Organic Framework Structures Research Articles

Impact of Postsynthetic Modification on the Covalent Organic Framework (COF) Structures.

Covalent organic frameworks (COFs) have emerged as a versatile class of materials owing to their well-defined crystalline structures and inherent porosity. In the realm of COFs, their appeal lies in their customizable nature, which can be further enhanced by incorporating diverse functionalities. Postsynthetic modifications (PSMs) emerge as a potent strategy, facilitating the introduction of desired functionalities postsynthesis. A significant challenge in PSM pertains to preserving the crystallinity and porosity of the COFs. In this study, we aim to investigate the intricate interplay between PSM strategies and the resulting crystalline and porous structures of the COFs. The investigation delves into the diverse methodologies employed in PSMs, to elucidate their distinct influences on the crystallinity and porosity of the COFs. Through a comprehensive analysis of recent advancements and case studies, the study highlights the intricate relationships among PSM parameters, including reaction conditions, precursor selection, and functional groups, and their impact on the structural features of COFs. By understanding how PSM strategies can fine-tune the crystalline and porous characteristics of COFs, researchers can harness this knowledge to design COFs with tailored properties for specific applications, contributing to the advancement of functional materials in diverse fields. This work not only deepens our understanding of COFs but also provides valuable insights into the broader realm of PSM strategies for other solid materials.

Co-Carbonization of Straw and ZIF-67 to the Co/Biomass Carbon for Electrocatalytic Nitrate Reduction

Electrocatalytic nitrate reduction enables the recovery of nitrate from water under mild conditions and generates ammonia for nitrogen fertilizer feedstock in an economical and green means. In this paper, Co/biomass carbon (Co/BC) composite catalysts were prepared by co-carbonization of straw and metal–organic framework material ZIF-67 for electrocatalytic nitrate reduction using hydrothermal and annealing methods. The metal–organic framework structure disperses the catalyst components well and provides a wider specific surface area, which is conducive to the adsorption of nitrate and the provision of more reactive active sites. The introduction of biomass carbon additionally enhances the electrical conductivity of the catalyst and facilitates electron transport. After electrochemical testing, Co/BC-100 exhibited the best performance in electrocatalytic nitrate reduction to ammonia, with an ammonia yield of 3588.92 mmol gcat.−1 h−1 and faradaic efficiency of 97.01% at −0.5 V vs. RHE potential. This study provides a promising approach for the construction of other efficient cobalt-based electrocatalysts.

Simultaneous achieving color‐tuning long persistent luminescence and phosphorescent quantum yield of 81.05% in 2D organic metal halide perovskite

AbstractIonically bonded organic metal halide perovskite‐like luminescent materials, which incorporate organic cations and metal halides, have emerged as a versatile multicomponent material system. However, these materials still face challenges in terms of low phosphorescence quantum yields and limited long persistent luminescence (LPL) colors. Herein, we present the design and synthesis of an intraligand charge‐transfer organic‐based metal halide perovskite‐like material, in which organic cations form a compact supramolecular hydrogen‐bonded organic framework (HOF) structure, exhibiting crystallization‐induced phosphorescence emission of ligand, while metal halides form a unique two‐dimensional (2D) structure that displays intrinsic self‐trapped excitons (STE) emission under the radiation of UV light. Notably, the metal halide hybrid is found to exhibit enhanced phosphorescent photoluminescence efficiency of up to 81.05% and tunable LPL from cyan to orange compared to the pristine organic phosphor, due to the structural distortion and scaffolding effects of 2D metal halides as well as a well‐packed HOF structure. Optical characterizations and theoretical calculations reveal that charge transfer from organic cations and halogen to ligand as well as STE from inorganic layers are responsible for the tunable LPL. Meanwhile, the high‐efficiency phosphorescent quantum yield is attributed to stronger hydrogen bond stacking as well as structural distortion of metal halogen bands. Thus, the obtained LPL provides potentials in anti‐counterfeiting, security systems, and so on.

