and the NC size, shape, and composition. This process provides for a variety of controlled materials with high surface area, tunable chemistry, and thermal and chemical stabilities. Furthermore, we demonstrate their utility for shape- and size-selective catalytic conversions both in oxidation and hydrogenation reactions, where they show increased selectivity by orders of magnitude compared to conventional polymer-supported metal catalysts. In light of the high degree of control in the composite structure, this method allows for the design and realization of catalysts for several reactions and reaction environments and for nanomaterials with other applications.

Fabrication of Polymer-Supported Metal Organic Framework Membrane and Its Gas Separation Performance

Fabrication of Polymer-Supported Metal Organic Framework Membrane and Its Gas Separation Performance

Polymer-supported metal catalysts for the heterogeneous polymerisation of lactones

Polymer-supported metal catalysts are used for the heterogeneous polymerisation of renewable lactones, towards the efficient and environmentally benign production of sustainable polymers.

Self-Heating-Induced Deterioration of Electromechanical Performance in Polymer-Supported Metal Films for Flexible Electronics

The retention of electrical performance under the combined conditions of mechanical strain and an electrical current is essential for flexible electronics. Here, we report that even below the critical current density required for electromigration, the electrical current can significantly deteriorate the electromechanical performance of metal film/polymer substrate systems. This leads to a loss of stretchability, and this effect becomes more severe with increasing strain as well as increasing current. The local increase of electrical resistance in the metal film caused by damage, such as localized deformations, cracks, etc., locally raises the temperature of the test sample via Joule heating. This weakens the deformation resistance of the polymer substrate, accelerating the necking instability, and consequently leading to a rapid loss of electrical conductivity with strain. To minimize such a current-induced deterioration of the polymer-supported metal films, we develop and demonstrate the feasibility of two methods that enhance the deformation resistance of the polymer substrate at elevated temperatures: increasing the thickness of the polymer substrate, and utilizing a polymer substrate with a high glass transition temperature.

Highly Active Multimetallic Palladium Nanoalloys Embedded in Conducting Polymer as Anode Catalyst for Electrooxidation of Ethanol.

Fabrication of multimetallic nanocatalysts with controllable composition remains a challenge for the development of low-cost electrocatalysts, and incorporating metal-based catalysts into active carbon nanoarchitectures represents an emerging strategy to improve the catalytic performance of electrocatalysts. Herein, a facile method developed for Pd nanoparticle (NP)-based multimetallic alloys incorporated on polypyrrole (Ppy) nanofibers by in situ nucleation and growth of NPs using colloidal radiolytic technique is described. Electrochemical measurement suggests that the as-prepared catalysts demonstrate dramatically enhanced electrocatalytic activity for ethanol oxidation in alkaline medium. The ultrasmall Pd30Pt29Au41/Ppy nanohybrids (∼8 nm) exhibit excellent electrocatalytic activity, which is ∼5.5 times higher than that of its monometallic counterparts (12 A/mg Pd, 5 times higher activity compared to that of Pd/C catalyst). Most importantly, the ternary nanocatalyst shows no obvious change in chemical structure and long-term stability, reflected in the 2% loss in forward current density during 1000 cycles. The superior catalytic activity and durability of the nanohybrids have been achieved due to the formation of Pt-Pd-Au heterojunctions with cooperative action of the three metals in the alloy composition, and the strong interactions between the Ppy nanofiber support with the metal NPs. The facile synthetic approach provides a new generation of polymer-supported metal alloy hybrid nanostructures as potential electrocatalysts with superior catalytic activity for fuel cell applications.

Explicit relationship between electrical and topological degradation of polymer-supported metal films subjected to mechanical loading

For a comprehensive characterization of mechanical reliability of metallization layers on polymer substrates, both electrical and mechanical degradation should be taken into account. Although it is evident that cracking of a conductive film should lead to electrical degradation, the quantitative relationship between the growth of electric resistance and parameters of the induced crack pattern has remained thus far unexplored. With the help of finite element modelling, we were able to find an explicit and concise expression which shows that electrical resistance grows with the fourth order of the crack length and second order of the areal crack density. The discovered relationship was verified by comparison with the experimental results of tensile testing of polymer-supported thin metal films. The presented model is independent of the length scale and can be applied to films with different thicknesses as long as Ohm's law is valid. It is demonstrated that the linear crack density is an ambiguous parameter, which does not properly capture the development of a crack pattern. For the unambiguous characterization of the intensity of a crack pattern, a universal dimensionless factor is proposed. The presented results show that there is a wide range of possible crack patterns which do not lead to electrical failure of a conductive film that can be used for the failure-free design of flexible electronic devices.

Nanoconfined Zeolitic Imidazolate Framework Membranes with Composite Layers of Nearly Zero Thickness.

