Coordination Polymers Research Articles

Practicality and Compatibility of Cd(II) Coordination Polymer as Luminescent Sensor in Selective and Sensitive Detection of 3‐Nitrotyrosine Biomarker

AbstractBased on the mixed ligands of 1,4‐bis(2,4,6‐tricarboxylpyrid‐5‐yl)benzene (H6BTPB) and 1,4‐bis(imidazol‐1‐yl)benzene (bib), a new cadmium(II) coordination polymer with the molecular formula of {[Cd(bib)(μ2‐H2O)(H2O)2](H4BTPB)0.5(bib)0.5}n (CdCP) was constructed under solvothermal condition, and displayed a 3D supramolecular structure expanded by the hydrogen bonds between the 1D [Cd(bib)(μ2‐H2O)(H2O)2]n ladder chain and the guests. Profiting from its superior stability and inherent luminescence, the prepared CdCP dispalyed great potential as a highly sensitive and selective luminescent sensor in trace detection of 3‐NT biomarker in both water and real bodily fluids through the luminescence quenching effects, with the Ksv and LODs being 2.408×105 M−1 and 30.3 nM in water, 2.230×105 M−1 and 44.7 nM in diluted urine, 2.249×105 M−1 and 43.9 nM in diluted serum, respectively. Subsequent mechanism studies indicated the synergistic effect of internal filtering effect, photo‐induced electron transfer, and fluorescence resonance energy transfer determining the luminescence quenching response of CdCP towards 3‐NT biomarker.

Two three-dimensional coordination polymers as fluorescence probes for the detection of nitrobenzene, tetracycline, fluazinam and their application in green pepper

Two coordination polymers (CPs), [Zn5(L)2(phen)5](1) and [Cd2(HL)(2,2-bpy)(H2O)3](2), were synthesized by using 2′,3,3′,5,5′-Diphenyl ether pentacarboxylic acid (H5L), phenanthroline (phen), and 2,2′-bipyridine (2,2′-bpy) under hydrothermal conditions. The L5- ligand adopts the μ6-к2: к2: к1: к1: к1: к1 mode in 1 and the μ5-к2: к2: к2: к2: к1 mode in 2. Sensing experiments show that 1 and 2 are fluorescence probes with high sensitivity and rapid detection of nitro explosives, antibiotics, and pesticides. In order to verify the ability of 2 to detect FLU in actual samples, we performed a spiked recovery experiment in green pepper water. The spiked recoveries were 97.77–101.18 %. Interestingly, because H5L is not completely deprotonated in 2, there is abundant hydrogen bonding, which makes the fluorescence quenching rate higher and the detection limit lower. The possible fluorescence quenching mechanism of 1 and 2 can be explained by their UV–VIS absorption spectra and orbital energy levels.

Multidimensional Hybrid Metal Phosphonate Coordination Networks as Synergistic Anticorrosion Coatings.

In the technologically important field of anticorrosion coatings, it is imperative to form well-defined and characterized films to protect the metal surface from corrosion. Phosphonate-based corrosion mitigation approaches are currently being exploited. Herein, the synergistic action of alkaline-earth metal ions and two carboxy-diphosphonates, PAIBA [N,N-bis(phosphonomethyl)-2-aminoisobutyric acid] and BPMGLY [N,N-bis(phosphonomethyl)glycine], is explored. Also, a family of four novel hybrid metal phosphonate materials is reported, Mg-PAIBA, Ca-PAIBA, Sr-PAIBA, and Sr-Na-PAIBA, whose topological analysis revealed a variety of underlying networks with the 6,10T9, unc, SP 1-periodic net (4,4)(0,2), and unique topologies. The synergistic metal/carboxy-diphosphonate blends were tested for their anticorrosion performance on carbon steel at preselected concentrations (0.1-1.0 mM) and pH values (4.0-6.0). The results showed an enhanced inhibitory performance in the presence of metal cations at higher concentrations. The inhibition of corrosion at pH 5.0 in the presence of BPMGLY, PAIBA, and their combination with Sr2+ was investigated in detail using electrochemical measurements. Enhanced inhibition was achieved with a 1:1 Sr2+/BPMGLY (or PAIBA) binary system. Polarization curves indicated that the system is a "mixed" inhibitor. This study widens the family of carboxyphosphonate coordination polymers, showing their potential as attractive hybrid coatings with anticorrosion performance.

