Archive storage boxes are preventive tools used by museums and archives to mitigate the impact of adverse external factors. In this study, quaternized chitosan and polyacrylamide double-network gel were used to load sodium octaborate tetrahydrate, which was then combined with paper fibers to produce storage boxes. By analyzing the physiological and biochemical changes of microbial cells and the microenvironment around the boxes, the antifungal effect of these storage boxes was explored. In addition to physical barrier function, the storage boxes can damage the permeability and morphological structure of mold spore membranes. They inhibit mold reproduction by affecting metabolic pathways such as protein synthesis, which can significantly reduce the number of microorganisms and the proportion of dominant bacterial species in library environments. This enhances the ability of the collection environment to resist harmful organisms and reduces the incidence of microbial diseases in cultural relic collections.

Simultaneous promotion of charge and mass transportation between catalytic centers and reactants is crucial for photocatalysis but remains a substantial challenge on account of the widespread use of homogeneous or heterogeneous photocatalysts that suffer from sluggish reactant-diffusion kinetics or interfacial electron-transport resistance, respectively. Herein, we demonstrate the construction of conjugated microporous polymer aerogels as available quasi-homogeneous photocatalysts by integrating structural designability, which allows for the incorporation of electron-acceptor building blocks featuring ultralong-lived excitons as high-concentration local catalytic centers, and hierarchically porous gel networks that wrap solvent and reactants to provide a "single" reaction phase without interfacial resistance. A total of 18 samples of C─H functionalization reactions underpinned by four different mechanisms were screened to showcase the general applicability of the obtained aerogel photocatalysts, which achieved remarkable conversion efficiencies, gram-scale productivities, and recyclability. By combining a designable structure for photophysical properties with hierarchical porosities for optimal charge/mass transfer, we believe microporous polymer aerogels can serve as a versatile design platform for quasi-homogeneously photocatalyzing challenging reactions.

Selective molecular recognition is an important alternative to the energy-intensive industrial separation process. Porous coordination polymers (PCPs) offer designing platforms for gas separation because they possess precise controllability over structures at the molecular level. However, PCPs-based gas separations are dominantly achieved using strong adsorptive sites for thermodynamic recognition or pore-aperture control for size sieving, which suffer from insufficient selectivity or sluggish kinetics. Developing PCPs that work at high temperatures and feature both high uptake capacity and selectivity is urgently required but remains challenging. Herein, we report diffusion-rate sieving of propylene/propane (C3H6/C3H8) at 300 K by constructing a PCP material whose global and local dynamics cooperatively govern the adsorption process via the mechanisms of the gate opening for C3H6 and the diffusion regulation for C3H8, respectively, yielding substantial differences in both uptake capacity and adsorption kinetics. Dynamic separation of an equimolar C3H6/C3H8 mixture reveals outstanding sieving performance with a C3H6 purity of 99.7% and a separation factor of 318. Porous coordination polymers (PCPs) are commonly used in gas separation processes but developing PCPs that work at high temperatures and feature both high uptake capacity and selectivity remains challenging. Here, the authors report diffusion-rate sieving of propylene/propane at 300 K by constructing a PCP whose global and local dynamics cooperatively govern the adsorption process via gate opening for propylene and diffusion regulation for propane.

The development of efficient and low-cost catalysts is essential for photocatalysis; however, the intrinsically low photocatalytic efficiency as well as the difficulty in using and recycling photocatalysts in powder morphology greatly limit their practical performance. Herein, we describe quasi-homogeneous photocatalysis to overcome these two limitations by constructing ultrastiff, hierarchically porous, and photoactive aerogels of conjugated microporous polymers (CMPs). The CMP aerogels exhibit low density but high stiffness beyond 10(5) m(2) s(-2), outperforming most low-density materials. Extraordinary stiffness ensures their use as robust scaffolds for scaled photocatalysis and recycling without damage at the macroscopic level. A challenging but desirable reaction for direct deaminative borylation is demonstrated using CMP aerogel-based quasi-homogeneous photocatalysis with gram-scale productivity and record-high efficiency under ambient conditions. Combined terahertz and transient absorption spectroscopic studies unveil the generation of high-mobility free carriers and long-lived excitonic species in the CMP aerogels, underlying the observed superior catalytic performance.