High‐Voltage Single‐Ion Covalent Organic Framework Electrolytes Enabled by Nitrile Migration Ladders for Lithium Metal Batteries

AbstractThe poor electrochemical stability window and low ionic conductivity in solid‐state electrolytes hinder the development of safe, high‐voltage, and energy‐dense lithium metal batteries. Herein, taking advantage of the unique electronic effect of nitrile groups, we designed a novel azanide‐based single‐ion covalent organic framework (CN−iCOF) structure that possesses effective Li+ transport and high‐voltage stability in lithium metal batteries. Density functional theory (DFT) calculations and molecular dynamics (MD) revealed that electron‐withdrawing nitrile groups not only resulted in an ultralow HOMO energy orbital but also enhanced Li+ dissociation through charge delocalization, leading to a high tLi+ of 0.93 and remarkable oxidative stability up to 5.6 V (vs. Li+/Li) simultaneously. Moreover, cyanation leveraging Strecker reaction transformed reversible imine‐linkage to a stable sp3‐carbon‐containing azanide anion, which facilitated contorted alignment of transport “ladders” along the one‐dimensional anionic channels and the ionic conductivity could reach 1.33×10−5 S cm−1 at ambient temperature without any additives. As a result, CN−iCOF allowed operation of solid‐state lithium metal batteries with high‐voltage cathodes such as LiNi0.8Mn0.1Co0.1O2 (NCM811), demonstrating stable lithium deposition up to 1,100 h and reversible battery cycling at ambient temperature up to 4.5 V, shedding light on the importance of discovering new functionality for forthcoming high‐performance batteries.

A universal machine learning framework to automatically identify high‐performance covalent organic framework membranes for CH4/H2 separation

AbstractA universal machine learning framework is proposed to predict and classify membrane performance efficiently and accurately, achieved by combining classical density functional theory and string method. Through application of this framework, we conducted high‐throughput computations under industrial conditions, utilizing an extensive database containing nearly 70,000 covalent organic framework (COF) structures for CH4/H2 separation. The best‐performing COF identified surpasses the materials reported in the previously documented MOF and COF databases, exhibiting an impressive adsorption selectivity for CH4/H2 exceeding 82 and a membrane selectivity reaching as high as 248. More impressively, some of the best candidates identified from this framework have been verified through previous experimental works. Furthermore, the automated machine learning framework and its corresponding scoring system not only enable rapid identification of promising membrane materials from a vast material space but also contribute to a comprehensive understanding of the governing mechanisms that determine separation performance.

High-Voltage Single-Ion Covalent Organic Framework Electrolytes Enabled by Nitrile Migration Ladders for Lithium Metal Batteries.

The poor electrochemical stability window and low ionic conductivity in solid-state electrolytes hinder the development of safe, high-voltage, and energy-dense lithium metal batteries. Herein, taking advantage of the unique electronic effect of nitrile groups, we designed a novel azanide-based single-ion covalent organic framework (CN-iCOF) structure that possesses effective Li+ transport and high-voltage stability in lithium metal batteries. Density functional theory (DFT) calculations and molecular dynamics (MD) revealed that electron-withdrawing nitrile groups not only resulted in an ultralow HOMO energy orbital but also enhanced Li+ dissociation through charge delocalization, leading to a high tLi+ of 0.93 and remarkable oxidative stability up to 5.6 V (vs. Li+/Li) simultaneously. Moreover, cyanation leveraging Strecker reaction transformed reversible imine-linkage to a stable sp3-carbon-containing azanide anion, which facilitated contorted alignment of transport "ladders" along the one-dimensional anionic channels and the ionic conductivity could reach 1.33×10-5 S cm-1 at ambient temperature without any additives. As a result, CN-iCOF allowed operation of solid-state lithium metal batteries with high-voltage cathodes such as LiNi0.8Mn0.1Co0.1O2 (NCM811), demonstrating stable lithium deposition up to 1,100 h and reversible battery cycling at ambient temperature up to 4.5 V, shedding light on the importance of discovering new functionality for forthcoming high-performance batteries.

