Metal-organic Coordination Polymers Research Articles

A new 1D Mn(II) coordination polymer: Synthesis, crystal structure, hirshfeld surface analysis and molecular docking studies

The synthesis of novel metal-organic coordination polymers (MOCP) with the chemical formula [Mn2L (SCN)2(OH)2]3·CH3OH [L = 1,5-bis(pyridine-4-ylmethylene) carbonohydrazide] {1} was accomplished using two different techniques: solvothermal and sonochemical ultrasonic-assisted. An investigation was carried out to examine the impact of various factors such as reaction time, sonication power, temperature, and reactant concentration on the morphology and size of the crystals. Interestingly, it was found that sonication power and temperature did not affect the crystals’ morphology and size. To further analyze the prepared microcrystals of MOCPs, SEM was utilized to examine their surface morphology, and XRD, elemental evaluation composition. The identification of the functional groups present in the prepared Mn-MOCPs was accomplished through the utilization of FT-IR spectroscopy. Subsequently, the calcination of 1 in an air atmosphere at 650 °C led to the formation of Mn3O4 nanoparticles. The geometric and electronic structure of the MOCPs was evaluated using density functional theory (DFT). The utilization of molecular docking methodologies demonstrated that the best cavity of the human androgen receptor possessed an interaction energy of −116.3 kJ mol−1. This energy encompassed a combination of both bonding and non-bonding interactions. The Results showed that steric interaction and electrostatic potential are the main interactions in AR polymer and Mn(II). These interactions in the defined cavity indicated that this polymer could be an effective anti-prostate candidate, because AR is involved in the growth of prostate cancer cells, and these interactions indicated the inhibition of prostate cancer cell growth.

Rapid Construction of Double Crystalline Prussian Blue Analogue Hetero-Superstructure.

The controllable construction of complex metal-organic coordination polymers (CPs) merits untold scientific and technological potential, yet remains a grand challenge of one-step construction and modulating simultaneously valence states of metals and topological morphology. Here, a thiocyanuric acid (TCA)-triggered strategy is presented to one-step rapid synthesis a double-crystalline Prussian blue analogue hetero-superstructure (PBA-hs) that comprises a Co3[Fe(CN)6]2 cube overcoated with a KCo[Fe(CN)6] shell, followed by eight self-assembled small cubes on vertices. Unlike common directing surfactants, TCA not only acts as a trigger for the fast growth of KCo[Fe(CN)6] on the Co3[Fe(CN)6]2 phase resulting in a PBA-on-PBA hetero-superstructure, but also serves as a flange-like bridge between them. By combining experiments with simulations, a deprotonation-induced electron transfer (DIET) mechanism is proposed for formation of second phase in PBA-hs, differing from thermally and photo-induced electron transfer processes. To prove utility, the calcined PBA-hs exhibits enhanced oxygen evolution reaction performance. This work provides a new method to design of novel CPs for enriching chemistry and material science. This work offers a practical approach to design novel CPs for enriching chemistry and material science.

Innovative modification of cellulose fibers for paper-based electrode materials using metal-organic coordination polymers

Cellulosic paper-based electrode materials have attracted increasing attention in the field of flexible supercapacitor. As a conductive polymer, polyaniline exhibits high theoretical pseudocapacitive capacitance and has been applied in paper-based electrode materials along with cellulose fibers. However, the stacking of polyaniline usually leads to poor performance of electrodes. In this study, metal-organic coordination polymers of zirconium-alizarin red S and zirconium-phytic acid are applied to modulate the polyaniline layer to obtain high-performance cellulosic paper-based electrode materials. Zirconium hydroxide is firstly loaded on cellulose fibers while alizarin red S and phytic acid are introduced to regulate the morphology of polyaniline through doping and coordination processes. The results show that the introduction of dual coordination polymers is effective to regulate the morphology of polyaniline on cellulose fibers. The performances of the paper-based electrode materials, including electrical conductivity and electrochemistry, are apparently improved. It provides a promising strategy for the potential development of economical and green electrode materials in the conventional paper-making process.