Designing efficient proton-conductive materials is crucial in fuel cells. Yet, it remains a substantial challenge because of the issues in proton mobility, proton-carrier amount, and orientation of proton host materials. Herein, we report an in-situ protonation strategy to produce a locally flexible porous coordination polymer (PCP) to enhance the proton-carrier loading and proton conductivity. The local dipole flipping of the ligand allows effective proton exchange with low activation energy, promoting interpore proton transport through the pore apertures and pore walls. The protonation induces substantial charges to the frameworks and enhances the interaction with proton carriers, thereby increasing the loading of the proton carriers. By this design strategy, the resulting PCP exhibits enhanced phosphoric acid loading and extraordinary proton conductivities under both aqueous and anhydrous conditions compared to its isoreticular analog that features rigidity without proton-exchange capability. Our work provides a new avenue for designing proton-conductive materials that combine structural dynamics with performance merits.

Over the long history of evolution, nature has developed a variety of biological systems with switchable recognition functions, such as the ion transmissibility of biological membranes, which can switch their ion selectivities in response to diverse stimuli. However, developing a method in an artificial host-guest system for switchable recognition of specific guests upon the change of external stimuli is a fundamental challenge in chemistry because the order in the host-guest affinity of a given system hardly varies along with environmental conditions. Herein, we report temperature-responsive recognition of two similar gaseous guests, CO 2 and C 2 H 2 , with selectivities switched by temperature change by a diffusion-regulatory mechanism, which is realized by a dynamic porous crystal featuring ultrasmall pore apertures with flip-flop locally-motive organic moiety. The dynamic local motion regulates the diffusion process of CO 2 and C 2 H 2 and amplifies their rate differences, allowing the crystal to selectively adsorb CO 2 at low temperatures and C 2 H 2 at high temperatures with separation factors of 498 (CO 2 /C 2 H 2 ) and 181 (C 2 H 2 /CO 2 ), respectively.

ConspectusThe precise and effective separation of similar mixtures is one of the fundamental issues and essential tasks in chemical research. In the field of gas/vapor separation, the size difference among the molecular pairs/isomers of light hydrocarbons and aromatic compounds is generally 0.3-0.5 Å, and the boiling-point difference is generally 6-15 K. These are necessary industrial raw materials and have great separation demands. Still, their separation mainly relies on energy-intensive distillation technology. On the other hand, remarkably similar substances such as oxygen/argon and isotopologues usually exhibit size differences of only 0-0.07 Å and boiling-point differences of only 1-3 K. Although their industrial separation can be realized, their efficiency is considerably low. Therefore, effectively separating remarkably similar mixtures is crucial in fundamental chemistry and industry, but it remains a significant challenge. Porous coordination polymers (PCPs) or metal-organic frameworks (MOFs) are emerging materials platforms for designing adsorbents for separating similar mixtures. However, the reported PCPs did not work well for separating remarkably similar substances. The framework structures of the mainstream PCPs remain unchanged (rigid) or significantly change (globally flexible) upon adsorption. However, rigid and globally flexible PCPs find controlling the pore aperture in subangstrom precision challenging, a prerequisite for distinguishing remarkably similar substances. Thus, novel mechanisms and materials design principles are urgently needed to realize PCPs-based adsorptive separation of remarkably similar mixtures.To confront the obstacles in separating remarkably similar mixtures, our group started contributing to this field in 2017. We employed locally flexible PCPs as the materials designing platform, whose local motions of the side substituent groups potentially regulate the pore apertures to design and control the gas/vapor diffusion in PCPs. Specifically, we encoded dynamic flipping molecular motions into the diffusion-regulatory gate functionality. The ligands were designed by integrating carboxylic coordination groups with nonplanar fused-ring moieties, with the latter moieties exhibiting flipping motion around their equilibrium positions with small energy increases. Such local motions of ligands lead to the dynamic opening and blocking of PCP channels, thus termed flipping dynamic crystals (FDCs). FDCs feature distinctive temperature-responsive adsorption behaviors due to the competition of thermodynamics and kinetics under diffusion regulation, enabling differentiation of remarkably similar mixtures by each gate-admission temperature much higher than the boiling-point temperature of each component. Even when the molecular sizes are the same in the water isotopologue mixtures, FDCs can separate each isotopologue by amplifying their diffusion-rate differences. Finally, by combining the thermodynamic and kinetic factors, FDCs achieve temperature-switched recognition of CO2/C2H2 and diffusion-rate sieving of C3H6/C3H8. Therefore, our work provides a platform for designing locally flexible PCPs by introducing subangstrom precision in flexibility. This opens up the feasibility of separating remarkably similar mixtures on scientific principles. In this Account, we summarize our above ongoing research contributions, including (i) the design of flipping ligands and FDCs, (ii) the characterization of flipping motions, (iii) the gas/isotopologue sorption behaviors, and (iv) the separation of gases and isotopologues. Overall, our studies offer a new aspect of soft porous crystals and provide future opportunities for relevant researchers in this field.

