Polymer Framework Research Articles

A donor-acceptor conjugated bipolar polymer with multielectron redox sites for long-cycle-life and high-rate aqueous zinc dual-ion batteries

Aqueous zinc-ion batteries (AZIBs) have hugely latent advantages in large-scale energy storage due to its innate safety, reasonable price, and sustainability. However, most AZIB cathode materials suffer from short cycling life and poor rate performance. Herein, a bipolar donor-acceptor (D-A) conjugated microporous polymer (PTZ-BDTB), consisting of electron-withdrawing benzo[1,2-b:4,5-b’]dithiophene-4,8-dione (BDTB) units and electron-donating phenothiazine (PTZ) units, is developed as the cathode material of aqueous zinc dual-ion batteries (AZDIBs). The D-A type structure design could reduce the band gap, thus promoting electron transfer in the polymer framework. Therefore, the PTZ-BDTB cathode in a 30 mol/kg (m) ZnCl2 water-in-salt electrolyte exhibits a high reversible capacity of 202 mA h g−1 at 0.05 A g−1 with excellent rate performance (109 mA h g−1 at 15 A g−1), which is far superior to its counterpart polymers PPTZ and PB-BDTB. Impressively, PTZ-BDTB shows ultra-stable cycle performance with capacity retention ratios of 76.2% after 460 cycles at 0.05 A g−1 and 96% after 27000 cycles at 5 A g−1. PTZ-BDTB also exhibits a low self-discharge ability with capacity retention about 76.4% after resting the battery for 28 days. These results demonstrate that D-A type structural design is a promising strategy for constructing high performance cathode materials for AZDIBs.

Impacting the Surface Chemistry of NiAu by Immobilizing on MgO/N-Rich Nanoporous Carbon Heterostructures for Boosting Catalytic Activities.

Tuning the physical and chemical interaction between metal-metal' (M-M') and metal-support is an ideal way to realize enhanced catalytic activity of metal nanoparticles (NPs). As a proof of concept, herein we report the fabrication of nickel-gold (Ni-Au) alloy nanoparticles attached to N-doped nanoporous carbon (NPC) intervened with MgO (Ni73Au27@MgO-NPC), achieved through the impregnation of metal precursors into Schiff-base network polymer (SNP) framework along with Mg(OH)2 and pyrolysis at 800 °C in N2 atmosphere. With high stability and heterogeneity, the nickel rich Ni73Au27@MgO-NPC exhibited higher catalytic activities with turnover frequencies of 29,272 h-1 (hydrogenation of p-nitrophenol), 93,843 h-1 (degradation of methyl orange), and 2,218 h-1 (epoxidation of stilbene), compared to commercial 10 wt % Pd/C. Enhanced catalytic activity is correlated to the synchronized electron density enhancement in Au, by Ni and MgO/N-rich nanoporous carbon heterostructures, as evident from detailed X-ray photoelectron spectroscopic studies.

INCLUSION OF AZULENE STRUCTURAL UNITS IN THE BASIS OF CONJUGATED POLYMERS: IMPROVEMENT OF PROTON SENSITIVITY AND FLUORESCENCE

The growing interest in aromatic polymer compounds with an extended π-electron coupling system is explained by their importance as functional materials for organic optoelectronics. At present, much attention is paid to arylated, as well as substituted by electron acceptor and/or electron donor groups, aromatic and heteroaromatic compounds. One of the advantages of such conjugated aromatic systems is that they can fine-tune the electronic structure of materials in order to optimize their performance and morphology. In this regard, the structural isomer of naphthalene - azulene is of considerable interest. The nonalternant aromatic hydrocarbon azulene has unique electronic and spectral properties, including a polarized structure with a dipole moment of the order of 1,08 D and abnormal Anti-Kasha fluorescence S2→S0. The article discusses the synthesis of two fluorene-azulene π-conjugated copolymers using the modern methodology of organic synthesis as the Suzuki − Miyaura -cross−coupling reaction. It was shown that the interaction of 1,3-dibromazulene, as well as 2,7-Bis(3-bromoazulen-1-yl)-9,9-dioctyl-fluorene with 2,2'-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(1,3,2-dioxaborinane) under Suzuki − Miyaura cross-coupling conditions, azulene conjugate copolymers were synthesized: poly[2,7-(9,9-dioctylfluorenyl)-alt-(1ꞌ,3ꞌ - azulenyl)] and poly[1,3-bis(9ꞌ,9ꞌ-dioctylfluoren-2ꞌ-yl)azulenyl]-alt-[1ꞌꞌ,3ꞌꞌ - azulenyl]. It is revealed that neutral solutions of the obtained copolymers are nonfluorescent, but they become luminescent upon addition of trifluoroacetic acid. The «launching» of fluorescence occurs as a result of the formation of a 6 π-electron azulenyl cation, which rearranges the general electronic character of polymers, in particular, HOMO-LUMO levels and band gap. The obtained results demonstrate that the introduction of azulene units into a conjugated polymer framework has great potential for application as new protic functional materials.