Salphen-Based Fe-N2O2@C Nanomaterial Applied in Synergistic Sonodynamic and Chemodynamic Therapy of Tumors

To synthesize a Salphen-based Fe-N2O2@C material with high peroxidase (POD)-mimicking activity and sonosensitivity for the synergistic sonodynamic (SDT) and chemodynamic (CDT) therapy of tumors. Fe-N2O2 was synthesized via the hydrothermal method, and Fe-N2O2@C was prepared by incorporating a ketjen black substrate. The morphology, structure, composition, enzyme mimic activity for reactive oxygen species (ROS) production, and sonosensitivity of the material were characterized. The ability and mechanism of Fe-N2O2@C to perform synergistic SDT and CDT killing of 4T1 mouse breast cancer cells were explored through in vitro experiments. The in vivo tumor-killing ability of Fe-N2O2@C combined with ultrasound irradiation was investigated using a subcutaneous 4T1 tumor-bearing mouse model. FFe-N2O2 and Fe-N2O2@C were both irregularly shaped nanospheres with average particle sizes of 25.9 nm and 36.2 nm, respectively. XRD, FTIR, and XPS analyses confirmed that both Fe-N2O2 and Fe-N2O2@C possessed a Salphen covalent organic framework structure with M-N2O2 coordination, and the ketjen black loading had no significant impact on this structure. Compared to Fe-N2O2, Fe-N2O2@C exhibited high POD-mimicking activity (with K m reduced from 19.32 to 5.82 mmol/L and v max increased from 2.51×10-8 to 8.92×10-8 mol/[L·s]) and sonosensitivity. Fe-N2O2@C in combination with ultrasound irradiation could produce a large amount of ROS within cells and a subsequent significant decrease in mitochondrial membrane potential, thereby inducing TEM-observable mitochondrial damage and causing cell apoptosis and death. In addition, in vivo experiments showed that Fe-N2O2@C in combination with ultrasound irradiation could effectively inhibit tumor growth in a 4T1 subcutaneous tumor-bearing mouse model without significant in vivo toxicity. In this study, we prepared a Salphen-based Fe-N2O2@C material with good biocompatibility, which can be used in combination with ultrasound irradiation to achieve SDT and CDT synergistic killing of tumor cells and inhibit tumor growth. This Salphen-based Fe-N2O2@C nanomaterial shows promising potential for multimodal tumor therapy.

Structure and oxygen evolution reaction performance of Ni-supported catalysts based on steam-exploded poplar

Using renewable steam-exploded poplar (SEP) as carbon source, nickel metal doped carbon hybrid materials were designed to synthesize catalysts (Ni/SEP) with certain oxygen evolution reaction (OER) properties and were compared with nickel catalysts supported on metal organic framework structure (ZIF67-Ni). The roles of SEP support in Ni-based catalyst were considered. Scanning electron microscope (SEM) images confirmed that the fiber could better hinder the aggregation of metal particles. Fourier transform infrared spectroscopy (FT-IR) indicated the presence of surface OH groups after the reduction process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the major form of metallic Ni in the resulting Ni catalysts. Carbon materials as carriers, the synergetic effect of Ni-doped, and carbon carrier played an important role in facilitating the kinetics of OER, which was similar to the carrier of metal-organic frame material. Notably, the Ni/SEP (11.3 mF/cm-2) and ZIF67-Ni (37.2 mF/cm-2) with better OER performance exhibited a smaller double layer capacitances (Cdl), suggesting the intrinsic OER catalytic activity of the Ni/SEP and ZIF67-Ni were much higher in comparison to the ZIF67-Ni/SEP. Moreover, the inferior performance of Ni/SEP further indicated that the synergistic effect between carbon and Ni/NiO contributes to the enhanced OER activity.

