Organometallic Coordination Polymers Research Articles

Controlling the thermoelectric properties of organo-metallic coordination polymers through backbone geometry.

Poly(nickel-benzene-1,2,4,5-tetrakis(thiolate)) (Ni-btt), an organometallic coordination polymer (OMCP) characterized by the coordination between benzene-1,2,4,5-tetrakis(thiolate) (btt) and Ni2+ ions, has been recognized as a promising p-type thermoelectric material. In this study, we employed a constitutional isomer based on benzene-1,2,3,4-tetrakis(thiolate) (ibtt) to generate the corresponding isomeric polymer, poly(nickel-benzene-1,2,3,4-tetrakis(thiolate)) (Ni-ibtt). Comparative analysis of Ni-ibtt and Ni-btt reveals several common infrared (IR) and Raman features attributed to their similar square-planar nickel-sulfur (Ni-S) coordination. Nevertheless, these two polymer isomers exhibit substantially different backbone geometries. Ni-btt possesses a linear backbone, whereas Ni-ibtt exhibits a more undulating, zig-zag-like structure. Consequently, Ni-ibtt demonstrates slightly higher solubility and an increased bandgap in comparison to Ni-btt. The most noteworthy dissimilarity, however, manifests in their thermoelectric properties. While Ni-btt exhibits p-type behavior, Ni-ibtt demonstrates n-type carrier characteristics. This intriguing divergence prompted further investigation into the influence of OMCP backbone geometry on the electronic structure and, particularly, the thermoelectric properties of these materials.

Growth mechanism of graphite-carbon encapsulated nickel catalysts and curvature effect of carbon layer on the performance of catalytic hydrogenation

This research focuses on the growth mechanism from organometallic coordination polymers precursor to encapsulated catalyst, which contributes to the guiding for the directional design and controlled preparation of the catalyst. Decomposition of organic matter, reduction of nickel, and dissolution/segregation of carbon in the nickel nanoparticles are three main steps for the conversion of Ni@C-OCPs to Ni@C under pyrolysis. The contents of reducing atmosphere during pyrolysis were reduced via selecting organic ligands with smaller molecular and higher C-H ratios. Thus, Ni@C-600 with smaller particle size and larger curvature of the carbon layer surface was obtained. Kinetic experiments showed that it corresponded to a lower apparent activation energy. In addition, density function theory simulation verified that the optimization of the electronic structure generated by the large curvature graphite carbon layer was one of the sources of its excellent activity.

Structure-controlled graphene-encapsulated nickel nanoparticle with tailored work function to steer chemoselective hydrogenation of nitroarenes

In recent years, novel carbon-layer encapsulation strategies have been emerging for the construction of heterogeneous catalysts. However, the mechanism action of thermos-catalytic systems is still unclear. The synergistic effect of metal particle size and carbon layer quantity on catalytic performance has not been reported. The strategy to control the carbon layer quantity and metal particle size is still a big challenge. Here, we proposed a novel idea to design catalysts connecting the performance and the structure via work function. The direct pyrolysis of organometallic coordination polymer is induced to control the carbon layer quantity and metal particle size of the carbon-encapsulated catalyst. The results show that the reduction in the nickel nanoparticle size and the carbon layer quantity were favorable for pumping electrons from the nickel core. There was a corresponding relationship between the work function of the catalyst and its selective hydrogenation performance of halogenated aromatic nitro compounds. With low carbon-halogen bond dissociation energy, a high work function decreased catalytic selectivity. Therefore, the work function can be served as a bridge connecting to the configurational relationship of catalysts.

A Novel Organometallic Coordination Polymer as a Heterogeneous Catalyst for C−C Bond Formation

One-pot solvothermal reaction of Ni(II) salt with 2-aminopyridine and thiethyl orthoformate in methanol afforded a novel one-dimensional nickel coordination polymer which can be regarded as a potential heterogeneous catalyst for nitroaldol (Henry) reaction.