Hydroxyl Defects-Mediated Hydrolytic Activation of Peroxydisulfate Under Nanoconfinement: Role of Lewis Basic Sites for Altering the Photosensitized Species and Pathways.

Herein, the pivotal mechanism of defect engineering-mediated triazine-based conjugated polymers (TCPs) is comprehensively elucidated for photosensitized activation of peroxydisulfate (PDS) under nanoconfinement by encapsulating the defective polymer framework into the nanochannel of SBA-15 (d-TCPs@SBA-15). The incorporated hydroxyl defects (-OH defects) substantially accelerate the accumulation of electrons at -OH defects, forming the Lewis basic sites. Due to the facilitated elongation of the S─O bond and reduced energy barrier of SO5* generation, the captured PDS undergo prehydrolysis process, oxidized into O2 - and 1O2 by surrounding h+, thereby setting apart from the conventional reductive activation of SO4 -/•OH generation occurred in pristine TCPs (p-TCPs). Crucially, this work represents a pioneering effort in exploring the PDS activation pathway upon the defective polymer under the nanoconfinement to leverage kinetic merits of slow photon effect and reactive oxygen species (ROSs) enrichment, and the novel prehydrolysis activation mechanism involved may catalyze the rational design of photocatalysts featuring Lewis-acid/base centers.

Capillary electrochromatography synergistic enantioseparation system for racemate malic acid based on a novel nanomaterial synthesized by chiral molecularly imprinted polymer and chiral metal-organic framework

BackgroundChirality is one of the most fundamental features of nature. In terms of biological activities, pharmacological effects, etc., enantiomers often show great differences among each other. Therefore, it is important to develop highly efficient enantioseparation and analysis methods. Capillary electrochromatography (CEC) is one of the most popular methods in the field of enantioseparation. In the chiral stationary phase of CEC, chiral molecularly imprinted polymers (CMIPs) and chiral metal-organic frameworks (CMOFs) have shown great potential of enantioseparation. However, the enantioseparation performance of CMOFs and CMIPs alone as chiral separation media is less satisfactory. ResultsIn this work, a novel nanomaterial synthesized by CMOFs and CMIPs was used as stationary phase in CEC synergistic enantioseparation system and the relevant reports have not been internationally found by authors. As a proof-of-concept demonstration, a coated capillary column was prepared by a one-step method using l-malic acid (template), [Cu2(D-Cam)2Dabco] (Cu-MOF) and dopamine (functional monomer/cross-linking agent), which greatly simplified the modification process of the capillary columns. Compared with Cu-MOF and CMIP alone, the CEC synergistic enantioseparation system based on Cu-MOF@MIP has significantly better enantioseparation performance of malic acid enantiomers (resolution: 1.03/0.58 → 4.22), and there is also a satisfactory performance in the quantitative analysis in real samples. Finally, through molecular docking and adsorption experiments, it was systematically proved that Cu-MOF@MIP had a significantly stronger binding ability for l-malic acid than d-malic acid. SignificanceCu-MOF with chiral recognition ability have synergize with CMIPs to greatly improve the chiral selectivity of Cu-MOF@MIP, which is firstly used for the construction of the CEC chiral separation system. This pioneering synergistic chiral separation system creates a potential direction for efficient enantioseparation. Considering the diversity of CMOFs and CMIPs, the stationary phases hold great promise in chiral separation science.