Conjugated coordination polymers (CCPs) have attracted extensive attention for various applications related to energy storage and conversion in the past few years, despite that there are many CCPs with unclear chemical states and structures. Here, linear CCPs (LCCPs), with metal-O4 active sites grown on carbon paper (CP) for oxygen evolution reaction (OER), are presented. The LCCPs with high crystallinity and simple structures exhibit the order of electrocatalytic activity of Co-O4  > Ni-O4  > Fe-O4 in terms of the metal-O4 centers. The Co-based LCCP shows higher OER performance (263 mV at 10 mA cm-2 ) and better durability (90 h at 30 mA cm-2 ) than commercial IrO2 /CP. The structures and chemical states of LCCPs are carefully investigated, and density functional theory is used to reveal the mechanism of OER at the central metal site. This investigation into LCCPs provides new sights for a better understanding of CCPs and expands the applications of LCCPs with metal-O4 sites.

Designing delocalized excitons with low binding energy (E b) in organic semiconductors is urgently required for efficient photochemistry because the excitons in most organic materials are localized with a high E b of >300 meV. In this work, we report the achievement of a low E b of ∼50 meV by constructing phenothiazine-based covalent organic frameworks (COFs) with inherent crystallinity, porosity, chemical robustness, and feasibility of bandgap engineering. The low E b facilitates effective exciton dissociation and thus promotes photocatalysis by using these COFs. As a demonstration, we subject these COFs to photocatalytic polymerization to synthesize polymers with remarkably high molecular weight without any requirement of the metal catalyst. Our results can facilitate the rational design of porous materials with low E b for efficient photocatalysis.

We report a multi-component synthetic strategy on a two-dimensional crystalline covalent organic framework (COF) by connecting acetonitrile with aromatic aldehyde and acetaldehyde moieties to form an unprecedented cyano-substituted buta-1,3-diene linkage. Different from most of the COFs that were crystallized from the condensations from two components, the presented COF is generated from two competitive and reversible reactions among three moieties. The buta-1,3-diene COF exhibits remarkable photoactivity with a low exciton binding energy of 44.4 ± 1.5 meV for promoted charge separation, which enables the buta-1,3-diene-linked COF as an efficient photocatalyst for various aerobic oxidation reactions under visible light. Our multi-component synthesis strategy may provide new sights for synthesizing COFs with structural diversity and functional variability that are hard to achieve by traditional COF synthesis.

Covalent organic frameworks (COFs) characterized by structural diversity, face-to-face stacking and open channels exhibit unique advantages as photothermal materials but have rarely been applied in solar-driven water evaporation due to complicated framework design, tedious synthesis, and low solar-to-vapor efficiency. Herein, we report a materials design strategy to produce efficient and robust photothermal COF by anchoring nonemissive radicals to the pore surface by a [2+2] cycloaddition-retroelectrocyclization reaction. The radical COF not only possesses the features of COFs such as crystallinity, porosity, and chemical robustness, but also the characteristics of radicals including high spin density and extended absorption to the near-infrared region, which endow the radical COF with outstanding photothermal properties. The radical COF achieves exceptional temperature increment and good photostability upon irradiation with an 808-nm laser, exhibits solar-to-vapor efficiency up to 90.7%, and is adaptable for efficient seawater desalination. Our results provide a new design strategy for the facile production of COF-based photothermal materials. [GRAPHICS] .

Hypercrosslinked polymers (HCPs), amorphous microporous three-dimensional networks based on covalent linkage of organic building blocks, are a promising class of materials due to their high surface area and easy functionalization; however, this type of material lacks processability due to its network rigidity based on covalent crosslinking. Indeed, the development of strategies to improve its solution processability for broader applications remains challenging. Although HCPs have similar three-dimensionally crosslinked networks to polymer gels, HCPs usually do not form gels but insoluble powders. Herein, we report the synthesis of HCP gels from a thermally induced polymerization of a tetrahedral monomer, which undergoes consecutive solubilization, covalent bond formation, colloidal formation, followed by their aggregation and percolation to yield a hierarchically porous network. The resulting gels feature concentration-dependent hierarchical porosities and mechanical stiffness. Furthermore, these HCP gels can be used as a platform to achieve molecular-level hybridization with a two-dimensional polymer during the HCP gel formation. This method provides functional gels and corresponding aerogels with the enhancement of porosities and mechanical stiffness. Used in column- and membrane-based molecular separation systems, the hybrid gels exhibited a separation of water contaminants with the efficiency of 97.9 and 98.6% for methylene blue and KMnO4, respectively. This result demonstrated the potentials of the HCP gels and their hybrid derivatives in separation systems requiring macroscopic scaffolds with hierarchical porosity.