Surface carbon layer controllable Ni3Fe particles confined in hierarchical N-doped carbon framework boosting oxygen evolution reaction

Developing high-efficiency and low-cost catalysts towards oxygen evolution reaction (OER) is extremely important for overall water splitting and rechargeable metal−air batteries. Herein we propose a promising organometallic coordination polymer (OCP) induced strategy to construct hierarchical N-doped carbon framework with NiFe nanoparticles encapsulated inside (N x Fe@N–C) as a highly active and stable OER catalyst. The synthesis of OCP precursor depends on the unique molecular structure of iminodiacetonitrile (IDAN), which can coordinate with metal ions to form Ni 2 Fe(CN) 6 with prussian blue analogs (PBA) structure. Unlike previous PBA-induced methods, the thickness of the carbon layer covering the surface of the metal core can be well controlled during the pyrolysis through adjusting the amount of IDAN, which builds a wonderful bridge for investigating the relationship between carbon layer thickness and catalytic performance. Both the experimental characterizations and theoretical studies validate that a suitable carbon layers thickness leads to optimal OER activity and stability. By optimizing the structure and composition, the optimized Ni 3 Fe@N–C with hierarchical framework exhibits the low overpotentials (260 ​mV at 10 ​mA ​cm −2 ; 320 ​mV at 50 ​mA ​cm −2 ), improved kinetics (79 ​mV dec −1 ), and robust long-term stability, which exceeds those of benchmark RuO 2 . • Iminodiacetonitrile and metal ions are coordinated to form Ni 2 Fe(CN) 6 ) prussian blue analogues. • Hierarchical Ni 3 Fe@N–C framework can be formed through the direct pyrolysis of Ni 2 Fe(CN) 6 ). • Thickness of carbon layer covered on Ni 3 Fe can be well controlled by adjusting IDAN amount. • Hierarchical Ni 3 Fe@N–C framework presents excellent electrocatalytic performance for the OER. • OER improvement mechanism is clarified through the experiment and theoretical combination.

Investigation of Adsorption Capacity of Metal-Organic Polymers

In this work, we studied a biocompatible hybrid material based on iron (III) and muconic acid oxoclusters. It has been shown that coordination polymers are a promising class as functional materials for various purposes (as sorbents, catalysts, conductors, storage materials, etc.). The adsorption capacity of the obtained adsorbent for removing dyes from the prepared solution was in the following order: CR> MB> MV. From the results of the study, we can conclude that the dye Congo red is best suited for adsorption by the coordination polymer. The maximum absorption of the dye on organometallic coordination polymers occurs in the pH range 5 - 7 with adsorption of ~ 90%, which is important for the potential practical application of such coordination polymers as carriers for drug delivery.

Investigation of Physical Properties of Fe(III) Containing Metal-Organic Polymers

In this work, we studied the properties of a specially synthesized organometallic coordination polymer - a porous coordination polymer with biocompatible structural elements based on oxoclusters of iron muconate (III). The samples were investigated by scanning electron microscopy, thermogravimetric analysis combined with differential scanning calorimetry, and the study of low-temperature nitrogen adsorption of a sample obtained by a modified solvothermal technique. It is shown that most of the pores of the sample have an average radius of 18,8 Å ~ 1,88 nm. Also, as a result of the study, it is necessary to conclude that the synthesized material has a developed surface area - it is 512,1 m2/g and the pore volume is ~ 0,48 cm3/g. It should be concluded that such materials are promising as components for a new generation of various kinds of functional materials with improved or unique characteristics. It is obvious that further research in this area is important from both fundamental and applied points of view.

Iminodiacetonitrile induce-synthesis of two-dimensional PdNi/Ni@carbon nanosheets with uniform dispersion and strong interface bonding as an effective bifunctional eletrocatalyst in air-cathode

Developing highly-active, stable and conductive bifunctional electrocatalysts towards both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a key step for rechargeable Zn-air batteries. From unique molecular structure of iminodiacetonitrile (IDAN), herein we design and build a novel organometallic coordination polymer (OCP) for the synthesis of hierarchical N-doped carbon nanosheets anchored PdNi/Ni hybrids (PdNi/Ni@N-C). The cyano ligands in IDAN can form a low spin planar tetragonal complex with M2+ (M=Pd and Ni) by dsp2 hybridization, while the amino ligands tend to form a high spin tetrahedral complex with M2+ by sp3 hybridization, which not only induce the formation of 2D carbon nanosheets, but also strengthen metal-carbon interaction after the pyrolysis. The optimized PdNi/Ni@N-C can function as an outstanding bifunctional electrocatalyst, presenting a positive half-wave potential of 0.89 V towards ORR and a low overpotential of 360 mV at 10 mA cm−2 towards OER, out-performing commercial precious-metal benchmarks. Theoretical calculations are performed to analyze the alloying effects of PdNi and identify the potential active sites for ORR/OER. Furthermore, the PdNi/Ni@N-C as an air-cathode can enable rechargeable liquid and flexible all-solid-state Zn–air batteries to achieve higher power density and longer cycle life than costly Pd/C+RuO2-driven batteries. This work offers a potential molecular design strategy for the development of efficient electrocatalysts for energy storage and conversion.

