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.

Temperature-Dependent Supramolecular Isomeric Co-CPs for Luminescence Recognition and Catalytic Oxidation.

Two Co-based supramolecular isomers were synthesized from a fluorinated carboxylic acid ligand under hydrothermal conditions at varying temperatures. Both exhibited similar one-dimensional chain structures while different bending connections of the aromatic rings led to different supramolecular structures, namely CoCP-1 and CoCP-2, respectively. The structural differences of two isomers resulted in discrepant performance with regards to luminescence sensing and catalysis. CoCP-1 demonstrated more significant luminescence quenching activity toward biomarkers 2,6-dipyridinoic acid (DPA) and high vanilloid acid (HVA), which could be distinguished in the presence of Eu3+. The limit of detection (LOD) was found to be as low as 3.4 and 1.3 µM, respectively. The recovery rate of for HVA and DPA was within the range of 89.6-101.2% and 99.7-117.9% in simulated urine and serum, respectively, indicating potential reliability in monitoring these two analytes in real samples. Notably, CoCP-2 exhibited catalytic activity for the oxidation of thioethers to sulfoxides. Our finding here suggests that the coordination conformation of the ligands within supramolecular isomers plays a pivotal role in determining the structure and luminescence sensing/catalysis performance.

Engineering Trifluoromethyl Groups in Porous Coordination Polymers to Enhance Stability and Regulate Pore Window for Hexane Isomers Separation.

Effective separation of hexane (C6) isomers is critical for a variety of industrial applications but conventional distillation methods are energy-intensive. Adsorptive separations based on porous coordination polymers (PCPs) offer a promising alternative due to their exceptional porosity and tunable properties. However, there is still an urgent need to develop PCPs with high stability and separation performance. This study investigates how substituting a methyl (-CH3) group with a trifluoromethyl (-CF3) group can regulate pores and hydrophobicity in PCPs. This precise adjustment aims to enhance stability and improve the kinetic separation performance of hydrophobic C6 isomers by considering the size and hydrophobicity of the trifluoromethyl group. Two isostructural PCPs with pcu topology, PCP-CH3 and PCP-CF3, were synthesized to vary pore diameters and hydrophobicity based on the presence of -CH3 or -CF3 groups. PCP-CF3 showed greater stability in water compared to PCP-CH3. While PCP-CH3 had high adsorption capacities, it lacked selectivity, whereas PCP-CF3 demonstrated improved selectivity, particularly in excluding dibranched isomers. Dynamic column separation experiments revealed that PCP-CF3 could selectively adsorb linear and monobranched isomers over dibranched isomers at room temperature. These findings highlight the potential of fluorine-modified PCPs for efficient isomer separation and underscore the importance of stability improvement strategies.

Rational Assembly of Three-component Coordination Polymers as Heterogeneous Catalysts for CO2 Cycloaddition and Cyanosilylation Reactions.

Four new coordination polymers based on 5-(((1H-imidazol-2-yl)methyl)amino) isophthalic acid (H3L) and auxiliary ligands (1,10-phenanthroline, 2,2'-bipyridine, and 4,4'-bipyridine), namely, {[Zn(HL)(phen)(H2O)]·2H2O}n (CP 1), {[Ni(HL)(phen)(H2O)]}n (CP 2), {[Ni(HL)(2,2'-bpy)(H2O)]·2H2O}n (CP 3) and {[Cd(HL)(4,4'-bpy)0.5(H2O)]·2H2O}n (CP 4) were rationally assembled. Furthermore, these four CPs were screened as heterogeneous catalysts for CO2 cycloaddition and cyanosilylation reactions under mild conditions. The catalytic experiments showed that CP 1 had the better catalytic performance, excellent substrate tolerance and recyclability for the above two reactions. It is speculated that the excellent activity of CP 1 may be due to the open Lewis base site and the Lewis acidic characteristics of the zinc (II) center. After five cycles, the catalytic activities of CP 1 did not significantly decrease, and the structures remained unchanged. Therefore, the CP 1 was considered efficient and stable heterogeneous catalysts for above the two reactions.