Multi-dimensional assembly of ZnO nanodots in the reticular carbon nanofibers for high-performance lithium-ion batteries

Due to the high theoretical specific capacity, abundant resources, easy availability, and environmental amicability, zinc oxide (ZnO) has been regarded as a promising alternative for lithium-ion battery anode. However, the further application of ZnO anode is still faced with great challenges such as huge volume transformation and intrinsic low conductivity. Herein, we propose a simple strategy for the preparation of ZnO/carbon clusters (∼50 nm) which are assembled with uniformly distributed ZnO nanodots (∼5 nm) in the three-dimensional carbon nanofibers (ZnO/CNFs) through an electrospinning and subsequent carbonization process using gallic acid-zinc coordination polymer (GAZ) as precursor. The multi-dimensional assembly of ZnO nanodots and reticular formation of conductive carbon network can effectively alleviate the volume change of ZnO anode during long-term cycling process and promote the fast transfer of electrolyte ions/electrons, greatly improving the rate and cycle performance. As a result, the ZnO/CNFs electrode exhibits excellent rate performance of 375.3 mAh g−1 at 2 A g−1 and long cycling stability with capacity retention of 92% over 600 cycles at 1 A g−1. These features indicate that the systematic combination of electrospinning and metal-organic coordination polymers have significant promise for the construction of high-performance metal derivative anodes.

Clinical and Preclinical Methods of Heat-Stabilization of Human Vaccines.

Vaccines have historically faced challenges regarding stability, especially in regions lacking a robust cold chain infrastructure. This review delves into established and emergent techniques to improve the thermostability of vaccines. We discuss the widely practiced lyophilization method, effectively transforming liquid vaccine formulations into a solid powdered state, enhancing storage and transportation ability. However, potential protein denaturation during lyophilization necessitates alternative stabilization methods. Cryoprotectants, namely, starch and sugar molecules, have shown promise in protecting vaccine antigens and adjuvants from denaturation and augmenting the stability of biologics during freeze-drying. Biomineralization, a less studied yet innovative approach, utilizes inorganic or organic-inorganic hybrids to encapsulate biological components of vaccines with a particular emphasis on metal-organic coordination polymers. Encapsulation in organic matrices to form particles or microneedles have also been studied in the context of vaccine thermostability, showing some ability to store outside the cold-chain. Unfortunately, few of these techniques have advanced to clinical trials that evaluate differences in storage conditions. Nonetheless, early trials suggest that alternative storage techniques are viable and emphasize the need for more comprehensive studies. This review underscores the pressing need for heat-stable vaccines, especially in light of the increasing global distribution challenges. Combining traditional methods with novel approaches holds promise for the future adaptability of vaccine distribution and use.

Multifaceted properties of an engineered three-dimensional Zn(ii)–metal–organic coordination polymer: synthesis, crystal structure, efficient photocatalytic degradation of an organic dye and selective luminescent sensing

Luminescent sensing of volatile organic solvents (VOCs), anions, cations, etc., and photocatalysts for aromatic dyes are two of the many emerging applications for metal-organic frameworks and coordination polymers (MOFs/CPs).

Mixed-valence system with near-infrared electrochromism of Fe(II)-based metal-organic coordination polymers

Near-infrared electrochromic materials have garnered great attention due to their potential applications in optical data storage and military camouflage. Herein, a networked metal-organic coordination polymer bearing multi-redox centra (Fe-MCP) was successfully prepared by coordination interaction of Fe ions with D-A-D-structure ligands through the liquid-liquid interface self-assembly strategy. The resultant uniform film exhibits improved NIR electrochromic attributed to the construction of mixed-valence system. Furthermore, a sandwich-structured electrochromic device was fabricated by combining Fe-MCP electrochromic layer, a gel composed of LiClO4, PMMA, and PC as the electrolyte layer, and anodically coloring PB as an ion storage layer. The resultant device illustrated an optical contrast of 31.4 % at 800 nm and 34.2 % at 1000 nm, a response speed of 4.0 s/8.3 s at 800 nm and 7.6 s/2.7 s at 1000 nm, and good cycling durability. The design principles proposed in this study provide a new insight for the preparation of high-performance NIR electrochromic materials.