N18 ring: A building block for constructing 1D and 2D polymeric nitrogen frameworks

Exploring the fundamental building block is essential for constructing functional materials with extended topological configurations. In the polymeric nitrogen system, no fundamental building blocks have been reported so far. Here, we successfully synthesize the buckled 1-dimensional (1D) band-shaped and 2-dimensional (2D) layered polymeric nitrogen frameworks with N18 ring as a fundamental building block for the first time. Furthermore, the dimensions of the polymeric nitrogen frameworks can be regulated by pressure conditions. Bader charge analyses indicate that the charge transfer from the La atom to the low-order bonded nitrogen atom plays a crucial role in stabilizing these two low-dimensional polymeric frameworks. Both LaN16 and LaN8 are promising high-energy-density materials (HEDMs). This study reveals that the N18 ring can serve as a fundamental building block, analogous to thesix-membered ring in carbon-based materials, enabling the construction of novel polymeric nitrogen materials with extended frameworks.

Durability of Implant Restorations with a Fiber-Reinforced Polymer Framework

Durability of Implant Restorations with a Fiber-Reinforced Polymer Framework

Regulating interfacial reactions via quasi-solid polymer electrolyte to enable high-voltage lithium metal batteries

Sulfolane (SUL), known for its low cost, environmental friendliness, and high voltage tolerance, stands out as a promising polar solvent for lithium (Li) metal batteries with high energy density. However, its long-term stability with Li metal is compromised due to its inherently low reduction resistance. To address this issue, we introduce a novel electrolyte strategy, where the reactive SUL is encapsulated within a fluorinated polymer framework formed through in-situ thermal polymerization. The polymer network’s specific structure interacts with SUL, effectively mitigating its electrochemical degradation on the Li metal anode and the NCM811 cathode, thus enhancing electrode stability. This approach not only extends the Li+ plating/stripping reversibility for over 1,000 h at a current density of 0.3 mA cm−2, but also delivers outstanding performance in NCM811||Li batteries, achieving a capacity retention of 78.56 % after 1,000 cycles at 30 °C and 87.14 % after 100 cycles at 60 °C under a high cutoff voltage of 4.5 V.

Supramolecular Polymer Frameworks with Controlled and Uniform Pore Apertures.

Porous frameworks with controlled pore structure and tunable aperture are greatly demanded. However, precise synthesis of this kind of materials is a formidable challenge. Herein, we report the fabrication of two-dimensional (2D) supramolecular polymer frameworks using a precisely synthesized rod-like helical polyisocyanide as link. Four three-arm star-shaped polyisocyanides with the degree of the polymerization of 10, 20, 30 and 40, and having 2-ureido-4[1H]-pyrimidinone (UPy) terminals were synthesized. 2D-Crystalline polymer frameworks with apertures of 5.3, 10.1, 13.9, and 19.1 nm were respectively obtained through intermolecular hydrogen bonding interaction between the terminal Upy units. The pore aperture is dependent on the length of polyisocyanide backbone. Thus, well-defined supramolecular polymer frameworks with controlled and uniform hexagonal pores were obtained, as proved by small-angle X-ray scattering (synchrotron radiation facility), atomic force microscopy, and Brunauer-Emmett-Teller analyses. The frameworks with uniform large pore aperture were used to purify nanomaterials and immobilize biomacromolecules. For instance, the membranes of the polymer frameworks could size-fractionation of silver nanoparticles into uniform nanoparticles with very low dispersity. The frameworks with large aperture facilitated the inclusion of myoglobin and enhanced the stability and catalytic activity.

Low swelling and high mechanical strength organosilane hybrid polydivinylbenzene microspheres for hydrophilic interaction chromatography applications.

In this work, monodisperse organosilane hybrid polymer microspheres with a particle size of about 5µm were synthesized using seed swelling polymerization. The organosilicon reagent methacryloxypropyltrimethoxysilane was introduced into the polymer framework as a copolymerization monomer, and the crosslinking degree of the microspheres was improved by the hydrolysis-condensation reaction of siloxanes. The synthesized hybrid microspheres have good mechanical strength as well as low swelling, with swelling propensity values of 0.167 and 0.348 in methanol and acetonitrile, respectively. Hybrid microspheres modified with cysteine have a hydrophilic interaction chromatography/reversed-phase liquid chromatography mixed-mode retention mechanism. Compared to the commercial cysteine-modified silica column, the synthesized stationary phase has higher separation selectivity for partially acidic or basic samples and better basic resistance for use under high pH mobile phase conditions (at least 10).