Dicyanamide Anion Protracted Assemblies of Cd(II)-Salen Type Coordination Polymers: Synthetic Perspective, Characterization, Crystallographic Notability, DFT Overview, and Biological Appraisal

Dicyanamide Anion Protracted Assemblies of Cd(II)-Salen Type Coordination Polymers: Synthetic Perspective, Characterization, Crystallographic Notability, DFT Overview, and Biological Appraisal

Effect of structure on sensing performance of nitro explosives with high sensitivity and mechanism of two Tb(III) coordination polymers

The use of a conjugate N-containing ligand resulted in the decreasing of structural dimensions from 2D network of [Tb(2-pyia)(Ac)(H2O)] (CP1) to 1D chain [Tb(2-pyia)(Ac)(IDP)] (CP2) (2-H2pyia = 5-(pyridin-2-ylmethoxy) isophthalic acid and IDP=imidazo[4,5-f]-[1,10] phenanthroline). Both of them exhibit the characteristic luminescence of Tb ions and could have high fluorescence sensing properties for cefixime and fluridine. The different sensing properties for nitro explosives are manifested as CP1 for nitrobenzene and CP2 for 4-nitrophenol due to the difference in structure. Furthermore, CP2 exhibits the ratiometric fluorescence sensing for Fe3+ ion with a low detection limit of 0.405 μM. The fluorescence sensing mechanism of the two Tb complexes for different analytes was investigated using experimental methods and theoretical calculations. CP1 was used for the detection of Flu residues in the actual system and better results were obtained. The work shows the introduction of the chelated ligand might affect the structural and sensing performance changes of coordination polymers.

Syntheses and antimicrobial activities of two coordination polymers assembled with Ag[sbnd]N and Ag[sbnd]O bonds

Two new coordination polymers ({[Ag(p-phda)2](BF4)} n (1) and {[Ag2(1,5-nds)(DMSO)2] DMSO}n (2) (p-phda: p-phenyldiacetonitrile, 1,5-nds: 1,5-naphthalene disulfonic acid, DMSO: dimethyl sulfoxide) were synthesized and characterized by IR, EA,TG and X-ray single crystal diffraction. 1 was revealed as a 2D “fishing net” assembled by AgN bonds with BF4− as equilibrium charge. IR and PXRD analysis showed the BF4− can be irreversibly exchanged by six anions varied in atomic numbers, sizes, configurations and coordination abilities. 2 is constructed by AgO bonds where DMSO function both as guest and bridging ligand. Further diffusion of NO into the solution of 1 and 2 generated two new compounds (1′ and 2′). All four compounds showed excellent broad-spectrum antimicrobial activities against gram-negative bacteria, gram-positive bacteria and yeast. The stronger antibacterial abilities of 1 against S. aureus and P. aeruginosa than those of 2 were evidenced by the smaller minimum inhibitory concentrations of silver ions (AgMICs) and the higher silver ion release rate in aqueous solution. It was concluded that the looser packing of 1 facilitate the silver ions releasing and play a more crucial role than binding mode and ligand-exchangeability. The enhanced P. aeruginosa inhibitions of 1′ and 2′ were elementarily ascribed to NO incorporation, supporting by their increased diameter of inhibition zones and decreased AgMICs.

On-Surface Formation and Chemical Transformations of Indigo Coordination Polymers