Enhancing catalytic activity through self-assembled hydrogen-bonded organic framework-based catalysts at liquid/liquid interface for 4-nitrophenol reduction and energy challenges in methanol fuel cell

Hydrogen-bonded organic frameworks (HOFs) are pure organic framework structures endowed with appropriate flexibility and porosity, which have attracted special attention in the field of energy and water, air, and soil remediation. In this study, six HOF-based materials were synthesized as thin film at the liquid/liquid (toluene/water) interface and characterized by FT-IR, Raman, UV–Vis, PXRD, ICP, AFM, SEM, TGA, and BET techniques. The self-assembled HOF-based thin films were employed as catalysts for the 4-nitrophenol removal from water medium and, for the first time, for methanol oxidation of fuel cell, with satisfying results. Simultaneous in situ catalyst formation and 4-nitrophenol reduction occurred in the case of Pt(0)@HOF thin film, but an extraordinary removal (not reduction) occurred in the presence of Pt(0)-trimesic acid thin film by formation of a new HOF from trimesic acid and 4-nitrophenol. Successful reduction of 4-nitrophenol occurred also in the presence of freshly prepared Pt(0)-trimesic acid, Pt(0)-melamine and Pt(0)@HOF catalysts (ex situ strategy). The chemical and thermal stability of HOF structure was improved by the interpenetration of ZIF-8 crystal structure, by increasing the hydrogen bonding and π-π stacking in the presence of 2-methylimidazole. The interpenetration of ZIF-8 to the crystal structure of HOF caused a significant decrease of the pore diameter of the structure. These pores acted as specific sites for the guest molecules, and their dimensions did not permit 4-nitrophenol to penetrate into the cavity of structures whereas allowed methanol penetration into these cavities due to its smaller size.

Hydroxide Ion Conduction through Viologen-Based Covalent Organic Frameworks (vCOFs): An Approach toward the Advancement.

Alkaline fuel cells rely on the movement of hydroxide anions (OH-) for their operation, yet these anions face challenges in efficient conduction due to their limited diffusion coefficient and substantial mass compared to proton (H+) transport. Within the covalent organic framework structure, ordered channels offer a promising solution for the OH- ion transport. Herein, we synthesized a cationic covalent organic framework (vTAPA) via the solvothermal-assisted Zincke reaction. vTAPA showcases excellent stability in harsh basic solution (12 M) and a wide range of pH. This framework facilitates OH- conduction through its one-dimensional network through the anion exchange process. We employed various tertiary ammonium salts (tetramethyl, tetraethyl, and tetrabutyl ammonium hydroxide) to exchange trapped anionic chloride ions inside the vTAPA structure with OH- ions. The density functional theory (DFT) study exhibited that the anion exchange process is very favorable, as the vTAPA framework offers preferable interaction sites for OH- ions. The impact of steric hindrance from these tertiary ammonium salts on the OH- conduction performance was extensively investigated. Butyl@vTAPA exhibited a high OH- ion conductivity of 1.05 × 10-4 S cm-1 at 90 °C under 98% relative humidity (RH). Our uniquely designed cationic covalent organic frameworks (COF) created a platform for a preferential transport network of hydroxide ions, and this is the first report of directly used COFs for hydroxide ion conduction without any vigorous postsynthetic modification.

Theoretical study on the ESIPT and photophysical properties for molecules with different extension π conjugation

In a recent study, Jincheng Si and coworkers designed four candidate linker units with different extension π conjugation sizes and directions. These molecules were used for the synthesis of metal–organic framework (MOF) structures known as Olympic rings, which can detect the Cr2O72- in the aqueous phase. However, the experimental work did not provide a qualitative understanding of the excited-state dynamic mechanism. Therefore, this research focused on investigating the excited state intramolecular proton transfer (ESIPT) process and the photophysical properties of these molecules. Density functional theory (DFT) and time-dependent DFT (TDDFT) methods were employed to conduct an in-depth analysis. The molecule structure properties were investigated by analyzing the hydrogen bond parameters and the infrared (IR) vibrational spectra. The calculated absorption and emission spectra were in good agreement with the experimental values, it was proved that the correctness of the optimized structure and the rationality of our calculation method, and we can judge their detection sensitivity by the sizes of the Stokes shift. The Hirshfeld method was used to study the enhancement mechanism of hydrogen bond interaction. Furthermore, the reaction mechanism and ESIPT reactivity of molecules with different extension π conjugation sizes and directions were explained by calculating and plotting the relaxed potential energy curve, electrostatic potentials (ESPs) and frontier molecular orbitals (FMOs). Our research found that extension π conjugation in different sizes and directions can either promote or inhibit the occurrence of the ESIPT reactions and the characteristic of intramolecular charge transfer (ICT), thereby altering the fluorescence performance. Based on our findings, we concluded that the ESIPT activity and photophysical properties of the H4BIHQC were higher than the other three molecules. This discovery enhances the potential application value of MOF as a fluorescence detection tool.