Synthesis and identification of 1,1,3,3-tetra-[1,2-dihydro-1,5-dimethyl-2-phenyl-3-oxopyrazole]propane

Pyrazole derivatives are of practical value as analytical reagents, dyes and medicinal substances. It is known that 1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3H-one (antipyrine) and its bidentate derivatives are good analytical reagents for d-metal ions (Cd2+, Fe3+, Sc3+, Ti4+, Zn2+, Co2+, etc.). The chelating ability of bi-, tri- and tetradentate antipyrine derivatives make them promising organic ligands for the synthesis of organometallic coordination polymers. Therefore, synthesis of new tetradentate derivatives of 1,2-dihydro-1,5-dimethyl-2-phenyl-3Hpyrazole-one seems to be a highly relevant research task. The aim of this work was to synthesize and study a new substance – 1,1,3,3-tetra-[1,2-dihydro-1,5-dimethyl-2-phenyl-3-oxopyrazole]propane (tetraantipyryl-propane). A review of existing methods for the synthesis of antipyrine derivatives through condensation of 1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one with aliphatic and aromatic aldehydes was carried out. A method was developed for the preparation and purification of 1,1,3,3-tetra-[1,2-dihydro-1,5-dimethyl-2-phenyl-3-oxopyrazole]propane by the reaction of electrophilic substitution of the protonated form of propandial (malonic dialdehyde) in the aromatic ring of the oxopyrazole heterocycle with a yield of 17.1%. The resulting compound is a white crystalline substance, readily soluble in organic polar and non-polar solvents, but insoluble in water. The purity of the recrystallized synthesis product was confirmed by measuring its melting point and conducting a qualitative reaction with sodium nitrite to detect an unsubstituted oxopyrazole cycle in the reaction substrate. The structure of 1,1,3,3-tetra-[1,2-dihydro-1,5-dimethyl-2-phenyl-3-oxopyrazole]propane was established by mass spectrometry and Raman spectroscopy.

Coordination polymers and discrete complexes of Ag(I)-N-(pyridylmethylene)anilines: synthesis, crystal structures and photophysical properties

Reactions of AgO2C2F3 with (E)-N-(pyridylmethylene)aniline in which the pyridyl N is in the p- or m-position yielded two 1-D coordination polymers, [(AgO2C2F3)2(La)2]n (La = (E)-2,6-diisopropyl-N-(pyrid-3-ylmethylene)aniline) (1) and [(AgOC2F3)2(Ld)2]n (Ld = (E)-2,6-diisopropyl-N-(pyrid-4-ylmethylene)aniline) (5), and three discrete complexes, [(AgO2C2F3)2(La)4] (2), [AgO2C2F3(Lb)2] (Lb = (E)-N-(pyrid-4-ylmethylene)aniline) (3) and [(AgOC2F3)2(Lc)4] (Lc = (E)-2,6-dimethyl-N-(pyrid-4-ylmethylene)aniline) (4). The structures were determined by MS, FT-IR and NMR spectroscopies, elemental analysis and single crystal XRD. 1 is an organometallic coordination polymer with silver in η1-arene coordination, but is a discrete dimeric complex 2 when crystallized from warm diethylether. The geometries around silver(I) in 1 and 4 are tetrahedral, ‘inverted seesaw’ in 2 and T-shaped in 3 and in all the anion seems to play a role. Ag(I) centers in 5 have distorted trigonal bipyramid and inverted seesaw geometries. The trifluoroacetate anions in these complexes display variable monodentate and short bridging coordination patterns. All complexes absorb and strongly emit UV-Vis radiation at room temperature.