Titanium dioxide/graphene oxide synergetic reinforced composite phase change materials with excellent thermal energy storage and photo-thermal performances

The development of advanced composite solid-solid phase change materials (SSPCMs) is urgent to explore for improving solar energy harvesting and storage. Herein, novel composite SSPCMs with synergetic cross-linking structure were fabricated through polymerization using GO and TiO2 constructed on the polyurethane framework skeleton. GO and TiO2 synergetic enhanced polymer framework played a role as skeletal structure to encapsulate PEG in the molecular chains, and provided as highly thermal conductive pathways for the composite SSPCMs. TiO2 nanoparticles performed as extended surface on the skeletal structure for further improvement in thermal conductivity. The composite SSPCMs exhibited a remarkably improved thermal conductivity as high as 0.7 W/(m‧K) and fast thermal response rate. The good light adsorption property of TiO2 enhanced the light absorbance efficiency of the composite SSPCMs by 94.4%. And the photo-thermal conversion efficiency of the composite SSPCMs highly reached 93.5%. Meanwhile, the composite SSPCMs exhibited excellent anti-leakage performance and shape stability under high temperature. Consequently, the as-prepared composite SSPCMs possessed a potential for applications in thermal energy storage and solar energy utilization systems.

Highly efficient and sustainable photocatalytic Fenton reactions utilizing catalyst-embedded inverse-opal structured membranes

The inverse opal (IO) structure, known for its photonic crystal properties and uniform pores, promotes multiple internal light scatterings and reflections. This leads to a decrease in photon group velocity, generating a slow photon effect. When integrated with photocatalysts, this effect enhances light absorption by extending photon interaction with the catalyst, thereby significantly enhancing the efficacy of IO structures in photocatalytic applications. However, the integration of inorganic photocatalysts into IO structures presents challenges, such as mechanical brittleness and a tendency to form powders. To overcome these obstacles, we have engineered IO-structured polymeric membranes coated with graphitic carbon nitride tailored for photocatalytic Fenton reactions. These membranes, which encapsulate photocatalysts within the polymeric porous IO framework, facilitate the straightforward reaction and separation of catalysts from byproducts. They demonstrated superior photocatalytic performance, as evidenced by Rhodamine B degradation (∼7.1 %) and benzene hydroxylation (∼7.3 %). Extensive durability (>30 days) and recyclability tests (>5 times) confirmed their robustness, establishing their utility for various organic conversion reactions. By combining the advantages of the IO structure with tailored photocatalytic properties, these membranes offer promising potential for sustainable and efficient water treatment and the production of fine chemicals in industrial settings.

In situ bridging soft polymer and robust metal-organic frameworks as electrolyte for long-cycling solid-state potassium-organic batteries

In situ bridging soft polymer and robust metal-organic frameworks as electrolyte for long-cycling solid-state potassium-organic batteries

An Ion-Pumping Quasi-Solid Electrolyte Enabled by Electrokinetic Effects for Stable Aqueous Zinc Metal Batteries.

The practical application of aqueous zinc (Zn) metal batteries (ZMBs) is hindered by the complicated hydrogen evolution, passivation reactions, and dendrite growth of Zn metal anodes. Here, an ion-pumping quasi-solid electrolyte (IPQSE) with high Zn2+ transport kinetics enabled by the electrokinetic phenomena to realize high-performance quasi-solid state Zn metal batteries (QSSZMBs) is reported. The IPQSE is prepared through the in situ ring-opening polymerization of tetramethylolmethane-tri-β-aziridinylpropionate in the aqueous electrolyte. The porous polymer framework with high zeta potential provides the IPQSE with an electrokinetic ion-pumping feature enabled by the electrokinetic effects (electro-osmosis and electrokinetic surface conduction), which significantly accelerates the Zn2+ transport, reduces the concentration polarization and overcomes the diffusion-limited current. Moreover, the Zn2+ affinity of the polymer and hydrogen bonding interactions in the IPQSE changes the Zn2+ coordination environment and reduces the amount of free H2O, which lowers the H2O activity and inhibits H2O-induced side reactions. Consequently, the highly reversible and stable Zn metal anodes are achieved. The assembled QSSZMBs based on the IPQSE display excellent cycling stability with high capacity retention and Coulombic efficiency. The high-performance quasi-solid state Zn metal pouch cells are demonstrated, showing great promise for the practical application of the IPQSE.