Facile synthesis of an Ni/LaAlO3 – Perovskite via an MOF gel precursor for the dry reforming of methane

A simple strategy to prepare the pure perovskite phase of lanthanum aluminate (LaAlO3) by calcination of a highly porous, dry MOF precursor gel has been developed. This study demonstrates that the structural and textural properties, such as specific surface area, pore volumes and pore sizes, of precursor-like metal–organic gels (MOG) (MOG-Al-La) based on metal–organic framework (MOF) structures can be modulated by optimizing the solvothermal treatment time. The perovskite obtained after solvothermal treatment at 120 °C for 12 h and calcination at 750 °C maintained the mesoporous characteristics of the MOF precursor, with a small particle size due to the decrease in crystallization temperature. These properties in the support allowed a good dispersion of the active Ni sites, low reducibility, and a strong interaction between them and the support, thus suppressing sintering under the severe catalytic reaction conditions evaluated (GHSV = 120,000 cm3/g·h) for the dry reforming of methane. The resulting MOX-(12 h)-LaAlO3-750-Ni catalyst gave a CH4 average conversion of 75% and CO2 average conversion of 80% after 20 h of reaction. The improved stability of the catalyst was attributed to suppression of the formation of the dense network of carbon filaments that can stress and subsequently fracture the support, cause attrition of the catalyst granules and hinder diffusion of the reactants both through the pores of the support and the interparticle spaces.

Diffusion controlled electrochemical analysis of MoS2 and MOF derived metal oxide–carbon hybrids for high performance supercapacitors

In the context of emerging electric devices, the demand for advanced energy storage materials has intensified. These materials must encompass both surface and diffusion-driven charge storage mechanisms. While diffusion-driven reactions offer high capacitance by utilizing the bulk of the material, their effectiveness diminishes at higher discharge rates. Conversely, surface-controlled reactions provide rapid charge/discharge rates and high power density. To strike a balance between these attributes, we devised a tri-composite material, TiO2/Carbon/MoS2 (T10/MoS2). This innovative design features a highly porous carbon core for efficient diffusion and redox-active MoS2 nanosheets on the surface. Leveraging these characteristics, the T10/MoS2 composite exhibited impressive specific capacitance (436 F/g at 5 mV/s), with a significant contribution from the diffusion-controlled process (82%). Furthermore, our symmetrical device achieved a notable energy density of ~ 50 Wh/kg at a power density of 1.3 kW/kg. This concept holds promise for extending the approach to other Metal–Organic Framework (MOF) structures, enabling enhanced diffusion-controlled processes in energy storage applications.

Hydrogen-Bonded Organic Framework-Polyoxometalate-Based System for Electrochromic Devices.

A porous hydrogen-bonded organic framework (HOF) structure was explored for the first time in the design of high-performance electrochromic devices (ECDs) using polyoxometalate (POM)-based charge-balancing layers as counter electrodes (CEs). The novelty of this work lies in the facile construction of films using small molecule-based EC materials to form a porous HOF structure. A full-cell model of an ECD was constructed by utilizing a POM-based CE to optimize the voltage distribution on the HOF-coated working electrode (WE). The addition of PW12O403- (PW12) on CE significantly enhanced the voltage distribution on EC electrodes and decreased the overvoltage on the WE, further preventing the formation of non-EC species and resulting in a 3.3-fold increase in the lifetime of the ECD. The optical contrast was enhanced from 47% (TiO2 only) to 68%, and the coloration efficiency was enhanced from 185 (TiO2 only) to 373 cm2 C-1. The optimized voltage distribution on the WE, leading to the fast response time and high optical EC contrast, could be explained by the charge-balancing effect. Overall, this new finding provides a robust framework for designing high-performance ECDs, taking advantage of the porous morphology and potential matching of the HOF and PW12.

