Bimetallic Coordination Research Articles

Synthesis and structure of a bismuth-cobalt bimetal coordination polymer for green efficient photocatalytic degradation of organic wastes under visible light

A novel BiCo-based bimetal coordination polymer (BiCo-MCP) with a molecular formula Bi2Co2C42H36N6O33 was synthesized by a mild hydrothermal method. BiCo-MCP was characterized via single crystal X-ray diffraction, SEM and XRD. BiCo-MCP is crystallized in a two-dimensional structure. The energy gap of BiCo-MCP is ~1.65 eV, which indicates that this material can absorb light both in visible and UV regions. This work is the first report on photocatalytic degradation of pesticide by a bismuth-containing bimetallic coordination polymer. The multiplication effect of pH and H2O2 together with BiCo-MCP on the degradation of imidacloprid pesticide wastewater showed that the catalyst system with 1< pH <3.5 and H2O2 (0.18 × 10−3 mmol/L) give the best degradation rate of 81% comparing to 35.4%(BiCo-MCP) under visible light for 5 h. The most interesting feature is that using BiCo-MCP as catalyst for photocatalytic degradation of imidacloprid can obtain the final environmentally friendly inorganic species decreasing the possible formation of a variety of organic intermediates. The influences of different pH on BiCo-MCP as photocatalyst to degradation of Rhodamine B (RhB) has also been investigated indicating the enhanced degradation properties of RhB by BiCo-MCP in acidic or alkaline aqueous solution.

Ni/Fe based bimetallic coordination complexes with rich active sites for efficient oxygen evolution reaction

Efficient electrocatalysts are vital for accelerating the sluggish oxygen evolution reaction (OER). Metal coordination complexes (MCCs) consisting of central metals and surrounding ligands generally possess abundant active sites owing to the rich boundaries between short-range crystalline components, making them promising candidates for tailored electrocatalysts. Herein, Ni/Fe based bimetallic MCCs with hybrid ligands are successfully constructed. With rich active sites residing in nanocrystal boundaries, bimetallic synergistic effect, and quick mass transfer derived from the nanosheet-like structure, excellent OER performance in terms of overpotential (229 mV at 10 mA cm−2) and Tafel slope (30 mV dce−1) is achieved. This unique architecture can shed light on the coordination design of highly efficient OER electrocatalysts.

Copper and copper-manganese 1D coordination polymers: Synthesis optimization, crystal structure and preliminary studies as catalysts for Baylis–Hillman reactions

This work reports the influence of experimental parameters (pH and counter-ion) in the synthesis of the 1D coordination polymer [Cu(IDA)(H2O)2]n (IDA = iminodiacetate), named here Cu-IDA. Copper-manganese bimetallic coordination polymers were also obtained by isomorphic replacement into Cu-IDA structure, with different molar ratio of Cu2+ and Mn2+ ions, denoted here as Cu/Mn-IDA (0.9/0.1; 0.7/0.3 and 0.5/0.5). New coordination polymers are isostructural to Cu-IDA and amounts of manganese atoms inserted into crystalline structure were evaluated by single-crystal X-ray diffraction and Rietveld refinement. All coordination polymers obtained were also characterized by infrared absorption spectroscopy and thermogravimetric analysis. Homometallic and bimetallic compounds were evaluated as catalysts for Baylis-Hillman reaction with yields and reaction times comparable or superior to those in the literature. Compounds containing manganese cations shows higher catalytic performance, especially Cu/Mn-IDA (0.9/0.1) with yield 91% in 5 h of reaction. Results also indicate an important role played by the metallic centre in the catalytic mechanism.

Bimetallic Salen-Based Compounds and Their Potential Applications

The new bimetallic coordination compounds [LNiAg(NO3)], [LCuMn(NO3)2], [LCuCu(NO3)2], [LCuZn(NO3)2], and [{LCuBi(NO3)3}(ACN)] have been synthesized from a salen-type ligand L containing two distinc...

Octacyanidorhenate(V) Ion as an Efficient Linker for Hysteretic Two-Step Iron(II) Spin Crossover Switchable by Temperature, Light, and Pressure.