Preparation and performance evaluation of heat resistant and salt resistant anionic fluid loss reducer for water‐based drilling fluid

AbstractIn this investigation, a new micro‐crosslinked anionic polymer resistant to elevated temperature and high salinity, PKDASN, was synthesized using 3‐chloropropyltriethoxysilane (KMB703), N, N‐Dimethylacrylamide (DMAM), 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), N‐vinyl caprolactam (NVCL), and sodium (4‐vinyl phenyl)methanesulfonate (SVM) employing free radical polymerization in a water‐based solution. The structure of PKDASN was analyzed using Fourier‐transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and X‐ray photoelectron spectroscopy, while its microstructure was analyzed using scanning electron microscopy. Thermogravimetric analysis showed that the pyrolysis temperature of PKDASN was above 294°C. Adding KMB703 enables the polymer to form a dense and stable spatial network. This intensified polymer network could interact with bentonite via intermolecular force and Coulomb force and form a dual grid structure, which presents impressive stability and control of filtration in saltwater. This is mainly achieved through creating a “silane coupling layer” on the particle surface by KMB703, which facilitates the crosslinking and aggregation of the polymer, thereby reinforcing the polymer's framework. This implies that under high‐temperature conditions of 230°C, 3 wt% PKDASN can improve the filtration effectiveness of drilling fluids and exhibit resistance to 15 wt% NaCl contamination. American Petroleum Institute filtration(FLAPI) and High temperature and high pressure filtration(FLHTHP) values were 4.6 and 23.0 mL, respectively. Therefore, this investigation provides a novel approach to utilizing the designated silane agent for the advancement of filtration loss additives in drilling fluids resistant to elevated temperature and high salinity.

Supramolecular Polymer Frameworks with Controlled and Uniform Pore Apertures

AbstractPorous frameworks with controlled pore structure and tunable aperture are greatly demanded. However, precise synthesis of this kind of materials is a formidable challenge. Herein, we report the fabrication of two‐dimensional (2D) supramolecular polymer frameworks using a precisely synthesized rod‐like helical polyisocyanide as link. Four three‐arm star‐shaped polyisocyanides with the degree of the polymerization of 10, 20, 30 and 40, and having 2‐ureido‐4[1H]‐pyrimidinone (UPy) terminals were synthesized. 2D‐Crystalline polymer frameworks with apertures of 5.3, 10.1, 13.9, and 19.1 nm were respectively obtained through intermolecular hydrogen bonding interaction between the terminal Upy units. The pore aperture is dependent on the length of polyisocyanide backbone. Thus, well‐defined supramolecular polymer frameworks with controlled and uniform hexagonal pores were obtained, as proved by small‐angle X‐ray scattering (synchrotron radiation facility), atomic force microscopy, and Brunauer–Emmett–Teller analyses. The frameworks with uniform large pore aperture were used to purify nanomaterials and immobilize biomacromolecules. For instance, the membranes of the polymer frameworks could size‐fractionation of silver nanoparticles into uniform nanoparticles with very low dispersity. The frameworks with large aperture facilitated the inclusion of myoglobin and enhanced the stability and catalytic activity.

Highly conductive and stretchable nanostructured ionogels for 3D printing capacitive sensors with superior performance

Ionogels are promising material candidates for ionotronics due to their excellent ionic conductivity, stretchability, and thermal stability. However, it is challenging to develop 3D printable ionogels with both excellent electrical and mechanical properties. Here, we report a highly conductive and stretchable nanostructured (CSN) ionogel for 3D printing ionotronic sensors. We propose the photopolymerization-induced microphase separation strategy to prepare the CSN ionogels comprising continuous conducting nanochannels intertwined with cross-linked polymeric framework. The resultant CSN ionogels simultaneously achieves high ionic conductivity (over 3 S m−1), high stretchability (over 1500%), low degree of hysteresis (0.4% at 50% strain), wide-temperature-range thermostability (−72 to 250 °C). Moreover, its high compatible with DLP 3D printing enables the fabrication of complex ionogel micro-architectures with high resolution (up to 5 μm), which allows us to manufacture capacitive sensors with superior sensing performances. The proposed CSN ionogel paves an efficient way to manufacture the next-generation capacitive sensors with enhanced performance.