The capture performance of An-MOF for fission gases: Insight from DFT and AIMD calculations

Radioactive fission gases have numerous negative effects on the biosphere, and the capture of fission gases is a primary issue for environmental safety. The actinide organic framework structures (An-MOFs) have extremely high stability under harsh conditions and are expected to be highly efficient adsorbents. In this work, we have investigated the adsorption behaviors of fission gases in An-MOFs (Th and U) through density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations. The potential energy surfaces of fission gases (Kr, Xe, and I2) on the non-periodic cluster model, 8-coordinated secondary building units (SBUs) are obtained. The results show that Th-8-SBU exhibits a stronger adsorption capacity for fission gases than U-8-SBU, and all An-gas interactions are primarily governed by electrostatic attraction interaction revealed by electronic density topological analyses. The periodic boundary condition (PBC) model was also utilized to study the adsorption in Th-MOF, the adsorption energy of I2 in periodic Th-MOF is −43.67 kJ/mol, significantly higher than Xe (−20.50 kJ/mol) and Kr (−14.71 kJ/mol). The charge density difference (CDD) and the partial density of states (PDOS) indicate the presence of significant charge accumulation between Th and I atoms, as well as the stronger Th–I bond formed by orbital hybridization, which are the main reasons for the stronger adsorption ability of Th-MOF to I2. Ab initio molecular dynamics simulations conducted at both 300 and 600 K confirm that Th-MOF can effectively capture I2 molecules. Our results highlight the good performance of Th-MOF for the sustainable capture of I2 gases, indicating its promising application in this field.

Phenyl/benzoxazole-extended tetraphenylethene derivatives for reversible mechanochromism and acidichromism

Four tetraphenylethene-extended phenyl/benzoxazole compounds (TPEPBZs 1–4) were synthesized, which exhibited aggregation-induced emission behavior and multi-stimuli-responsive properties. Single-crystal structural analyses revealed that TPEPBZ-2 possessed the most planar conformation and a unique hydrogen-bonded organic framework structure, resulting in a redshifted emission. After being ground in an agate mortar, the morphologies of TPEPBZs 1–4 transformed from crystalline to amorphous state, and their luminescence was simultaneously shifted bathochromically to a green emission. It was proposed that the slight modification of substituents on the aggregation-induced emission luminogens (AIEgens) was a facile strategy to change their solid structures and further mechanochromic contrasts before and after grinding. The initial emission of TPEPBZs 1–4 could be returned upon fuming with dichloromethane vapor, indicating reversible mechanochromic properties. Moreover, TPEPBZs 1–4 exhibited significant acidichromic behavior. The emission of TPEPBZs 1–4 could change reversibly between their initial color and subsequent orange emission under trifluoroacetic acid and triethylamine stimuli. Finally, TPEPBZ-1 with the best mechanochromic and acidichromic properties was successfully applied to paper for anti-counterfeiting applications.

A Water-Free Ionic Covalent Organic Polymer with High Electrorheological Activity and Temperature Stability

Ionic polymers are important electrorheological (ER) materials, whose ER effect originates from ion motion-induced interfacial polarization. However, the first-generation ionic polymer ER material based on traditional polyelectrolyte needs adsorbed water to make ion movement to activate the ER effect. This results in poor temperature and cycling stability. Although the second-generation ionic polymer ER material based on polyethylene oxide-salt complexes and the currently developed poly(ionic liquid) ER material do not require adsorption of water to activate the ER effect due to decreased ion-pair dissociation energy, low glass transition temperature still limits their temperature and cycling stability. Herein, we report an ionic polymer ER material based on ionic covalent organic polymer (iCOP) synthesized via the Menshutkin reaction and ion exchange, which exhibits not only a highly anhydrous ER effect due to lots of hydrophobic fluoric counterion-induced strong interfacial polarization but also excellent temperature stability and cycling stability due to a unique covalent organic framework structure. In particular, its leaking current density and power consumption are far lower than those of the ER system of traditional polyelectrolytes, polyethylene oxide-salt complexes, and poly(ionic liquid)s. These make iCOP possess large potential as a platform to develop next-generation ionic polymer ER material with high performance.