Metal-Organic Coordination Polymers of Cadmium Based on Anilate Ligands

Metal-Organic Coordination Polymers of Cadmium Based on Anilate Ligands

Metal-/carboxylate-directed four d10 piperazine-amide-based coordination polymers for the fluorescent detection of nitrophenol and nitroaniline in various water environments

Four piperazine-amide-bridged d10 metal-organic coordination polymers, namely, [Zn(L)0.5(1,3-BDC)∙H2O]∙H2O (1), [Cd(L)(1,3-BDC)] (2), [Zn(L)0.5(5-MIP) ∙H2O]·H2O (3), [Cd(L)(5-MIP)] (4) were synthesized by the L ligand [N, N'-bis[(3-pyridin)acrylophenone] piperazine (L)] and two carboxylic acids with Zn/Cd(II) chloride under hydrothermal conditions. The title complexes were characterized by IR spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. Complex 1 is a 1D ladder-like structure. Complex 2 is a 3D NaCl type framework. Complexes 3 and 4 are 63 and 44 connected 2D structures. The different structural details of the title complexes directed by caroxylates and the central metals were compared. The complexes 1–4 can be used as excellent fluorescent sensors toward nitrophenol (NOP) and nitroaniline (NA) with a low limit of detection and a high quenching constant, and have good anti-interference and recyclable characteristics. The feasibility of actual sample detection was verified by tap water, river water and wastewater samples. Taking complex 3 as an example, the mechanism was also explored by fluorescence lifetime experiment and the UV-visible absorption spectroscopy. The 3-modified visual detection cloth and test paper were also prepared by solid phase deposition method.

Multicolor Phosphorescence Modulated by Excitation and Temperature in Zn-Based Coordination Polymers.

Color-tunable room-temperature phosphorescence (RTP) with potential in many fields is of great importance but extremely challenging. It is necessary to comprehend the correlation between the molecular structure and property to design and synthesize such materials. Metal-organic coordination polymers (CPs) with good predesignability and precise structure have become a platform to construct RTP materials. Herein, three zinc-based CPs containing halogen and a flexible tetradentate ligand are synthesized. All of these CPs present two constant emission regions and an excitation-dependent emission region. Structure-property analysis shows that these emissions originate from isolated chromophores and dimerized chromophores as well as various charge transfers. The phosphorescence colors of these CPs can be modulated by excitation and temperature. This study provides a novel strategy to construct multicolor and multiresponsive RTP materials based on metal-organic coordination polymers.

Nitrogen-Doped Carbon Dots Encapsulated a Polyoxomolybdate-Based Coordination Polymer as a Sensitive Platform for Trace Tetracycline Determination in Water.

The requirement of simple, efficient and accurate detection of tetracycline (TC) in water environments poses new challenges for sensing platform development. Here, we report a simple method for TC sensing via fluorescence detection based on metal-organic coordination polymers (MOCPs, (4-Hap)4(Mo8O26)) coated with nitrogen-doped carbon dots (NCDs). These NCDs@(4-Hap)4(Mo8O26) composites showed excellent luminescence features of NCDs with stable bright-blue emission under UV light. The results of the sensing experiment showed that the fluorescence of NCDs@(4-Hap)4(Mo8O26) can be quenched by TC (166 µM) with 94.1% quenching efficiency via the inner filter effect (IFE) in a short time (10 s), with a detection limit (LOD) of 33.9 nM in a linear range of 8-107 µM. More significantly, NCDs@(4-Hap)4(Mo8O26) showed a high selectivity for TC sensing in the presence of anions and metal cations commonly found in water environments and can be reused in at least six cycles after washing with alcohol. The potential practicality of NCDs@(4-Hap)4(Mo8O26) was verified by sensing TC in real water samples with the standard addition method, and satisfactory recoveries from 91.95% to 104.72% were obtained.

Zinc Carnosine Metal-Organic Coordination Polymer as a Potent Broadly Active Influenza Vaccine Platform with In Vitro Shelf-Stability.

Current seasonal influenza vaccines are limited in that they need to be reformulated every year in order to account for the constant mutation of the virus. Hemagglutinin (HA) immunogens have been developed using a computationally optimized broadly reactive antigen (COBRA) methodology, which are able to elicit an antibody response that neutralizes antigenically distinct influenza strains; however, subunit proteins are not immunogenic enough on their own to generate a substantial immune response. Due to this, different delivery strategies and adjuvants can be used to improve immunogenicity. Recently, we reported a new coordination polymer composed of the dipeptide carnosine and zinc (ZnCar) that is able to deliver protein antigens along with CpG to generate a potent immune response. In the present work, ZnCar was used to deliver the COBRA HA immunogen Y2 and the adjuvant CpG. We incorporated Y2 into ZnCar using two different methods to assess which would be the most immunogenic. Mice vaccinated with Y2 and CpG complexed with ZnCar showed an improved humoral and cellular response when compared to mice vaccinated with soluble Y2 and CpG. Further, we demonstrate in vitro that when Y2 and CpG are coordinated with ZnCar, they are protected from degradation at 40 °C for 3 months or 24 °C for 6 months. Overall, ZnCar shows promise as a delivery vehicle for subunit vaccines, given its superior immunogenicity and in vitro storage stability.