A high-flash-point quasi-solid polymer electrolyte for stable nickel-rich lithium metal batteries

In the exploration of next-generation high-energy–density batteries, lithium metal is regarded as an ideal candidate for anode materials. However, lithium metal batteries (LMBs) face challenges in practical applications due to the risks associated with organic liquid electrolytes, among which their low flash points are one of the major safety concerns. The adoption of high flash point quasi-solid polymer electrolytes (QSPE) that is compatible with the lithium metal anode and high-voltage cathode is therefore a promising strategy for exploring high-performance and high-safety LMBs. Herein, we employed the in-situ polymerization of poly (epoxidized soya fatty acid Bu esters-isooctyl acrylate-ditrimethylolpropane tetraacrylate) (PEID) to gel the liquid electrolyte that formed a PEID-based QSPE (PEID-QSPE). The flash point of PEID-QSPE rises from 25 to 82 °C after gelation, contributing to enhanced safety of the battery at elevated temperatures, whereas the electrochemical window increases to 4.9 V. Moreover, the three-dimensional polymer framework of PEID-QSPE is validated to facilitate the uniform growth of the solid electrolyte interphase on the anode, thereby improving the cycling stability of the battery. By employing PEID-QSPE, the Li|LiNi0.9Co0.05Mn0.05O2 cell achieved long-term cycling stability (Coulombic efficiency, 99.8%; >200 cycles at 0.1 C) even with a high cathode loading (∼5 mg cm−2) and an ultrathin Li (∼50 μm). This electrolyte is expected to afford inspiring insights for the development of safe and long-term cyclability LMBs.

Characterization of gelatin-oxidized riclin cryogels and their applications as reusable ice cubes in shrimp preservation

Traditional ice is usually employed to preserve food freshness and extend shelf life. However, ice cannot bear repeated freeze − thaw cycles during the transportation and retailing process, resulting in microbial cross-contamination and spoilage of foods. Herein, succinoglycan riclin was oxidated (RO) and crosslinked with gelatin (Ge), the Ge-RO cryogels were prepared via Schiff base reaction and three freeze − thaw cycles. The Ge-RO cryogels showed improved storage modulus (G′) and thermal stability compared with pure gelatin hydrogel. The polymer framework of Ge-RO gels exhibited stable properties against ice crystals destructions during nine freeze − thaw treatments. During the storage and repeated freeze − thaw treatments of shrimps, Ge-RO cryogels exhibited a remarkable preservation effect on shrimps, and their freshness was evaluated using an electronic nose technique equipped with ten sensors. The results demonstrated that the shrimp muscle preserved in ice generated off-odors and resulted in high sensor responses. The sensor responses were reduced sharply of shrimps preserved in cryogels. Moreover, 1H NMR-based metabolomics analysis revealed that shrimps in Ge-RO cryogels group reversed the metabolic perturbations compared with the traditional ice group, the metabolic pathways were related to energy metabolism, nucleotide metabolism, and amino acid metabolism, which provide new clues to the freshness of shrimps. Furthermore, RO exhibited superior antimicrobial activity against E. coli and S. aureus microorganisms. Thus, the crosslinked cryogels are potentially applicable to food preservation, offering sustainable and reusable solutions against traditional ice.

Reversible Adsorption of Ammonia in the Crystalline Solid of a CO2H-Functionalized Cyclic Oligophenylene.

Ammonia (NH3) is a viable candidate for the storage and distribution of hydrogen (H2) due to its exceptional volumetric and gravimetric hydrogen energy density. Therefore, it is desirable to develop NH3 storage materials that exhibit robust stability across numerous adsorption-desorption cycles. While porous materials with polymeric frameworks are often used for NH3 capture, achieving reversible NH3 uptake remains a formidable challenge, primarily due to the high reactivity of NH3. Here, we advocate the use of CO2H-functionalized cyclic oligophenylene 1a with high chemical stability as a novel single-molecule-based adsorbent for NH3. Simple reprecipitation of 1a selectively yielded microporous crystalline solid 1a (N). Crystalline 1a (N) adsorbs up to 8.27 mmol/g of NH3 at 100 kPa and 293 K. Adsorbed NH3 in the pore of 1a (N) has a packing density of 0.533 g/cm3 at 293 K, which is close to the density of liquid NH3 (0.681 g/cm3 at 240 K). Crystalline 1a (N) also exhibits reversible NH3 adsorption over at least nine cycles, sustaining its storage capacity (1st cycle: 8.27 mmol/g; 9th cycle: 8.25 mmol/g at 100 kPa and 293 K) and crystallinity. During each desorption cycle, NH3 was removed from 1a (N) under reduced pressure (∼65 Pa), leaving <3% of the total uptake, and 1a (N) was fully purged under dynamic vacuum conditions (∼5 × 10-4 Pa at 293 K for 1 h) before the subsequent adsorption cycles. Thus, microporous crystalline 1a (N) can reliably adsorb and desorb NH3 repeatedly, which avoids the need for heat-based activation between cycles.