CONSPECTUS: Porous organic polymers (POPs), essentially including polymers with intrinsic microporosity (PIMs), conjugated microporous polymers (CMPs), covalent organic frameworks (COFs), hyper-cross-linked polymers (HCPs) and so on, have recently attracted broad interest in many application areas because of their structural diversity and functional tunability. However, except for linear PIMs that can dissolve in organic solvents for solution processing into membranes, most POPs are highly cross-linked (hereafter termed CPOPs) and are synthesized as insoluble and unprocessable powders, which prevent CPOPs in many applications. Developing methodologies for solution processing CPOPs to high-quality membranes, monoliths, and (aero)gels has been a major challenge in this field because of the following issues. First, the inherently cross-linked structures and the strong framework-framework interactions in CPOPs give rise to very weak solvation of the frameworks, leading to easy aggregation and precipitation in solutions. Next, to date, several methods for preparing CPOP membranes have been proposed, but their conditions vary with different systems, and there lacks a general strategy for membrane formation of most CPOPs (or at least CPOPs of the same category). Additionally, CPOP-based monoliths and (aero)gels are rarely reported, and it has been considered difficult to control the hierarchical porosity to form the monoliths and (aero)gels during the CPOP syntheses. Last, the effects of the forms of membranes/ (aero)gels on the transport (electron, ion, and mass) properties have not been intensively investigated for the lack of suitable systems. Therefore, since it was first announced accompanied by the birth of CPOPs, research studies regarding solution-processed CPOPs have been underexplored for a long time without significant advances being achieved. To break the unprocessable shackles of CPOPs, our group started to make contributions to this field in 2018. We developed two general strategies, namely, "charge-induced dispersion (CID) " and "thermal hyper-cross-linking (THC) " strategies, to produce high-quality CPOP membranes and (aero)gels, respectively. For the CID strategy, we found that the introduction of plenty of charges to the frameworks of CPOPs substantially enhanced their interactions with polar solvents, rendering the transparent, stable, and solution-like CPOP sols which could be further processed into membranes. For the THC strategy, we intensively investigated the gelation mechanism and found that this system was synthetically controllable to produce CPOP (aero)gels and could serve as a platform for hybridization with many porous materials to achieve a molecular-level entanglement. Moreover, we successfully demonstrated that the transport properties in the CPOP membranes and gels were largely promoted by 1-2 orders of magnitude compared to their powder forms, thereby expanding the use of CPOP membranes and gels in the fields of electronic conduction, proton conduction, iodine adsorption, and molecular separation with superior performance. In this Account, we summarize our above contributions, including (i) three detailed methods in CID strategy to produce CPOP membranes, (ii) THC strategy and the gelation mechanism, and (iii) transport properties in CPOP membranes/gels and the structure-function relationship. Overall, our studies not only provide an unprecedented paradigm of solution processing of previously unprocessable materials but also broaden the opportunities for future applications for CPOPs.

The discovery of a method to separate isotopologues, molecular entities that differ in only isotopic composition(1), is fundamentally and technologically essential but remains challenging(2,3). Water isotopologues, which are very important in biological processes, industry, medical care, etc. are among the most difficult isotopologue pairs to separate because of their very similar physicochemical properties and chemical exchange equilibrium. Herein, we report efficient separation of water isotopologues at room temperature by constructing two porous coordination polymers (PCPs, or metal-organic frameworks) in which flip-flop molecular motions within the frameworks provide diffusion-regulatory functionality. Guest traffic is regulated by the local motions of dynamic gates on contracted pore apertures, thereby amplifying the slight differences in the diffusion rates of water isotopologues. Significant temperature-responsive adsorption occurs on both PCPs: H2O vapour is preferentially adsorbed into the PCPs, with substantially increased uptake compared to that of D2O vapour, facilitating kinetics-based vapour separation of H2O/HDO/D2O ternary mixtures with high H2O separation factors of around 210 at room temperature.