A two-step hysteretic FeII spin crossover (SCO) effect was achieved in programmed layered Cs{[Fe(3-CNpy)2 ][Re(CN)8 ]}⋅H2 O (1) (3-CNpy=3-cyanopyridine) assembly consisting of cyanido-bridged FeII -ReV square grid sheets bonded by Cs+ ions. The presence of two non-equivalent FeII sites and the conjunction of 2D bimetallic coordination network with non-covalent interlayer interactions involving Cs+ , [ReV (CN)8 ]3- ions, and 3-CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin-transition phenomenon could be tuned by an external pressure giving the room-temperature range of SCO, as well as by visible-light irradiation, inducing an efficient recovery of the high-spin FeII state at low temperatures. We prove that octacyanidorhenate(V) ion is an outstanding metalloligand for induction of a cooperative multistep, multiswitchable FeII SCO effect.

Octacyanidorhenate(V) Ion as an Efficient Linker for Hysteretic Two‐Step Iron(II) Spin Crossover Switchable by Temperature, Light, and Pressure

AbstractA two‐step hysteretic FeII spin crossover (SCO) effect was achieved in programmed layered Cs{[Fe(3‐CNpy)2][Re(CN)8]}⋅H2O (1) (3‐CNpy=3‐cyanopyridine) assembly consisting of cyanido‐bridged FeII‐ReV square grid sheets bonded by Cs+ ions. The presence of two non‐equivalent FeII sites and the conjunction of 2D bimetallic coordination network with non‐covalent interlayer interactions involving Cs+, [ReV(CN)8]3− ions, and 3‐CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin‐transition phenomenon could be tuned by an external pressure giving the room‐temperature range of SCO, as well as by visible‐light irradiation, inducing an efficient recovery of the high‐spin FeII state at low temperatures. We prove that octacyanidorhenate(V) ion is an outstanding metalloligand for induction of a cooperative multistep, multiswitchable FeII SCO effect.

RETRACTED ARTICLE: CRYSTAL STRUCTURE AND ANTICANCER ACTIVITY ON RETINOBLASTOMA OF AN In(III)–Na(I) COORDINATION POLYMER BASED ON FLEXIBLE 4,4′-DITHIODIBENZOIC ACID

A bimetallic coordination polymer is prepared via a hydrothermal reaction of H2DDBA and In(NO3) water with NaOH as a pH regulator. Its chemical formula is [In2Na(H2O)6(ddba)3](NO3)(H2O)7 (1, H2ddba = 4,4′-dithiodibenzoic acid). The composition and atomic arrangement of the prepared complexes are studied by the elemental analysis (EA) and the thermogravimetric analysis (TGA), powder and single crystal X-ray diffraction measurements. Moreover, a process of sonochemistry with oleic acid treatment at 453 K is used to produce nanostructure the biological function detection, a miRNA relative expression is detected via RT-PCR and Bcl-2 expression level is determined with the Western blot. The Annexin V-FITC/PI staining is performed to detect retinoblastoma cell apoptosis after treatment with nano-1.

RETRACTED ARTICLE: Synthesis, Crystal Structure, and Anti-Gastric Cancer Activity of a Heterometallic Coordination Polymer Based on Flexible 6,6-Dithiodinicotinic Acid

A new bimetallic coordination polymer [In2Na(H2O)2(ddca)3](NO3)·4H2O (1, H2ddca = 6,6′-dithiodinicotinic acid) is produced via a hydrothermal reaction of In(NO3)3, H2ddca with NaOH as the pH modulator. Various characterization methods, such as thermogravimetric analysis (TGA), elemental analysis (EA), single crystal and powder X-ray diffraction measurements, are used. Furthermore, a process of sonochemistry with oleic acid at 453 K is used to produce nanoparticles of 1 (nano-1). In terms of the biological function of the synthesized complex, the real-time reverse transcription-polymerase chain reaction is carried out to explore the relative mRNA expression of miR-181 in MGC-803, BGC-823, and SGC-7901 gastric cancer cell lines, and the western blot is used to explore the protein expression of apoptotic protein Bcl-2.

Lithium-Lanthanide Bimetallic Metal-Organic Frameworks towards Negative Electrode Materials for Lithium-Ion Batteries.