Sodium chloride nanorods from nanorods of one-dimensional pencil-shaped sodium coordination polymer

By considering the structure of one-dimensional pencil-shaped organometallic coordination polymer that was previously reported, we designed and synthesized [Na(μ2-Hdcpa)(μ3-dcpa)]n (1), [Hdcpa = 2,4-dichlorophenoxyacetic acid], which has one-dimensional pencil-shaped structure too. The Na atoms are surrounded with the aromatic phenyl rings of Hdcpa similar to graphite of a pencil. Metalophilic interactions also exists in 1 between Na(I) ions similar to argentophilic interaction in our previous compound which results in formation of chain structure similar to graphite structure of a pencil. Compound 1 nanorods were formed under ultrasonic irradiation and applied as template to fabricate sodium chloride nanorods. The interesting feature of our work is the formation of sodium chloride nanorods from compound 1 nanorods which have one-dimensional structure in the solid state.

New Twists and Turns for Actinide Chemistry: Organometallic Infinite Coordination Polymers of Thorium Diazide.

Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

New Twists and Turns for Actinide Chemistry: Organometallic Infinite Coordination Polymers of Thorium Diazide

AbstractTwo organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self‐assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

Mono- and heterometallic europium (III) and terbium (III) complexes: Synthesis, crystal structures and luminescent properties

Four new rare earth organometallic coordination polymers [EuIII(Hbidc)(pdc)·2(H2O)]2·4H2O (1), [TbIII(Hbidc)(pdc)·2(H2O)]2 (2), and {[LnIIIAgI(bidc)(pdc)·2(H2O)]}n·H2O (Ln=Eu (3), Tb (4)) (H2bidc=1H-benzimidazole-5,6-dicarboxylic acid, H2pdc=2,6-pyridine dicarboxylic acid) have been synthesized through self-assembly reactions. The X-ray single crystal diffraction indicates that these complexes are isomorphous, namely triclinic P −1. Interlayer O–H⋯O and C–H⋯O hydrogen bonding has been observed in the structure of four complexes, generating 1D zigzag infinite chain, 2D plane layer, and even 3D ladder-like supramolecular framework. Addition of silver nitrate to chemicals leads to massive restructuring and emission intensity enhancement of complexes 3 and 4. Furthermore, thermal stabilities and luminescent of 1–4 have also been discussed in detail.

Organotin–oxotungstate coordination polymer: An efficient catalyst for the selective oxidation of amines

The organometallic coordination polymer [(nBu3Sn)2WO4] catalyzed the selective oxidation of secondary and primary amines to nitrones and oximes, respectively. The catalyst was found to be reusable for five catalytic cycles without any appreciable loss in activity. Under the optimized reaction conditions [4 mol% catalyst, 3–4 equiv of hydrogen peroxide (30 wt%, aqueous solution), methanol as the solvent, r.t.], the corresponding nitrones and oximes were obtained with good efficiency.

Synthesis and characterization of nanowire coils of organometallic coordination polymers for controlled cargo release.

Nanowire coils of organometallic coordination polymers have been synthesized for the first time by using the emulsion periphery polymerization technique. An amphiphilic triblock copolymer terminated with inclusion complex of β-cyclodextrin and 4,4'-bipyridine self-assembles into oil-in-water emulsion in a toluene/water mixture. Subsequent coordination of bipyridine with Ni(II) in periphery of emulsions results in the formation of coordination polymer nanowire coils. The nanowire coils are composed of nanowires with diameter of 2 nm. Nanowire coils exhibit enhanced thermal stability in contrast to their parent triblock copolymer. Interestingly, nanowire coils are capable of encapsulating organic cargoes. Encapsulated cargoes can be selectively extracted from nanowire coils without damaging nanowire coils. Nanowire coils are potential candidates for encapsulating and controlled release of organic cargoes.

Amphiphilic nanocapsules entangled with organometallic coordination polymers for controlled cargo release.

A class of new amphiphilic nanocapsules entangled with organometallic coordination polymers has been developed for the first time. Poly(2-(N,N-dimethyl amino)ethyl methacrylate)-b-polystyrene capped with β-cyclodextrin (β-CD) (CD-PDMAEMA-b-PS) is first synthesized using sequent RAFT polymerization of styrene and 2-(N,N-dimethyl amino)ethyl methacrylate with xanthate modified β-CD as chain transfer agent. The end group of β-CD is allowed to include 4,4'-bipyridine through host-guest inclusion to yield PDMAEMA-b-PS terminated with an inclusion complex of β-CD and bipyridine (bpy-PDMAEMA-b-PS), which is then used as surfactant to prepare emulsion droplets in toluene/water mixture. Upon addition of Ni(II), bipyridine coordinates with Ni(II) to form coordination polymers in the periphery of emulsion droplets, affording amphiphilic capsules entangled with organometallic coordination polymers, as confirmed by GPC, (1)H NMR, SEM, TEM, DLS, and so on. The organometallic coordination polymer capsules are capable of encapsulating organic cargoes. Interestingly, encapsulated cargoes can be extracted from the capsules without damaging the capsules. Such capsules are potential candidates for encapsulating and controlled release of organic cargoes.