Synthesis and Characterization of Highly Fluorinated Hydrophobic Rare-Earth Metal-Organic Frameworks (MOFs).

Tuning a material's hydrophobicity is desirable in several industrial applications, such as hydrocarbon storage, separation, selective CO2 capture, oil spill cleanup, and water purification. The introduction of fluorine into rare-earth (RE) metal-organic frameworks (MOFs) can make them hydrophobic. In this work, the linker bis(trifluoromethyl)terephthalic acid (TTA) was used to make highly fluorinated MOFs. The reaction of the TTA and RE3+ (RE: Y, Gd, or Eu) ions resulted in the primitive cubic structure (pcu) exhibiting RE dimer nodes (RE-TTA-pcu). The crystal structure of the RE-TTA-pcu was obtained. The use of the 2-fluorobenzoic acid in the synthesis resulted in fluorinated hexaclusters in the face-centered cubic (fcu) framework (RE-TTA-fcu), analogous to the UiO-66 MOF. The RE-TTA-fcu has fluorine on the linker as well as in the cluster. The MOFs were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, and contact angle measurements.

Tuning structural modulation and magnetic properties in metal-organic coordination polymers [CH3NH3]CoxNi1-x(HCOO)3.

Three solid solutions of [CH3NH3]CoxNi1-x(HCOO)3, with x = 0.25 (1), x = 0.50 (2) and x = 0.75 (3), were synthesized and their nuclear structures and magnetic properties were characterized using single-crystal neutron diffraction and magnetization measurements. At room temperature, all three compounds crystallize in the Pnma orthorhombic space group, akin to the cobalt and nickel end series members. On cooling, each compound undergoes a distinct series of structural transitions to modulated structures. Compound 1 exhibits a phase transition to a modulated structure analogous to the pure Ni compound [Cañadillas-Delgado, L., Mazzuca, L., Fabelo, O., Rodríguez-Carvajal, J. & Petricek, V. (2020). Inorg. Chem. 59, 17896-17905], whereas compound 3 maintains the behaviour observed in the pure Co compound reported previously [Canadillas-Delgado, L., Mazzuca, L., Fabelo, O., Rodriguez-Velamazan, J. A. & Rodriguez-Carvajal, J. (2019). IUCrJ, 6, 105-115], although in both cases the temperatures at which the phase transitions occur differ slightly from the pure phases. Monochromatic neutron diffraction measurements showed that the structural evolution of 2 diverges from that of either parent compound, with competing hydrogen bond interactions that drive the modulation throughout the series, producing a unique sequence of phases. It involves two modulated phases below 96 (3) and 59 (3) K, with different q vectors, similar to the pure Co compound (with modulated phases below 128 and 96 K); however, it maintains the modulated phase below magnetic order [at 22.5 (7) K], resembling the pure Ni compound (which presents magnetic order below 34 K), resulting in an improper modulated magnetic structure. Despite these large-scale structural changes, magnetometry data reveal that the bulk magnetic properties of these solid solutions form a linear continuum between the end members. Notably, doping of the metal site in these solid solutions allows for tuning of bulk magnetic properties, including magnetic ordering temperature, transition temperatures and the nature of nuclear phase transitions, through adjustment of metal ratios.

Emerging Roles of Gossypol in Therapy: Innovations in Prodrug Design and Nanoformulation Frontiers.

Stimuli activatable systems have the potential to deliver drugs to targeted areas by releasing therapeutic agents in response to diseased specific microenvironments such as the acidic environment commonly found in diseased tissues. This review article focuses on gossypol, a bioactive compound with inherent toxicity attributed to various factors, including the presence of its formyl groups. It highlights the potential of imine-linked gossypol-based prodrugs and nanoparticle formulations for targeted delivery and controlled release. The unique presence of polyphenolic cores on gossypol can be utilized to prepare nanoparticles. This review offers valuable insights into designing safer and more effective drug delivery systems by elucidating the masking effect and stimuli-responsive release mechanisms. Numerous examples demonstrate the conversion of formyl groups to imines, creating prodrugs that mask reactive functionalities and offer pH-responsive release. This insight can guide the design of combination therapeutics, where a second drug with an amine terminal group can form imine-linked prodrugs. Additionally, the second part discusses the use of polyphenolic moieties to create stable nanoparticles from infinite polymeric networks. Through a comprehensive examination of gossypol's properties and applications, this review emphasizes the broader implications of such a masking strategy for optimizing the therapeutic benefits of many similar bioactive compounds while minimizing adverse effects.