Novel lithium-lanthanide (Ln: cerium and praseodymium) bimetallic coordination polymers with formulas C10 H2 LnLiO8 (Ln: Ce (CeLipma) and Pr (PrLipma)) and C10 H3 CeO8 (Cepma) were prepared through a simple hydrothermal method. The three compounds were characterized by means of FTIR spectroscopy, X-ray diffraction, single-crystal X-ray diffraction, SEM, TEM, and X-ray photoelectron spectroscopy. The results of structural refinement show that they belong to triclinic symmetry and P space group with cerium (or praseodymium) and lithium cations, forming coordination bonds to oxygen atoms from different pyromellitic acid molecules, and leading to the construction of 3D structures. It is interesting to note that the frameworks exclude any coordination water and lattice water. As an electrode material for lithium-ion batteries, CeLipma exhibits a maximum capacity of 800.5 mAh g-1 and a retention of 91.4 % after 50 cycles at a current density of 100 mA g-1 . The favorable electrochemical properties of the lanthanide coordination polymers show potential application prospects in the field of electrode materials.

Bimetallic coordination polymer composites: A new choice of electrode materials for lithium ion batteries

Coordination polymers (CPs) have shown promising potential as electrode materials for lithium ion batteries (LIBs). However, their practical applications are plagued by poor cyclability and unsatisfactory rate performance. Herein, a composite, combining a novel Ce-Co bimetallic coordination polymer with cerium dioxide and graphene nanoplatelets (Ce-Co-CP/CeO2/G), is synthesized and applied as anode materials for LIBs. It is found that the addition of graphene can significantly enhance the conductivity of electrode material. Furthermore, the graphene nanoplatelets can act as a template for the formation of a lamellar morphology of Ce-Co-CP/CeO2/G, which is beneficial to shorten the pathway for Li+-ion migration and thus improves the electrochemical performance. Consequently, the charge capacity of the sample reaches 454.3 mAh/g after 100 cycles at a current of 100 mA/g. Even at a high current density of 1000 mA/g, it can still deliver a capacity of 196.2 mAh/g after 1000 cycles. This work shows a development potential of bimetallic CP materials as a candidate for electrode materials for the next-generation LIBs.

A brand-new bimetallic copper-lithium HEDP complex of fast ion migration as a promising anode for lithium ion batteries

A 3-dimensional (3D) structural copper-lithium bimetallic coordination polymer is synthesized via a facile hydrothermal method. Linked by the hydrogen bonds between adjacent 2-dimensional (2D) layers, the constructed hybrid 3D supramolecular frameworks and its unique ordered skeleton structure can provide stable channels for Li+ insertion and extraction. Modified with graphene nanoplatelets, the designed composite shows superior durability with a specific capacity of 369 mAh/g after 100 cycles at a current density of 50 mA/g. In addition, the rate performance indicates a decent ability of the composite for fast Li+ migration. These results reveal a promising perspective of coordination polymer for applying as an anode material of lithium ion batteries.

Magnetic Properties of Fe(II) Complexes of Cyclam Derivative with One p-Aminobenzyl Pendant Arm

In order to prepare an Fe(II) spin crossover (SCO) complex that could be consequently modified to a bimetallic coordination compound that possesses another magnetic property of interest, a specially designed ligand L-NH2 (1-(4-aminobenzyl)-4,11-bis(pyridine-2-ylmethyl)- 1,4,8,11-tetraazacyclotetradecane) was prepared. This ligand consists of a macrocyclic cyclam part containing two 2-pyridylmethyl pendant arms (expecting SCO upon Fe(II) complexation) and one p-aminobenzyl pendant arm with an NH2 group. The presence of this group enables the consequent transformation to various functional groups for the selective complexation of other transition metals or lanthanides (providing the second property of interest). Furthermore, the performed theoretical calculations (TPSSh/def2-TZVP) predicted SCO behavior for the Fe(II) complex of L-NH2. Thus, Fe(II) complexes [Fe(L-NH2)](ClO4)2 (1) and [Fe(L-NH2)]Cl2·6H2O (2) were synthesized and thoroughly characterized. Based on the crystal structure of an isostructural analogous Ni(II) complex [Ni(L-NH2)]Cl2·6H2O (3), the coordination number six was confirmed with an octahedral coordination sphere and a cis-arrangement of the pyridine pendant arms. The measured magnetic data confirmed the high-spin behavior of both compounds with large magnetic anisotropy (D = 17.8 for 1 and 20.9 cm−1 for 2 complemented in both cases also with large rhombicity), though unfortunately without any indication of the SCO behavior with decreasing temperature. The lack of SCO can be ascribed to the crystal packing and/or the non-covalent intermolecular interactions stabilizing the high-spin state in the solid state.