Coordination polymers are attractive candidates for miniaturized electronics. With unconventional electronic and magnetic properties posited, they are interesting for multiple applications including magnetic information storage and spintronics. Natural products are appealing to tailor advanced new materials, bearing inherent advantages in biodegradation. Among them, we distinguished indigo, a common natural dye with a distinctive blue color, used as a pigment since antiquity. Motivated by its optical properties and the reported metal complexes [1], we employed it as a molecular building block for the surface formation of coordination polymers with iron.We report on the on-surface formation of extended coordination polymers which controllably feature the cis and the transmonomers of the molecular building block. The reaction products of indigo and Fe were characterized atomically by a combination of state-of-the -art experimental and theoretical techniques. By a combination of X-ray photoelectron spectroscopy and scanning tunneling microscopy (STM), it is found that indigo deprotonates and coordinates with Fe atoms on silver surfaces. We identify unambiguously well-defined coordination polymers composed of (1 dehydroindigo : 1 Fe) repeat units with STM, bond-resolving atomic force microscopy and density functional theory (DFT) simulations. On both Ag(100) and on Ag(111), the trans configuration of dehydroindigo results in N,O-chelation in the polymer chains. On the more inert Ag(111) surface, the molecules undergo thermally induced isomerization from the trans to the cisconfiguration and afford N,N- plus O,O-chelation (see figure). This is enabled by the dehydrogenation and is preferential solely in the environment of the coordination chain on Ag(111). DFT calculations also confirm that the coordination polymers of the cis-isomers on Ag(111) and of the trans-isomers on Ag(100) are energetically favored.Our results demonstrate post-synthetic linker isomerization in interfacial metal-organic nanosystems. Both types of coordination polymers are predicted to be spin-crossover systems and the isomerization is anticipated to have a significant impact on their magnetic properties.

Pristine Metal-Organic Frameworks for Efficient Oxygen Evolution Electrocatalysis

Green energy technologies propose the use of hydrogen as fuel instead of fossil fuels that have drawbacks of limited supplies and greenhouse gas emission during their combustion. Though hydrogen is the most abundant element on the Earth, hydrogen gas is commonly not found in pure form, but bound in compounds such as water or hydrocarbons. Thus, hydrogen gas is a synthetic fuel that needs to be produced. For the energy to be completely green, hydrogen should be produced using renewable energy. Currently, most of the hydrogen is produced using fossil fuels and only ca. 5% is produced using electrolytic water splitting. It is the high cost of the water-splitting process that limits its use on the wider scale. To reduce the associated high energy input to break a water molecule, resulting in high cost of hydrogen produced by water splitting, expensive electrocatalysts are typically used.The aim of this work is to design novel and low cost metal-organic frameworks (MOF) or coordination polymers (CP) utilizing different ligands (for instance, amide functionalized ligands) towards their application in energy conversion reactions such as oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). MOFs are rarely used in their pristine form; literature reports typically focus on MOF-derived carbon materials. Moreover, herein special attention is given to OER as the efficiency-limiting reaction within the water electrolysis process.The first part of the work focuses on the synthesis and characterization of ligands and MOFs/CPs based on transition metals, nickel and cobalt. The morphology and structure of these composites is examined using electron microscopy and X-ray diffraction analysis. The second part of the work focuses on the pristine materials’ electrocatalytic activity involving standard electrochemical techniques, i.e., voltammetry, impedance spectroscopy, and chronoamperometry to identify the material with the optimum performance and stability. Main reactions parameters including onset potential, overpotential at defined current density as well as current density at defined potential and Tafel slope, are determined.This work presents step towards green hydrogen production within search for solutions for the current energy crisis. Acknowledgments This work was supported by the Science Fund of the Republic of Serbia, grant number 7750219, Advanced Conducting Polymer-Based Materials for Electrochemical Energy Conversion and Storage, Sensors and Environmental Protection-AdConPolyMat (IDEAS programme).