Poly[[µ3-2-(benzotriazol-1-yl)acetato-κ3 O:O':N 3]chlorido-(ethanol-κO)cobalt(II)].

In the title compound, [Co(C8H6N3O2)Cl(C2H5OH)] n , the CoII atoms adopt octa-hedral trans-CoN2O4 and tetra-hedral CoCl2O2 coordination geometries (site symmetries and m, respectively). The bridging µ3-O:O:N 2-(benzotriazol-1-yl)acetato ligands connect the octa-hedral cobalt nodes into (010) sheets and the CoCl2 fragments link the sheets into a tri-periodic network. The structure displays O-H⋯O hydrogen bonding and the ethanol mol-ecule is disordered over two orientations.

Coordination-Driven Nanomedicine Mitigates One-Lung Ventilation-Induced Lung Injury via Radicals Scavenging and Cell Pyroptosis Inhibition.

One-lung ventilation (OLV) during thoracic surgery often leads to post-operative complications, yet effective pharmacological interventions are lacking. This study reports a baicalin-based metal-coordination nanomedicine with disulfiram (DSF) co-loading to address one-lung ventilation-induced lung injury and reperfusion injury (OLV-LIRI). Baicalin, known for its robust antioxidant properties, suffers from poor water solubility and stability. Leveraging nanotechnology, baicalin's coordination is systematically explored with seven common metal ions, designing iron/copper-mediated binary coordination nanoparticles to overcome these limitations. The self-assembled nanoparticles, primarily formed through metal coordination and π-π stacking forces, encapsulated DSF, ensuring high colloidal stability in diverse physiological matrices. Upon a single-dose administration via endotracheal intubation, the nanoparticles efficiently accumulate in lung tissues and swiftly penetrate the pulmonary mucosa. Intracellularly, baicalin exhibits free radical scavenging activity to suppress inflammation. Concurrently, the release of Cu2+ and DSF enables the in situ generation of CuET, a potent inhibitor of cell pyroptosis. Harnessing these multifaceted mechanisms, the nanoparticles alleviate lung injury symptoms without notable toxic side effects, suggesting a promising preventive strategy for OLV-LIRI.

Dual-Function Nanoscale Coordination Polymer Nanoparticles for Targeted Diagnosis and Therapeutic Delivery in Atherosclerosis.

Atherosclerosis is the primary cause of cardiovascular events such as heart attacks and strokes. However, current medical practice lacks non-invasive, reliable approaches for both imaging atherosclerotic plaques and delivering therapeutic agents directly therein. Here, a biocompatible and biodegradable pH-responsive nanoscale coordination polymers (NCPs) based theranostic system is reported for managing atherosclerosis. NCPs are synthesized with a pH-responsive benzoic-imine (BI) linker and Gd3+. Simvastatin (ST), a statin not used for lowering blood cholesterol but known for its anti-inflammatory and antioxidant effects in mice, is chosen as the model drug. By incorporating ST into the hydrophobic domain of a lipid bilayer shell on NCPs surfaces, ST/NCP-PEG nanoparticles are created that are designed for dual purposes: they diagnose and treat atherosclerosis. When administered intravenously, they target atherosclerotic plaques, breaking down in the mild acidic microenvironment of the plaque to release ST, which reduces inflammation and oxidative stress, and Gd-complexes for MR imaging of the plaques. ST/NCP-PEG nanoparticles show efficacy in slowing the progression of atherosclerosis in live models and allow for simultaneous in vivo monitoring without observed toxicity in major organs. This positions ST/NCP-PEG nanoparticles as a promising strategy for the spontaneous diagnosis and treatment of atherosclerosis.