Janus coordination polymer derived PdO/ZnO nanoribbons for efficient 4-nitrophenol reduction

Bimetallic coordination polymers–Zn(MAA)2/Pd(ii) nanoribbons are prepared by employing two terminal units with distinct hard–soft properties of the smallest semi-rigid methacrylate anion to combine with two different metal ions.

Synthesis, crystal structure, and anti-gastric cancer activity of a heterometallic coordination polymer based on flexible 6,6′-dithiodinicotinic acid

A new bimetallic coordination polymer [In2Na(H2O)2(ddca)3](NO3)×4H2O (1, H2ddca = 6,6'-dithiodinicotinic acid) is produced via a hydrothermal reaction of In(NO3)3, H2ddca with NaOH as the pH modulator. Various characterization methods, such as thermogravimetric analysis (TGA), elemental analysis (EA), single crystal and powder X-ray diffraction measurements, are used. Furthermore, a process of sonochemistry with oleic acid at 453 K is used to produce nanoparticles of 1 (nano-1). In terms of the biological function of the synthesized complex, the real-time reverse transcription-polymerase chain reaction is carried out to explore the relative mRNA expression of miR-181 in MGC-803, BGC-823, and SGC-7901 gastric cancer cell lines, and the western blot is used to explore the protein expression of apoptotic protein Bcl-2.

General approach to construct hierarchical-structured porous Co–Ni bimetallic oxides for efficient oxygen evolution

A novel, general and controllable approach was developed to produce a series of hierarchical-structured porous Co–Ni bimetallic oxides via topochemical transformation of bimetallic coordination polymers for boosted oxygen evolution catalysis.

Crystal structure and anti-cancer activity on retinoblastoma of an In(III)—Na(I) coordination polymer based on flexible 4,4′-dithiodibenzoic acid

A bimetallic coordination polymer is prepared via a hydrothermal reaction of H2DDBA and In(NO3)3 in water with NaOH as a pH regulator. Its chemical formula is [In2Na(H2O)6(ddba)3]·(NO3)(H2O)7 (1, H2ddba = 4,4'-dithiodibenzoic acid). The composition and atomic arrangement of the prepared complexes are studied by the elemental analysis (EA) and the thermogravimetric analysis (TGA), powder and single crystal X-ray diffraction measurements. Moreover, a process of sonochemistry with oleic acid treatment at 453 K is used to produce nano­structure 1. In the biological function detection, a miRNA relative expression is detected via RT-PCR and Bcl-2 expression level is determined with the Western blot. The Annexin V-FITC/PI staining is performed to detect retinoblastoma cell apoptosis after treatment with nano-1.

Ni–Co bimetallic coordination effect for long lifetime rechargeable Zn–air battery