Curcuminoids and Related for on-Surface Synthesis and Electronics

Increasingly, technological progress in miniaturisation for electronic purposes requires synergy between different disciplines, with the connection between chemists, physicists, biologists, theorists, and engineers, for example, being crucial. This is clearly demonstrated in the multidisciplinary approach of OSS, where experimental physics coexists with a solid application of chemical reactivity, supported by theoretical studies, which together have demonstrated the ability to develop 0D-3D molecular-based systems with promising prospects. From a chemical point of view, this fosters the exploration of new families of molecules that may provide different properties, inspire new synthetic routes, and broaden knowledge (and thus new applications).In relation to this, in FunNanoSurf (Functional Nanomaterials and Surfaces, https://funnanosurf.icmab.es/) we focus on the synthesis of curcuminoid species (CCMoids)[1] and derivatives and explore their different uses, apart from their well-known biological applications. CCMoids are linear molecules containing a conjugated backbone, with a central keto-enol moiety and aromatic groups at both ends of the molecular unit, conferring the final system with an overall symmetry. Thanks to their high chemical versatility, straightforward synthesis, and purification, in recent years, we have demonstrated that these systems are excellent molecular platforms and can be used in areas related to molecular electronics (as nanowires),[2] coordination polymers (as excellent heterodiotopic linkers)[3] and now also in OSS exploration.This work aims to make known precisely these points about CCMoid systems and derivatives: their growing potential for use in the same way as other molecular families. Examples of their synthetic plurality, applications, and their possible expansion on surfaces, mainly for electronic purposes, will be presented.[1] Riba-Lopez, D,. Zaffino, R., Herrera, D., Matheu, R., Silvestri, F., Ferreira da Silva, J., Sanudo, E. C., Mas-Torrent, M., Barrena, E., Pfattner, R., Ruiz, E., Gonzalez-Campo, A., Aliaga-Alcalde, N. iScience, 25(12),105686 (2022).[2] (a) Olavarria-Contreras, I. J., Etcheverry-Berrios, A., Qian, W., Gutierrez-Ceron, C., Campos-Olguin, A., Sanudo, E. C., Dulić, D., Ruiz, E., Aliaga-Alcalde, N., Soler, M., van der Zant, H. S. J.Chem. Sci., 9, 34, 6988-6996 (2018). (b) Etcheverry-Berríos, A., Díaz-Torres, R., Jullian, D., Ponce, I., Vásquez, S. O., Olavarria, I., Perrin, M. L., Frisenda, R., van der Zant, H. S. J., Dulić, D., Aliaga-Alcalde, N., Soler, M. Chem. Eur. J., 22, 12808-12818 (2016). (c) Burzurí, E., Island, J., Díaz-Torres, R., Fursina, A., González-Campo, A., Roubeau, O., Teat, S. J., Aliaga-Alcalde, N., Ruiz, E., van der Zant, H. S. J. ACS Nano, 10 (2), 2521-2527 (2016).[3] (a) Rodríguez-Cid, L., Qian, W., Iribarra-Araya, J., Etcheverry-Berríos, Á., Martínez-Olmos, E., Choquesillo-Lazarte, D., Sañudo, E. C., Roubeau, O., López-Periago, A. M., González-Campo, A., Planas, J. G., Soler, M., Domingo, C., Aliaga-Alcalde,N. Dalton Trans. 50, 7056-7054 (2021). (b) L. Rodríguez-Cid, E. C. Sañudo, A. M. López-Periago, A. González-Campo, N. Aliaga-Alcalde, C. Domingo, Crystal Growth and Design, 20, 6555-6564 (2020).

Two new coordination polymers: crystal structures and photodegradation of the organic dye RhB

The solvothermal assemblies of a silicon-centered tetrahedral ligand as a principal building block, an N-donor ancillary ligand, and the corresponding metal salts yield two new transition metal coordination polymers (CPs), [Zn3(OH)(H2O)3L(ttb)]·3H2O (1) and [Co3(OH)(H2O)2L(ttb)(DMF)2]·2H2O (2) [H4L = 4,4',4'',4'''-silanetetrayltetrabenzoic acid, ttp = 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene, DMF = N,N-dimethylformamide]. Photocatalytic test results indicate that 1 and 2 can serve as excellent photocatalysts for Rhodamine B (RhB) degradation.

(Invited) Electrochemical Random Access Memory for Neuromorphic Computing

Electrochemical random access memory (ECRAM) is a three terminal device that functions by tuning electronic conductance in functional materials through solid-state electrochemical redox reactions, and is one of several emerging device concepts that are currently being investigated in academic and industrial laboratories for enabling energy efficient brain inspired computing. Early demonstrations of nearly ideal analog switching and the realization that electrochemical ion insertion can be used to tune the electronic properties of many types of materials including transition metal oxides, layered 2D material, organic and coordination polymers, has sparked tremendous interest in ECRAM. Depending on the specific material, the resulting changes in conduction can range from gradual increments needed for analog elements, to large, abrupt changes for dynamically reconfigurable adaptive architectures. At its core, ECRAM shares many fundamental aspects with rechargeable batteries, where ion insertion materials are used extensively for their ability to reversibly store charge and energy. Computing applications, however, present drastically different requirements: systems will require many millions of devices, scaled down to less than 100 nanometers, all while achieving reliable electronic-state tuning at scaled-up rates (~109 Hz) and endurances (>1012 cycles), and with minimal energy dissipation and noise. In my presentation, I will briefly cover the history of ECRAM, the recent progress in devices spanning various types of materials, circuits, architectures, and discuss the rich portfolio of challenging, fundamental questions and how we can harness ECRAM to realize a new paradigm for low power neuromorphic computing.