The key to preparing dense composite membranes is reducing the thickness of the composite layer with stable separation performance. Herein, we report a nanoconfined composite membrane prepared by in situ growth of Zeolitic Imidazolate Framework (ZIF) nanocrystals in the nanoporous layer of the substrate via a fine-tuning contra-diffusion method. The thickness of the composite layer on the membrane surface was nearly zero. The formed ZIF nanoconfined composite membranes showed state-of-art flux and high stability in removing dyes from water. This new strategy is expected to offer great opportunities for the potential practical application of polymer-supported metal-organic framework (MOF) composite membranes.

Relationship between mechanical damage and electrical degradation in polymer-supported metal films subjected to cyclic loading

A detailed investigation of the correlation between mechanical damage and the change in electrical resistance induced by cyclic tensile loading is performed for polymer-supported gold, copper, and printed silver films. Four distinct types of resistance response to mechanical loading are described and linked to the mechanical properties and microstructure of thin films. It is shown that significant topographical changes induced by cyclic loading can result in minor changes in the overall electrical resistance. Presented results show that an underestimation of mechanical damage can be made when only the electrical failure criterion is used for reliability characterization of polymer-supported metal films.

Synthesis and structural studies of polymer-supported transition metal complexes: Efficient catalysts for oxidation of phenol

In this work, a new simple and reproducible method for preparation of a series of novel recyclable complexes is described. The series includes unsupported 3-MHBdMBn–Met complexes (Met = iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) ions), and polystyrene anchored (P-3-MHBdMBn–Met) metal ion complexes, supported by—ONNO-tetradentate Schiff-base ligand. These free and polymer anchored metal complexes are prepared by the reactions of metal solution with one molar equivalent of unsupported 3-MHBdMBn (N,N'-bis(2-hydroxy-3-methylbenzaldehyde)-4-methylbenzene-1,2-diamine) or polymer-supported (P-3-MHBdMBn) Schiff-base ligands in methanol under nitrogen atmosphere. The greatest advantage of this catalyst system over other polymer-supported catalysts is a remarkably low cost and the quality of being recycled up to six times. These benefits are due to the easily accessible materials and the simple synthetic route. A higher efficiency of complexation of metal ions on the polymer anchored 3-MHBdMBn Schiff base compared to that shown by an unsupported analogue is another advantages of this catalyst system. The structural study reveals that iron(III) complex is octahedral in geometry, whereas cobalt(Il), nickel(II) and copper(II) complexes are square planar and zinc(II) complex is of tetrahedral geometry. The catalytic activities of polystyrene-supported metal complexes toward the oxidation of phenol are investigated. Experimental results indicate that the reactivity of P-3-MHBdMBn–Met is dramatically affected by the polymer support and iron complexes are more active than other complexes. The rate of phenol conversion is high (2.41 × 10–6 mol dm–3 s–1) in the presence of polystyrene-supported 3-MHBdMBn Schiff base complexes of iron(III) ions and low in the presence of zinc(II) analogue (1.36 × 10–6 mol dm–3 s–1).

Ductility of thin metal film on a polymer substrate for stretchable electronics

This study investigates the influence of various factors on the ductility of thin metal films on polymer substrates through structural modeling of these polymer-supported metal films using finite element analysis software ABAQUS. The various system parameters include the thickness of the film h, the thickness of the polymer substrate H, the thickness ratio between the film and substrate h/H and the Young’s modulus of the substrate Es. The results demonstrate that each parameter influences the ductility of films except the thickness ratio between the film and substrate h/H. Furthermore, an orthogonal experiment is performed to analyze the combined action of the parameters on the ductility of polymer-supported metal films. It can be concluded that the most dominating factor that influences the ductility of films on polymer substrate is the thickness of the thin metal film h, while the Young’s modulus of the substrate while Es plays a secondary role.

Synthesis of glycerol carbonate from urea and glycerol using polymer-supported metal containing ionic liquid catalysts

Polystyrene-supported, metal containing imidazolium salt [PS-(Im)2MX2] catalysts were prepared and characterized by various analytical methods, and their role in the synthesis of glycerol carbonate from glycerol and urea was investigated under mild conditions. Among different metal containing PS-(Im)2MBr2 catalysts, the yield of GC increased Cu<Mg<Zn, which is the order of acid–base balance of the catalysts. PS-(Im)2ZnI2 catalyst, which showed a good balance of the acid–base properties, was the most active and selective catalyst; it was readily recoverable and reusable in the subsequent reaction cycles. Furthermore, the reaction pathway for the glycerolysis of urea was studied with the time-on-line analysis of the products via a combination of FT-IR spectroscopy and 13C NMR analysis. The effects of reaction parameters such as temperature, degree of vacuum, catalyst loading, and the ratio of reactants on the reactivity were also investigated to elucidate the reaction mechanism.