The development of bifunctional oxygen electrocatalysts with high efficiency, high stability, and low cost is of great significance to the industrialization of rechargeable Zn–air batteries. A widely accepted view is that the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) follow different catalytic mechanisms, and accordingly they need different active sites for catalysis. Transition metal elements have admirable electronic acceptance ability for coordinating with reactants, and this can weaken the bond energy between reactants, thus promoting the ORR or OER reactions. Herein, the ORR and OER activities of different transition metal supported nitrogen-doped carbon nanotubes were systematically studied and compared. The optimal catalyst for synchronous ORR and OER was obtained by pyrolyzing melamine, cobalt nitrate, and nickel nitrate on carbon nanotubes, called cobalt–nickel supported nitrogen-mixed carbon nanotubes (CoNi–NCNT), which were equipped with two types of high-performance active sites—the Co/Ni–N–C structure for the ORR and CoNi alloy particles for the OER—simultaneously. Remarkably, the optimized CoNi–NCNT exhibited a satisfactory bifunctional catalytic activity for both the ORR and OER. The value of the oxygen electrode activity parameter, ΔE, of CoNi–NCNT was 0.81 V, which surpasses that of catalysts Pt/C and Ir/C, and most of the non-precious metal-based bifunctional electrocatalysts reported in previous literatures. Furthermore, a specially assembled rechargeable Zn–air cell with CoNi–NCNT loaded carbon paper as an air cathode was used to evaluate the practicability. As a result, a superior specific capacity of 744.3 mAh/gZn, a peak power density of 88 mW/cm2, and an excellent rechargeable cycling stability were observed, and these endow the CoNi–NCNT with promising prospects for practical application.

Unpaired 3d Electrons on Atomically Dispersed Cobalt Centres in Coordination Polymers Regulate both Oxygen Reduction Reaction (ORR) Activity and Selectivity for Use in Zinc-Air Batteries.

Reversible oxygen conversion is important for various green energy technologies. Herein we synthesize a series of bimetallic coordination polymers by varying the Ni/Co ratio and using HITP (HITP=2,3,6,7,10,11-hexaiminotriphenylene) as the ligand, to interrogate the role of metal centres in modulating the activity of the oxygen reduction reaction (ORR). Co3 HITP2 and Ni3 HITP2 are compared. Unpaired 3d electrons in Co3 HITP2 result in less coplanarity but more radical character. Thus, despite of a reduced crystallinity and conductivity, the best ORR activity, comparable to 20 % Pt/C, is obtained for Co3 HITP2 , showing the 3d orbital configuration of the metal centre promotes ORR. Experimental and DFT studies show a transition of ORR pathway from four-electron for Co3 HITP2 to two-electron for Ni3 HITP2 . Rechargeable zinc-air batteries using Co3 HITP2 as the air cathode catalyst demonstrate excellent energy efficiency and stability.

Unpaired 3d Electrons on Atomically Dispersed Cobalt Centres in Coordination Polymers Regulate both Oxygen Reduction Reaction (ORR) Activity and Selectivity for Use in Zinc–Air Batteries

AbstractReversible oxygen conversion is important for various green energy technologies. Herein we synthesize a series of bimetallic coordination polymers by varying the Ni/Co ratio and using HITP (HITP=2,3,6,7,10,11‐hexaiminotriphenylene) as the ligand, to interrogate the role of metal centres in modulating the activity of the oxygen reduction reaction (ORR). Co3HITP2 and Ni3HITP2 are compared. Unpaired 3d electrons in Co3HITP2 result in less coplanarity but more radical character. Thus, despite of a reduced crystallinity and conductivity, the best ORR activity, comparable to 20 % Pt/C, is obtained for Co3HITP2, showing the 3d orbital configuration of the metal centre promotes ORR. Experimental and DFT studies show a transition of ORR pathway from four‐electron for Co3HITP2 to two‐electron for Ni3HITP2. Rechargeable zinc–air batteries using Co3HITP2 as the air cathode catalyst demonstrate excellent energy efficiency and stability.

A new water-insoluble coordination polymer as efficient dye adsorbent and olefin epoxidation catalyst

A new water-insoluble bi-metallic coordination polymer was simply prepared via polymerization-precipitation of molybdenum complex building blocks with Zn2+ cation. The linker was a di-carboxylic acid consisting of two coordination sites i.e. N,O and COO− suitable for coordinating to MoO2 unit and Zn2+, respectively. Characterization of the prepared coordination polymer was carried out with various physicochemical methods which confirmed the proposed structure. The prepared coordination polymer preferentially adsorbed methylene blue (more than 92% of methylene blue after 2 min) relative to methyl orange and can be reused at least four times without any loss of adsorption efficiency. The adsorption process of both dyes followed the pseudo-second order kinetic equation. Additionally, the obtained coordination polymer catalyzed epoxidation of olefins with tert-butylhydroperoxide (TBHP) quantitatively with excellent selectivity (>99%) under mild reaction conditions.