(Invited) Selective Ammonia Separation Using Prussian Blue Analogues

Prussian blue analogues (PBAs) are a three-dimensional coordination polymer with iron and transition metals bridged with cyanide ligands, creating open-framework structures for hosting guest ions into interstitial sites. These sites can be occupied by cations via adsorption/desorption or intercalation/deintercalation, which has been widely utilized in developing separation processes and energy storage devices. Additionally, it has been well established that the size of the channel provides selectivity between monovalent cations based on their hydrated radii. Using these unique functionalities allows for selective ammonia recovery from wastewater. The feasibility of selective separation has been demonstrated using PBA-based electrodes that showed reversible and selective intercalation/deintercalation of NH4 + by cyclic operation. To enable continuous separation, we recently developed an electrochemically driven membrane process, where PBAs provided selective ion-conducting channels. An improved selectivity for NH4 + relative to Na+ was achieved using synthetic and domestic wastewaters, which was attributed to a thin layer of PBA created on the surface of a cation exchange membrane. These results collectively show that the use of PBAs for selective ammonia separation could lead to the development of efficient electrochemical processes for nutrient recovery.

Structural Diversity Enables Dramatic Changes in Photocatalytic Efficiency of Porphyrinosilica Particles in Chem-Bio Binary Applications

Because of their potential applications in catalysis, separation, and gas storage, porous materials such as metal–organic frameworks (MOFs), porous coordination polymers (PCPs), porous organic polymers (POPs), and polymers with intrinsic microporosity (PIMs) have received much attention. Various building blocks have been introduced with various functional groups. Among the various organic building blocks, porphyrin has become one of the most important building blocks for the construction of such materials witnessed by a wide range of molecular architectures using porphyrin derivatives with various applications. In addition, they are often used to modify the surface of porous silica materials such as SBA-15, MCM-41 and MCM-48, because these porous silica materials exhibit narrow pore size distributions, high thermal stability and easy accessibility.In this presentation, a series of highly ordered mesoporous porphyrinosilicas akin to MCM-41 will be discussed, as novel recyclable heterogeneous photocatalysts, demonstrating their efficacy in the selective oxidation. Porphyrins are recognized as efficient photocatalysts for oxidation reactions, attributed to their capacity to generate reactive oxygen species (ROS). Integrating them into a mesoporous silica framework can mitigate self-degradation, thereby yielding an efficient catalytic system with an extended operational lifetime.

Carboxylate-Based Metal-Organic Framework and Coordination Polymer Glasses: Progress and Perspectives.