Superprotonic Conductivity by Synergistic Blending of Coordination Polymers with Organic Polymers: Fabrication of Durable and Flexible Proton Exchange Membranes.

Creation of an efficient and cost-effective proton exchange membrane (PEM) has emerged as a propitious solution to address the challenges of renewable energy development. Coordination polymers (CPs) have garnered significant interest due to their multifunctional applications and moldability, along with long-range order. To leverage the potential of CPs in fuel cells, it is essential to integrate microcrystalline CPs into organic polymers to prepare membranes and avoid grain boundary issues. In this study, we designed and synthesized CPs containing imidazole and sulfonate moieties via gel-to-crystal transformation. The integration of CPs into the PVDF-PVP matrix resulted in superprotonic conductivity in the order of 10-2 S cm-1 at room temperature (30 ºC) and 98% RH. The proton conductivity achieved with CP-integrated composite membrane was 4.69 × 10-2 S cm-1 at 80 °C and 98% RH, the highest among all CP/MOF-integrated PVDF-PVP membranes under hydrous conditions. The excellent compatibility of CPs with PVDF-PVP produced highly flexible membranes with superior mechanical, chemical, and thermal stability. About 25 times higher proton conductivity value was achieved with membrane, compared to intrinsic CPs, at RT and 98% RH. Thus, we present a cost-effective CP-integrated mixed-matrix membrane with superprotonic conductivity and long-term durability for cutting-edge fuel cell development.

Coordination Site Selective Occupation Strategy for Tuning the Photosalient Effects of Photoactive Cd Complexes.

The application of photo responsive crystals to useful actuation demands a rational design to elicit controllable movement. The [2+2] photocycloaddition reaction triggers mechanical motion using associated photosalient (PS) effects. We herein report a coordination site selective occupation strategy to modulate the arrangement of C=C bonds and thereby tune the PS effect. Replacing or repositioning the donor atom at one end of the linear ligand allowed for a greater level of molecular structural flexibility, facilitating [2+2] photocycloaddition. The distance between photoreactive centres and coordination sites was adjusted by ligand design to regulate PS behaviour. This work suggests new avenues for modulating PS movement to achieve useful motion.

Structural Reconstruction of a Cobalt- and Ferrocene-Based Metal-Organic Framework during the Electrochemical Oxygen Evolution Reaction.

Metal-organic frameworks (MOFs) are increasingly being investigated as electrocatalysts for the oxygen evolution reaction (OER) due to their unique modular structures that present a hybrid between molecular and heterogeneous catalysts, featuring well-defined active sites. However, many fundamental questions remain open regarding the electrochemical stability of MOFs, structural reconstruction of coordination sites, and the role of in situ-formed species. Here, we report the structural transformation of a surface-grown MOF containing cobalt nodes and 1,1'-ferrocenedicarboxylic acid linkers (denoted as CoFc-MOF) during the OER in alkaline electrolyte. Ex situ and in situ investigations of CoFc-MOF film suggest that the MOF acts as a precatalyst and undergoes a two-step restructuring process under operating conditions to generate a metal oxyhydroxide phase. The MOF-derived metal oxyhydroxide catalyst, supported on nickel foam electrodes, displays high activity toward the OER with an overpotential of 190 mV at a current density of 10 mA cm-2. While this study demonstrates the necessity of investigating structural evolution of MOFs during electrocatalysis, it also shows the potential of using MOFs as precursors in catalyst design.

A Series of Lanthanide Coordination Polymers as Luminescent Sensors for Selective Detection of Inorganic Ions and Nitrobenzene.