Precisely Amplifying Intracellular Oxidative Storm by Metal-Organic Coordination Polymers to Augment Anticancer Immunity.

Oxidative stress accompanying the reactive oxygen species (ROS) burst governs immunocyte infiltration, activation, and differentiation in tumor microenvironments and thus can elicit robust antitumor immunity. Here, we identify a photoactive metal-organic coordination polymer (MOCP), composed of an organometallic core formed by cytotoxic mitoxantrone (MTX) acylates and photosensitive Ru(BIQ)-HDBB [BIQ = 2,2'-biquinoline, HDBB = 4,4'-di(4-benzoato)-2,2'-bipyridine] linked by Fe(II) ions via coordinate covalent bonds and an amphipathic shell encapsulating cholesterol-modified siRNA against GPX4 (siGPX4) via hydrophobic force, to precisely amplify intracellular oxidative storm. MOCPs simultaneously encapsulated MTX, Ru, and siGPX4 with efficiencies >98% and loaded Fe with efficiencies of ∼0.49%. With longer blood circulation and higher tumor accumulation, MOCPs with a 670 nm LED irradiation generate abundant ROS to induce biomembrane dysfunction and subsequently contribute to ferroptotic and immunogenic cell death, which drive tumor-associated antigen-specific immunity. MTX analogs contributed to Type I immunogenic cell death (ICD), while oxidative storm served as a damager for endo/lysosomal escape, an initiator for ferroptosis, and an inducer for type II ICD. Moreover, the blockade of CD73 that reduces extoATP catabolism unleashes immunosuppression, finally enhancing antitumor immune stimulation of MOCPs to promote orthotopic mammary cancer regression and prevent postoperative advanced cancer from recurrence and metastasis. MOCPs by exposing sufficient antigenicity thus provide a platform to synergize immune checkpoint inhibitors for the treatment of immunologically cold tumors.

Self-Catalysis Transformation of Metal-Organic Coordination Polymers.

Designing a multidimensional transformation of metal-organic coordination polymers (MOPs) is highly attractive yet very challenging. Herein, by combining the dynamicity of the coordination bond with the controllability of the chemical reaction, the concept of self-catalysis transformation of MOPs is first proposed. It uses the metal in MOPs as the catalyst to catalyze the chemical reaction of the ligand in the frameworks, simultaneously changing the coordination environment of the metal and the structure of the ligand, resulting in the controllable multidimensional transformation in the morphology and structure of MOPs. The self-catalysis transformation of MOPs can be triggered by heat or light, and crystals with various morphologies and structures can be obtained. Significantly, because the self-catalysis reaction is constraint in the framework, the products at different transformation processes are relatively stable. Monitoring and characterizing the transformation of MOPs give evidences for the exploration of the self-catalysis reaction, and a plausible transformation mechanism is proposed and proved. It can be foreseen that this novel self-catalysis transformation strategy might open up a new direction for the diverse development of MOPs and provide a powerful tool for the study of organic reaction mechanism.

Isobutene isomerization via metal-organic coordination polymer catalyst

One-dimensional, two-dimensional and three-dimensional Ni-containing metal-organic coordination polymer (1D-Ni, 2D-Ni and 3D-Ni MOCP) catalysts were solvothermally synthesized and used for isomerization of isobutene. These catalysts showed the same conversion of isobutene and selectivity for 2-butene as homogeneous catalysts. At the same time, 1D-Ni catalyst evacuated at 100 °C revealed the conversion of isobutene and selectivity to 2-butene were up to 89.2% and 100.0%, respectively. Moreover, the results demonstrated that the conversion of isobutene was different depending on metal coordination mode, dimension of coordination polymer, and the reaction pressure. In addition, The MOCP catalysts were relatively environmentally friendly, and easily recovered and recycled. Finally, the mechanism of metal hydride addition elimination was proposed.