ConspectusCoordination polymers (CPs) and metal-organic frameworks (MOFs) represent versatile materials with diverse structural and functional properties, making them appealing for various applications. However, their conventional forms, which are typically synthesized as powders or crystals, pose challenges due to limited processability and mechanical fragility. Recently, CP/MOF glasses have emerged as promising alternatives, offering enhanced processability while retaining some of the unique characteristics shown in the mother crystalline materials. Despite the prevalence of carboxylate ligands in CP/MOF synthesis, the development of carboxylate-based CP/MOF glasses has been limited compared to that of zeolitic-imidazole framework (ZIF)-based glasses. This is attributed to the strong metal-ligand bonds and low thermal stability of carboxylic acids, which hinder their melting in CP/MOF structures. Nonetheless, recent advancements have led to a surge in methods for synthesizing carboxylate-based CP/MOF glasses. So far, desolvation and melt-quenching have been introduced for achieving glass structures from CP/MOF precursors.The first melt-quenched MOF glass was reported in 2015 with ZIFs. However, we informally observed the melting of the MOF during thermal decomposition research of aliphatic carboxylate-based MOFs as a sacrificial template dating back to 2013. In that study, aliphatic ligands, instead of aromatic carboxylate, were employed due to their high lability, lower thermal stability, and high degree of freedom, which facilitated pyrolysis. The results were published with a focus on synthesizing hierarchically porous MgO via the pyrolysis of an aliphatic ligand-based Mg-MOF in an inert environment. A decade later, it was revisited and studied as the first melt-quenched carboxylate-based MOF glass, converted from a crystalline MOF through the liquid phase before decomposition during the heating process.This Account aims to introduce six studies, including the aforementioned example, on the synthesis of CP/MOF glasses from carboxylate-based CPs/MOFs that have been published so far. To overcome the challenges with aromatic carboxylates in CP/MOF glass formation, the metal coordination sphere should be altered and the degree of freedom in the ligands should be increased. Based on these approaches, the strategies for vitrification of carboxylate-based CPs/MOFs can be divided into two categories: desolvation and melt-quenching. Desolvation can be preceded by vapor perturbation such as hydration. Carboxylate-based CP/MOF glasses possess the potential to expand into a broader range of applications beyond those of existing CP/MOF glasses. Alongside the diversity offered by carboxylic acid ligands, these materials mirror the extensive range of applications previously explored in the existing carboxylate-based CP/MOF crystals. Moreover, their high processability, inherent to glass materials, enables their applications in various industrial fields. This versatility may extend to previously unexplored areas of utilization such as a novel class of bioactive glass.

Highly efficient Cu(II) coordination polymer catalyst for the conversion of hazardous volatile organic compounds

Three novel coordination polymers (CPs), namely [Cu(μ-1κO,2κN-L)2]n (1), [Zn (μ-1κO,2κN-L)2(H2O)2]n (2) and [Cd (μ-1κOO’,2κN-L)2]n (3) [where HL = 4-(pyrimidin-5-ylcarbamoyl)benzoic acid], were synthesized and characterized by elemental analysis, ATR-IR, TGA, XPS and single-crystal X-ray diffraction. Despite having the same organic ligand, the various metal cations had an impact in the subsequent frameworks. Hirshfeld surface analysis was performed to investigate the intermolecular interactions and to examine the stability of the crystal structures of the three polymers. Their catalytic performances were screened for the peroxidative oxidation of Volatile Organic Compounds (VOCs), with toluene and p-xylene selected as model substrates. Tert-butyl hydroperoxide (t-BuOOH or TBHP) (aq. 70 %) was employed as the oxidant. The catalytic oxidation of toluene yielded benzyl alcohol, benzaldehyde and benzoic acid. The copper CP 1 exhibited the highest total yield for toluene oxidation, reaching approximately 36% in an aqueous medium. For p-xylene oxidation, tolualdehyde, methylbenzyl alcohol, and toluic acid were produced as the primary products, accompanied by minor ones. The experiments were conducted under diverse conditions, manipulating key parameters such as the choice of solvent (water or acetonitrile), type of oxidant (t-BuOOH or H2O2), the concentration of the oxidant and reaction temperature. In the presence of catalyst 1, a maximum total yield of ca. 80% was achieved for p-xylene oxidation.

Novel Co-CP/γ-MnO2 composite as a powerful catalyst for C–C Suzuki coupling reaction

Developing low-cost catalytic systems for C–C coupling reactions is desirable but challenging. Herein, a coordination polymer (Co-CP) was fabricated on the surface of γ-MnO2 through a layer-by-layer growth technique to obtain a cost-effective heterogeneous catalyst. Various physicochemical analyses endorsed the presence of both components, γ-MnO2 and Co-CP in the prepared composite. This compound demonstrated a remarkable catalytic performance (in some cases more than 99 %) in the Suzuki coupling reaction of a wide range of arylboronic acids and aryl bromides in water:DMF medium. In particular, the prepared catalyst was efficient and maintained its activity after five consecutive utilizations. From the viewpoint of economics, the present catalytic system gathers noticeable advantages, like the use of earth-abundant and cheap metals (Co and Mn).