Unlocking New Topologies in Zr-Based Metal-Organic Frameworks by Combining Linker Flexibility and Building Block Disorder.

The outstanding diversity of Zr-based frameworks is inherently linked to the variable coordination geometry of Zr-oxo clusters and the conformational flexibility of the linker, both of which allow for different framework topologies based on the same linker-cluster combination. In addition, intrinsic structural disorder provides a largely unexplored handle to further expand the accessibility of novel metal-organic framework (MOF) structures that can be formed. In this work, we report the concomitant synthesis of three topologically different MOFs based on the same M6O4(OH)4 clusters (M = Zr or Hf) and methane-tetrakis(p-biphenyl-carboxylate) (MTBC) linkers. Two novel structural models are presented based on single-crystal diffraction analysis, namely, cubic c-(4,12)MTBC-M6 and trigonal tr-(4,12)MTBC-M6, which comprise 12-coordinated clusters and 4-coordinated tetrahedral linkers. Notably, the cubic phase features a new architecture based on orientational cluster disorder, which is essential for its formation and has been analyzed by a combination of average structure refinements and diffuse scattering analysis from both powder and single-crystal X-ray diffraction data. The trigonal phase also features structure disorder, although involving both linkers and secondary building units. In both phases, remarkable geometrical distortion of the MTBC linkers illustrates how linker flexibility is also essential for their formation and expands the range of achievable topologies in Zr-based MOFs and its analogues.

A neutrophil mimicking metal-porphyrin-based nanodevice loaded with porcine pancreatic elastase for cancer therapy

Precise discrimination and eradication of cancer cells by immune cells independent of antigen recognition is promising for solid tumor therapeutics, yet remains a tremendous challenge. Inspired by neutrophils, here we design and construct a tumor discrimination nanodevice based on the differential histone H1 isoform expression. In this nanodevice, neutrophil membrane camouflage and glutathione (GSH)-unlocking effect on Fe-porphyrin metal−organic framework structure ensures selectivity to cancer cells. The released porcine pancreatic elastase (PPE) simulates neutrophils’ action to induce histone H1 release-dependent selective cancer cell killing. Meanwhile, nuclear localization signal (NLS) peptide-tagged porphyrin (porphyrin-NLS) acts as in-situ singlet oxygen (1O2) generator to amplify histone H1 nucleo-cytoplasmic translocation by inducing DNA double-strand breaks (DSBs) under laser irradiation, further promoting elimination of cancer cells. The overexpressed histone H1 isoform in cancer cells improves selectivity of our nanodevice to cancer cells. In vivo studies demonstrate that our design can not only inhibit primary tumor growth, but also induce adaptive T-cell response-mediated abscopal effect to against distal tumors.

Self-activated antibacterial MOF-based coating on medically relevant polypropylene

Modern medicine is virtually unimaginable without using various auxiliary materials and devices such as catheters or implants. In this context, there is a potential risk of bacterial colonization and biofilm formation on the surface of these devices, which can lead to serious infections and endanger the health of patients. To prevent bacterial colonization, the preparation and utilization of an intelligent self-activating antibacterial coating on the surface of medically-relevant polypropylene (PP) are proposed in this work. The 3D periodic metal–organic framework structure (copper-1,3,5-benzenetricarboxylate, further referred as CuBTC) was covalently immobilized on the surface of the PP film. The immobilized CuBTC layer can effectively release NO• radicals from its endogenous donor – S-Nitrosoglutathion (GSNO). Local NO• generation ensures the surface antifouling properties and efficiently inhibits the bacterial adhesion to PP. Unlike materials requiring an external stimulus to activate their antibacterial properties, the proposed coating responds to increasing concentration of GSNO in body fluids (increasing of GSNO concentration is commonly associated with bacterial infection and inflammatory response). So that, the proposed coating can be efficiently self-activated on the right place and at the right time. Considering the application area of medical PP, we also estimated the stability of CuBTC antimicrobial response.