Fluorescent Probes Based on Metal and Aggregation-induced Luminescent Organic Molecule Complexes for Bioimaging and Sensing Applications

Metal-Organic Coordination polymer (MOCPs) is an emerging class of inorganic-organic porous hybrid materials with infinite coordination polymers (CPs) or metal-organic backbones (MOFs) formed by the interaction between metal ions and organic ligands and ligand functional groups. The molecular structure of the organic ligands composing MOCPs is rich in variation, while inorganic metal ions generally have good photoelectromagnetic properties. Therefore, MOCPs have diverse structural variations, adjustable pore size, high stability and controllable synthesis, and have received wide attention in gas storage, multiphase catalysis, chemical sensing and biological applications. Fluorescence properties are one of the most widely used techniques for bioimaging and sensing detection. However, conventional luminescent groups are usually affected by aggregation-induced quenching (ACQ) effects. Aggregation-induced luminescence molecules (AIEs) based on metal-organic coordination polymers combine the advantages of organic AIEs and transition metal centers to improve photophysical properties and therapeutic effects.

In-Situ Fabrication of Electroactive Cu2+-Trithiocyanate Complex and Its Application for Label-Free Electrochemical Aptasensing of Thrombin.

The preparation of an electroactive matrix for the immobilization of the bioprobe shows great promise to construct the label-free biosensors. Herein, the electroactive metal-organic coordination polymer has been in-situ prepared by pre-assembly of a layer of trithiocynate (TCY) on a gold electrode (AuE) through Au-S bond, followed by repetitive soaking in Cu(NO3)2 solution and TCY solutions. Then the gold nanoparticles (AuNPs) and the thiolated thrombin aptamers were successively assembled on the electrode surface, and thus the electrochemical electroactive aptasensing layer for thrombin was achieved. The preparation process of the biosensor was characterized by an atomic force microscope (AFM), attenuated total reflection-Fourier transform infrared (ATR-FTIR), and electrochemical methods. Electrochemical sensing assays showed that the formation of the aptamer-thrombin complex changed the microenvironment and the electro-conductivity of the electrode interface, causing the electrochemical signal suppression of the TCY-Cu2+ polymer. Additionally, the target thrombin can be label-free analyzed. Under optimal conditions, the aptasensor can detect thrombin in the concentration range from 1.0 fM to 1.0 μM, with a detection limit of 0.26 fM. The spiked recovery assay showed that the recovery of the thrombin in human serum samples was 97.2-103%, showing that the biosensor is feasible for biomolecule analysis in a complex sample.

Low-Temperature Synthesis of Metal–Organic Coordination Polymers Based on Oxo-centered Iron Complexes: Magnetic and Adsorption Properties

Low-Temperature Synthesis of Metal–Organic Coordination Polymers Based on Oxo-centered Iron Complexes: Magnetic and Adsorption Properties

Low-Temperature Synthesis of Metal–Organic Coordination Polymers Based on Oxo-centered Iron Complexes: Magnetic and Adsorption Properties

Low-Temperature Synthesis of Metal–Organic Coordination Polymers Based on Oxo-centered Iron Complexes: Magnetic and Adsorption Properties

Bismuth Coordination Polymers with Fluorinated Linkers: Aqueous Stability, Bivolatility, and Adsorptive Behavior.

Bismuth metal-organic frameworks and coordination polymers (CP) are challenging to synthesize, given the poor solubility of bismuth precursors and asymmetric and labile ligation of Bi3+ due to its intrinsic lone pair. Here, we synthesize and structurally characterize three Bi3+-CPs, exploiting a tetrafluoroterephtalate (F4BDC) linker to determine the effect of high acidity on these synthesis and coordination challenges. Single-crystal X-ray diffraction characterization showed that pi-pi stacking of linkers directs framework arrangement and generally deters open porosity in the three structures, respectively featuring Bi chains (Bi chain -F 4 BDC), Bi dimers (Bi 2 -F 4 BDC) linked into chains, and Bi tetramers (Bi 4 -F 4 BDC). Powder X-ray diffraction and microscopic imaging show the high purity and stability of these compounds in water. Naphthalenedisulfonate (NDS) was used as a mineralizer in the synthesis of (Bi chain -F 4 BDC) and (Bi 4 -F 4 BDC), and studies of its role in assembly pathways yielded two additional structures featuring mixed NDS and F4BDC, respectively, linking monomer and octamer Bi nodes, and confirmed that F4BDC is the preferred (less labile) linker. Methylene blue (MB) adsorption studies show differing efficacies of the three Bi-F4BDC phases, attributed to surface characteristics of the preferential growth facets, while generally most effective adsorption is attributed to the hydrophobicity of fluorinated ligands. Finally, thermogravimetric analysis of all three Bi-F4BDC phases indicates simultaneous ligand degradation and in situ formation of volatile Bi compounds, which could be exploited in the chemical vapor deposition of Bi-containing thin films.