Extending Cyanogel and Prussian Blue Analogue Chemistry to Octacyanometallate-Based Coordination Polymers: Reduced Temperature Routes to Materials Based on Molybdenum and Tungsten

Extending Cyanogel and Prussian Blue Analogue Chemistry to Octacyanometallate-Based Coordination Polymers: Reduced Temperature Routes to Materials Based on Molybdenum and Tungsten

Two new 3D cobalt(II) coordination polymers constructed by semi-rigid carboxylic acid ligand: Syntheses, structures and properties

Two novel coordination polymers, {[Co2(L)(H2O)5]·H2O}n (1), and {[Co5(L)2(H2O)6(μ3-OH)2]·2C3H7NO·2H2O}n (2) (H4L = 3, 3′, 5, 5′-diphenyl ether tetracarboxylic acid, C16H10O9) have been synthesized by assembling semi-rigid aromatic polycarboxylic acids with transition-metal cobalt salts, and structurally characterized by elemental analysis, thermogravimetric analysis, IR spectrum, powder X-ray diffraction, and single crystal X-ray diffraction analysis. Structural analysis showed both the L ligands in CP 1 and CP 2 were regarded as 4 connection points, while the binuclear clusters in CP 1 and the pentanuclear clusters in CP 2 were regarded as 4 connection points and 8 connection points, respectively. Finally, both CP 1 and CP 2 were 3D network structures connected by two nodes (4, 4-connected for CP 1 and 4, 8-connected for CP 2). In addition, temperature-dependent susceptibilities have been measured in the range of 2 to 300 K, indicating that both CP 1 and CP 2 have antiferromagnetic coupling between adjacent Co(II) ions. Finally, Electrochemical experiments show that the CP 1 and CP 2 have good electrochemical behaviors.

Encapsulating Nickel-Iron Alloy Nanoparticles in a Polysilazane-Derived Microporous Si-C-O-N-Based Support to Stimulate Superior OER Activity.

The in situ confinement of nickel (Ni)-iron (Fe) nanoparticles (NPs) in a polymer-derived microporous silicon carboxynitride (Si-C-O-N)-based support is investigated to stimulate superior oxygen evolution reaction (OER) activity in an alkaline media. Firstly, we consider a commercial polysilazane (PSZ) and Ni and Fe chlorides to be mixed in N,N-dimethylformamide (DMF) and deliverafter overnight solvent reflux a series of Ni-Fe : organosilicon coordination polymers. The latter are then heat-treated at 500 °C in flowing argon to form the title compounds. By considering a Ni : Fe ratio of 1.5, face centred cubic (fcc) NixFey alloy NPs with a size of 15-30 nm are in situ generated in a porous Si-C-O-N-based matrixdisplaying a specific surface area (SSA) as high as 237 m2 ⋅ g-1. Hence, encapsulated NPs are rendered accessible to promote electrocatalytic water oxidation. An OER overpotential as low as 315 mV at 10 mA ⋅ cm-2 is measured. This high catalytic performance (considering that the metal mass loading is as low as 0.24 mg cm-2) is rather stable as observed after an activation step; thus, validating our synthesis approach. This is clearly attributed to both the strong NP-matrix interaction and the confinement effect of the matrix as highlighted through post mortem microscopy observations.

Progress and Challenges of Monometallic Titanium Coordination Polymers.

The realm of titanium coordination polymer research is still in its nascent stages and presents a formidable challenge in the field of coordination chemistry. In recent decades, the focus has predominantly been on manipulating titanium reactions in solution, resulting in the synthesis of ≈60 targeted compounds. Despite the limited number of documented instances, these materials showcase a diverse array of structures, encompassing 1D chains, 2D layers, and 3D frameworks. This suggests potential for fine-tuning coordination modes and structural features in future investigations. Moreover, titanium coordination polymers not only exhibit photo-active and photo-responsive properties but also hold promise for various other significant applications. This article offers an exhaustive review tracing the evolution of titanium coordination polymer development while providing an update on recent advancements. The review encompasses a synopsis of reported synthetic strategies, methodologies, structural diversity, and associated applications. Additionally, it delves into critical issues that necessitate attention for future progressions and proposes potential avenues to effectively propel this research field forward at an accelerated pace.