Multifunctionality of Organometallic Quinonoid Metal Complexes: Surface Chemistry, Coordination Polymers, and Catalysts

Quinonoid metal complexes have potential applications in surface chemistry, coordination polymers, and catalysts. Although quinonoid manganese tricarbonyl complexes have been used as secondary building units (SBUs) in the formation of novel metal-organometallic coordination networks and polymers, the potentially wider applications of these versatile linkers have not yet been recognized. In this Account, we focus on these diverse new applications of quinonoid metal complexes, and report on the variety of quinonoid metal complexes that we have synthesized. Through the use of [(η(6)-hydroquinone)Mn(CO)3](+), we are able to modify the surface of Fe3O4 and FePt nanoparticles (NPs). This process occurs either by the replacement of oleylamine with neutral [(η(5)-semiquinone)Mn(CO)3] at the NP surface, or by the binding of anionic [(η(4)-quinone)Mn(CO)3](-) upon further deprotonation of [(η(5)-semiquinone)Mn(CO)3] at the NP surface. We have demonstrated chemistry at the intersection of surface-modified NPs and coordination polymers through the growth of organometallic coordination polymers onto the surface modified Fe3O4 NPs. The resulting magnetic NP/organometallic coordination polymer hybrid material exhibited both the unique superparamagnetic behavior associated with Fe3O4 NPs and the paramagnetism attributable to the metal nodes, depending upon the magnetic range examined. By the use of functionalized [(η(5)-semiquinone)Mn(CO)3] complexes, we attained the formation of an organometallic monolayer on the surface of highly ordered pyrolitic graphite (HOPG). The resulting organometallic monolayer was not simply a random array of manganese atoms on the surface, but rather consisted of an alternating "up and down" spatial arrangement of Mn atoms extending from the HOPG surface due to hydrogen bonding of the quinonoid complexes. We also showed that the topology of metal atoms on the surface could be controlled through the use of quinonoid metal complexes. A quinonoid rhodium complex showed catalytic activity in Suzuki-Miyaura type reaction. As a result of the excellent stability of the homogeneous catalyst [(quinone)Rh(COD)](-) in water, we also successfully demonstrated catalyst recycling in 1,2- and 1,4-addition reactions. The compound [(quinone)Ir(COD)](-) showed significantly poorer catalytic activity in 1,4-addition reactions. Following upon the excellent coordination ability of the quinonoid rhodium complexes to metal centers, we synthesized organometallic coordination polymer nanocatalysts and silica gel-supported quinonoid rhodium catalysts, the latter using a surface sol-gel technique. The resulting heterogeneous catalysts showed activity in the stereospecific polymerization of phenylacetylene.

The Synthesis of Organometallic Coordination Polymer Flowers of Prussian Blue with Ultrathin Petals by Using Crystallization‐Assisted Interface Coordination Polymerization (CAICP)

Tiny flowers: A conceptually new method for fabricating polymer/Prussian blue (PB) hybrid flowers with ultrathin petals by using a CAICP technique has been developed. The PB hybrid flowers exhibit enhanced thermal stability, emit deep-blue light, and are electrochemically active. Their intriguing microstructure and enhanced structure-dependent properties make them potentially useful in nanodevices, biosensors, and photoluminescent devices.

Benzene sorption by a microporous coordination polymer based on a zinc carboxylate

Benzene vapor sorption by the organometallic coordination polymer [Zn2(bdc)2(dabco)] (H2bdc = benzene-1,4-dicarboxylic acid, dabco = diazabicyclo[2.2.2]octane) is reported. The [Zn2(bdc)2(dabco)] polymer has a high C6H6 sorption capacity of up to 3.8 mol of benzene per formula unit. The heat of sorption has been determined, and its dependence on the composition of the inclusion compound has been investigated. Included benzene molecules are nonequivalent in terms of the energy of their interaction with the metal-organic framework.