Polymer-based room-temperature phosphorescence (RTP) materials with high flexibility and large-area producibility are highly promising for applications in organic electronics. However, achieving such photophysical materials is challenging because of difficulties in populating and stabilizing susceptible triplet excited states at room temperature. Herein large-area, flexible, transparent, and long-lived RTP systems prepared by doping rationally selected organic chromophores in a poly(vinyl alcohol) (PVA) matrix were realized through a hydrogen-bonding and coassembly strategy. In particular, the 3,6-diphenyl-9H-carbazole (DPCz)-doped PVA film shows long-lived phosphorescence emission (up to 2044.86 ms) and a remarkable duration of afterglow (over 20 s) under ambient conditions. Meanwhile, the 7H-dibenzo[c,g]carbazole (DBCz)-doped PVA film exhibits high absolute luminance of 158.4 mcd m2 after the ultraviolet excitation source is removed. The RTP results not only from suppressing the nonradiative decay by abundant hydrogen-bonding interactions in the PVA matrix but also from minimizing the energy gap (ΔEST) between the singlet state and the triplet state through the coassembly effect. On account of the outstanding mechanical properties and the afterglow performance of these RTP materials, they were applied in the fabrication of flexible 3D objects with repeatable folding and curling properties. Importantly, the multichannel afterglow light-emitting diode arrays were established under ambient conditions. The present long-lived phosphorescent systems demonstrate a bright opportunity for the production of large-area, flexible, and transparent emitting materials.

Long-lived organic room-temperature phosphorescent (RTP) materials have attracted widespread attention because of their fantastic properties and application prospects. The current methods for developing RTP materials are mainly based on the synthesis of new chromophore molecules and crystallization engineering. However, there are great challenges in the preparation of new chromophore molecules and the use of crystalline materials. Herein, dynamic stimulus-responsive long-lived RTP systems with various emission colors are realized by doping organic chromophore molecules into polymer matrix prepared from vinyl acetate and acrylic acid. Through UV light irradiation, the growth process of long-lived RTP phenomena can be observed for up to 10 s. In particular, the phosphorescence intensity, lifetime, afterglow brightness, and quantum yield of one representative film (P2-M2) increase by 155, 262, 414, and 8 times after the irradiation, respectively. The unique photophysical phenomena are ascribed to the oxygen consumption characteristics of the polymer matrix under UV irradiation. Meanwhile, the information storage devices are prepared with these RTP systems. This work provides a strategy for achieving small organic molecule-doped polymer RTP systems that are easy to prepare, low-cost, and widely adaptable.

Defects are prevalent in covalent organic frameworks (COFs) constructed based on reversible covalent chemistries. However, manipulating defects in COFs to achieve functionalities remains a significant challenge. Herein, a facial method is provided to regulate the boundary unreacted defects in π‐conjugated COFs to generate distinct and stable paramagnetic radicals, which endow the COFs with a bulk ferromagnetic transition behavior at low temperature, and the efficient photothermal conversion with application in solar vapor generation and seawater desalination. This work not only provides new insights to tailor and control the physicochemical properties of COFs by defect engineering but also enriches the applications of COFs in solar energy utilization.

Conjugated organic radical polymers with stable radical features are difficult to design because the π conjugation in the polymer backbones makes the radicals readily delocalize and tend to undergo covalent bonding processes. In this work, we report an electronic isolation strategy to design stable porous radical polymers by homocoupling reaction from a meta-position active monomer. The meta linkage ensures less conjugation in the polymer skeletons, localizes the resonant radicals, and prevents them from recombination. The resulting porous radical polymer exhibits exceptional radical characters with ultralow band gap of 0.68 eV, strong yet extended UV/Vis-NIR absorption up to 1800 nm, and high spin density. The above features make the polymer very promising in the photothermal conversion with record-high photothermal temperature increment of ≈∼240 °C and striking solar-driven water evaporation efficiency of 96.8 %. Our results demonstrate the feasibility of electronic isolation of radicals for producing outstanding photothermal materials.

Developing novel long-lived room-temperature polymer phosphorescence (RTPP) materials could significantly expand their application scope. Herein, a series of RTPP materials based on eight simple vanilla derivatives for security ink application are reported. Attributed to strong mutual hydrogen bonding with polyvinyl alcohol (PVA) matrix, vanilla-doped PVA films exhibit ultralong phosphorescence emission under ambient conditions observed by naked eyes, where methyl vanillate shows the longest emission time up to 7 s. Impressively, when vanilla-doped PVA materials are utilized as invisible security inks, and the inks not only present excellent luminescent emission stability under ambient conditions but also maintain perfect reversibility between room temperature and 65°C for multiple cycles. Owing to the unique RTPP performance, an advanced anticounterfeiting data encoding/reading strategy based on handwriting technology and complex pattern steganography is developed.