Synthesis, characterization and spectroscopic investigation of pyrazinoporphyrazine network polymer-supported metal (II)-based catalysts

Chloranil through condensation reaction with vicinal diamine such as diaminomaleonitrile produced heterocyclic monomer, p-benzoquinonebis[2,3-b; 2′,3′-b′]pyrazine-5,6-dinitrile. The tetranitrile monomer was cyclo-tetramerised using lithium/pentanol and acetic acid affording the corresponding tetra p-benzoquinone bis[2,3-b; 2′,3′-b′]pyrazinoporphyrazine)]-based network polymer (2H-Pz). The tetranitril monomer was cyclo-tetramerised using metal salt and quinoline affording the corresponding porphyrazinato-metal II-based network polymers (M-Pz), M = Co, Ni or Cu. Elemental analytical results, IR and NMR spectral data of the prepared molecules are consistent with their assigned formulations. Molecular masses and metal contents of the synthesized polymers proved to be of high molecular masses which confirm the efficiency of tetramerization polymerization and complexation reactions. The prepared pyrazinoporphyrazines were used as efficient catalysts for the oxidation of thiophenol and benzylthiol to their disulfides in the presence of air atmosphere. The results of oxidation of thiophenol and benzylthiol show that after 15 min the maximum yield of the corresponding disulfides reached 95%, 91%, respectively.

Removal of Thiophene and Its Derivatives from Model Gasoline Using Polymer-Supported Metal Chlorides Ionic Liquid Moieties

A series of polymer-supported metal chlorides imidazolium ionic liquid (IL) moieties, M/CMPS-Im(Cl) (M = CuCl, ZnCl2 and FeCl3), were synthesized by grafted method using chloromethylated polystyren...

Self-Assembled Poly(imidazole-palladium): Highly Active, Reusable Catalyst at Parts per Million to Parts per Billion Levels

Metalloenzymes are essential proteins with vital activity that promote high-efficiency enzymatic reactions. To ensure catalytic activity, stability, and reusability for safe, nontoxic, sustainable chemistry, and green organic synthesis, it is important to develop metalloenzyme-inspired polymer-supported metal catalysts. Here, we present a highly active, reusable, self-assembled catalyst of poly(imidazole-acrylamide) and palladium species inspired by metalloenzymes and apply our convolution methodology to the preparation of polymeric metal catalysts. Thus, a metalloenzyme-inspired polymeric imidazole Pd catalyst (MEPI-Pd) was readily prepared by the coordinative convolution of (NH(4))(2)PdCl(4) and poly[(N-vinylimidazole)-co-(N-isopropylacrylamide)(5)] in a methanol-water solution at 80 °C for 30 min. SEM observation revealed that MEPI-Pd has a globular-aggregated, self-assembled structure. TEM observation and XPS and EDX analyses indicated that PdCl(2) and Pd(0) nanoparticles were uniformly dispersed in MEPI-Pd. MEPI-Pd was utilized for the allylic arylation/alkenylation/vinylation of allylic esters and carbonates with aryl/alkenylboronic acids, vinylboronic acid esters, and tetraaryl borates. Even 0.8-40 mol ppm Pd of MEPI-Pd efficiently promoted allylic arylation/alkenylation/vinylation in alcohol and/or water with a catalytic turnover number (TON) of 20,000-1,250,000. Furthermore, MEPI-Pd efficiently promoted the Suzuki-Miyaura reaction of a variety of inactivated aryl chlorides as well as aryl bromides and iodides in water with a TON of up to 3,570,000. MEPI-Pd was reused for the allylic arylation and Suzuki-Miyaura reaction of an aryl chloride without loss of catalytic activity.

Competing failure mechanisms of thin metal films on polymer substrates under tension

The ductility of thin metal films on polymer substrates reported in recent experiments has a huge disparity, ranging from less than 1 % up to more than 50 %. To reveal the underpinning origins for such a large variation, this paper reports a systematic computational study of two competing failure mechanisms: metal film necking and grain boundary cracking. The quantitative results suggest that strong grain boundaries and metal/polymer interfacial adhesion are keys to achieve high ductility of polymer-supported metal films.

Coordination and Organometallic Nanomaterials: A Microreview

Nanomaterials/nanocomposites on the basis of metal complexes are reviewed. Most attention is paid to N-, O-, S-, N, O- coordination compounds, σ- and π-organometallics and polymer-supported metal complexes. A brief description of metal complexes as precursors for inorganic nanomaterials is given.

Synthesis, characterization and catalytic activity of polymer anchored transition metal complexes toward oxidation reactions

The polymer-anchored Schiff base complexes of Cu(II), Co(II), Ni(II), Mn(II) and Fe(III) were prepared by reacting polystyrene amine with 2-pyridinecarbaldehyde followed by loading of metal atom in methanol. These complexes were characterized by using different physico-chemical and spectroscopic methods. The catalytic activity of these polymer-supported metal catalysts was tested for the oxidation of various olefins and alcohols. Influence of various reaction parameters, such as reaction temperature, reaction time, oxidant, substrate-to-oxidant mole ratio and nature of solvent, was studied for the oxidation of cyclohexene with these catalysts. Among the catalysts studied, Cu-Cat showed higher catalytic activity toward oxidation reactions than the other catalysts. Moreover, hot filtration experiments proved that these catalysts are truly heterogeneous and can be reused a number of times without significant loss of activity.