Seven new lanthanide coordination polymers, namely [Ln(cpt)3H2O)]n(Ln = La (1), Pr (2), Sm (3), Eu (4), Gd (5), Dy (6), and Er (7)), which were synthesized under hydrothermal conditions using 4'-(4-(4-carboxyphenyloxy)phenyl)-4,2':6',4'-tripyridine (Hcpt) as the ligand. The crystal structures of these seven complexes were determined using single-crystal X-ray diffraction, and they were found to be isostructural, crystallizing in the triclinic P1- space group. The Ln(III) ions were nine-coordinated with tricapped trigonal prism coordination geometry. The Ln(III) cations were coordinated by carboxylic and pyridine groups from (cpt)- ligands, forming one-dimensional ring-chain structures. Furthermore, the luminescent properties of complexes 1-7 were investigated using fluorescent spectra in the solid state. The fluorescence sensing experiments demonstrated that complex 4 exhibits high selectivity and sensitivity for detecting Co2+, Cu2+ ions, and nitrobenzene. Moreover, complex 3 shows good capability for detecting Cu2+ ions and nitrobenzene. Additionally, the sensing mechanism was also thoroughly examined through theoretical calculations.

A multifunctional sensor for detecting tetracycline, 4-nitrophenol, and pesticides.

In recent years, due to the abuse of antibiotics, nitro explosives and pesticides, which have caused great harm to the environment and human health, social concerns have prompted researchers to develop more sensitive detection platforms for these pollutants. In this paper, a novel two-dimensional Zn (II) coordination polymer, [Zn(L)0.5(1,2-bimb)]·DMF (1), [H4L=[1,1':4',1''-terphenyl]-2, 2'',4, 4'' -tetracarboxylic acid, 1,2-bimb = 1,2-bis(imidazol-1-ylmethyl)benzene] was synthesized using a hydro-solvothermal method. Among commonly used organic solvents, 1 exhibits significant stability. Fast and efficient fluorescence response can be achieved for tetracycline (TET), 4-nitrophenol (4-NP), fluazinam (FLU), and abamectin benzoate (AMB) with low detection limits. A binary intelligent logic gate device with FLU and AMB as chemical input signals is successfully constructed, which provides a new idea for biochemical detection. In addition, a portable visual test paper has been prepared, which has high sensitivity, good selectivity, and simple operation. It can be used for rapid detection of pollutants in daily life and has broad application prospects. Finally, a detailed discussion was conducted on the fluorescence sensing mechanism of 1 for detecting TET, 4-NP, AMB and FLU.

Single Crystal to Single Crystal Transformation of Porous Materials Based on Zinc Nodes and Mercaptobenzoic Acid.

Porous coordination polymers (PCPs) are an excellent class of porous crystalline materials with tunable properties and intriguing potential applications spanning multiple disciplines. In this work, we report the synthesis and characterization of a PCP (HI-103) based on 4,4'-dithiodibenzoic acid ligand and zinc nitrate with two DMF molecules residing in the porous network. The stability of the porous network was analyzed by heating the compound at 60.0 °C for two days, and the structural analysis revealed a new PCP (HI-104) was formed with one of the DMF molecules, indicating a single-crystal to single-crystal (SCSC) transformation. The solvent molecules were completely removed by extensive drying (HI-103-dry), and the integrity of the porous network was verified by powder X-ray diffraction (PXRD) and thermogravimetric analysis. The reversibility of SCSC transformation was confirmed by treating HI-103-dry with DMF molecules, resulting in HI-103 after five days. The adsorption studies of HI-103-dry with other solvents revealed that SCSC transformation was not observed for DMA and DEA, but some structural changes were observed in the presence of DMSO. The adsorption studies performed in the presence of an equimolar mixture of DMF, DMA, and DMA indicated that HI-103-dry could selectively adsorb DMF molecules from the analogous mixture.

Synthesis, crystal structure and properties of poly[di-µ3-chlorido-di-µ2-chlorido-bis-[4-methyl-N-(pyridin-2-yl-methyl-idene)aniline]dicadmium(II)].

The title coordination polymer with the 4-methyl-N-(pyridin-2-yl-methyl-idene)aniline Schiff base ligand (L, C13H12N2), [Cd2Cl4(C13H12N2)] n (1), exhibits a columnar structure extending parallel to [100]. The columns are aligned in parallel and are decorated with chelating L ligands on both sides. They are elongated into a supra-molecular sheet extending parallel to (01) through π-π stacking inter-actions involving L ligands of neighbouring columns. Adjacent sheets are packed into the tri-periodic supra-molecular network through weak C-H⋯Cl hydrogen-bonding inter-actions that involve the phenyl CH groups and chlorido ligands. The thermal stability and photoluminescent properties of (1) have also been examined.

Cu(II)-based complex loaded with drug paclitaxel hydrogels against thyroid cancer and optimizing novel derivatives.

This study introduces a novel approach for synthesizing a Cu(II)-based coordination polymer (CP), {[Cu(L)(4,4´-OBA)]·H2O}n (1), using a mixed ligand method. The CP was successfully prepared by reacting Cu(NO3)2·3H2O with the ligand 3,6-bis(benzimidazol-1-yl)pyridazine in the presence of 4,4´-H2OBA, demonstrating an innovative synthesis strategy. Furthermore, a novel hydrogel composed of hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) with a porous structure was developed for drug delivery purposes. This hydrogel facilitates the encapsulation of CP1, and enables the loading of paclitaxel onto the composite to form HA/CMCS-CP1@paclitaxel. In vitro cell experiments demonstrated the promising modulation of thyroid cancer biomarker genes S100A6 and ARID1A by HA/CMCS-CP1@paclitaxel. Finally, reinforcement learning simulations were employed to optimize novel metal-organic frameworks, underscoring the innovative contributions of this study.

Spiderweb-Shaped Iron-Coordinated Polymeric Network as the Novel Coating on Microneedles for Transdermal Drug Delivery Against Infectious Wounds.

Coated microneedles (CMNs) are a minimally invasive platform for immediate-release transdermal drug delivery. However, the practical applications of CMNs have been significantly hindered by the challenges associated with complex formulations, single function, and limited drug loading capacity. This study has developed a spiderweb-shaped iron-coordinated polymeric nanowire network (Fe-IDA NWs). The resulting Fe-IDA NWs are endowed with a certain viscosity due to the synergy of multiple supramolecular interactions. This allows them to replace traditional polymeric thickeners as microneedle coatings. The Fe-IDA NWs-coated microneedles (Fe-IDA MNs) display rapid disintegration in the skin model, which also enables the swift diffusion of Fe-IDA NWs and their payloads into the deeper skin layers. Additionally, Fe-IDA MNs exhibit desirable enzymatic activity and potential antibacterial ability. Thus, Fe-IDA MNs can enhance the therapeutic efficacy against wound infection through synergistic effects, and avoid the overly complicated formulation and the release of nontherapeutic molecules of conventional CMNs. As a proof-of-concept, Fe-IDA MNs loaded with chlorin e6 showed a synergistic chemodynamic-photodynamic antibacterial effect in a methicillin-resistant Staphylococcus aureus-infected wound model in mice. Collectively, this work has significant implications for the future of CMNs-based transdermal drug delivery systems and expands the application fields of metal coordination polymer (MCP) materials.

The Use of Photocycloaddition Reactions to Drive Mechanical Motions Resembling Humanoid Movements.

With the aim of producing a photomechanical material for incorporation in soft microrobots, a one-dimensional diene coordination polymer (CP) [Cd(F-bpeb)(3-CBA)2]n (CP1, F-bpeb=4,4'-((1E,1'E)-(2,5-difluoro-1,4-phenylene)bis(ethene-2,1-diyl))dipyridine, 3-HCBA=3-chlorobenzoic acid) was synthesized and characterized. Irradiation of CP1 with ultraviolet (UV) or visible light causes [2+2] photocycloaddition reactions resulting in the introduction of crystal strain which triggers various types of crystal movements. Composite films of CP1-PVA (SC) fabricated by dispersing CP1 crystals into polyvinyl alcohol (PVA) solution allow amplification of the crystal movement so that the film strips exhibit fast and flexible curling upon photoirradiation. The composite films may be cut into long rectangular strips and folded to simulate soft microrobots which exhibit a variety of fast, flexible and continuous photomechanical movements resembling a human performing various gymnastic exercises.